折面螺旋折流板换热器的流动传热性能

A kind of shell-and-tube heat exchangers with fold helical baffles was proposed to eliminate the triangular leakage zones between adjacent baffles and shell. The effect of helical angle and overlapped degree on flow and heat transfer for shell-and-tube heat exchanger with fold helical baffles was studied based on investigation. The experimental correlations of convection heat transfer coefficient and resistance coefficient in shell side were obtained. The results show that the shell-side total pressure drop, shell-side tube bundle pressure drop, shell-side heat transfer coefficient and comprehensive performance all increase with the decrease of helical angle and the increase of overlapped degree under same shell-side volume flow rate. The flow and heat transfer performance of shell-and-tube heat exchanger with helical baffles is the best when helical angle is 18° and overlapped degree is 50%. The helical angle and overlapped degree as correction factor are added into experimental correlations. It is found that the average relative error between experimental values and experimental correlation of Nusselt number is 1.13%, the average relative error is 6.84% between experimental values and experimental correlation of resistance coefficient, which illustrates the fitting is correct and reliable. The results have a degree of theoretical guidance for design of shell-and-tube heat exchangers with fold helical baffles.