Experiment of air flow behavior and heat transfer characteristics in microchannels with different aspect ratios
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摘要: 针对不同宽高比微小矩形通道内流动和换热特性进行了实验研究.微小矩形通道宽0.4mm,宽高比分别为2/5、1/2、2/3和1.实验以空气作为工质.流动雷诺数Re范围是200~1600.实验结果表明:宽高比对微小矩形通道流动换热特性的影响不可忽略.微小矩形通道摩擦因子随着Re增大而减小,泊肃叶数Po随着Re增大而增大,二者随着宽高比增大同时减小;努塞尔数Nu随着Re增大而增大,随着宽高比增大而减小.针对宽高比对微小矩形通道流动换热特性的影响拟合了相应经验关系式.Abstract: Experiments were conducted to investigate the flow behavior and heat transfer characteristics in minichannels with different aspect ratios. The widths of microchannels are constant of 0.4mm. The aspect ratiosof the microchannels are 2/5, 1/2, 2/3 and 1, respectively. All tests were performed with air. The experiments were completed with the Reynolds number in the range of 200 to 1600. Results of experiments show that the aspect ratios of microchannels have a remarkable effect on the performance of flow behavior and heat transfer characteristics. The friction factors decrease with the increase of the Reynolds numbers. The Poiseuille numbers increase when the Reynolds numbers keep rising. Both of the friction factors and Poiseuille numbers drop as the aspect ratios increase. Nusselt numbers increase as Reynolds numbers increase, but decrease with the increase of aspect ratios. The corresponding empiric equations for the flow resistance and heat transfer characteristics in microchannels with different aspect ratios are fitted.
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Key words:
- microchannels /
- aspect ratio /
- flow /
- heat transfer /
- empiric equations
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