Blockage of triangle leakage zones in heat exchanger with helical baffles

Four fan-shaped baffles are used to form a pitch in shell side of heat exchangers with helical baffles. There are two triangular leakage zones between the two adjacent baffles, making the shell-side fluid deviate from ideal plug flow and degrading the heat transfer performance of the heat exchanger. In this paper, the structure of fold baffle is used to block the external triangular leakage zones, so the shell-side fluid flows in approximately continuous spiral flow. The heat transfer experiments are used to evaluate the performance of the improved heat exchanger. The experimental results show that the shell-side heat transfer coefficient is increased by 11.6%-21.6% and the overall heat transfer coefficient is increased by 6.7%-19.1% with an average value of 16.9%, compared with that of conventional heat exchanger with plain baffles. The heat transfer of improved heat exchanger is intensified obviously. Although the shell-side pressure drop increases correspondingly, the increment in pumping power consumption is limited. The values of thermal performance factor are all above 1.0, with an average value of 1.071.It demonstrates that taking into account heat transfer coefficient and pressure drop, better integrative performance is obtained through the configuration optimization of baffles. It is benefit to optimizing design for heat exchangers with helical baffles.