Heat dissipation in high-power semiconductor lasers with heat pipe cooling system

This study focuses on the application of heat pipes in thermal management for high-power semiconductor lasers. The heat pipe cooling systems are used for heat dissipation in high-power semiconductor lasers. These systems are used instead of water cooling machines to realize a compact and lightweight laser module. The n-shaped heat pipe cooling system, which consists of eight 6 mm copper heat pipes with sintered powder wicks, can easily handle a heat load of up to 73 W from a single-laser unit. The fabricated U-shaped heat pipe cooling system, which consists of ten 12 mm copper heat pipes with sintered powder wicks, can easily handle a heat load of up to 300 W from five laser units. The optical power of the multi-laser module cooled by the U-shaped heat pipe cooling system reaches 210 W. These results indicate that high-power semiconductor lasers can be cooled using heat pipe cooling systems instead of water cooling machines.     

数据中心用热管空调系统研究进展

针对回路热管机房空调在数据中心冷却中的适用性问题,总结了数据中心用回路热管空调系统最新研究进展,对比分析了重力型、气相动力型和液相动力型3种回路热管机房空调系统,并介绍了3种回路热管自然冷却与蒸气压缩主动制冷相结合的一体式机房空调系统的构成方式与运行性能,结果表明3种回路热管在不同的应用场景下都具有良好的节能效果:从驱...     

强制冷却下闭式回路脉动热管启动性能的试验研究

针对闭式脉动热管搭建试验平台,用紫铜管做试件,管内径2.7mm,全长1384mm,6弯头,丙酮为工质,采用底部电加热、上部分别采用强制对流冷却和自然对流冷却,分析了强制对流下脉动热管的启动特征及性能,对比了不同冷却方式对脉动热管启动性能的影响。结果表明,脉动热管在强制冷却下存在两种启动方式:低功率下呈现间歇性温度突变型启动特征;高功率下呈现光滑缓慢连续启动特征并可以稳定运行。强制对流冷却方式不仅能够改善脉动热管传热,更有助于脉动热管的稳定运行。     

微电子芯片高热流密度相变冷却技术

介绍了微电子芯片高热流密度相变冷却技术,包括热管、热虹吸、环路热管、毛细泵吸环路,分析了各自的优缺点,提出LHP和CPL技术是唯一能替代热管技术的先进相变冷却技术,将是今后微电子芯片高热流密度冷却的主要方向.     

Increase in production efficiency due to the use of modernized rubber-processing rollers

The results of the calculation of cooling rubber-processing rollers executed in the form of heat pipes, are presented. The novelty is confirmed by a patent for the installation. The necessary amount of a filling heat carrier, consumption of a cooling medium, and its temperature are determined for the specified heat flux density from processed rubber and a temperature on a working roller surface.     

Increasing the safety and efficiency of metal cooling in the process of fabricating a hollow mold

The results of heat exchange during the cooling of aluminum in a mold with a central core in the form of a heat pipe are presented and compared with the heat exchange data obtained in the case of an uncooled core. The novelty of the results is confirmed by patents. Heat pipes used for metal cooling make it possible to improve the ecological situation, to prolong the service life of the core and molds, and to increase reliability of the structures. The obtained results can be used when designing heat-pipe-based systems for metal cooling and crystallizers of machines.     

Cooling of extraction electrode of an ion source in long-pulse operation

Experimental studies were made on the cooling of extraction electrodes of an ion source in the case of long-pulse operation. Copper electrodes with forced water cooling pipes were tested under the condition that an ion beam of 1 to 5 A at 30 keV was extracted for up to 10 s. The average heat loading to the grid are of the electrode was as high as 130 W/cm2. This high heat flux was obtained by a set of electrodes artificially arranged to produce poor beam optics, and hence the high heat loading. Temperature of the ground electrode was measured at two points by thermocouples buried and silver brazed in it, and was kept below 230 degrees C due to a large boiling heat transfer coefficient of the cooling water. No evidences of deformation or deterioration of the electrodes was observed after repetitious beam extraction. This heat loading was still a half of that on the grid of the ion source for the JT-60 NBI.     

Performance comparison of microchannel evaporators with refrigerant R-22

An experimental study on the performance comparison of microchannel evaporators with refrigerant R-22 was conducted. Six microchannel evaporators were designed and manufactured for a residential air-conditioner. They were tested with psychrometric calorimeter test facilities. The experiment was performed with both vapor compression system and refrigerant circulation system. Each evaporator was made up of two parallel flow heat exchangers connected with several return pipes. The parallel flow heat exchanger had 41 microchannel tubes inserted between inlet and outlet headers. The microchannel tube had 8 rectangular ports with the hydraulic diameter of 1.3 mm. For the vapor compression system, the flow area ratio and the number of return pipes had a great effect on the cooling capacity. Type 3 with a flow area ratio of 73% and 58% showed the best cooling capacity. It had 12 return pipes and 3 circuits. There is a merging manifold in it. The effect of the number of circuits and merging manifold on the cooling capacity was relatively small. For the refrigerant circulation system, the effect of the mass flow rate on the cooling capacity was slightly superior to that of inlet quality. The effect of the number of circuits on the cooling capacity was different from the result of the vapor compression system. The effect of merging manifold was negligible, which was consistent with the result of the vapor compression system. The cooling capacity proportionally increased as the vertical inclination angle of the evaporator increased due to gravity force.     

带有强化冷凝段的热管散热器三维温度场数值模拟分析

为了解决高热流密度器件的散热问题而设计一种带有强化冷凝段的热管散热器,模拟不同的运行工况,对其散热效果进行了数值计算,并与其他类型的热管散热器进行了比较。结果表明:新型散热器由于热管设计结构的改变,使其换热温差增大,而且使散热器底板的均温效果更好,可以有效地降低高热流密度器件的工作温度。     

热管换热器用于LED冷却系统的试验研究

研发了一种将大功率发光二极管(LED)散热和热管传热相结合的用于大功率LED冷却的热管散热器,并对设计出的热管散热器的传热性能进行了试验研究。结果表明,该热管散热器具有良好的散热能力,在输入功率为50W的情况下能控制节点温度在70℃以下,而且热管换热器的散热能力和工作倾角有密切关系,倾角越小,散热能力越好,垂直使用时散热能力最差,最后从理论上加以分析。     

船舶中央空调系统换热器效果差的原因分析

随着制冷设备的发展,循环冷却设备的应用日趋广泛,船舶冷却循环系统中的水在循环时不可避免地会产生结垢、菌藻滋生和腐蚀这3大危害,从而造成传热效率下降及换热设备寿命缩短等问题,严重时会造成设备腐蚀穿孔、管道堵塞和被迫停机等后果。忽视换热效果是制冷循环系统管理中普遍存在的突出问题。     

电子设备热设计工作点评

本文就电子设备热设计工作中涉及的,如散热器、风机、冷板、热管、温差电器件以及密闭机箱的温度控制等一些工程应用问题,进行了评述,以期引起业内人士的关注。     

Cooling a slab continuous-casting mold

The results of calculation of cooling the walls of a slab continuous-casting mold, effected by way of heat pipes, for steel casting are presented. The novelty is confirmed by a patent for a method of cooling the mold during casting a high-temperature metal and by a device for its implementation. At a given heat-flux density in the wide wall from the steel casting, the temperatures of the operating surface of the mold wall, coolant vapor flow rate and its temperature, and the cooling medium flow rate are determined.     

余热驱动多功能热管型吸附制冰机组的性能

介绍一种以氯化钙/活性炭复合吸附剂和氨作为吸附工质对的多功能热管型吸附式制冰机组,该机组利用低品位余热作为驱动热源进行制冰。为了强化机组换热及防止余热腐蚀现象,采用热管技术完成吸附床的加热解吸、冷却吸附及回热过程,吸附床加热解吸时,形成以余热发生装置为热管蒸发段、以吸附床为热管冷凝段的热管型加热回路;两吸附床间回热时形成以高温解吸床为热管蒸发段、以低温吸附床为热管冷凝段的热管型回热回路;吸附床冷却吸附时,形成以吸附床为热管蒸发段、以冷却器为热管冷凝段的热管型冷却回路。在此基础上采用新回质回热循环方式对机组性能进行了研究。试验结果表明：新回质回热方式与传统回质回热方式相比,可大幅度增加机组制冷量,单位质量吸附剂制冷功率,(Specific cooling power,SCP)和性能系数(Coefficient of performance,COP)增大幅度均在17 %以上;相对基本循环,传统回质回热方式可使机组COP提高43.8 %,新回质回热方式可使机组COP提高幅度高达68.7 %。可见采用新回质回热方式更有利于提高吸附制冰机组的工作性能。     

Trends in Using Passive Thermal Imaging Diagnostics in Power Engineering and Industry

The regions of application of thermal imaging technique for testing the heat shielding of building structures, diagnostics of smoke pipes, boilers, cooling ponds, and thermal service lines are described.     

A cooling system using wickless heat pipes for multichip modules: Experiment and analysis

The present study is concerned with a cooling package system for electronic components such as multichip modules (MCM) which are used in many electronic system. The im of the cooling capacity up to heat flux of 4 W/cm² was achieved. A heat flux of 4 W/cm² is about two to three times of the value generally accepted as the limit by forced air cooling together with heat pipes (Kishimoto et al., 1994). The data obtained from the experimental program was used to manifest the deficiency and inaccuracies of multitude of the empirical correlations for various heat transfer modes involved in the computer simulation of the proposed system. The dominant role of the temperature distributions in the system and the related two-phase flow heat transfer have been quantitatively identified and the limit of the computer simulation for such system as proposed in the present study has been advanced.     

某相控阵雷达天线阵面的热设计与验证

为了解决某高热流密度相控阵雷达天线阵面的散热问题,文中采用强迫通风冷却的散热方式,在天线阵面热设计中使用了高效换热的风–风换热器和高导热热管,满足了天线阵面组件壳体温度要求。同时,在设计天线阵面流场时,采用了内外风道隔离、内循环风道风机并联的送风方式,满足了天线阵面组件壳体的均温性要求。最后通过数值仿真和搭建平台测试两种方法,验证了该热设计方案的可行性。     

某机载毫米波雷达天线仿真热设计

针对某型机载毫米波雷达天线热设计难题,提出了热管结合强迫风冷的新型冷却方式,设计了专用风道。应用数值模拟方法首先对T/R组件进行了热仿真计算,其次对天线背部风机抽风、吹风进行了仿真比较,再对散热翅片和风量分配进行了仿真优化,最后对3 km高空状态进行了仿真计算。计算结果表明,天线背部风机吹风明显好于抽风;翅片厚度0.8 mm,翅片数134,占空比23.8%的翅片结构散热较好;限流板阻力系数为5时风量分配较均匀;高空环境下满足天线工作要求。该方式合理可行,满足系统热设计要求,为同类产品的热设计提供了重要参考。     

Heat pipes with variable thermal conductance property for space applications

The activities presented in this paper demonstrate a new approach to provide passive thermal control using heat pipes, as demonstrated on the electronic unit of DLR’s MASCOT lander, which embarked on the NEA sample return mission Hayabusa 2 (JAXA). The focus is on the development and testing of heat pipes with variable thermal conductance in a predetermined temperature range. These heat pipes act as thermal switches. Unlike standard gasloaded heat pipes and thermal-diode heat pipes construction of presented heat pipes does not include any additional elements. Copper heat pipes with metal fibrous wicks were chosen as baseline design. We obtained positive results by choosing the heat carrier and structural parameters of the wick (i.e., pore diameter, porosity, and permeability). The increase in the thermal conductivity of the heat pipes from 0.04 W/K to 2.1 W/K was observed in the temperature range between ?20 °C and +55 °C. Moreover, the heat pipes transferred the predetermined power of not less than 10 W within the same temperature range. The heat pipes have been in flight since December 2014, and the supporting telemetry data were obtained in September 2015. The data showed the nominal operation of the thermal control system.     

Modeling a Heat Source/Heat Sink for Tribological Applications©

The surface temperature of contact elements is one of the most important factors that influences the performance and life of tribological systems. Heat-pipe cooling seems to be a promising means for enhanced heat transfer. The heat input at the surface and the heat pipe as a heat sink represent a system of heat source/heat sink (HSHS). In this paper, the function of the heat pipe is mathematically described and the heat-transfer characteristics of the HSHS system are investigated. A semi-empirical model is developed to shed some light on the surface flash temperature control employing the HSHS system. Both steady-state and transient analyses show that heat pipes can be employed to reduce the flash temperature effectively. The possibility of applying this concept to composite materials is also analyzed.