板状相变蓄冷单元快速释冷特性实验研究
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摘要
间歇工作高通量发热设备的紧凑高效冷却系统中需用到快速相变蓄冷单元。以膨胀石墨基定型相变材料为主要原料制备了板状相变蓄冷单元,在自建实验台上通过改变取冷流体的进口温度和流量对其快速释冷特性进行实验研究。结果表明:在释冷过程中,瞬时释冷强度q持续减小,先快后慢;累积释冷量Q持续增大,亦先快后慢;综合传热系数K则先快速减小,继而平缓波动;取冷流体流量仅对K有明显影响,进口温度对K、q和Q均有明显影响。在8种实验工况下,潜热释冷阶段K的平均值在279～402W/(m~2·K)范围内,10min内q的平均值为2.67～3.82kW,Q可达2 300kJ以上,基本满足特定情况下的使用要求。下一步应优化板状快速相变蓄放冷单元表面的传热纹理结构,进一步改善释冷特性。
Rapid phase change cold-storage units are needed in compact and efficient cooling systems of the high-throughput heating equipment for intermittent work.Plate-shaped phase change cold-storage units are prepared with the expanded graphite stable phase change materials as the main component.Their quick cold-release characteristics are studied by changing the inlet temperature and flow rate of cooling fluid on homemade experimental platform.Results show:①during the cold-release process,the instantaneous cold release intensity(q)continuously decreases,rapidly first and then slowly with time,and the accumulative cooling capacity(Q)continuously increases rapidly first and then slowly,while the comprehensive heat transfer coefficient(K)at first falls quickly followed by gentle undulation;②the inlet flow of fluid only affects K,while the inlet temperature of fluid obviously influences all of the above parameters;③ under the eight experimental conditions,the mean K falls within the range of 279～402 W/(m~2·K)during the latent heat release stage,the mean q within the range of 2.67～3.82 kW during the first 10 minutes,Qrespectively attains above 2 300 kJ.In general,the plate-shaped phase change cold-storage units basically meet the use requirement under certain circumstances.To further improve the cold-release characteristics,the surface heat transfer texture of plate-shaped phase change coldstorage units needs to be designed and optimized.
Rapid phase change cold-storage units are needed in compact and efficient cooling systems of the high-throughput heating equipment for intermittent work.Plate-shaped phase change cold-storage units are prepared with the expanded graphite stable phase change materials as the main component.Their quick cold-release characteristics are studied by changing the inlet temperature and flow rate of cooling fluid on homemade experimental platform.Results show:①during the cold-release process,the instantaneous cold release intensity(q)continuously decreases,rapidly first and then slowly with time,and the accumulative cooling capacity(Q)continuously increases rapidly first and then slowly,while the comprehensive heat transfer coefficient(K)at first falls quickly followed by gentle undulation;②the inlet flow of fluid only affects K,while the inlet temperature of fluid obviously influences all of the above parameters;③ under the eight experimental conditions,the mean K falls within the range of 279～402 W/(m~2·K)during the latent heat release stage,the mean q within the range of 2.67～3.82 kW during the first 10 minutes,Qrespectively attains above 2 300 kJ.In general,the plate-shaped phase change cold-storage units basically meet the use requirement under certain circumstances.To further improve the cold-release characteristics,the surface heat transfer texture of plate-shaped phase change coldstorage units needs to be designed and optimized.
引文
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[2]韩宗伟,王一茹,阿不来提,等.太阳能热泵相变蓄热供暖系统参数影响研究[J].太阳能学报,2015,36(8):2028-2035.
[3]杨波,李汛,赵军.移动蓄热技术的研究进展[J].热能动力工程,2013,32(3):515-520.
[4]张焱.蓄热式相变换热器的设计与数值模拟优化[D].西安:西安建筑科技大学,2016.
[5]王爱华,梁新刚,任建勋.短时大功率系统控温波动分析[J].航天器工程,2004,13(2):20-25.
[6]Phelan P E,Gupta Y.Energy efficiency of refrigeration systems for high-heat-flux microelectr-onics[J].Journal of Thermal Science and Engineering Applications,2010(2):1-4.
[7]曾秒,郭朝红,袁俊飞,等.用于大功率电器冷却的板翅式相变换热器模拟设计[A].中国工程热物理学会传热传质学[C],东莞,2012.
[8]袁俊飞,唐大伟,曾秒,等.盘管式冰蓄冷器释冷过程实验研究[J].环境工程,2014,32(s1):1048-1050.
[9]Phelan P E,Gupta Y.Energy efficiency of refrigeration systems for high-heat-flux microelectr-onics[J].Journal of Thermal Science and Engineering Applications,2010(2):1-4.
[10]晏华,李云涛,汪宏涛,等.膨胀石墨基复合相变材料的热稳定性研究[J].化工新型材料,2017,45(2):46-48.
[11]李琳,李东旭,刘洋,等.月桂酸-肉豆蔻酸/膨胀石墨封装复合相变储能材料的制备及表征[J].太阳能学报,2016,36(10):2627-2631.
[12]华建社,张娇,张焱,等.膨胀石墨/石蜡复合相变蓄热材料的热性能及定形性研究[J].材料导报,2016,30(12):61-64.
[13]夏莉,张鹏,周圆,等.石蜡与石蜡/膨胀石墨基复合材料充放热性能研究[J].太阳能学报,2010,31(5):610-614.
[14]仵斯,李廷贤,闫霆,等.高性能定形复合相变储能材料的制备及热性能[J].化工学报,2015,66(12):5127-5134.