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Design and optimization of fluid lubricated bearings operated with extreme working performances——a comprehensive review
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作者 Guohua Zhang Ming Huang +6 位作者 Gangli Chen Jiasheng Li Yang Liu Jianguo He Yueqing Zheng Siwei Tang Hailong Cui 《International Journal of Extreme Manufacturing》 SCIE EI CAS CSCD 2024年第2期325-376,共52页
Fluid lubricated bearings have been widely adopted as support components for high-end equipment in metrology,semiconductor devices,aviation,strategic defense,ultraprecision manufacturing,medical treatment,and power ge... Fluid lubricated bearings have been widely adopted as support components for high-end equipment in metrology,semiconductor devices,aviation,strategic defense,ultraprecision manufacturing,medical treatment,and power generation.In all these applications,the equipment must deliver extreme working performances such as ultraprecise movement,ultrahigh rotation speed,ultraheavy bearing loads,ultrahigh environmental temperatures,strong radiation resistance,and high vacuum operation,which have challenged the design and optimization of reliable fluid lubricated bearings.Breakthrough of any related bottlenecks will promote the development course of high-end equipment.To promote the advancement of high-end equipment,this paper reviews the design and optimization of fluid lubricated bearings operated at typical extreme working performances,targeting the realization of extreme working performances,current challenges and solutions,underlying deficiencies,and promising developmental directions.This paper can guide the selection of suitable fluid lubricated bearings and optimize their structures to meet their required working performances. 展开更多
关键词 fluid lubricated bearings structural design performance optimization extreme working performances
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A Review on Technologies for the Use of CO2 as a Working Fluid in Refrigeration and Power Cycles
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作者 Orelien T. Boupda Hyacinthe D. Tessemo +3 位作者 Isidore B. Nkounda Fongang Francklin G. Nyami Frederic Lontsi Thomas Djiako 《Energy and Power Engineering》 2024年第6期217-256,共40页
The use of carbon dioxide as a working fluid has been the subject of extensive studies in recent years, particularly in the field of refrigeration where it is at the heart of research to replace CFC and HCFC. Its ther... The use of carbon dioxide as a working fluid has been the subject of extensive studies in recent years, particularly in the field of refrigeration where it is at the heart of research to replace CFC and HCFC. Its thermodynamic properties make it a fluid of choice in the efficient use of energy at low and medium temperatures in engine cycles. However, the performance of transcritical CO2 cycles weakens under high temperature and pressure conditions, especially in refrigeration systems;On the other hand, this disadvantage becomes rather interesting in engine cycles where CO2 can be used as an alternative to the organic working fluid in small and medium-sized electrical systems for low quality or waste heat sources. In order to improve the performance of systems operating with CO2 in the field of refrigeration and electricity production, research has made it possible to develop several concepts, of which this article deals with a review of the state of the art, followed by analyzes in-depth and critical of the various developments to the most recent modifications in these fields. Detailed discussions on the performance and technical characteristics of the different evolutions are also highlighted as well as the factors affecting the overall performance of the systems studied. Finally, perspectives on the future development of the use of CO2 in these different cycles are presented. 展开更多
关键词 Refrigeration Cycle Power Cycle System Performance Transcritical CO2 Cycles working fluid
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Maximum power output of a class of irreversible non-regeneration heat engines with a non-uniform working fluid and linear phenomenological heat transfer law 被引量:13
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作者 XIA ShaoJun CHEN LinGen SUN FengRui 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2009年第12期1961-1970,共10页
Maximum power output of a class of irreversible non-regeneration heat engines with non-uniform working fluid,in which heat transfers between the working fluid and the heat reservoirs obey the linear phenomenological h... Maximum power output of a class of irreversible non-regeneration heat engines with non-uniform working fluid,in which heat transfers between the working fluid and the heat reservoirs obey the linear phenomenological heat transfer law [q ∝Δ(T-1)],are studied in this paper. Optimal control theory is used to determine the upper bounds of power of the heat engine for the lumped-parameter model and the distributed-parameter model,respectively. The results show that the maximum power output of the heat engine in the distributed-parameter model is less than or equal to that in the lumped-parameter model,which could provide more realistic guidelines for real heat engines. Analytical solutions of the maximum power output are obtained for the irreversible heat engines working between constant temperature reservoirs. For the irreversible heat engine operating between variable temperature reservoirs,a numerical example for the lumped-parameter model is provided by numerical calculation. The effects of changes of reservoir's temperature on the maximum power of the heat engine are analyzed. The obtained results are,in addition,compared with those obtained with Newtonian heat transfer law [q ∝Δ(T)]. 展开更多
关键词 linear PHENOMENOLOGICAL heat transfer law MAXIMUM power non-uniform working fluid optimal control finite time THERMODYNAMICS
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CAD/CAE OF THE WORKING CHARACTERISTICS OF A NEW TYPE OF FLUID COUPLING SHOCK ABSORBER 被引量:4
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作者 Yang Ping Zhong Yifang Zhou JiSchool of Mechanical Science and Engineering, Huazhong University of Science and Technology,Wuhan 430074, ChinaLiu Yong Guilin Institute of Electronic Technology 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2002年第3期222-227,共6页
For purpose of simulation of the working characteristics of a new type offluid coupling shock absorber for vibration protection of sensitive equipment, a physical model ispresented by analyzing the internal fluid dyna... For purpose of simulation of the working characteristics of a new type offluid coupling shock absorber for vibration protection of sensitive equipment, a physical model ispresented by analyzing the internal fluid dynamic phenomenon with respect to the coupling shockabsorber and implemented in MATLAB software package. Using the model it is possible to evaluate theimportance of different factors for design of the shock absorber. In the meantime, the key-modelmachine is designed for coupling dynamic test. Comparisons with experimental results confirm thevalidity of the model. So the CAD/CAE software has been developed in MATLAB for design andexperimental test of the new coupling shock absorber. 展开更多
关键词 fluid coupling shock absorber working characteristics MODEL SIMULATION
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Measurement and Prediction of Vapor Pressure for H20 + CHaOH] C2HsOH + [BMIM][DBP] Ternary Working Fluids 被引量:4
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作者 张晓冬 胡大鹏 赵宗昌 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2013年第8期886-893,共8页
The ionic liquid, 1-butyl-3-methylimidazolium dibutylphosphate ([BMIM][DBP]) was prepared and the vapor pressures of three set of binary solutions H2O(1)/CH3OH(1)/C2H5OH(1) + [BMIM][DBP](2) were measured at different ... The ionic liquid, 1-butyl-3-methylimidazolium dibutylphosphate ([BMIM][DBP]) was prepared and the vapor pressures of three set of binary solutions H2O(1)/CH3OH(1)/C2H5OH(1) + [BMIM][DBP](2) were measured at different temperature and in the ILs mole fraction range from 0.1 to 0.6 with a static equilibrium apparatus. The measured vapor pressures were correlated with Non-Random Two Liquid (NRTL) activity coefficient model and the average relative deviations (ARD) between experimental and correlated vapor pressures for these binary solutions were 3.19%, 2.42% and 2.95%, respectively. Then, the vapor pressures of two set of ternary solutions H2O(1) + CH3OH(2)/C2H5OH(2) + [BMIM][DBP](3) were measured with an inclined boiling apparatus and further predicted with NRTL activity coefficient model based on the binary interaction parameters coming from fitting the vapor pressures of the binary solutions. The results indicated that the ternary solutions containing [BMIM][DBP] were shown a strong negative deviation from Raoult's Law when the mole fraction of [BMIM][DBP] was larger than 0.2, which meant that ternary solutions could absorb the refrigerant vapors at the same or below solution temperature. Meanwhile, the average relative deviations between experimental and predicted vapor pressures for ternary solutions were 2.92% and 3.06%, respectively. Consequently, the NRTL active coefficient model used for non-electrolyte solutions was still valid for predicting vapor-liquid equilibrium of binary or ternary solutions containing ILs. 展开更多
关键词 ionic liquid ternary working fluids vapor pressure NRTL model absorption refrigeration
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Effects of ORC Working Fluids on Combined Cycle Integrated with SOFC and ORC for Stationary Power Generation 被引量:2
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作者 Osagie Matthew Sen Nieh 《Energy and Power Engineering》 2019年第4期167-185,共19页
The purpose of this study is to explore the effects of working fluid on conventional combined cycle integrated with pressurized solid oxide fuel cell (SOFC) and waste heat recovery organic Rankine cycle (ORC) for stat... The purpose of this study is to explore the effects of working fluid on conventional combined cycle integrated with pressurized solid oxide fuel cell (SOFC) and waste heat recovery organic Rankine cycle (ORC) for stationary utility power generation. The mathematical model of a natural gas fueled design configuration is developed in Matlab and Simulink and simulated with 14 working fluids. The effluent gases of SOFC undergo combustion in the combustion chamber and it is utilized in the gas turbine, steam turbine cycle and ORC. The model is compared with those found in literature and the parametric studies of temperature, flow rate, fuel utilization factor and exhaust gas on the system efficiency are examined. Results revealed that working fluids show a closely related behavior in efficiency at low pressure ratio and high flow fraction, fuel utilization, and temperature. R-123 was found to perform the best among 14 working fluids studied, yielding a system energy efficiency of 70% in the combined cycle integrated with SOFC and ORC. 展开更多
关键词 Solid OXIDE Fuel Cell Efficiency Combined CYCLE Organic Rankine CYCLE working fluidS
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Evaluation of working fluids for organic Rankine cycles using group-contribution methods and second-law-based models 被引量:1
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作者 MA Wei-wu WANG Lin +1 位作者 LIU Tao LI Min 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第8期2234-2243,共10页
The group-contribution (GC) methods suffer from a limitation concerning to the prediction of process-related indexes, e.g., thermal efficiency. Recently developed analytical models for thermal efficiency of organic Ra... The group-contribution (GC) methods suffer from a limitation concerning to the prediction of process-related indexes, e.g., thermal efficiency. Recently developed analytical models for thermal efficiency of organic Rankine cycles (ORCs) provide a possibility of overcoming the limitation of the GC methods because these models formulate thermal efficiency as functions of key thermal properties. Using these analytical relations together with GC methods, more than 60 organic fluids are screened for medium-low temperature ORCs. The results indicate that the GC methods can estimate thermal properties with acceptable accuracy (mean relative errors are 4.45%-11.50%);the precision, however, is low because the relative errors can vary from less than 0.1% to 45.0%. By contrast, the GC-based estimation of thermal efficiency has better accuracy and precision. The relative errors in thermal efficiency have an arithmetic mean of about 2.9% and fall within the range of 0-24.0%. These findings suggest that the analytical equations provide not only a direct way of estimating thermal efficiency but an accurate and precise approach to evaluating working fluids and guiding computer-aided molecular design of new fluids for ORCs using GC methods. 展开更多
关键词 organic Rankine cycles (ORCs) group contribution methods working fluids property estimation computer-aided molecular design
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Analysis on optimal working fluid flowrate and unstable power generation for miniaturized ORC systems 被引量:1
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作者 刘克涛 朱家玲 +1 位作者 胡开永 吴秀杰 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第5期1224-1231,共8页
For efficient utilization of a limited geothermal resource in practical projects,the cycle parameters were comprehensively analyzed by combining with the heat transfer performance of the plate heat exchanger,with a va... For efficient utilization of a limited geothermal resource in practical projects,the cycle parameters were comprehensively analyzed by combining with the heat transfer performance of the plate heat exchanger,with a variation of flowrate of R245 fa.The influence of working fluid flowrate on a 500 W ORC system was investigated.Adjusting the working fluid flowrate to an optimal value results in the most efficient heat transfer and hence the optimal heat transfer parameters of the plate heat exchanger can be determined.Therefore,for the ORC systems,optimal working fluid flowrate should be controlled.Using different temperature hot water as the heat source,it is found that the optimal flowrate increases by 6-10 L/h with 5 ℃ increment of hot water inlet temperature.During experiment,lower degree of superheat of the working fluid at the outlet the plate heat exchanger may lead to unstable power generation.It is considered that the plate heat exchanger has a compact construction which makes its bulk so small that liquid mixture causes the unstable power generation.To avoid this phenomenon,the flow area of plate heat exchanger should be larger than the designed one.Alternatively,installing a small shell and tube heat exchanger between the outlet of plate heat exchanger and the inlet of expander can be another solution. 展开更多
关键词 organic Rankine cycle (ORC) plate heat exchanger optimal working fluid flowrate unstable power generation
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Tribological Properties and Machining Performance of Vegetable Oil Based Metal Working Fluids—A Review 被引量:1
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作者 Tamalapura Puttaswamy Jeevan Saligrama Ramachandra Jayaram 《Modern Mechanical Engineering》 2018年第1期42-65,共24页
Lubricants are playing an important role in world industrial and economic development, mainly by reducing friction and wear in mechanical contacts. The outlook for eco-friendly MWFs for the next decade is 15% of globa... Lubricants are playing an important role in world industrial and economic development, mainly by reducing friction and wear in mechanical contacts. The outlook for eco-friendly MWFs for the next decade is 15% of global volume share. Due to ever increasing demand for environmentally acceptable products suitable for use as MWFs, vegetable oil-based MWFs are drawing the attention of researchers across the globe. Owing to the desirable properties of vegetable oils as cutting fluids, vegetable oil-based cutting fluids play an important role in conserving the environment by means of sustainability. This paper focuses on various vegetable oil being developed to promote biodegradable MWFs across the world. The performance of vegetable oils with respect to cutting and thrust force, tool wear, temperature, surface roughness in turning, drilling, milling and grinding a wide variety of materials are studied and reported. The review also throws light on the tribological behavior of vegetable oils that influence the lubricity in Metal working process. The review reveals that vegetable oils offer an alternative, eco-friendly and sustainable MFWs for the future of manufacturing. 展开更多
关键词 Metal working fluidS VEGETABLE OILS TRIBOLOGY ECO-FRIENDLY and SUSTAINABLE
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Pressure transient characteristics of non-uniform conductivity fractured wells in viscoelasticity polymer flooding based on oil-water two-phase flow
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作者 Yang Wang Jia Zhang +2 位作者 Shi-Long Yang Ze-Xuan Xu Shi-Qing Cheng 《Petroleum Science》 SCIE EI CAS CSCD 2024年第1期343-351,共9页
Polymer flooding in fractured wells has been extensively applied in oilfields to enhance oil recovery.In contrast to water,polymer solution exhibits non-Newtonian and nonlinear behavior such as effects of shear thinni... Polymer flooding in fractured wells has been extensively applied in oilfields to enhance oil recovery.In contrast to water,polymer solution exhibits non-Newtonian and nonlinear behavior such as effects of shear thinning and shear thickening,polymer convection,diffusion,adsorption retention,inaccessible pore volume and reduced effective permeability.Meanwhile,the flux density and fracture conductivity along the hydraulic fracture are generally non-uniform due to the effects of pressure distribution,formation damage,and proppant breakage.In this paper,we present an oil-water two-phase flow model that captures these complex non-Newtonian and nonlinear behavior,and non-uniform fracture characteristics in fractured polymer flooding.The hydraulic fracture is firstly divided into two parts:high-conductivity fracture near the wellbore and low-conductivity fracture in the far-wellbore section.A hybrid grid system,including perpendicular bisection(PEBI)and Cartesian grid,is applied to discrete the partial differential flow equations,and the local grid refinement method is applied in the near-wellbore region to accurately calculate the pressure distribution and shear rate of polymer solution.The combination of polymer behavior characterizations and numerical flow simulations are applied,resulting in the calculation for the distribution of water saturation,polymer concentration and reservoir pressure.Compared with the polymer flooding well with uniform fracture conductivity,this non-uniform fracture conductivity model exhibits the larger pressure difference,and the shorter bilinear flow period due to the decrease of fracture flow ability in the far-wellbore section.The field case of the fall-off test demonstrates that the proposed method characterizes fracture characteristics more accurately,and yields fracture half-lengths that better match engineering reality,enabling a quantitative segmented characterization of the near-wellbore section with high fracture conductivity and the far-wellbore section with low fracture conductivity.The novelty of this paper is the analysis of pressure performances caused by the fracture dynamics and polymer rheology,as well as an analysis method that derives formation and fracture parameters based on the pressure and its derivative curves. 展开更多
关键词 Polymer flooding Non-Newtonian fluid non-uniform fracture conductivity Two-phase flow Pressure transient analysis
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Selection of organic Rankine cycle working fluid based on unit-heat-exchange-area net power 被引量:1
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作者 郭美茹 朱启的 +2 位作者 孙志强 周天 周孑民 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第4期1548-1553,共6页
To improve energy conversion efficiency, optimization of the working fluids in organic Rankine cycles(ORCs) was explored in the range of low-temperature heat sources. The concept of unit-heat-exchange-area(UHEA) net p... To improve energy conversion efficiency, optimization of the working fluids in organic Rankine cycles(ORCs) was explored in the range of low-temperature heat sources. The concept of unit-heat-exchange-area(UHEA) net power, embodying the cost/performance ratio of an ORC system, was proposed as a new indicator to judge the suitability of ORC working fluids on a given condition. The heat exchange area was computed by an improved evaporator model without fixing the minimum temperature difference between working fluid and hot fluid, and the flow pattern transition during heat exchange was also taken into account. The maximum UHEA net powers obtained show that dry organic fluids are more suitable for ORCs than wet organic fluids to recover low-temperature heat. The organic fluid 1-butene is recommended if the inlet temperature of hot fluid is 353.15-363.15 K or443.15-453.15 K, heptane is more suitable at 373.15-423.15 K, and R245 ca is a good option at 483.15-503.15 K. 展开更多
关键词 organic Rankine cycle(ORC) working fluid selection net power heat exchange area
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Working Fluid Selection for Medium Temperature Organic Rankine Cycle 被引量:1
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作者 CHEN Qicheng XU Jinliang MIAO Zheng 《中国电机工程学报》 EI CSCD 北大核心 2013年第32期I0001-I0001,共1页
关键词 朗肯循环 工作液 中温 ORC 流体性质 介质温度 源驱动 甲苯
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Hydrothermal analysis of non-Newtonian fluid flow(blood)through the circular tube under prescrib e d non-uniform wall heat flux 被引量:1
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作者 Shahin Faghiri Shahin Akbari +1 位作者 Mohammad Behshad Shafii Kh.Hosseinzadeh 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2022年第4期275-285,共11页
The present article aims to investigate the Graetz-Nusselt problem for blood as a non-Newtonian fluid obeying the power-law constitutive equation and flowing inside the axisymmetric tube subjected to nonuniform surfac... The present article aims to investigate the Graetz-Nusselt problem for blood as a non-Newtonian fluid obeying the power-law constitutive equation and flowing inside the axisymmetric tube subjected to nonuniform surface heat flux.After the flow field is determined by solving the continuity and the momentum equations,the energy equation is handled by employing the separation of variables method.The resulting Eigen functions and Eigen values are numerically calculated using MATLAB built-in solver BVP4C.The analysis is first conducted for the situation of constant heat flux and subsequently generalized to apply to the case of sinusoidal variation of wall heat flux along the tube length,using Duhamel’s Theorem.Furthermore,an approximate analytic solution is determined,employing an integral approach to solve the boundary layer equations.With respect to the comparison,the results of approximate solution display acceptable congruence with those of exact solution with an average error of 7.4%.Interestingly,with decreasing the power-law index,the discrepancy between the two presented methods significantly reduces.Eventually,the influences of the controlling parameters such as surface heat flux and power-law index on the non-Newtonian fluid flow’s thermal characteristics and structure are elaborately discussed.It is found that switching from constant wall heat flux to non-uniform wall heat flux that sinusoidally varies along the tube length significantly improves the simulation’s accuracy due to the better characterization of the heat transport phenomenon in non-Newtonian fluid flow through the tube.In the presence of sinusoidally varying wall heat flux with an amplitude of 200 W/m 2 and when the power-law index is 0.25,the maximum arterial wall temperature is found to be about 311.56 K. 展开更多
关键词 Non-newtonian fluid Power-law model non-uniform heat flux Analytical solution
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Heat Transfer Characteristics of Work Fluid Including Phase Change Material That Flow into Heating Surface from Narrow Path 被引量:1
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作者 Shin-Ichi Morita Yasutaka Hayamizu +4 位作者 Takanobu Yamada Akihiko Horibe Naoto Haruki Toshiaki Setoguchi Kazuma Adachi 《Open Journal of Fluid Dynamics》 2014年第5期454-462,共9页
Use of the low temperature (less than 100°C) energy contributes to effective use of heat resources. The cost recovery by power generation is difficult by using an existing system (the binary cycle or the thermoel... Use of the low temperature (less than 100°C) energy contributes to effective use of heat resources. The cost recovery by power generation is difficult by using an existing system (the binary cycle or the thermoelectric conversion element), because the initial investment is large. The final purpose of this research is development of the low temperature difference drive engine supposing use in a hot-springs resort as a power source for electric power generation. In order that a traveler may look at and delight a motion of an engine, it is made to drive at low-speed number of rotations. An engine cycle of this study is aimed at the development of Stirling cycle engine which can maintain high efficiency in small size. This kind of engine has simple structure;it brings low cost, and it is easy to perform maintenance. However, it is difficult to obtain enough output by this type of engine, because of its low temperature difference. This paper deals with the heat transfer characteristic that the working fluid including a phase change material flows into the heating surface from the narrow path. In order to increase the amount of the heat transmission, Diethylether is added to the working fluid. Diethylether is selected as a phase change material (PCM) that has the boiling point which exists between the heat source of high temperature and low temperature. The parameters of the experiment are additive amount of PCM, rotational speed of the displacer piston and temperature of heat transfer surface. It is shown that it is possible to make exchange of heat amount increase by adding phase change material. The result of this research shows the optimal condition of the difference in temperature in heat processing, number of revolutions, and addition concentration of PCM. 展开更多
关键词 Phase CHANGE Material Heat TRANSFER Low Temperature DIFFERENCE working fluid
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Boundary Layer Flow of an Unsteady Dusty Fluid and Heat Transfer Over a Stretching Sheet with Non-Uniform Heat Source/Sink 被引量:1
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作者 Bijjanal J. Gireesha Govinakovi S. Roopa Channabasappa S. Bagewadi 《Engineering(科研)》 2011年第7期726-735,共10页
An analysis has been carried out to study the effect of hydrodynamic laminar boundary layer flow and heat transfer of a dusty fluid over an unsteady stretching surface in the presence of non-uniform heat source/sink. ... An analysis has been carried out to study the effect of hydrodynamic laminar boundary layer flow and heat transfer of a dusty fluid over an unsteady stretching surface in the presence of non-uniform heat source/sink. Heat transfer characteristics are examined for two different kinds of boundary conditions, namely 1) variable wall temperature and 2) variable heat flux. The governing partial differential equations are transformed to system of ordinary differential equations. These equations are solved numerically by applying RKF-45 method. The effects of various physical parameters such as magnetic parameter, dust interaction parameter, number density, Prandtl number, Eckert number, heat source/sink parameter and unsteadiness parameter on velocity and temperature profiles are studied. 展开更多
关键词 UNSTEADY Flow HEAT Transfer Boundary Layer Flow Stretching Surface DUSTY fluid fluid-Particle Interaction Parameter and non-uniform HEAT Source/Sink
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Effect of Non-Uniform Temperature Gradient on the Onset of Rayleigh-Bénard Electro Convection in a Micropolar Fluid
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作者 Subbarama Pranesh Riya Baby 《Applied Mathematics》 2012年第5期442-450,共9页
The effects of electric field and non-uniform basic temperature gradient on the onset of Rayleigh-Bénard convection in a micropolar fluid are studied using the Galerkin technique. The eigenvalues are obtained for... The effects of electric field and non-uniform basic temperature gradient on the onset of Rayleigh-Bénard convection in a micropolar fluid are studied using the Galerkin technique. The eigenvalues are obtained for free-free, rigid-free and rigid-rigid velocity boundary combinations and for isothermal and/or adiabatic temperature boundaries. The microrotation is assumed to vanish at the boundaries. A linear stability analysis is performed. The influence of various micropolar fluid parameters and electric Rayleigh number on the onset of convection has been analyzed. One linear and five non-uniform temperature profiles are considered and their comparative influence on onset is discussed. 展开更多
关键词 MICROPOLAR fluid RAYLEIGH Number ELECTRO CONVECTION non-uniform Temperature Gradients GALERKIN Technique
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Effect of Non-Uniform Basic Temperature Gradient on the Onset of Rayleigh-Bénard-Marangoni Electro-Convectionin a Micropolar Fluid
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作者 Thadathil Varghese Joseph Sree Ramaiah Manjunath Subbarama Pranesh 《Applied Mathematics》 2013年第8期1180-1188,共9页
The effects of electric field and non-uniform basic temperature gradient on the onset of Rayleigh-Bénard-Marangoni convection in a micropolar fluid are studied using the Galerkin technique. The eigenvalues are ob... The effects of electric field and non-uniform basic temperature gradient on the onset of Rayleigh-Bénard-Marangoni convection in a micropolar fluid are studied using the Galerkin technique. The eigenvalues are obtained for an upper free/adiabatic and lower rigid/isothermal boundaries. The microrotation is assumed to vanish at the boundaries. A linear stability analysis is performed. The influence of various micropolar fluid parameters and electric Rayleigh number on the onset of convection has been analysed. Six different non-uniform temperature profiles are considered and their comparative influence on onset is discussed. 展开更多
关键词 Rayleigh-Bénard-Marangoni non-uniform Temperature GRADIENT Electric Field MICROPOLAR fluid GALERKIN Technique
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MY WORK IN THE FIELD OF FLUID MECHANICS
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作者 Zhou Heng(Tianjin University) 《Bulletin of the Chinese Academy of Sciences》 1996年第1期69-69,共1页
I graduated from the National Peiyang University (now called Tianjin University) in 1950, majoring in hydraulic engineering. Starting from 1952, my teaching work was basically in mechanics.My first academic probe was ... I graduated from the National Peiyang University (now called Tianjin University) in 1950, majoring in hydraulic engineering. Starting from 1952, my teaching work was basically in mechanics.My first academic probe was in cybernetics, resulting in the publication of the first Chinese paper concerning optimal control. After 1963, I worked on the theory of hydrodynamic stability. My explorative thrust is at the eigenvalues of the Orr Sommerfeld Equation,a non-self adjoint problem in 展开更多
关键词 MY work IN THE FIELD OF fluid MECHANICS
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天然气井井筒解堵工作液的研究进展 被引量:1
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作者 李善建 杜进繁 +3 位作者 贺建英 孙冬 乔林胜 王帅 《应用化工》 CAS CSCD 北大核心 2024年第1期238-241,共4页
通过文献调研,分析了各种井筒解堵工作液的解堵机理,综述了各类型常用井筒解堵工作液的应用进展及优缺点;介绍了有机解堵工作液、有机缓释微乳酸解堵工作液、复合型解堵工作液等新型解堵工作液的研究进展;分析了解堵工作液在制备与实际... 通过文献调研,分析了各种井筒解堵工作液的解堵机理,综述了各类型常用井筒解堵工作液的应用进展及优缺点;介绍了有机解堵工作液、有机缓释微乳酸解堵工作液、复合型解堵工作液等新型解堵工作液的研究进展;分析了解堵工作液在制备与实际应用过程中存在的问题,并提出了未来解堵工作液的发展趋势。 展开更多
关键词 解堵工作液 井筒堵塞 解堵 发展趋势
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基于过程解耦和工质物性的有机朗肯循环性能分析
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作者 韩中合 沈明轩 +3 位作者 杨伊琳 刘世通 赵文升 李鹏 《太阳能学报》 EI CAS CSCD 北大核心 2024年第6期226-233,共8页
通过对有机朗肯循环工作过程的拆分解耦,利用工质物性中的临界温度、偏心因子结合循环参数推导其热力学性能表征式,进而建立循环的热力学模型,并借助该模型分析循环参数对循环热力学性能评价指标的影响规律。研究结果显示:当蒸发温度升... 通过对有机朗肯循环工作过程的拆分解耦,利用工质物性中的临界温度、偏心因子结合循环参数推导其热力学性能表征式,进而建立循环的热力学模型,并借助该模型分析循环参数对循环热力学性能评价指标的影响规律。研究结果显示:当蒸发温度升高时,循环热效率会增大,但其净输出功和效率先增大,然后再降低;当冷凝温度升高时,循环的热效率、净输出功和效率都会下降;当过热度升高时,循环的净输出功和效率随过之降低,而循环的热效率随之增大。基于工质物性引入雅各布数,循环的净输出功和热效率随雅各布数的增大分别呈现出增大和减小的趋势,而临界温度越高热效率随之升高。 展开更多
关键词 有机朗肯循环 循环性能 解耦 工质物性
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