Numerical simulation for configuration optimization of heat exchanger with helical baffles

An improved structure of heat exchangers with ladder-type fold baffle is proposed to eliminate the triangular leakage zones between two adjacent baffles of conventional heat exchangers with helical baffle. The improved ladder-type fold baffle is formed by folding one plane twice, which consists of three planes, two of which are perpendicular to the tube bundle axis, and the third plane keeps the same angle with the other two planes. The configuration of the ladder-type fold baffle is optimized with CFD simulation. The results show that the triangular leakage zones are eliminated due to the folded plane structure and the overlap between two adjacent straight edges of ladder-type fold baffles. The shell-side flow field is improved significantly, which forms a continuous spiral flow in shell side of the improved heat exchanger, hence heat transfer in the heat exchanger is strengthened. When the bend degree is taken as 0.3, the cutting percentage as 90% and the bend angle as 37°, the overall performance of heat exchanger reaches the best. The thermal performance factor rises by 28.4%-30.7%, or 29.9% on an average.