Numerical optimization of forced thermal convection in transverse tube bundles based on double-distribution-function lattice Boltzmann method

Abstract

Forced thermal convection of transverse tube bundles is common in various thermal equipment, such as boiler economizers and air pre-heaters. In this study, the forced thermal convection in transverse tube bundles is simulated based on the double-distribution-function lattice Boltzmann method (DDF-LBM). The coupled lattice BGK (CLBGK) model is applied to construct the algorithm. The tube's normal gradient of temperature is calculated by the generalized four-point bilinear interpolation method. The algorithm is verified by the simulations of the flow at a low Re∞ around a cylinder, natural thermal convection in the cavity, and forced thermal convection in staggered transverse tube bundles. Remax, S*T and S*L are the three most important factors optimization heat transfer efficiency. The range, variance, and significance analyses of the orthogonal test conclude that S*T and Remax have the most significant impact on the evaluation index j and G, and fc, respectively. In Origin 2018, the fitting accuracy of the fitting curve and the original data is judged by Reduced Chi-Sqr, and the error is judged by Adj. R-Square. The present study's conclusions can guide the parameter selection design to obtain the best thermal performance of transverse tube bundles with a lowest economic cost.