Field synergy analysis on shell-side flow and heat transfer of heat exchanger with staggered overlap helical baffles

Numerical investigation was carried out to study the effects of overlap size on shell-side flow and heat transfer characteristics of heat exchanger with helical baffles under the same helix pitch. Results show that, with the increase of overlap size, both convection heat transfer coefficient and pressure drop decrease; leakage from triangle zone mitigates, local flow resistance decreases, leakage from marginal triangle zone enhances the axial and rotating flow at the region closed to shell; the heat transfer on the central tube drop sharply, the heat transfer on the tube close to shell vary slightly. Field synergy analysis shows that, the leakage from triangle zone enhances heat transfer, the leakage from marginal zone impairs heat transfer. The bigger overlap size, the better global field synergy between flow field and heat flux field.