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Optimization of baffle structure in shellandtube heat
exchanger based on new heat transfer evaluation index |
College of Petroleum Engineering, Liaoning Shihua University, Fushun, Liaoning 113001, China |
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Abstract To accurately evaluate the heat transfer effect and ensure the safe and stable operation of heat exchanger, a new heat transfer evaluation index η was proposed, which was equal to the ratio of convection heat transfer coefficient to the onethird power of pressure drop. With special consideration of the effect of pressure drop on heat exchange, the baffle structure was simulated and optimized by CFD software. The optimized baffle spacing was determined, and the optimized baffle cut height was then determined. The results show that with the increasing of baffle spacing and cut height, fluid velocity, pressure drop and convection heat transfer coefficient are decreased, while heat transfer evaluation index is decreased with latter increasing. The heat transfer effect is dependent on convection heat transfer coefficient and pressure drop. For the specific heat exchanger with the length of 1 632 mm, the optimal heat transfer effect was obtained under the conditions with baffle spacing of 350 mm and baffle cut height of 0.375D. The simulation results are in good agreement with the results of the baffle structure of heat exchanger in atmosphericvacuum distillation unit of a refinery.
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