Shell-Pass Heat Transfer Enhancement in Helical Baffles Heat Exchangers through Structure Improvement

摘要

The shell-pass flow and heat transfer properties of regular helical baffles heat exchangers are studied with numerical simulation. In the simulation, Reynolds Stress Model (RSM) and wall function are used through FLUENT software. At first, the simulation results for the regular helical baffles heat exchangers at different flow rates are obtained and compared with the results from experiments. The results are in accordance with the experiment data, which prove the accuracy of the numerical model. Then the simulation results are examined, which show that the turbulence intensity is different at different radius position along the shell-pass radial direction for the regular helical baffles heat exchangers. The tube arrangement is designed based on the observation to improve the shell-pass structure. At last, the improved shell-pass structure of helical baffles heat exchanger is remodeled and simulated numerically. The simulation results show that both the overall heat transfer coefficient and the overall heat transfer coefficient per unit pressure drop of the new heat exchanger are improved. The improvement is more obvious with the flow rate increases.