THE EFFECT OF GEOMETRICAL FEATURES ON AIR-SIDE HEAT TRANSFER AND FRICTION CHARACTERISTICS, AND OPTIMIZATION OF A LARGE-SIZE PLAIN FIN-AND-TUBE HEAT EXCHANGER BY 3-D NUMERICAL SIMULATION

摘要

The effect of geometrical features on the air-side heat transfer and friction characteristics of an industrial plain fin-and-tube heat exchanger is investigated by 3-D numerical modeling and simulations. The heat exchanger has been designed and employed as an intercooler in a gas power plant and is a large-size compact heat exchanger. Most of the available design correlations developed so far for plain fin-and-tube heat exchangers have been prepared for small-size exchangers and none of them fits completely to the current heat exchanger regarding the geometrical limitations of correlations. It is shown that neglecting these limitations and applying improper correlations may generate considerable amount of error in the design of such a large-size heat exchanger. The geometry required for numerical modeling is produced by Gambit~? software and the boundary conditions are defined regarding the real operating conditions. Then, three-dimensional simulations based on the SIMPLEalgorithm in laminar flow regime are performed by FLUENT? code. The effect of fin pitch, tube pitch, and tube diameter on the thermo-hydraulic behavior of the heat exchanger is studied. Some variations in the design of the heat exchanger are suggested for optimization purposes. It is finally concluded that the current numerical model is a powerful tool to design and optimize of large-size plain fin-and-tube heat exchangers with acceptable accuracy.