检索结果-南通市图书馆

Experimental Study on Cooling Down Process of a Nitrogen-Charged Cryogenic loop heat pipe

Journal of Thermal Science 2023年第1期32卷 153-165页

作者： ZHAO Ya'nan YAN Tao LIANG Jingtao Key Laboratory of Space Energy Conversion Technology Technical Institute of Physics and ChemistryChinese Academyof SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

Cryogenic loop heat pipes are highly efficient heat transfer devices at cryogenic temperature range,which have promising application prospects in satellites,spacecrafts,electronics,and so on.Cooling down process is a most critical process for a CLHP before startup.At present,secondary loop is a major way for a CLHP to fulfil cooling down and most studies are concentrated on heat transfer characteristics during normal operation.However,few investigations have been carried out on the cooling down process.In this paper,the cooling down process of a nitrogen-charged CLHP assisted with a secondary loop was experimentally investigated.A simple qualitative approach to estimate the cooling down time was proposed according to the law of conservation of energy.The two flow paths of the working fluid in the CLHP during the cooling down process were described.Experimental studies on the cooling down process with various secondary heat loads and working fluid inventory were presented in detail.With the increase of secondary heat load,the elapsed time of Stage III decreased significantly due to the larger mass flow rate in Path I.In addition,the effect of the working fluid inventory on the cooling down time was generally small in the range from 2.99 MPa to 3.80 MPa.However,with 2.80 MPa working fluid inventory,it required much longer cooling down time,which was because of the lack of liquid in the CLHP with low working fluid inventory.Moreover,the influence of gravity on the temperature variation of the components during the experiments was analyzed.This work is beneficial for better understanding of the cooling down process and optimizing of CLHPs.

关键词： cryogenic loop heat pipe secondary loop cooling down heat transfer

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Visualization Investigation on Temperature Oscillation and Two-Phase Behaviors of A Flat loop heat pipe

引用

Journal of Thermal Science 2023年第4期32卷 1536-1546页

作者： DU Sheng ZHANG Quan LING Li ZOU Sikai LIU Lijun MENG Fanxi College of Civil Engineering Hunan UniversityChangsha410082China School of Civil Engineering Hunan University of TechnologyZhuzhou412007China

To better analyzing the temperature oscillation and the two-phase behavior inside a flat loop heat pipe,visual studies were conducted.Under the 20℃ water cooling and horizontal orientation,the effects of the filling ratio and heat loads on the temperature oscillation were analyzed.Based on the experimental data,the results indicate that owing to the increased system pressure,the temperature oscillation decays as the filling ratio increases from 34%to 58%.Meanwhile,during the startup process,temperature oscillation tends to occur during the boiling and steady stages due to the more violent two-phase behavior,while the temperature curves are smooth during the slow evaporation stage.Moreover,as the heat load increases,the evaporation becomes more intense at the active zone of evaporator,leading to a faster startup process and a higher oscillation frequency.Besides,owing to the synergistic effect of two-phase flow in the compensation chamber caused by heat leak and subcooled liquid backflowing,a“breathing”oscillation behavior of the vapor-liquid interface is observed at the compensation chamber,which further leads to the unstable operation behavior of the loop heat pipe system.

关键词： loop heat pipe temperature oscillation visualization observations two-phase flow patterns start-up characteristics vapor-liquid interface fluctuation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Experimental investigation on operating behaviors of loop heat pipe with thermoelectric cooler under acceleration conditions

引用

Chinese Journal of Aeronautics 2020年第3期33卷 852-860页

作者： Yongqi XIE Xinyu LI Sujun DONG Hongxing ZHANG Hongwei WU School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China Beijing Key Laboratory of Space Thermal Control Technology China Academy of Space TechnologyBeijing 100094China School of Engineering and Computer Science University of HertfordshireHatfield AL109ABUnited Kingdom

An experimental study was carried out in this article to investigate the transient operating performance of a Dual Compensation Chamber loop heat pipe(DCCLHP) with Thermoelectric Cooler(TEC) under acceleration conditions and ammonia was selected as the working fluid.For the purpose of comparison, experimental work was conducted under terrestrial gravity.Sensitivity analysis was performed to explore the effect of several control parameters such as the heat load, acceleration magnitude and TEC assist on the startup and operating performance of the DCCLHP.Experimental results indicate that the DCCLHP can get to a steady-state operation when the heat load changes from 25 W to 300 W under terrestrial gravity.While under acceleration conditions, the DCCLHP can work at a high operating temperature or even fail to operate, which shows the acceleration effect plays a significant impact on the loop operation.The TEC assist with power of 10 W can improve the operating performance and reduce the operating temperature for the case of small heat load and acceleration magnitude.When the acceleration exceeds 3 g at large heat load, the effect of TEC assist on the operation at large heat load can be ignored.

关键词： Acceleration Electronic cooling loop heat pipe Operating performance Thermoelectric cooler

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Experimental Investigation and Visualization Study of the Condensation Characteristics in a Propylene loop heat pipe

引用

Journal of Thermal Science 2021年第5期30卷 1803-1813页

作者： YAN Kaifenu XIE Rongjian LI Nanxi XU Guangming WU Yinong University of Chinese Academy of Sciences Beijing 100049China Shanghai Institute of Technology and Physics Shanghai 200083China

At present,the structural design of a loop heat pipe(LHP)condenser mostly relies on experience.To analyze the condensation flow pattern in an LHP and to find a more accurate empirical correlation that can better guide condenser design in existing empirical correlations,a test system was designed and fabricated to observe the condensation phenomenon in the condenser and to evaluate the LHP’s heat transfer performance.Since propylene has a wide temperature range to different temperature control requirements,it was chosen as the working fluid.In this paper,the condensation process in the condenser was observed,and the operating parameters of a propylene LHP were measured at 283 K.The condensation flow patterns in the 2.5 mm×2.5 mm channel mainly included stratified flow,wavy flow and intermittent flow.By comparing the experimental results with four typical condensation flow regime maps,it was found that the Breber and Cavallini flow regime maps can successfully predict most of the condensation flow patterns of the LHP even with ultra-small mass flux.In addition,four condensation heat transfer coefficient correlations were selected to compare the predicted values of heat transfer coefficient with the experimental results.The study showed that the predicted values from the correlation by Cavallini et al.matched 90%of the experimental values well with an error of less than 20%,and this correlation is recommended for highly accurate LHP design.

关键词： loop heat pipe condensation visualization flow pattern

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Mass-Spring-Damper Model with Steady State Parameters for Predicting the Movement of Liquid Column and Temperature Oscillation in loop heat pipe

引用

Journal of Harbin Institute of Technology(New Series) 2016年第5期23卷 82-89页

作者： Ge Zhang Di Chen Yingying Hong Li Liu School of Mechanical Engineering University of Science and Technology Beijing School of Advanced Engineer University of Science and Technology Beijing

In order to investigate the mechanism of the temperature oscillation in loop heat pipes,this paper investigated the movement of the phase interface as the changed input power by a mass-spring-damper model.The model was solved with MATLAB and was used to explain the high-frequency and low-amplitude temperature oscillation.Temperature variation with the input power from 20 W to 75 W was investigated based on a LHP prototype in a literature.The model agreed well with the experimental data in the literature.The simulation results suggested that the movement of the liquid column was caused by the fluctuation of pressure difference applied on the liquid column and the stiffness coefficients of the vapor springs increasing with the input power.According to parameter analyses,the temperature oscillation at the outlet of the condenser can be weakened by increasing the mass of the liquid column and keeping the temperature at the outlet of the condenser steady.

关键词： loop heat pipe temperature oscillation displacement mass-spring-damper model steady state parameters

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Experimental Investigation of loop heat pipe with Two Evaporators/Two Condensers under Thermal Vacuum Condition

引用

Journal of Applied Mathematics and Physics 2016年第8期4卷 1460-1469页

作者： Xinyu Chang Hosei Nagano Department of Aero-Space Engineering Nagoya University Nagoya Japan

Multiple loop heat pipe is a high-functional thermal transport device. This work was conducted to confirm the working performance of Multiple loop heat pipe under thermal vacuum ambience with the working fluid ammonia. Asmall multiple loop heat pipe with two evaporators and two ra- diators was designed and fabricated. Then thermal vacuum test was conducted. The heaters were fasten on both evaporators, both radiators, both compensation chambers. In the case that both evaporators were heated, the multiple loop heat pipe can transport 120/120 W for 1.5 m, in the case that only one evaporator was heated, evaporator 1 can transport 80 W for 1.5 m, while eva- porator 2 can transport 120 W for 1.5 m. Two flow regulators were installed near the confluence of liquid line to prevent uncondensed vapor penetrating into returning liquid when the tempera- ture difference exists between two radiators. In the case that the heat load at both evaporators were 40/40 W and one radiator was heated, the flow regulator1 can tolerate the 160 W of heat load which was supplied to radiator1 while the flow regulator2 can tolerate the 100 W of heat load which was supplied to radiator2. To demonstrate the multiple loop heat pipe’s startup behavior at lowheat load, each of the compensation chamber was preheated to change the initial distribution of liquid and vapor in the evaporator and compensation chamber, in the result, each evaporator can start up at 5W through preheating.

关键词： loop heat pipe Ammonia Thermal Vacuum Test Two Phase Flow

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Experimental Investigation on Thermal Characteristics of Long Distance loop heat pipes

引用

Journal of Thermal Science 2022年第3期31卷 741-750页

作者： ZHAO Ya’nan YAN Tao LIANG Jingtao Key Laboratory of Space Energy Conversion Technology Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100190China

loop heat pipes(LHPs)are attractive two-phase thermal control devices for satellites,electronics and many other applications.They are capable of transporting heat efficiently for long distances up to several meters at any orientation.This paper investigated the heat transfer characteristics of loop heat pipes with long distances and small diameter transport lines.Small stainless steel tubes of 2 mm and 3 mm in inner diameters were chosen as liquid lines and vapor lines of the LHPs.The local thermal resistances in the evaporator of the 6 m-LHP were researched and analyzed,which indicated that the thermal resistance between the aluminum block and the vapor in the vapor channel accounted for a major proportion of the total thermal resistance.The effect of heat sink temperatures on the performance of the 6 m-LHP were compared with 10°C,15°C,20°C and 25°C cooling water temperatures.Moreover,the thermal characteristics of LHPs with transport distances of 2 m and 16 m were also experimentally investigated.The 16 m-LHP could achieve a heat transfer capacity of 100 W and the 2 m-LHP could reach more than 339 W,on the premise of the evaporator temperature below 100°C.The thermal resistance of the 2 m-LHP could achieve 0.125°C/W.

关键词： loop heat pipe thermal management heat transport long distance thermal resistance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Microscale Infrared Observation of Liquid-Vapor Phase Change Process on the Surface of Porous Media for loop heat pipe

引用

Journal of Electronics Cooling and Thermal Control 2016年第2期6卷 33-41页

作者： Kimihide Odagiri Masahito Nishikawara Hosei Nagano Department of Aerospace Engineering Nagoya University Nagoya Japan Department of Mechanical Engineering Toyohashi University of Technology Toyohashi Japan Department of Mechanical Science and Engineering Nagoya University Nagoya Japan

loop heat pipe (LHP) performance strongly depends on the performance of a wick that is porous media inserted in an evaporator. In this paper, the visualization results of thermo-fluid behavior on the surface of the wick with microscopic infrared thermography were reported. In this study, 2 different samples that simulated a part of wick in the evaporator were used. The wicks were made by different two materials: polytetrafluoroethylene (PTFE) and stainless steel (SUS). The pore radii of PTFE wick and SUS wick are 1.2 μm and 22.5 μm. The difference of thermo-fluid behavior that was caused by the difference of material was investigated. These two materials include 4 different properties: pore radius, thermal conductivity, permeability and porosity. In order to investigate the effect of the thermal conductivity on wick’s operating mode, the phase diagram on the q-keff plane was made. Based on the temperature line profiles, two operating modes: mode of heat conduction and mode of convection were observed. The effective thermal conductivity of the porous media has strong effect on the operating modes. In addition, the difference of heat leak through the wick that was caused by the difference of the material was discussed.

关键词： Evaporator Liquid-Vapor Phase Change loop heat pipe Microscale Infrared Observation Porous Media

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：