纵向涡发生器几何参数对微通道流动传热特性的影响研究

为增强微通道的流动和换热特性,对微通道结合纵向涡发生器进行了数值模拟,分析不同雷诺数下纵向涡发生器的长度、横向间隙对微通道流动与换热性能指标的影响。结果表明:在进口速度为0.5～2 m/s时,雷诺数的增加会引起微通道内的换热性能增强,摩擦因子减小及综合传热性减小;涡发生器长度对换热影响较小,但增加涡发生器长度会引起阻力增加,横向间距对阻力影响较小,但增加横向间距会引起换热性能提高;涡发生器长度为0.30～0.40 mm时综合因子为0.94～1.21,横向间隙为0.1～0.5 mm时综合因子为0.88～1.17;纵向涡发生器长度为0.3 mm和横向间隙为0.5 mm时,有利于综合传热性能的提高。在低雷诺数时微通道结合纵向涡发生器的强化传热和综合传热因子要比高雷诺数时好。

Study on the Influence of Geometric Parameters of Longitudinal Vortex Generators on the Flow and Heat Transfer Characteristics of Microchannel

In order to enhance the flow and heat transfer characteristics of microchannels,the numerical investigation of the microchannels combined with LVGs (longitudinal vortex generators,LVGs) has been carried out.The influence of the parameters of the LVGs including the length and transverse space of the LVGs has been discussed under the different Reynolds number.The results show that for the inlet velocity ranging from 0.5 m/s to 2 m/s,the increase of Reynolds number increases the heat transfer of the microchannel and decreases the friction factor and overall factor.The influence of the length of the LVGs on the heat transfer enhancement of the microchannel is unapparent.The flow resistance characteristic of the microchannel increases with the length of the LVGs while the influence of the transverse space of the LVGs is unapparent.The heat transfer characteristic of the microchannel increases with the increase of the transverse space of the LVGs.With the scope of this paper the overall factor varies from 0.94 to 1.21 for the l ranging from 0.30 mm to 0.40 mm.The overall factor varies from 0.88 to 1.17 for the s ranging from 0.1 mm to 0.5 mm.Comparing the overall performance factor,it can be seen that the short length (0.3 mm) and large transverse space (0.5 mm) of the LVGs are beneficial to enhance the overall performance of the microchannel.The LVGs shows better overall heat transfer performance under the low Reynolds number condition.