超流氦系统负压低温板翅式换热器新型波纹-锯齿翅片的性能研究

Study on the Performance of a New-Type Sine-Offset Fin for Negative Pressure Low Temperature Plate-fin Heat Exchanger in Superfluid Helium System

为提高超流氦系统负压低温板翅式换热器的流动及换热性能,结合传统波纹翅片和锯齿翅片提出一种新型波纹-锯齿翅片,并提出将锯齿密度作为一个新的结构参数对新型翅片进行描述。采用数值模拟的方法,分别研究分析了波纹-锯齿翅片通道内流动换热物理场,并与传统翅片进行了对比。结果表明:相较于传统的波纹翅片和锯齿翅片,波纹-锯齿翅片的传热因子j分别提升19.97%~38.22%和25.09%~33.83%,且在低雷诺数时性能提升更加明显;j随波长、锯齿密度的增大而减小,随双波高的增大而增大;摩擦因子f随波长的增大而减小,随双波高的增大而增大,且随锯齿密度的增加呈先增大后减小的变化趋势。新型翅片提高了换热及综合性能,该研究结果可为负压低温板翅式换热器的优化设计提供参考。

In order to improve the flow and heat transfer performance of the negative pressure low temperature plate-fin heat exchanger in superfluid helium system,a new-type sine-offset fin was proposed by combining traditional offset fin and sine-wavy fin,and the offset density was proposed as a new structural parameter to describe the new sine-offset fin.The physical field of flow and heat transfer in sine-offset fin channel,the comparison of flow and heat transfer performance in three kinds of fin channels,and the influence of fin structural parameters on fin performance were studied and analyzed by numerical simulation.The results show that compared with traditional offset fin and sine-wavy fin,the heat-transfer factor j of the sine-offset fin was increased by 19.97%-38.22%and 25.09%-33.83%,respectively,and the improvement of the comprehensive performance is more obvious at lower Reynolds numbers;the j factor decreases with the increase of wavelength and offset density,and increases with the double waveheight.In addition,the friction factor f decreases with the wavelength and increases with the double waveheight,and increases first and then decreases with the increase of offset density.The new sine-offset fin structure can improve the heat transfer and comprehensive performance of plate-fin heat exchanger.This research may provide a reference for the optimal design of plate-fin heat exchanger.