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地源热泵地下换热系统的实验研究 总被引:1,自引:0,他引:1
地源热泵地下换热系统对于地源热泵系统的稳定运行和地源热泵系统的投入成本起着关键的作用.为了对地下换热系统换热效果和周围土壤的温度场进行实验研究,我们在北京工业大学高科技能源楼建立了一套包含60套不同结构地下换热系统的实验台.利用温度及流量测试装置获得运行过程中温度变化并计算换热量,探求不同结构地下换热系统的换热情况.本实验台还可以收集系统运行过程中地下换热系统的传热温度扩散半径,实验系统不仅为地源热泵的设计提供了数据,而且为地源热泵的深入研究提供了平台.本文给出的部分实验结果证明,根据当地地质情况、负荷需求及系统运行模式配置能源井是至关重要的. 相似文献
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《Revue Generale de Thermique》1998,37(5):323-352
In the frame of the BRITE-EURAM european programme (KHIEPCOOL project), a literature survey on the main heat pipe and micro heat pipe technologies developed for thermal control of electronic equipment has been carried out. The conventional heat pipes are cylindrical, flat or bellow tubes, using wicks or axial grooves as capillary structures. In the field of micro heat pipes, three and four corner tubes have been developed. The pipes are mounted on single chips, in-line chip arrays or integrated into the component interconnection substrate. The best performances were achieved with Plesch's axially grooved flat miniature heat pipe [1], which is able to transfer a heat flux of about 60 W·cm−2. Theoretical models have shown that the performance of micro heat pipe arrays increase with increasing tube diameter, decreasing tube length and increasing heat pipe density. The heat pipe technologies are classified and compared according to their geometry and location in the system. A list of about 150 references, classified according to their subjects, is presented. 相似文献
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CPU温度的持续增高导致了能量分布不均匀,所以高热流密度热控制或大型服务器的冷却处理方式成为研究的热点。文中研究了翅片中带有热管的散热器,对其温度分布进行了数值模拟和实验研究分析,并与物理模型相同散热较好的平板型热管散热器进行了比较。结果表明:翅片中带有热管的散热器不仅可以提高散热器的传热温差,加强了散热底板的均温效果,而且使得翅片散热得到强化,更有效地降低了CPU的中心温度。 相似文献
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研发了一系列将发光二极管(LED)散热与热管传热相结合的用于大功率LED冷却的热管散热器,并对其传热性能进行了实验研究。结果表明,该系列热管散热器具有良好的散热能力,能将节点温度控制在70℃以下,满足了大功率LED对结点温度的控制要求;实验结果还表明,翅片结构不同,换热器散热能力明显不同,所研发系列异形翅片热管换热器的散热能力明显高于目前常用的普通矩形翅片热管换热器,其中以外翻形翅片热管换热器散热能力最好;还研究了热管换热器工作倾角对其散热能力的影响,并给出了热管排布数量、翅片材质及结构对换热器散热性能、换热装置体积、成本及质量的影响。 相似文献
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针对高超声速飞行器前缘疏导式防热结构的特点,设计前缘内嵌高导热率材料结构和一体化层板热管结构两类对比实验,用于验证前缘疏导式防热结构的可行性.利用球形短弧氙灯作为辐射热源模拟气动加热,分别对钢质前缘、内嵌铜材料的钢质前缘和一体化层板式热管前缘进行加热,测量前缘驻点区域和尾部翼面区域的温度变化.实验结果表明:内嵌高导热率材料的前缘疏导结构能够降低头部驻点区的温度,提高尾部低温区的温度,实现对前缘结构的热防护;以蒸馏水作为工质一体化层板式热管前缘结构,在较低热流条件下也能够实现对前缘驻点区的疏导式热防护,但在较高热流条件下,由于水蒸气压力过大使得层板式前缘结构发生破坏,体现出热管内部工作介质对结构防热效果和应用范围都起到的关键作用. 相似文献
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为了对某型号相机进行热平衡试验,在真空环境下进行太阳模拟灯热仿真分析,根据热平衡试验需要,提出了技术要求,对关键结构的刚性和应力分布进行了有限元分析,并根据有限元分析结果对设计进行优化,满足了关键结构件的刚性要求,主要技术难题是灯极导热问题,为了这一难题,采用了主动控制技术,专门设计了导热机构,充分利用了热管的高导热率,建立了科学合理的有限元热模型进行热分析,通过仿真设计,采用热管导热技术完成了太阳模拟灯结构的热设计,解决了太阳模拟灯使用时的导热问题。 相似文献
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《中国科学:物理学 力学 天文学(英文版)》2021,(11)
The thermal issue is of great importance during the layout design of heat source components in systems engineering, especially for high functional-density products. Thermal analysis requires complex simulation, which leads to an unaffordable computational burden to layout optimization as it iteratively evaluates different schemes. Surrogate modeling is an effective method for alleviating computation complexity. However, the temperature field prediction(TFP) with complex heat source layout(HSL) input is an ultra-high dimensional nonlinear regression problem, which brings great difficulty to traditional regression models. The deep neural network(DNN) regression method is a feasible way for its good approximation performance. However, it faces great challenges in data preparation for sample diversity and uniformity in the layout space with physical constraints and proper DNN model selection and training for good generality, which necessitates the efforts of layout designers and DNN experts. To advance this cross-domain research, this paper proposes a DNN-based HSL-TFP surrogate modeling task benchmark. With consideration for engineering applicability, sample generation, dataset evaluation, DNN model, and surrogate performance metrics are thoroughly investigated. Experiments are conducted with ten representative state-of-the-art DNN models. A detailed discussion on baseline results is provided, and future prospects are analyzed for DNN-based HSL-TFP tasks. 相似文献
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《Heat Recovery Systems and CHP》1988,8(3):235-246
This paper summarizes the results of an investigation involving the use of ceramic heat pipe recuperators for high-temperature heat recovery from industrial furnaces. The function of the recuperator is to preheat combustion air with furnace exhaust gas. To maximize fuel savings, a very high air preheat temperature is desirable; this necessitates the use of ceramic elements in the recuperator.The heat pipe recuperator comprises a bundle of individual ceramic heat pipes acting in concert, with a partition separating the air and exhaust gas flow streams. The heat pipe fluid is a liquid metal. The ceramic heat pipe recuperator concept offers several advantages as compared to tubular type ceramic recuperators. Because each heat pipe is essentially an independent heat exchanger, the failure of a single tube does not compromise recuperator integrity and has only a minimal effect on overall heat exchanger performance. This independent element characteristic also enables easier replacement of individual heat pipes in the recuperator. In addition, the heat pipe acts as an essentially isothermal heat transfer device, leading to a high thermodynamic efficiency.Cost estimates developed for heat pipe recuperator systems indicate favorable payback periods. Laboratory studies have demonstrated the feasibility of fabricating the required ceramic tubes, coating the inside of the tubes with CVD tungsten (which functions as both a protective layer and a heat pipe fluid wick), and sealing the heat pipe with an electron-beam-welded or vacuum-brazed end cap. 相似文献
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《Heat Recovery Systems and CHP》1989,9(6):499-512
A review is given of heat pipe research and development in China. It includes data presented at the 2nd National Heat Pipe Conference in 1988, and covers basic research, heat pipe performance and applications. The applications range from heat exchangers (gas-gas and waste heat boilers), to electric motor cooling, spacecraft and solar collectors. 相似文献
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微热管以其效率高、响应快且无能耗,在高功率集成微电子散热方面应用广泛。针对电子器件的小型化、高能耗发展趋势,本文提出一种新型沟槽道微热管结构,对该沟槽道微热管进行稳态和瞬态热性能实验研究,研究了风速、角度、加热功率等因素对该新型热管的热性能影响规律。结果表明,该微热管在整个散热器传热上起主导作用,性能比达到0.88,冷凝端温差为0.8℃,具有良好的均温性,该微热管加热功率为140 W,空气流速1.5 m/s时,换热系数可达2 359 W/(m^2·℃),热阻为0.27℃/W;高功率状态下可保持良好的热扩散性能,有效避免微热管的热应力集中,有望高效解决集成电子器件的散热问题。 相似文献
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通过光-机-热集成分析,用简单可靠的热控方法,对空间太阳望远镜直径为1m的主镜进行了热设计:采用周边绝热、将热量从正面传导到背面,再设计装有控温回路和热管的集热板,以及与卫星平台辐射器冷板连接散热,保证了主镜的温度水平和稳定性;在主镜压紧结构前设置挡光板,减少压紧结构引起的主镜温度不均匀.结果表明,利用智能型高准确度控温仪和加热回路的优化设计实现主构架均匀性热设计,采用高传热性能热管排散准直镜热反射面极高热流密度,可以消除主镜周围热环境对主镜温度影响的结论. 相似文献
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ZHONG Yingjie DENG Kai ZHANG Guojun LIN Haihao LI Hua 《声学学报:英文版》2008,27(3):238-249
Based on the results of fluid dynamics, heat transfer and acoustics, a Computational Fluid Dynamics (CFD) method was utilized to study the acoustic characteristics and self-excited pulsation mechanism inside a Rijke pipe. To avoid settling the irrational boundary conditions of the finite-amplitude standing wave in the Rijke thermo-acoustic system, the simulation modeling in the flow field, which coupled the inner of pipe with its outer space, was carried out to replace the traditional way in form of internal flow field numerical investigations. A hypothesis for heat source in energy equation including the relationship on unsteady heat of air around heat source, oscillation pressure and oscillation velocity was presented. To reflect the essence of Rijke pipe, simulation on self-excited oscillation was conducted by means of its own pulsation of pressure, velocity and temperature. This method can make the convergence process steady and effectively avoid divergence. The physical phenomenon of the self-excited Rijke pipe was analyzed. Moreover, the mechanisms on the Rijke pipe's self-excited oscillation were explained. Based on this method, comparative researches on the acoustic characteristic of the Rijke pipe with different size and different shape of nozzle were performed. The simulation results agreed with the experimental data satisfactorily. The results show that this numerical simulation can be used to study the sound pressure of nozzle for the engineering application of Rijke pipes. 相似文献
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The sorption heat pipe (SHP) is a new heat transfer device, which can be used as a sorption cooler or as a heat pipe. The SHP has a sorbent bed (adsorber/desorber and evaporator) at one end and a condenser+evaporator at the other end. This device is insensitive to some “g” acceleration and could be suggested for space and ground application. The most crucial feature of this device is that in different cases it can be used, for example, as a loop heat pipe, because they have the same evaporator and condenser, or as a SHP. The SHP can be used also as a cryogenic cooler. The SHP is convenient for cryogenic fluid storage, when the system does not work at low pressure and room temperature, and for use in the active cryogenic thermal control systems of spacecraft in orbit (cold plates for infrared observation of the Earth or space), or as an efficient electronic component cooling device. 相似文献
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热管技术已在电子设备散热领域得到广泛应用。热管的传热能力虽然很大,但不能无限加大热负荷。文中讨论了热管的主要极限如沸腾极限、毛细极限、粘性极限、声速极限、携带极限等的理论表达式,就一种实验用微槽平板热管进行了理论计算,得出了毛细极限是实验热管主要传热极限的结论。 相似文献
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Maziar Mohammadi Mehdi Taslimifar Mohammad Behshad Shafii Hossein Afshin Siamak Kazemzadeh Hannani 《实验传热》2013,26(3):296-312
Thermal management of electronic devices is presently a serious concern. This article investigates the thermal performance of a five-turn open-loop pulsating heat pipe in both start-up and steady thermal conditions. The effects of working fluid, namely water and ferrofluid, heat input, charging ratio, ferrofluid concentration, orientation, as well as application of magnetic field, are explored. Experimental results show that using ferrofluid enhances the thermal performance in comparison with the case of distilled water under certain conditions. In addition, applying a magnetic field on the open-loop pulsating heat pipe charged with ferrofluid improves its thermal performance. Charging ratios that lead to lower thermal are mentioned. Optimum concentration of ferrofluid in steady-state performance is 2.5 g/L. This study helps to design electronic cooling devices more efficiently. 相似文献