【作者】 陈新；

【导师】 张镜洋；

【作者基本信息】 南京航空航天大学 ， 机械， 2023， 硕士

【摘要】 相比传统腔式黑体结构微小面源黑体体积小、重量轻、智能化程度高,更适合于面阵红外探测器的实时快速定标,是当前精准热探测领域的“焦点”、“核心”技术。宽温域面源黑体多基于正逆热电制冷器进行精密温度控制,热电制冷器及其散热结构对于黑体性能起着决定性作用。本文在面源黑体热结构仿真分析基础上,针对其在大电流、弱换热条件下的散热结构进行优化设计研究,并提出散热端耦合相变蓄热(PCM)的热电制冷器优化结构和脉冲式激励电流加载方式,以改进热电制冷器制冷性能和一类微小面源黑体的低温性能。本文的主要研究内容如下:首先,以热电制冷器为研究对象,建立非对称二级热电制冷器热、电多物理场仿真模型。为了保证计算准确性,对热电制冷器网格模型进行网格无关性验证以及模型准确性验证,为面源黑体热设计以及热电制冷器优化提供模型基础。其次,设计一款以热电制冷器进行控温的微小面源黑体,数值研究了该微型面源黑体在不同电流、散热风速、散热翅片结构等条件下的靶面制冷最低温度以及温度均匀性,结果表明,在大激励电流条件下,靶面制冷温度随电流的增大会出现温度逆上升现象,这主要受散热端弱散热条件影响而导致的。因此,对热电制冷器散热方式和激励电流加载方式等进行优化,对于提升热电制冷器制冷效果和拓展黑体可控温度范围十分必要。随后,提出了散热端耦合PCM的热电制冷器优化结构,通过数值仿真验证了该结构对于强化热电制冷器热端散热和制冷性能的有效性,并数值优化了PCM材料及结构参数。研究结果表明:激励电流为3.5A时,与无PCM情况相对比散热段耦合PCM可使制冷温度下降约20K,功耗降低约10W,COP提升约3%,这表明了该结构对于改善弱散热条件下热电制冷器性能的有效性。在本文研究参数范围内,当PCM材料为伍德合金、PCM块厚度与一级热电粒子长度比为0.5时,热电制冷器制冷性能较优。最后,拟通过脉冲激励电流加载方式改善热电制冷器制冷性能。通过数值仿真研究不同波形、脉宽、幅值的激励电流对散热端耦合PCM的热电制冷器制冷性能的影响。仿真结果表明,使用方波、三角波、斜上升波、斜下降波时,使用方波的热电制冷器获得最大为6.13K的过冷温降以及最小为4.27K的过热温升;脉宽约为5s～6s时,脉冲幅值约为基础电流的3倍时,可以获得最大的过冷温降以及最小的过热温升。本文研究成果为面源黑体及热电制冷器设计提供技术参考。更多还原

【Abstract】 Compared with the traditional cavity blackbody structure,the micro surface source blackbody has the advantages of small size,light weight and high intelligence.It is more suitable for the realtime and rapid calibration of the area array infrared detector.It is the ’ focus ’ and ’ core ’ technology in the field of precision thermal detection.The wide temperature range surface source blackbody is mostly based on the forward and reverse thermoelectric cooler for precise temperature control.The thermoelectric cooler and its heat dissipation structure play a decisive role in the performance of the blackbody.In this paper,based on the simulation analysis of the thermal structure of the surface source blackbody,the optimization design of the heat dissipation structure under the condition of large current and weak heat transfer is studied,and the optimized structure of the thermoelectric cooler with phase change heat storage(PCM)coupled at the heat dissipation end and the pulse excitation current loading method are proposed to improve the refrigeration performance of the thermoelectric cooler and the low temperature performance of a class of small surface source blackbody.The main research contents of this paper are as follows :Firstly,taking the thermoelectric cooler as the research object,the thermal and electrical multiphysical field simulation model of the asymmetric two-stage thermoelectric cooler is established.In order to ensure the accuracy of the calculation,the grid independence verification and model accuracy verification of the thermoelectric cooler grid model are carried out to provide a model basis for the surface source blackbody thermal design and thermoelectric cooler optimization.Secondly,a small surface source blackbody with thermoelectric cooler for temperature control is designed.The minimum temperature and temperature uniformity of the target surface refrigeration of the micro surface source blackbody under different current,cooling wind speed,heat dissipation fin structure and other conditions are numerically studied.The results show that under the condition of large excitation current,the target surface refrigeration temperature will rise inversely with the increase of current,which is mainly affected by the weak heat dissipation condition of the heat dissipation end.Therefore,it is necessary to optimize the heat dissipation mode and excitation current loading mode of thermoelectric cooler to improve the cooling effect of thermoelectric cooler and expand the controllable temperature range of blackbody.Subsequently,an optimized structure of thermoelectric cooler with heat sink coupled with PCM is proposed.The effectiveness of the structure on enhancing the heat dissipation and cooling performance of the hot end of the thermoelectric cooler is verified by numerical simulation,and the PCM material and structural parameters are numerically optimized.The results show that when the excitation current is 3.5A,the cooling section coupled with PCM can reduce the cooling temperature by about 20 K,reduce the power consumption by about 10 W,and increase the COP by about 3 %compared with the case without PCM,which indicates that the structure is effective for improving the performance of thermoelectric cooler under weak heat dissipation conditions.In the range of parameters studied in this paper,when the PCM material is Wood alloy and the ratio of PCM block thickness to the length of the first-order thermoelectric particle is 0.5,the thermoelectric cooler has better cooling performance.Finally,it is proposed to improve the cooling performance of thermoelectric cooler by pulse excitation current loading.The influence of excitation current with different waveform,pulse width and amplitude on the cooling performance of thermoelectric cooler coupled with PCM at the heat dissipation end is studied by numerical simulation.The simulation results show that when using square wave,triangular wave,oblique rising wave and oblique falling wave,the thermoelectric cooler using square wave obtains the maximum supercooling temperature drop of 6.13 K and the minimum overheating temperature rise of 4.27 K.When the pulse width is about 5s ～ 6s and the pulse amplitude is about 3 times of the basic current,the maximum supercooling temperature drop and the minimum overheating temperature rise can be obtained.The research results of this paper provide data support for future surface source blackbody.更多还原