新型温控热管运行特性及启动过程实验研究

提出了一种新型分离式温控热管并进行了实验研究,该热管能够在保持传热温度变化很小的情况下自动改变传热功率来适应负荷变化的需要。实验结果表明,当温控热管传热功率增加200％时,热管工作温度变化小于5％,温控热管的启动过程较常规热管快;在实验范围内,不凝性气充气压力越高,启动过程越短。     

基于航空散热板的内嵌热管传热模型分析

对一种非规则截面的航空散热板轴向槽道热管,分别建立了基于SINDA软件HEATPIPE算法的一维模型和基于QFLOW算法的二维模型,比较了两种传热模型和算法下热管的暂态和稳态传热特性。结果表明,两种模型对热管平均工作温度的计算结果吻合较好,由于一维模型没有考虑热管壳体的周向传热以及热管的结构对边界条件施加的影响,最大传热能力的计算结果小于二维模型。一维模型适于对航空热管进行系统级的初步热设计,二维模型适于对非规则截面热管的定量传热分析。     

分离式温控热管实验研究

根据热能工程及化工领域中的某些实际需要,提出了一种新型分离式温控热管并进行了实验研究。该种热管能够在保持传热温度变化很小的情况下自动改变传热功率来适应负荷变化的需要。实验结果表明,当温控热管传热功率增加200％时,热管工作温度变化小于5％。     

低温环路热管综述

环路热管是以多孔毛细芯抽吸力为动力的相变传热设备,可根据实际应用改变结构形式,能在远距离传热的同时保持良好的均温性,并且可在微重力环境下运行。环路热管工作温区较广,按照其工作温区一般可分为高温环路热管(350 K以上)、常温环路热管(200～350 K)和低温环路热管(200 K以下)。为了满足深空探测的需要,低温环路热管广泛应用于航天设备温控系统中并表现出优异的性能。按照孔隙特征和结构形式将用于环路热管的毛细芯分为四种,简要阐述每种毛细芯制备和特点;综合分析了近年来低温环路热管技术主要理论和实验研究成果,将目前低温环路热管常见的工作温区分成五个部分,分析影响低温环路热管传热性能的因素,包括工质充装量、反重力高度、次蒸发器功率等。最后,提出优化措施以满足未来深空以及地面应用的需求。     

两相闭式热虹吸管的强化传热实验研究

一、前言 两相闭式热虹吸管作为传热元件的重力热管散热器用于硅元件低温差风冷散热在电力电子设备中开始得到一些应用。随着电力电子设备不断向大功率和小型化方向发展,要求在散热器重量和体积尽可能小的情况下,不断提高散热器的散热功率。采用强化热虹吸管的沸腾和凝结换热的措施,减小蒸发和凝结热阻,对于改善重力热管散热器的性能,提高散热功率有重要意义。     

重力对微槽平板热管传热性能的影响

系统地研究了重力对微槽平板热管传热性能的影响,分析了工作温度、冷却方式和倾角等影响因素。通过对比实验发现重力对热管的轴向液膜分布影响非常明显,在周向只在大充液率时有明显的影响,从而使得倾角较大地影响了热管的传热能力。研究表明深槽平板热管具有优良的传热性能,在微电子器件冷却等微小空间散热方面有着良好的应用前景。     

发动机尾气余热蒸发换热器的设计研究

简要介绍了余热回收理论和热管原理及工作特性,并在此基础上进行了热管传热过程计算、热阻分析、热管设计和选型、材料选择和热管换热器结构计算等,设计了一台尾气余热回收甲醇蒸发器,并根据设计参数进行三维建模。最后对该设计进行校核计算,结果表明,本文设计的发动机尾气余热甲醇蒸发器不仅能满足换热需求,而且具有较小的压力损失,能满足实际需求,对指导生产具有一定意义。     

高效能热管

据美国航空和航天管理局《技术摘要》1986年4月报道,现正研究一种用在极大空间中的散热系统的热管.该热管具有将近2.5×10~6瓦厘米的传热能力,比目前的热管的传热能力数量级要大得多.该新设计热管辐射传热效率很高,并且结构简单、液体和蒸汽流通面积又大.     

工业实用钢-水重力热管的研究

本文对钢水重力热管的传热过程进行了理论分析,建立了实用钢水重力热管最大传热量的理论模型.并在实验室对工业常用的钢水重力热管进行实验研究,确立了计算最大传热量的计算公式,得到了重力热管的最大传热量与管径、倾角、工作温度之间的定量关系,从而可指导重力热管在工程上安全应用.图7     

高温热管太阳能接收器的开发及传热特性分析

分析了碟式太阳能热发电系统接收器的工作特点及所应满足的条件,针对目前高温热管接收器的现状,提出了组合式热管接收器的开发理念,并从接收器总体结构、热管单元结构以及接收器工作原理等方面做了详细阐述。为探讨所开发接收器的传热特性,对热管接收器的传热过程进行了分析计算,结果表明组合式高温热管接收器具有优良的热传递性能,可以适应碟式太阳能热发电系统的运行需求。     

热管型吸附器的性能模拟及优化分析

针对一种热管型吸附器结构形式，对具有翅片的热管型吸附器内传热特性进行了数值模拟，并基于此对热管型吸附器的吸附制冷系统的性能进行了分析，此外讨论了热管的传热极限以及管外传热特性对吸附器的影响。     

Major applications of heat pipe and its advances coupled with sorption system: a review

Heat pipe utilizes continuous phase change process within a small temperature drop to achieve high thermal conductivity. For decades, heat pipes coupled with novel emerging technologies and methods (using nanofluids and self-rewetting fluids) have been highly appreciated, along with which a number of advances have taken place. In addition to some typical applications of thermal control and heat recovery, the heat pipe technology combined with the sorption technology could efficiently improve the heat and mass transfer performance of sorption systems for heating, cooling and cogeneration. However, almost all existing studies on this combination or integration have not concentrated on the principle of the sorption technology with acting as the heat pipe technology for continuous heat transfer. This paper presents an overview of the emerging working fluids, the major applications of heat pipe, and the advances in heat pipe type sorption system. Besides, the ongoing and perspectives of the solid sorption heat pipe are presented, expecting to serve as useful guides for further investigations and new research potentials.     

Characterization of cooling systems based on heat pipe principle to control operation temperature of high-tech electronic components

The use of cooling systems based on heat pipe principle to control operation temperature of electronic components is very efficient. They have an excellent miniaturizing capacity and this fact creates adaptability for more practical situations. Starting from the observation that these cooling systems are not precisely characterized from the thermal efficiency point of view, the present paper proposes a methodology of data acquisition for their thermal characterization. An experimental set-up and a data processing algorithm are shown to describe the cooling of a heat generating electronic device using heat pipes. A Thermalright SI-97 PC cooling system is employed as a case-study to determine the heat transfer characteristics of a fins cooler.     

Analysis on Heat Transfer Characteristics of Constant‐Temperature Heat Pipe in Waste Heat Utilization for Semi‐Coke

In the coal chemical industry, an internal heating retort furnace is applied to the processing of low‐temperature coal pyrolysis so as to produce semi‐coke. Because the cooling water is used to reduce the temperature of semi‐coke from 500 °C to 60 °C, the waste heat carried by the semi‐coke is released. Meanwhile, the waste water of higher temperature involved with the hazardous substances is discharged into rivers or lakes, causing serious environmental pollution. In the present work, a constant temperature heat pipe is used to recover the waste heat. An iterative method is adopted to numerically solve the thermal resistances and the overall heat transfer coefficients. Results show that the conductivity thermal resistance decreases as the tube diameter increases. In the heating section, the main factors affecting the heat transfer are the thermal resistances of both the radiation heat transfer and the convective heat transfer. As the pressure climbs, the thermal resistance of radiation heat transfer increases, while the thermal resistance of convective heat transfer decreases. In addition, the overall heat transfer coefficients increase with the pressure. The heat transfer efficiency of the heat pipe is about 30%, and a higher economic benefit can be obtained.     

不同加热功率下充液率对无芯环路热管性能的影响

设计了以铝为管材、丙酮为传热工质的无芯环路热管。其蒸发段采用加热带加热,冷凝段用风冷降温。热管依靠蒸发压头使工质循环,并依靠重力作用,使冷凝液回流到蒸发段。搭建试验台并研究了不同加热功率下充液率对无芯环路热管的传热温差、传热量、热效率、热阻和当量导热系数的影响。结果表明:加热功率为150.00 W、充液率为30%时,无芯环路热管的均温性最好;传热温差和热阻均最小,分别为6.75℃、0.045 K/W。传热量132.00 W、热效率0.88、当量导热系数168 125 W/(m·K),均达到最大值。所以,该无芯环路热管在本实验研究范围内的最佳工作条件为加热功率150.00 W、充液率30%。     

用于电子元件散热的集成热管换热特性研究

本文对应用于电子元件散热的热管换热器在不同的加热功率、不同风量情况下的传热特性进行了实验研究，从而得出换热量、总热阻、翅片表面阻力系数、换热系数、总热阻与加热功率及风道内空气肫数的关系，并与市场上的SP-94型热管散热器及传统纯铜散热器进行了比较，发现该热管换热器无论是散热量、平均换热系数还是总热阻都有明显的优势。因此，这种散热器在实际工程应用中必将有着广泛的潜力。     

Cooling of spherical products: Part II—heat transfer parameters

This paper presents a study on the determination of the heat transfer parameters, namely surface heat transfer coefficients, thermal conductivities, thermal diffusivities, specific heats and Biot numbers, for the individual product being cooled with water and with air. An analytical model was developed to determine the surface heat transfer coefficients of the products depending on the thermal properties and cooling process parameters. The results of the present study indicate that surface heat transfer coefficients decrease with increasing batch weight in water cooling and increase with increasing air flow velocity in air cooling. The proposed model can be used to determine easily and accurately surface heat transfer coefficients of different spherically shaped objects subjected to cooling.     

Optimization of a wickless heat pipe flat plate solar collector

The transient thermal behaviour of wickless heat pipe flat plate solar collectors has been analyzed with regard to various parameters. These parameters include global solar radiation intensity, inlet cooling water temperature, absorber plate material and thickness, ratio of pitch distance to wickless heat pipe diameter and ratio of condenser section length to total wickless heat pipe length. The results show that the selection of an absorber plate having a high value of conduction heat transfer rate per unit temperature difference is limited by the pitch distance.     

An Experimental Study on the Performance of a Stainless Steel-Water Loop Heat Pipe under Natural Cooling Condition简

Aiming to improve the thermal characteristics of modern electronics, we experimentally study the performance of a stainless steel/water loop heat pipe （LHP） under natural cooling condition. The LHP heat transfer performance, including start-up performance, temperature oscillation and total thermal resistance at different heat loads and with different incline angles have been investigated systematically. Experimental results show that at an optimal heat load （i.e. 60 W） and with the LHP being inclined 60~ to the horizontal plane, the total thermal resistance is lowered to be -0.24 K/W, and the temperature of evaporator could be controlled steadily at around 90~C.     

复合热沉环路热管的热点散热性能模拟研究

针对芯片功耗与集成度提高而导致的局部热点问题,设计了一种用于芯片散热的复合热沉环路热管系统。建立了环路热管蒸发段模型,通过数值模拟的方法,证明了复合热沉环路热管系统能够降低热点温度,提高散热表面的温度均匀程度,且散热效果与热点的分布位置有关。当热点的热流密度为160W/cm2,热沉横向、纵向导热率分别为1500W/(m?K)、24W/(m?K)时,热点温度为88.88°C,相比于无热沉时降低了5.96°C。研究了不同热沉导热率下的热沉厚度对热点温度的影响,结果表明：若导热率各项同性,热点温度随热沉厚度的增加而降低,之后趋向不变;若为各项异性,存在最优的热沉厚度,使热点温度最低。