A Phase-change thermal control unit( PTCU) filled with metallic phase change material( PCM) Bismuth alloy for electric devices thermal protection was developed and investigated experimentally. The PTCU filled with PCM...A Phase-change thermal control unit( PTCU) filled with metallic phase change material( PCM) Bismuth alloy for electric devices thermal protection was developed and investigated experimentally. The PTCU filled with PCM was designed and manufactured. Resistance heating components( RCHs) produced 1 W,3 W, 5 W,7W,and 10 W for simulating heat generation of electronic devices. At various heating power levels,the performance of PTCU were tested during heating period and one duty cycle period. The experimental results show that the PTCU delays RCH reaching the maximum operating temperature. Also,a numerical model was developed to enable interpretation of experimental results and to perform parametric studies. The results confirmed that the PTCU is suitable for electric devices thermal control.展开更多
In previous years, several high-power micro-satellites below ~100 kg have been developed for high-functional spacecraft. This paper proposes a functional and high-power thermal control system with no power supply and ...In previous years, several high-power micro-satellites below ~100 kg have been developed for high-functional spacecraft. This paper proposes a functional and high-power thermal control system with no power supply and a simple configuration for micro-satellite: 100 W, 3 U. The proposed system consists of a heat storage panel (HSP) with pitch type CFRP (Carbon Fiber Reinforced Polymer), a micro loop heat pipe (m-LHP) and a flexible re-deployable radiator (FRDR) as an active thermal control system. The aim of this research is to try not only to verify the thermal control devices, but also to perform a water phase change experiment as a payload using an electric power generation of 100 W in space environment. In this paper, the basic design of the satellite, the analysis of the feasibility by the thermal mathematical model, and the fabrication of thermal test model including water phase chamber are reported. The main results of thermal analysis as feasibility verification showed that the paddles could absorb the thermal energy up to 97 W at the solar input of 180 W, and the operating temperature of bus equipment became within the allowable temperature range (0°C - 40°C). At thermal vacuum test, the difference between the analysis and the experiment for the temperature history of water due to the discordance for the value of thermal conductance was discussed.展开更多
Phase-change material(PCM)is widely used in thermal management due to their unique thermal behavior.However,related research in thermal rectifier is mainly focused on exploring the principles at the fundamental device...Phase-change material(PCM)is widely used in thermal management due to their unique thermal behavior.However,related research in thermal rectifier is mainly focused on exploring the principles at the fundamental device level,which results in a gap to real applications.Here,we propose a controllable thermal rectification design towards building applications through the direct adhesion of composite thermal rectification material(TRM)based on PCM and reduced graphene oxide(rGO)aerogel to ordinary concrete walls(CWs).The design is evaluated in detail by combining experiments and finite element analysis.It is found that,TRM can regulate the temperature difference on both sides of the TRM/CWs system by thermal rectification.The difference in two directions reaches to 13.8 K at the heat flow of 80 W/m^(2).In addition,the larger the change of thermal conductivity before and after phase change of TRM is,the more effective it is for regulating temperature difference in two directions.The stated technology has a wide range of applications for the thermal energy control in buildings with specific temperature requirements.展开更多
Purpose The Hard X-ray Modulation Telescope is China’s first X-ray astronomy satellite launched on June 15,2017,dubbed Insight-HXMT.Active and passive thermal control measures are employed to keep devices at suitable...Purpose The Hard X-ray Modulation Telescope is China’s first X-ray astronomy satellite launched on June 15,2017,dubbed Insight-HXMT.Active and passive thermal control measures are employed to keep devices at suitable temperatures.In this paper,we analyzed the on-orbit thermal monitoring data of the first 5 years and investigated the effect of thermal deformation on the point spread function(PSF)of the telescopes.Methods We examined the data of the on-orbit temperatures measured using 157 thermistors placed on the collimators,detectors and their support structures and compared the results with the thermal control requirements.The thermal deformation was evaluated by the relative orientation of the two star sensors installed on the main support structure.Its effect was estimated with evolution of the PSF obtained with calibration scanning observations of the Crab nebula.Conclusion The on-orbit temperatures met the thermal control requirements thus far,and the effect of thermal deformation on the PSF was negligible after the on-orbit pointing calibration.展开更多
In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relat...In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relationship and functions of the integrated database,the intelligent thermal control system and the efficient liquid cooling system in the ATMS are elaborated upon.For the complex thermal field regulation system and extreme space thermal environment,a modular simulation and thermal field planning method are proposed,and the feasibility of the planning algorithm is verified by numerical simulation.A solar array liquid cooling system is developed,and the system simulation results indicate that the temperatures of the solar arrays meet the requirements as the spacecraft flies by perihelion and aphelion.The advanced thermal management study supports the development of the SCOPE program and provides a reference for the thermal management in other deep-space exploration programs.展开更多
A rotary-concentrating device for thermal conduction is constructed to control and guide thermal energy transmitting in elastic plates.The designed device has the ability of concentrating for thermal conduction and co...A rotary-concentrating device for thermal conduction is constructed to control and guide thermal energy transmitting in elastic plates.The designed device has the ability of concentrating for thermal conduction and controlling the processes of thermal diffusion in a plate.The multilayered isotropic material properties of the rotary-concentrating device are derived based on the transformation and rotary medium method and a rotation parameter to control the thermal diffusion process is introduced.The efficiency of the rotary-concentrating device for thermal conduction is verified.Stability of temperature fields in a plate with the rotary-concentrating device is analyzed to study the performance of rotary-concentrating.Numerical examples show that the constructed rotary-concentrating device for thermal conduction can effectively rotate and focus on the thermal energy into the device for a wide range of diffusion temperatures,which can enhance the thermal conduction.Therefore,this study can provide a theoretical support for potential applications in fields of energy harvesting and thermal conduction control.展开更多
Several studies have reported about power semiconductors and capacitors being the most sensitive components in power converters.The lifetime of these devices is associated with the mission profile and the resulting te...Several studies have reported about power semiconductors and capacitors being the most sensitive components in power converters.The lifetime of these devices is associated with the mission profile and the resulting temperature profile.For preventing failures,it is of interest to estimate the Remaining Useful Lifetime(RUL)and several condition monitoring methods have been proposed for this purpose.Moreover,modular power converters consist of a high number of components and methods have been proposed to reduce the thermal stress and therefore extend the lifetime of a system with software,referred to as active thermal control.For power converters with limited accessibility,the RUL detected by the condition monitoring system may not fit to the scheduled maintenance of the system and devices may still have a significant RUL when their replacement is scheduled.Therefore,this work proposes to control the stress of the most deteriorated components in the system such that the failure probability of multiple building blocks is equalized when the next maintenance is scheduled.Moreover,this concept is proposed to extend the time to the next maintenance and reduce the number of maintenance instances without affecting the mean lifetime of the system.展开更多
Indoor temperature is a critical environmental factor for piglets that affects the health,welfare,and production efficiency of domesticated pigs.However,there are limited reports about wireless intelligent thermal con...Indoor temperature is a critical environmental factor for piglets that affects the health,welfare,and production efficiency of domesticated pigs.However,there are limited reports about wireless intelligent thermal control and management system for piglets in largescale pig farms,and evaluation energy saving.This paper presents an Automatic Thermal Control and Management System(ATCMS)of micro-environment for piglets,that could provide a suitable production environment and reduce the energy consumption.ATCMS includes automatic temperature control system(ATCS),multipoint temperature management system(MTMS)and remote access.The infrared heating lamps are chosen in the ATCS for their good performance in heating rate and heating distribution.In order to meet a scientific temperature requirements of piglet growth,the suitable thermal ranges of each growth-stage(STREG)are employed as intelligent control strategies to generate an automatic and precise heating control.MTMS is responsible for communicating with ATCSs and transmitting information to database server for record based on wireless technology.Remote access offers information services for remote administrators by smart phones and clients via Internet.The experiments of ATCMS were carried out both in winter and summer at Binsheng Breeding Piggery Farm,Acheng City,Heilongjiang Province,China.Results showed that the temperature provided by ATCS had been kept in STREG of piglets during the whole winter period.When the indoor temperature during summer period were in or above STREG,heating lamps were turned off by ATCS for a long time.The energy consumption of ATCS were 63.60%in winter and 39.35%in summer with continuous heating system operation.Therefore,ATCMS could take the suitable thermal ranges of each growth-stage as an intelligent control principle to give an automatic and precise control to heating devices in order to meet a scientific temperature requirements of piglet growth.展开更多
Conductive polymer composites(CPCs) as the thermo-sensitive materials have attracted much attention in thermal control field due to their reliable self-regulating behaviors, high efficiency and mechanical flexibility....Conductive polymer composites(CPCs) as the thermo-sensitive materials have attracted much attention in thermal control field due to their reliable self-regulating behaviors, high efficiency and mechanical flexibility. However, the development of these materials needs to manage the normal conflicting requirements, such as effective heating performance and good self-regulating capability. This paper presents a series of novel CPCs material having different amounts of hybrid fillers of multi-walled carbon nanotubes(CNTs) and carbon black(CB). The positive temperature coefficient intensity is enhanced to 105.2, and the roomtemperature resistivity is optimized to 320 ? cm. Besides, the Curie temperatures are regulated to room-temperature range by incorporating the low-melting-point blend matrix into the poly(ethylene-co-vinyl acetate)/CNTs/CB composite. The thermalcontrol experiment demonstrates that CPCs-heating elements can adjust the equilibrium temperature of controlled equipment near their Curie temperatures without any control methods. Compared with the ordinary resistor, the CPCs materials have the remarkable adaptive thermal control behavior. Furthermore, the temperature control capability is particularly prominent in the changing environment temperature. The CPCs as a safe and reliable adaptive heating element is potential to replace the conventional active thermal control means.展开更多
For distribution optimization of the flow rate of cold fluid and heat transfer area in the parallel thermal network of the thermal control system in spacecraft,a physical and mathematical model is set up,analyzed and ...For distribution optimization of the flow rate of cold fluid and heat transfer area in the parallel thermal network of the thermal control system in spacecraft,a physical and mathematical model is set up,analyzed and discussed with the entransy theory.It is found that the optimization objective of this problem and the optimization direction of the extremum entransy dissipation principle are consistent in theory.For a two-branch thermal network system,the distributions of the flow rate of the cold fluid and the heat transfer area are optimized by calculating the extremum entransy dissipation with the Newton method.The influential factors of the optimized distributions are also analyzed and discussed.The results show that the main influence factors are the heat transfer rate of the branches and the total heat transfer area.The total flow rate of the cold fluid has a threshold,beyond which further increasing its value brings very little influence on the optimization results.Moreover,the difference between the extremum entransy dissipation principle and the minimum entropy generation principle is also discussed when they are used to analyze the problem in this paper,and the extremum entransy dissipation principle is found to be more suitable.In addition,the Newton method is mathematically efficient to solve the problem,which could accomplish the optimized distribution in a very short time for a ten-branch thermal network system.展开更多
Thermal controllers equipped with phase-change materials are widely used for maintaining the moderate temperatures of various electric devices used in spacecraft. Yet, the structures of amounts of thermal controllers ...Thermal controllers equipped with phase-change materials are widely used for maintaining the moderate temperatures of various electric devices used in spacecraft. Yet, the structures of amounts of thermal controllers add up to such a large value that restricts the employment of scientific devices due to the limit of rocket capacity. A lightweight structure of phase-change thermal controllers has been one of the main focuses of spacecraft design engineering. In this work, we design a lightweight phase-change thermal controller structure based on lattice cells. The structure is manufactured entirely with AlSi10 Mg by direct metal laser melting. The dimensions of the structure are 230 mm × 170 mm × 15 mm, and the mass is 190 g, which is 60% lighter than most traditional structures(500–600 g) with the same dimensions. The 3 D-printed structure can reduce the risk of leakage at soldering manufacture by a welding process. Whether the strength of the designed structure is sufficient is determined through mechanical analysis and experiments. Thermal test results show that the thermal capacity of the lattice-based thermal controller is increased by50% compared to that of traditional controllers with the same volume.展开更多
The Alpha Magnetic Spectrometer(AMS) is an instrument for the international scientific experiment,composed of six detectors and 650 micro-electronics.The objective of AMS experiment is to search for dark matter and an...The Alpha Magnetic Spectrometer(AMS) is an instrument for the international scientific experiment,composed of six detectors and 650 micro-electronics.The objective of AMS experiment is to search for dark matter and anti-matter in space.In this paper,the thermal control system for AMS cryocoolers is designed,analyzed and experimentally studied.Using loop heat pipes(LHPs) as the main heat dissipation component,the thermal control system has sufficient heat dissipation capability to prevent the cryocoolers from over temperature(+40℃) in hot environment,meanwhile to ensure temperatures of the cryocoolers higher than their lower limit(-20℃) in cold environment.Experiment results show that the thermal control system for AMS cryocoolers functions stably satisfying design specification.展开更多
Since its installation on the International Space Station(ISS)in mid-May 2011,the Alpha Magnetic Spectrometer(AMS)has spent over two years on orbit,fully operational,collecting an enormous amount of data including the...Since its installation on the International Space Station(ISS)in mid-May 2011,the Alpha Magnetic Spectrometer(AMS)has spent over two years on orbit,fully operational,collecting an enormous amount of data including the temperatures from the on-board 1118 sensors for thermal control.A large database is continuously updated and analyzed to understand the thermal behavior of the experiment in the space environment and its interaction with the ISS.This paper specifies the design,building,analysis and testing of the thermal control system and its various components for an overview of the AMS thermal control system and its space environment.Also given are some examples of analysis and correlation of the space environmental and ISS parameters with the thermal behaviors of various AMS components.展开更多
A micro thermal control device with polyimide based micro louver was proposed.The device structure was designed,the actuation voltage was analyzed theoretically and fabrication process was described.The micro louver p...A micro thermal control device with polyimide based micro louver was proposed.The device structure was designed,the actuation voltage was analyzed theoretically and fabrication process was described.The micro louver prototype was fabricated using UV laser micromachining,electrochemistry etch and magnetron sputtering deposition technologies.The main parameters were tested and results were presented.展开更多
Thermal control coatings were fabricated by mixing of La1-xSrxMnO3(LSMO)powder and acrylic resin and brushed on Al alloy substrate.The powders of La0.7Sr0.3MnO3 and La0.8Sr0.2MnO3 were prepared using sol-gel method.XR...Thermal control coatings were fabricated by mixing of La1-xSrxMnO3(LSMO)powder and acrylic resin and brushed on Al alloy substrate.The powders of La0.7Sr0.3MnO3 and La0.8Sr0.2MnO3 were prepared using sol-gel method.XRD results reveal the phase structure of LSMO powders are perovskite.The transition temperature from metal to insulator of La0.7Sr0.3MnO3 and La0.8Sr0.2MnO3 are 300 and 275 K,respectively.The emissivity evolution with temperature of the coatings was measured.For La0.7Sr0.3MnO3/acrylic resin coating,the emissivity increases from 0.56 to 0.88,and for La0.7Sr0.3MnO3/acrylic resin coating from 0.50 to 0.90.展开更多
The interaction between the heat source location, its intensity, thermal expansion coefficient, the machine system configuration and the running environment creates complex thermal behavior of a machine tool, and also...The interaction between the heat source location, its intensity, thermal expansion coefficient, the machine system configuration and the running environment creates complex thermal behavior of a machine tool, and also makes thermal error prediction difficult. To address this issue, a novel prediction method for machine tool thermal error based on Bayesian networks (BNs) was presented. The method described causal relationships of factors inducing thermal deformation by graph theory and estimated the thermal error by Bayesian statistical techniques. Due to the effective combination of domain knowledge and sampled data, the BN method could adapt to the change of running state of machine, and obtain satisfactory prediction accuracy. Ex- periments on spindle thermal deformation were conducted to evaluate the modeling performance. Experimental results indicate that the BN method performs far better than the least squares (LS) analysis in terms of modeling estimation accuracy.展开更多
This paper presents an overview of the AMS thermal control system and its thermal environment on the ISS.We give examples of analysis and correlation of space environmental impacting on the thermal control system of A...This paper presents an overview of the AMS thermal control system and its thermal environment on the ISS.We give examples of analysis and correlation of space environmental impacting on the thermal control system of AMS.The most critical factors that affect the thermal environment to AMS are beta angle,attitude of ISS,ISS solar array and ISS radiator positions.The design of a special sandwich structure with embedded heat pipes provides the radiator with higher heat transfer ability for electronics and power crates,and it provides a large heat retaining capacity to balance the frequent changes of the space environment temperatures as well.In cold cases,the thermostatically controlled heaters are working actively to protect AMS.However,sometimes,because of ISS special operations plus extreme beta angle condition,AMS needs to request NASA to adjust the ISS configuration for thermal control.The AMS thermal control system is reliable and stable,which has been verified by its operation on the ISS for more than three years.All the detectors operate normally,the electronics and crates work within their specific temperature limits.展开更多
A thermal control system (TCS) based on the resistance heating method is designed for the High Energy Detector (HED) on the Hard X-ray Modulation Telescope (HXMT). The ground-based experiments of the active thermal co...A thermal control system (TCS) based on the resistance heating method is designed for the High Energy Detector (HED) on the Hard X-ray Modulation Telescope (HXMT). The ground-based experiments of the active thermal control for the HED with the TCS are performed in the ambient temperature range from -15 to 20 by utilizing the pulse width to monitor the interior temperature of a NaI(Tl) crystal. Experimental results show that the NaI(Tl) crystal's interior temperature is from 17.4 to 21.7 when the temperature of the PMT shell is controlled within (20±3) with the TCS in the interesting temperature range, and the energy resolution of the HED is maintained at 16.2% @122 keV, only a little worse than that of 16.0% obtained at 20 . The average power consumption of the TCS for the HED with a low-emissivity shell is about 4.3 W, which is consistent with the simulation.展开更多
In this paper, the novel control structures of differential pressure thermally coupled reactive distillation process for methyl acetate hydrolysis were proposed. The RadFrac module of Aspen Plus was adopted in the ste...In this paper, the novel control structures of differential pressure thermally coupled reactive distillation process for methyl acetate hydrolysis were proposed. The RadFrac module of Aspen Plus was adopted in the steady-state simulation. Sensitive analysis was applied to find the stable initial value and provide a basis for the improved control structure design. The Aspen Dynamics software was adopted to study the process dynamic behaviors, and two novel control structures provided with feed ratio controllers and sensitive tray temperature controllers were proposed. The reflux ratio controllers were applied in the improved novel control structures. Both control structures abandoned the composition controllers that were replaced by simpler controllers with which the product purity could meet the specification requiring under a ± 20% disturbance to the total feed flowrate/MeAc composition.展开更多
A dynamic thermal transfer model of a proton exchange membrane fuel cell (PEMFC) stack is developed based on energy conservation in order to reach better temperature control of PEMFC stack. Considering its uncertain p...A dynamic thermal transfer model of a proton exchange membrane fuel cell (PEMFC) stack is developed based on energy conservation in order to reach better temperature control of PEMFC stack. Considering its uncertain parameters and disturbance, we propose a robust adaptive controller based on backstepping algorithm of Lyaponov function. Numerical simulations indicate the validity of the proposed controller.展开更多
文摘A Phase-change thermal control unit( PTCU) filled with metallic phase change material( PCM) Bismuth alloy for electric devices thermal protection was developed and investigated experimentally. The PTCU filled with PCM was designed and manufactured. Resistance heating components( RCHs) produced 1 W,3 W, 5 W,7W,and 10 W for simulating heat generation of electronic devices. At various heating power levels,the performance of PTCU were tested during heating period and one duty cycle period. The experimental results show that the PTCU delays RCH reaching the maximum operating temperature. Also,a numerical model was developed to enable interpretation of experimental results and to perform parametric studies. The results confirmed that the PTCU is suitable for electric devices thermal control.
文摘In previous years, several high-power micro-satellites below ~100 kg have been developed for high-functional spacecraft. This paper proposes a functional and high-power thermal control system with no power supply and a simple configuration for micro-satellite: 100 W, 3 U. The proposed system consists of a heat storage panel (HSP) with pitch type CFRP (Carbon Fiber Reinforced Polymer), a micro loop heat pipe (m-LHP) and a flexible re-deployable radiator (FRDR) as an active thermal control system. The aim of this research is to try not only to verify the thermal control devices, but also to perform a water phase change experiment as a payload using an electric power generation of 100 W in space environment. In this paper, the basic design of the satellite, the analysis of the feasibility by the thermal mathematical model, and the fabrication of thermal test model including water phase chamber are reported. The main results of thermal analysis as feasibility verification showed that the paddles could absorb the thermal energy up to 97 W at the solar input of 180 W, and the operating temperature of bus equipment became within the allowable temperature range (0°C - 40°C). At thermal vacuum test, the difference between the analysis and the experiment for the temperature history of water due to the discordance for the value of thermal conductance was discussed.
基金This work was supported in part by Tsinghua University-Zhuhai Huafa Industrial Share Company Joint Institute for Architecture Optoelectronic Technologies(JIAOT KF202204)in part by STI 2030—Major Projects under Grant 2022ZD0209200+2 种基金in part by National Natural Science Foundation of China under Grant 62374099,Grant 62022047in part by Beijing Natural Science-Xiaomi Innovation Joint Fund under Grant L233009in part by the Tsinghua-Toyota JointResearch Fund,in part by the Daikin-Tsinghua Union Program,in part sponsored by CIE-Tencent Robotics XRhino-Bird Focused Research Program.
文摘Phase-change material(PCM)is widely used in thermal management due to their unique thermal behavior.However,related research in thermal rectifier is mainly focused on exploring the principles at the fundamental device level,which results in a gap to real applications.Here,we propose a controllable thermal rectification design towards building applications through the direct adhesion of composite thermal rectification material(TRM)based on PCM and reduced graphene oxide(rGO)aerogel to ordinary concrete walls(CWs).The design is evaluated in detail by combining experiments and finite element analysis.It is found that,TRM can regulate the temperature difference on both sides of the TRM/CWs system by thermal rectification.The difference in two directions reaches to 13.8 K at the heat flow of 80 W/m^(2).In addition,the larger the change of thermal conductivity before and after phase change of TRM is,the more effective it is for regulating temperature difference in two directions.The stated technology has a wide range of applications for the thermal energy control in buildings with specific temperature requirements.
基金This work was based on the data from Insight-HXMT mission,a project funded by the China National Space Administration(CNSA)and the Chinese Academy of Sciences(CAS)We gratefully acknowledge the support from the National Program on Key Research and Development Project(Grant No.2021YFA0718500)from the Ministry of Science and Technology of China(MOST)+2 种基金All authors appreciate the supports from the National Natural Science Foundation of China under Grants 12273043,U1838201,U1838202,U1938102,and U1938108This work was partially supported by International Partnership Program of Chinese Academy of Sciences(Grant No.113111KYSB20190020)Appreciate Zeyu Song from IHEP for meticulous translation and revision.Appreciate Yongping Li from IHEP for helping with star sensor quaternion calculation.
文摘Purpose The Hard X-ray Modulation Telescope is China’s first X-ray astronomy satellite launched on June 15,2017,dubbed Insight-HXMT.Active and passive thermal control measures are employed to keep devices at suitable temperatures.In this paper,we analyzed the on-orbit thermal monitoring data of the first 5 years and investigated the effect of thermal deformation on the point spread function(PSF)of the telescopes.Methods We examined the data of the on-orbit temperatures measured using 157 thermistors placed on the collimators,detectors and their support structures and compared the results with the thermal control requirements.The thermal deformation was evaluated by the relative orientation of the two star sensors installed on the main support structure.Its effect was estimated with evolution of the PSF obtained with calibration scanning observations of the Crab nebula.Conclusion The on-orbit temperatures met the thermal control requirements thus far,and the effect of thermal deformation on the PSF was negligible after the on-orbit pointing calibration.
文摘In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relationship and functions of the integrated database,the intelligent thermal control system and the efficient liquid cooling system in the ATMS are elaborated upon.For the complex thermal field regulation system and extreme space thermal environment,a modular simulation and thermal field planning method are proposed,and the feasibility of the planning algorithm is verified by numerical simulation.A solar array liquid cooling system is developed,and the system simulation results indicate that the temperatures of the solar arrays meet the requirements as the spacecraft flies by perihelion and aphelion.The advanced thermal management study supports the development of the SCOPE program and provides a reference for the thermal management in other deep-space exploration programs.
基金Project supported by the National Natural Science Foundation of China(Grant No.12102150)the Natural Science Foundation of Jiangsu Province+3 种基金China(Grant Nos.BK20200884 and BK20201414)the Natural Science Foundation of Colleges and Universities in Jiangsu Province,China(Grant No.20KJB130004)China Postdoctoral Science Foundation(Grant No.2021M702444)the Jiangsu’s Mass Entrepreneurship and Innovation Program of Jiangsu Province。
文摘A rotary-concentrating device for thermal conduction is constructed to control and guide thermal energy transmitting in elastic plates.The designed device has the ability of concentrating for thermal conduction and controlling the processes of thermal diffusion in a plate.The multilayered isotropic material properties of the rotary-concentrating device are derived based on the transformation and rotary medium method and a rotation parameter to control the thermal diffusion process is introduced.The efficiency of the rotary-concentrating device for thermal conduction is verified.Stability of temperature fields in a plate with the rotary-concentrating device is analyzed to study the performance of rotary-concentrating.Numerical examples show that the constructed rotary-concentrating device for thermal conduction can effectively rotate and focus on the thermal energy into the device for a wide range of diffusion temperatures,which can enhance the thermal conduction.Therefore,this study can provide a theoretical support for potential applications in fields of energy harvesting and thermal conduction control.
文摘Several studies have reported about power semiconductors and capacitors being the most sensitive components in power converters.The lifetime of these devices is associated with the mission profile and the resulting temperature profile.For preventing failures,it is of interest to estimate the Remaining Useful Lifetime(RUL)and several condition monitoring methods have been proposed for this purpose.Moreover,modular power converters consist of a high number of components and methods have been proposed to reduce the thermal stress and therefore extend the lifetime of a system with software,referred to as active thermal control.For power converters with limited accessibility,the RUL detected by the condition monitoring system may not fit to the scheduled maintenance of the system and devices may still have a significant RUL when their replacement is scheduled.Therefore,this work proposes to control the stress of the most deteriorated components in the system such that the failure probability of multiple building blocks is equalized when the next maintenance is scheduled.Moreover,this concept is proposed to extend the time to the next maintenance and reduce the number of maintenance instances without affecting the mean lifetime of the system.
基金supported by the project of National Natural Science Foundation of China(NSFC)(32072787)the project of scholar plan at Northeast Agriculture University(19YJXG02),China+1 种基金the Earmarked Fund for China Agriculture Research System(CARS-35),Chinathe Key Laboratory of Swine Facilities Engineering,Ministry of Agriculture,P.R.China.
文摘Indoor temperature is a critical environmental factor for piglets that affects the health,welfare,and production efficiency of domesticated pigs.However,there are limited reports about wireless intelligent thermal control and management system for piglets in largescale pig farms,and evaluation energy saving.This paper presents an Automatic Thermal Control and Management System(ATCMS)of micro-environment for piglets,that could provide a suitable production environment and reduce the energy consumption.ATCMS includes automatic temperature control system(ATCS),multipoint temperature management system(MTMS)and remote access.The infrared heating lamps are chosen in the ATCS for their good performance in heating rate and heating distribution.In order to meet a scientific temperature requirements of piglet growth,the suitable thermal ranges of each growth-stage(STREG)are employed as intelligent control strategies to generate an automatic and precise heating control.MTMS is responsible for communicating with ATCSs and transmitting information to database server for record based on wireless technology.Remote access offers information services for remote administrators by smart phones and clients via Internet.The experiments of ATCMS were carried out both in winter and summer at Binsheng Breeding Piggery Farm,Acheng City,Heilongjiang Province,China.Results showed that the temperature provided by ATCS had been kept in STREG of piglets during the whole winter period.When the indoor temperature during summer period were in or above STREG,heating lamps were turned off by ATCS for a long time.The energy consumption of ATCS were 63.60%in winter and 39.35%in summer with continuous heating system operation.Therefore,ATCMS could take the suitable thermal ranges of each growth-stage as an intelligent control principle to give an automatic and precise control to heating devices in order to meet a scientific temperature requirements of piglet growth.
基金supported by the National Natural Science Foundation of China (Grant No. 51225602)。
文摘Conductive polymer composites(CPCs) as the thermo-sensitive materials have attracted much attention in thermal control field due to their reliable self-regulating behaviors, high efficiency and mechanical flexibility. However, the development of these materials needs to manage the normal conflicting requirements, such as effective heating performance and good self-regulating capability. This paper presents a series of novel CPCs material having different amounts of hybrid fillers of multi-walled carbon nanotubes(CNTs) and carbon black(CB). The positive temperature coefficient intensity is enhanced to 105.2, and the roomtemperature resistivity is optimized to 320 ? cm. Besides, the Curie temperatures are regulated to room-temperature range by incorporating the low-melting-point blend matrix into the poly(ethylene-co-vinyl acetate)/CNTs/CB composite. The thermalcontrol experiment demonstrates that CPCs-heating elements can adjust the equilibrium temperature of controlled equipment near their Curie temperatures without any control methods. Compared with the ordinary resistor, the CPCs materials have the remarkable adaptive thermal control behavior. Furthermore, the temperature control capability is particularly prominent in the changing environment temperature. The CPCs as a safe and reliable adaptive heating element is potential to replace the conventional active thermal control means.
基金supported by Tsinghua University Initiative Scientific Research Program
文摘For distribution optimization of the flow rate of cold fluid and heat transfer area in the parallel thermal network of the thermal control system in spacecraft,a physical and mathematical model is set up,analyzed and discussed with the entransy theory.It is found that the optimization objective of this problem and the optimization direction of the extremum entransy dissipation principle are consistent in theory.For a two-branch thermal network system,the distributions of the flow rate of the cold fluid and the heat transfer area are optimized by calculating the extremum entransy dissipation with the Newton method.The influential factors of the optimized distributions are also analyzed and discussed.The results show that the main influence factors are the heat transfer rate of the branches and the total heat transfer area.The total flow rate of the cold fluid has a threshold,beyond which further increasing its value brings very little influence on the optimization results.Moreover,the difference between the extremum entransy dissipation principle and the minimum entropy generation principle is also discussed when they are used to analyze the problem in this paper,and the extremum entransy dissipation principle is found to be more suitable.In addition,the Newton method is mathematically efficient to solve the problem,which could accomplish the optimized distribution in a very short time for a ten-branch thermal network system.
基金supports from Beijing Institute of Spacecraft System Engineering and the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(Nos.2017QNRC001,2016QNRC001)
文摘Thermal controllers equipped with phase-change materials are widely used for maintaining the moderate temperatures of various electric devices used in spacecraft. Yet, the structures of amounts of thermal controllers add up to such a large value that restricts the employment of scientific devices due to the limit of rocket capacity. A lightweight structure of phase-change thermal controllers has been one of the main focuses of spacecraft design engineering. In this work, we design a lightweight phase-change thermal controller structure based on lattice cells. The structure is manufactured entirely with AlSi10 Mg by direct metal laser melting. The dimensions of the structure are 230 mm × 170 mm × 15 mm, and the mass is 190 g, which is 60% lighter than most traditional structures(500–600 g) with the same dimensions. The 3 D-printed structure can reduce the risk of leakage at soldering manufacture by a welding process. Whether the strength of the designed structure is sufficient is determined through mechanical analysis and experiments. Thermal test results show that the thermal capacity of the lattice-based thermal controller is increased by50% compared to that of traditional controllers with the same volume.
基金supported by the Major Project of Technology Transfer of Shandong Province (2009ZHZX1A1105)
文摘The Alpha Magnetic Spectrometer(AMS) is an instrument for the international scientific experiment,composed of six detectors and 650 micro-electronics.The objective of AMS experiment is to search for dark matter and anti-matter in space.In this paper,the thermal control system for AMS cryocoolers is designed,analyzed and experimentally studied.Using loop heat pipes(LHPs) as the main heat dissipation component,the thermal control system has sufficient heat dissipation capability to prevent the cryocoolers from over temperature(+40℃) in hot environment,meanwhile to ensure temperatures of the cryocoolers higher than their lower limit(-20℃) in cold environment.Experiment results show that the thermal control system for AMS cryocoolers functions stably satisfying design specification.
文摘Since its installation on the International Space Station(ISS)in mid-May 2011,the Alpha Magnetic Spectrometer(AMS)has spent over two years on orbit,fully operational,collecting an enormous amount of data including the temperatures from the on-board 1118 sensors for thermal control.A large database is continuously updated and analyzed to understand the thermal behavior of the experiment in the space environment and its interaction with the ISS.This paper specifies the design,building,analysis and testing of the thermal control system and its various components for an overview of the AMS thermal control system and its space environment.Also given are some examples of analysis and correlation of the space environmental and ISS parameters with the thermal behaviors of various AMS components.
文摘A micro thermal control device with polyimide based micro louver was proposed.The device structure was designed,the actuation voltage was analyzed theoretically and fabrication process was described.The micro louver prototype was fabricated using UV laser micromachining,electrochemistry etch and magnetron sputtering deposition technologies.The main parameters were tested and results were presented.
基金NSFC(51001039)National Basic Research Program of China(2007CB607602)+1 种基金Fundamental Research Funds for the Central Universities(HIT.NSRIF.2009030)Program of Excellent Teams of Harbin Institute of Technology
文摘Thermal control coatings were fabricated by mixing of La1-xSrxMnO3(LSMO)powder and acrylic resin and brushed on Al alloy substrate.The powders of La0.7Sr0.3MnO3 and La0.8Sr0.2MnO3 were prepared using sol-gel method.XRD results reveal the phase structure of LSMO powders are perovskite.The transition temperature from metal to insulator of La0.7Sr0.3MnO3 and La0.8Sr0.2MnO3 are 300 and 275 K,respectively.The emissivity evolution with temperature of the coatings was measured.For La0.7Sr0.3MnO3/acrylic resin coating,the emissivity increases from 0.56 to 0.88,and for La0.7Sr0.3MnO3/acrylic resin coating from 0.50 to 0.90.
基金Project supported by National Natural Science Foundation of China(No. 50675199)the Science and Technology Project of Zhejiang Province (No. 2006C11067), China
文摘The interaction between the heat source location, its intensity, thermal expansion coefficient, the machine system configuration and the running environment creates complex thermal behavior of a machine tool, and also makes thermal error prediction difficult. To address this issue, a novel prediction method for machine tool thermal error based on Bayesian networks (BNs) was presented. The method described causal relationships of factors inducing thermal deformation by graph theory and estimated the thermal error by Bayesian statistical techniques. Due to the effective combination of domain knowledge and sampled data, the BN method could adapt to the change of running state of machine, and obtain satisfactory prediction accuracy. Ex- periments on spindle thermal deformation were conducted to evaluate the modeling performance. Experimental results indicate that the BN method performs far better than the least squares (LS) analysis in terms of modeling estimation accuracy.
基金supported by the Shandong Province Outstanding Young Scientist Award Fund(Grant No.BS2013NJ026)the National Basic Research Program of China("973"Project)(Grant No.2013CB228305)
文摘This paper presents an overview of the AMS thermal control system and its thermal environment on the ISS.We give examples of analysis and correlation of space environmental impacting on the thermal control system of AMS.The most critical factors that affect the thermal environment to AMS are beta angle,attitude of ISS,ISS solar array and ISS radiator positions.The design of a special sandwich structure with embedded heat pipes provides the radiator with higher heat transfer ability for electronics and power crates,and it provides a large heat retaining capacity to balance the frequent changes of the space environment temperatures as well.In cold cases,the thermostatically controlled heaters are working actively to protect AMS.However,sometimes,because of ISS special operations plus extreme beta angle condition,AMS needs to request NASA to adjust the ISS configuration for thermal control.The AMS thermal control system is reliable and stable,which has been verified by its operation on the ISS for more than three years.All the detectors operate normally,the electronics and crates work within their specific temperature limits.
基金Supported by 973 Program (2009CB824800), NSFC (10978001)Knowledge Innovation Program of Chinese Academy of Sciences (200931111192010)
文摘A thermal control system (TCS) based on the resistance heating method is designed for the High Energy Detector (HED) on the Hard X-ray Modulation Telescope (HXMT). The ground-based experiments of the active thermal control for the HED with the TCS are performed in the ambient temperature range from -15 to 20 by utilizing the pulse width to monitor the interior temperature of a NaI(Tl) crystal. Experimental results show that the NaI(Tl) crystal's interior temperature is from 17.4 to 21.7 when the temperature of the PMT shell is controlled within (20±3) with the TCS in the interesting temperature range, and the energy resolution of the HED is maintained at 16.2% @122 keV, only a little worse than that of 16.0% obtained at 20 . The average power consumption of the TCS for the HED with a low-emissivity shell is about 4.3 W, which is consistent with the simulation.
基金supported financially by the Fundamental Research Funds for the Central Universities (Grant No.18CX02120A)the Promotive Research Fund for Excellent Young and Middle-aged Scientists of Shandong Province(Grant No. BS2014NJ010)the National Natural Science Foundation of China (Grant No. 21506255)
文摘In this paper, the novel control structures of differential pressure thermally coupled reactive distillation process for methyl acetate hydrolysis were proposed. The RadFrac module of Aspen Plus was adopted in the steady-state simulation. Sensitive analysis was applied to find the stable initial value and provide a basis for the improved control structure design. The Aspen Dynamics software was adopted to study the process dynamic behaviors, and two novel control structures provided with feed ratio controllers and sensitive tray temperature controllers were proposed. The reflux ratio controllers were applied in the improved novel control structures. Both control structures abandoned the composition controllers that were replaced by simpler controllers with which the product purity could meet the specification requiring under a ± 20% disturbance to the total feed flowrate/MeAc composition.
文摘A dynamic thermal transfer model of a proton exchange membrane fuel cell (PEMFC) stack is developed based on energy conservation in order to reach better temperature control of PEMFC stack. Considering its uncertain parameters and disturbance, we propose a robust adaptive controller based on backstepping algorithm of Lyaponov function. Numerical simulations indicate the validity of the proposed controller.
