Inverse CFD method for thermal analysis of 3D turbulent natural convection in fin-enhanced cavities for HVAC applications

Background

Closed cavities with a heated bottom surface are commonly used in electronic cooling and HVAC industries, where effective thermal management is essential. This study aims to investigate 3D turbulent free convective thermal transport within such a chamber equipped with various fins.

Methods

An inverse CFD technique, coupled with extensive experimental temperature measurements, was employed. Various turbulence models, combined with RMSE, were used to forecast the fluid dynamics model and the unidentified thermal transport rate of the heater.

Significant Findings

The results identified the RNG k-ε model and the zero-equation model as appropriate flow models. Nusselt numbers, air temperature contours, and flow patterns compared well with existing correlations and experimental data. As the number of fins and cavity height increased, the configuration of cells and vortices could blend and restructure, affecting the formation of Rayleigh-Bénard convection cells. Increasing the number of fins also accelerated the flow speed in the cavity. The study confirmed that the fin material and heater temperature have minimal impact on air velocity patterns and temperature contours. This investigation is novel in applying the inverse CFD technique to this problem, providing new insights into the behavior of turbulent natural convection in finned cavities. The appropriate flow models are the RNG k-ε model with N_f=3 and the zero-equation method with N_f=0 and 7, respectively. In addition, N_f=3 provides the maximum convective heat transfer coefficient.