船用膜式螺旋管换热器传热和流动特性研究

Numerical studies on heat transfer and flow of membrane spiral-tube marine heat exchanger

采用数值模拟方法研究膜式螺旋管换热器在高温高压的工况下顺列结构和2种错列结构的对流换热和流动特性,分析径向节距对顺列和错列结构换热和流动特性的影响。模拟结果与试验结果符合较好。研究发现:顺列和错列结构对于换热及流动的影响随着径向节距的变化而变化。当径向节距s1/d<1.6时,顺列结构的换热系数和流动阻力高于错列结构;当1.6<s1/d<2.0时,顺列结构的平均换热系数与和错列结构几乎相等,错列结构的流动阻力小于顺列结构;当s1/d>2.0时,换热器的平均换热系数和压降与膜式螺旋管的布置方式无关,即顺列和错列结构的换热系数及流动阻力基本相等。

Numerical investigations were conducted to understand the flow and heat transfer characteristics of synthesis gas（ syngas） in membrane helical- coil heat exchanger heat exchanger for different arrangement. Simulations were performed for different radial pitch. The numerical results are in a good agreement with the experimental works on heat transfer in membrane helical-coil annular channels. The heat transfer coefficients of the membrane helical coil were found to be strongly associated with the radial pitch. The results show the heat transfer coefficients and flow resistance for aligned membrane helical coil is higher than those for staggered membrane helical coil at s1/ d 〈1. 6; the heat transfer coefficients for aligned membrane helical coil is almost equal to those for staggered membrane helical coil at 1. 6 〈s1/ d 〈2. 0,and the flow resistance for aligned membrane helical coil is higher than those for staggered membrane helical coil; the heat transfer coefficients and flow resistance for aligned membrane helical coil is almost equal to those for staggered membrane helical coil at s1/ d 〉2. 0.