In some data centers,cold air is required to act on the cabinet to achieve cooling requirements,and the mixing of cold air and hot air reduces the utilization efficiency of cold air.In order to solve this problem,a je...In some data centers,cold air is required to act on the cabinet to achieve cooling requirements,and the mixing of cold air and hot air reduces the utilization efficiency of cold air.In order to solve this problem,a jet cooling model is established to solve the optimal position of the outlet through the movement of cold air.展开更多
Green cooling is an important technology in green manufacturing. In the way of jetting, cooling airflo-w in used in the experiments of metal material cutting, by comparison of the changes of some technological factors...Green cooling is an important technology in green manufacturing. In the way of jetting, cooling airflo-w in used in the experiments of metal material cutting, by comparison of the changes of some technological factors, such as cutting heat, surface finish, in the process of jet cooling, pour cooling and natural cooling, we can draiv the conclusion that air jet cooling has a better cooling effect and green function. It can be 'widely used in both traditional and automatic green manufacturing.展开更多
The Double-Jet Film-Cooling （DJFC） technology is invented by the authors and comprises a significant enhancement of the adiabatic film-cooling effectiveness due to the formation of anti-kidney vortices. The DJFC tec...The Double-Jet Film-Cooling （DJFC） technology is invented by the authors and comprises a significant enhancement of the adiabatic film-cooling effectiveness due to the formation of anti-kidney vortices. The DJFC technology places a second ejection hole with compound angle in a double-hole arrangement downstream the first hole. The second hole creates a second jet with another dominating vortex rotating in opposite direction to the first one and then combines both jets to one jet. The basic applicability and function of the DJFC technology has been proven by the numerical studies and testing in a test rig. The comparison of the experimental results of the adiabatic film cooling effectiveness to the numerical results for the same blowing ratio （M=（pc）c/（pc）h） shows qualitatively similar distributions. However, the experimental results show enhanced mixing-out of the cooling air and, thus, the experimental values of the adiabatic film cooling effectiveness are lower compared to the numerical values.展开更多
Some of the main cooling processes and equipment that are currently being used in the continuous annealing process line （CAPL） at Baosteel are introduced, as well as their cooling control model techniques, the model...Some of the main cooling processes and equipment that are currently being used in the continuous annealing process line （CAPL） at Baosteel are introduced, as well as their cooling control model techniques, the modeling principium and their application results. With charts indicating the control trends in real processes, the powerful adjusting ability of the control models with process variable differences and their excellent control precision are shown in this study.展开更多
Jet impingement cooling with supercritical pressure carbon dioxide in a multi-layer cold plate during the heat flux of 400 W/cm_(2) is investigated numerically.The generation and distribution of pseudocritical fluid w...Jet impingement cooling with supercritical pressure carbon dioxide in a multi-layer cold plate during the heat flux of 400 W/cm_(2) is investigated numerically.The generation and distribution of pseudocritical fluid with the high specific heat of supercritical pressure carbon dioxide and the mechanism of the heat transfer enhancement led by the high specific heat are analyzed.For a given nozzle diameter,the effects of the geometric parameters of a multi-layer cold plate such as the relative nozzle-to-plate distance,relative plate thickness,and relative upper fluid thickness on the average heat transfer coefficient are studied.The results show that the target surface is cooled effectively with supercritical pressure carbon dioxide jet impingement cooling.When the radial distance is less than 6 mm,the maximum wall temperature is 368 K,which is 30 K lower than the maximum junction temperature for a silicon-based insulated gate bipolar transistor,a typical electronic power device.There is a pseudocritical fluid layer near the target surface,where specific heat reaches above 34 kJ/(kg·K)locally.The drastic rise of the specific heat leads to obvious heat transfer enhancement.Within a certain range,the local heat transfer coefficient and the specific heat are linearly correlated and Stanton number remains constant over this range.The heat transfer coefficient is at a maximum when the relative nozzle-to-plate distance is 1.As the relative plate thickness increases from 0.5 to 3.5 or the relative upper fluid thickness increases from 0.5 to 2.5,the average heat transfer coefficient decreases monotonically.展开更多
Bone grinding is an essential and vital procedure in most surgical operations.Currently,the insufficient cooling capacity of dry grinding,poor visibility of drip irrigation surgery area,and large grinding force leadin...Bone grinding is an essential and vital procedure in most surgical operations.Currently,the insufficient cooling capacity of dry grinding,poor visibility of drip irrigation surgery area,and large grinding force leading to high grinding temperature are the technical bottlenecks of micro-grinding.A new micro-grinding process called ultrasonic vibration-assisted nanoparticle jet mist cooling(U-NJMC)is innovatively proposed to solve the technical problem.It combines the advantages of ultrasonic vibration(UV)and nanoparticle jet mist cooling(NJMC).Notwithstanding,the combined effect of multi parameter collaborative of U-NJMC on cooling has not been investigated.The grinding force,friction coefficient,specific grinding energy,and grinding temperature under dry,drip irrigation,UV,minimum quantity lubrication(MQL),NJMC,and U-NJMC micro-grinding were compared and analyzed.Results showed that the minimum normal grinding force and tangential grinding force of U-NJMC micro-grinding were 1.39 and 0.32 N,which were 75.1%and 82.9%less than those in dry grinding,respectively.The minimum friction coefficient and specific grinding energy were achieved using U-NJMC.Compared with dry,drip,UV,MQL,and NJMC grinding,the friction coefficient of U-NJMC was decreased by 31.3%,17.0%,19.0%,9.8%,and 12.5%,respectively,and the specific grinding energy was decreased by 83.0%,72.7%,77.8%,52.3%,and 64.7%,respectively.Compared with UV or NJMC alone,the grinding temperature of U-NJMC was decreased by 33.5%and 10.0%,respectively.These results showed that U-NJMC provides a novel approach for clinical surgical micro-grinding of biological bone.展开更多
文摘In some data centers,cold air is required to act on the cabinet to achieve cooling requirements,and the mixing of cold air and hot air reduces the utilization efficiency of cold air.In order to solve this problem,a jet cooling model is established to solve the optimal position of the outlet through the movement of cold air.
文摘Green cooling is an important technology in green manufacturing. In the way of jetting, cooling airflo-w in used in the experiments of metal material cutting, by comparison of the changes of some technological factors, such as cutting heat, surface finish, in the process of jet cooling, pour cooling and natural cooling, we can draiv the conclusion that air jet cooling has a better cooling effect and green function. It can be 'widely used in both traditional and automatic green manufacturing.
文摘The Double-Jet Film-Cooling （DJFC） technology is invented by the authors and comprises a significant enhancement of the adiabatic film-cooling effectiveness due to the formation of anti-kidney vortices. The DJFC technology places a second ejection hole with compound angle in a double-hole arrangement downstream the first hole. The second hole creates a second jet with another dominating vortex rotating in opposite direction to the first one and then combines both jets to one jet. The basic applicability and function of the DJFC technology has been proven by the numerical studies and testing in a test rig. The comparison of the experimental results of the adiabatic film cooling effectiveness to the numerical results for the same blowing ratio （M=（pc）c/（pc）h） shows qualitatively similar distributions. However, the experimental results show enhanced mixing-out of the cooling air and, thus, the experimental values of the adiabatic film cooling effectiveness are lower compared to the numerical values.
文摘Some of the main cooling processes and equipment that are currently being used in the continuous annealing process line （CAPL） at Baosteel are introduced, as well as their cooling control model techniques, the modeling principium and their application results. With charts indicating the control trends in real processes, the powerful adjusting ability of the control models with process variable differences and their excellent control precision are shown in this study.
基金supported by the Ministry of Science and Technology,the National Key Research and Development Program of China,under Grant No.2016YFE0201200。
文摘Jet impingement cooling with supercritical pressure carbon dioxide in a multi-layer cold plate during the heat flux of 400 W/cm_(2) is investigated numerically.The generation and distribution of pseudocritical fluid with the high specific heat of supercritical pressure carbon dioxide and the mechanism of the heat transfer enhancement led by the high specific heat are analyzed.For a given nozzle diameter,the effects of the geometric parameters of a multi-layer cold plate such as the relative nozzle-to-plate distance,relative plate thickness,and relative upper fluid thickness on the average heat transfer coefficient are studied.The results show that the target surface is cooled effectively with supercritical pressure carbon dioxide jet impingement cooling.When the radial distance is less than 6 mm,the maximum wall temperature is 368 K,which is 30 K lower than the maximum junction temperature for a silicon-based insulated gate bipolar transistor,a typical electronic power device.There is a pseudocritical fluid layer near the target surface,where specific heat reaches above 34 kJ/(kg·K)locally.The drastic rise of the specific heat leads to obvious heat transfer enhancement.Within a certain range,the local heat transfer coefficient and the specific heat are linearly correlated and Stanton number remains constant over this range.The heat transfer coefficient is at a maximum when the relative nozzle-to-plate distance is 1.As the relative plate thickness increases from 0.5 to 3.5 or the relative upper fluid thickness increases from 0.5 to 2.5,the average heat transfer coefficient decreases monotonically.
基金supported by the National Natural Science Foundation of China (Grant Nos.51905289 and 51975305)the National Key R&D Program of China (Grant No.2020YFB2010500)+3 种基金the Natural Science Foundation of Shandong Province,China (Grant Nos.ZR2022QE159,ZR2020KE027,ZR2020ME158,and ZR2019PEE008)the China Postdoctoral Science Foundation (Grant No.2021M701810)the Innovation Talent Supporting Program for Postdoctoral Fellows of Shandong Province,China (Grant No.SDBX2020012)the Qingdao Postdoctoral Researchers Applied Research Project Funding,China (Grant No.A2020-072).
文摘Bone grinding is an essential and vital procedure in most surgical operations.Currently,the insufficient cooling capacity of dry grinding,poor visibility of drip irrigation surgery area,and large grinding force leading to high grinding temperature are the technical bottlenecks of micro-grinding.A new micro-grinding process called ultrasonic vibration-assisted nanoparticle jet mist cooling(U-NJMC)is innovatively proposed to solve the technical problem.It combines the advantages of ultrasonic vibration(UV)and nanoparticle jet mist cooling(NJMC).Notwithstanding,the combined effect of multi parameter collaborative of U-NJMC on cooling has not been investigated.The grinding force,friction coefficient,specific grinding energy,and grinding temperature under dry,drip irrigation,UV,minimum quantity lubrication(MQL),NJMC,and U-NJMC micro-grinding were compared and analyzed.Results showed that the minimum normal grinding force and tangential grinding force of U-NJMC micro-grinding were 1.39 and 0.32 N,which were 75.1%and 82.9%less than those in dry grinding,respectively.The minimum friction coefficient and specific grinding energy were achieved using U-NJMC.Compared with dry,drip,UV,MQL,and NJMC grinding,the friction coefficient of U-NJMC was decreased by 31.3%,17.0%,19.0%,9.8%,and 12.5%,respectively,and the specific grinding energy was decreased by 83.0%,72.7%,77.8%,52.3%,and 64.7%,respectively.Compared with UV or NJMC alone,the grinding temperature of U-NJMC was decreased by 33.5%and 10.0%,respectively.These results showed that U-NJMC provides a novel approach for clinical surgical micro-grinding of biological bone.
