Thermal performance of condensation phase change in the shell side of discontinuous helical baffle heat exchanger

Abstract

The discontinuous helical baffle heat exchanger is widely used in industrial applications due to its high heat transfer efficiency and uniform flow distribution. This study, focused on the recovery of the waste heat from steam condensation in power plants, establishes a three-dimensional geometric model of a discontinuous helical baffle heat exchanger and numerically simulates the condensation process within the shell side of the heat exchanger using Ansys Fluent 2020R1. The characteristics of flow and temperature fields is analyzed and the effects of steam inlet temperature, steam inlet velocity, and cooling water inlet velocity on the condensation performance of shell side are investigated. The results indicate that, with a constant cooling water velocity in the tube side, the heat transfer coefficient in the shell side increases with rising steam inlet velocity and decreases with increasing superheat degree of the steam. When steam inlet velocity increases from 5 m∙s⁻¹ to 20 m∙s⁻¹, the shell-side heat transfer coefficient increases by 81.22 % on average. When steam inlet velocity is 20 m∙s⁻¹, as steam inlet superheat increases from 10 K to 50 K, the shell-side heat transfer coefficient decreases by 16.69 %. This study provides scientific support for further research on discontinuous helical baffle heat exchangers.