异形孔隔板换热器壳侧传热与阻力性能的试验研究

对正方形孔、三角圆头孔、网状孔、六角梅花孔隔板换热器及弓形折流板换热器的传热性能和压降性能进行了测试试验.试验件采用公用管壳可拆卸芯体管束结构,针对其特点将壳侧轴向雷诺数作为自变量,利用单位壳侧轴向欧拉数的壳侧努谢尔特数指标来反映换热器的综合性能.试验结果表明,网状孔隔板换热器的壳侧换热系数与弓形折流板换热器相当,但该换热器的压降较低,在试验范围内综合性能指标的相对值为1.274;六角梅花孔、三角圆头孔和正方形孔隔板换热器的壳侧换热系数和综合性能均不及弓形折流板换热器.此外,不同的异形孔隔板换热器的传热性能与异形孔的形状或通流孔数目有关,流动阻力与通流孔的总面积和水力周长有关.

Experimental study on shell-side heat transfer and flow resistance performance of heat exchangers with non-round orifice baffles

The shell-side heat transfer and flow resistance performances of shell-and-tube heat exchangers with different non-round orifice baffle(square,fillet triangle,mesh and cinquefoil) and a segment baffle heat exchanger were tested.A common heat exchanger shell and replaceable tube bundles were adopted.The shell-side axial Reynolds number is used as the independent variable versus the characteristics of the testing heat exchangers.The integrated index of the shell-side Nusselt number over the axial Euler number is suggested for evaluation of the heat exchanger performance of different schemes.The experimental results show that the mesh orifice baffle has the equivalent heat transfer coefficient as the segment baffle.But the pressure drop of the former is lower,and in the experimental range the average value of the relative comprehensive performance of the shell-side Nusselt number over the axial Euler number is about 1.274.Both the heat transfer coefficients and the comprehensive performance indexes of the heat exchangers with cinquefoil,fillet triangle and square orifice are lower than those of the segment baffle heat exchanger.The heat transfer performance of the heat exchangers with non-round orifice baffles is related to the shape and the number of the orifices,and the flow resistance is related to the total area and hydraulic perimeter of the flow orifices.