周向重叠三分螺旋折流板换热器壳侧性能试验研究

对倾斜角为20°、24°、28°和32°的单头以及32°的双头周向重叠三分螺旋折流板换热器和弓形折流板换热器的传热和压降性能进行了测试,换热器采用公共壳体和可更换管芯结构。采用壳侧轴向雷诺数和轴向欧拉数分别作为反映壳侧流量和阻力系数的无因次参数。试验结果显示在试验范围内周向重叠三分螺旋折流板换热器壳侧换热系数、壳侧压降和综合性能指标都随着倾斜角增大而减小;倾斜角20°方案的性能指标最佳,其平均壳侧努塞尔数和轴向欧拉数与弓形折流板方案的数值之比分别为1.123和0.45;双头螺旋折流板方案的换热系数和压降都大于同样倾斜角的单头螺旋折流板方案,但两者的综合性能较接近。

Experimental Study on Shell Side Heat Transfer Performance of Circumferential Overlap Trisection Helical Baffle Heat Exchangers

The heat transfer performance test were conducted of circumferential overlap trisection helical baffle heat exchangers with single thread schemes of baffle tilt angles of 20°,24°,28°,32°, and dual thread scheme of baffle tilt angle 32°,in contrast to a segmental baffle heat exchanger.The testing heat exchanger is constructed of a common cylinder case and replaceable tube bundle cores. The axial Reynolds number and axial Euler number are adopted respectively as the dimensionless variables for shell side flow rate and resistant coefficient.The results show that within the testing range the shell side heat transfer coefficient,pressure drop and comprehensive index are all decreased with the increase of the tilt angle of the baffles,and the optimum scheme is the one with baffle tilt angle of 20°,and the ratios of the mean values of shell side Nusselt number and axial Euler number of the helical scheme with baffle tilt angle of 20°over those of the segmental baffle scheme are 1.123 and 0.45 respectively;and that the dual thread scheme has higher heat transfer coefficient and pressure drop than the single thread one with same tilt angle.