Optimal Design of Tube Banks in Crossflow Using Entropy Generation Minimization Method

Abstract

An entropy generation minimization, EGM, method is applied as a unique measure to study the thermodynamic losses caused by heat transfer and pressure drop for a fluid in crossflow with tube banks. The use of EGM allows the combined eect of heat transfer and pressure drop to be assessed through the simultaneous interaction with the tube bank. A general dimensionless expression for the entropy generation rate is obtained by considering a control volume around a tube bank and applying the conservation equations for mass and energy with the entropy balance. Analytical/empirical correlations for heat transfer coecients and friction factors are used, where the characteristic length is used as the diameter of the tubes and reference velocity used in Reynolds number and pressure drop is based on the minimum free area available for the fluid flow. Both in-line and staggered arrangements are studied and their relative performance is compared for the same thermal and hydraulic conditions. A parametric study is also performed to show the eects of dierent design variables on the overall performance of tube banks. It is shown that all relevant design parameters for tube banks, including geometric parameters and flow conditions can be simultaneously optimized.