Analysis of heatline based visualization for thermal management during mixed convection of hot/cold fluids within entrapped triangular cavities

Abstract A comprehensive investigation has been carried out to analyze the fluid and heat flow during mixed convection in entrapped triangular cavities for heat disposal (case 1: hot inclined and cold horizontal wall) and heat recovery (case 2: cold inclined and hot horizontal walls) to/from the industrial fluids via heatline approach. Galerkin finite element method is employed to solve the governing equations and the results are illustrated for various Grashof numbers (10 3 ≤ Gr ≤ 10 5 ), Prandtl numbers ( P r = 0.026 and 7.2) and Reynolds numbers (1 ≤ Re ≤ 100). At R e = 1 , the symmetric fluid circulation cells occur whereas, the asymmetric fluid circulation cells occur at Re ≥ 10 and G r = 10 5 in both the cases and both Pr . The conduction dominant heat transfer is observed at P r = 0.026 and G r = 10 5 involving all Re . In contrast to P r = 0.026 , the heat flow field is highly influenced by the fluid flow field at P r = 7.2 for all Re and G r = 10 5 . In the upper cavity, the average Nusselt number of the top wall ( N u t ¯ ) is higher at Re → 0, G r = 10 5 for the case 1, and at R e = 100 , G r = 10 3 for the case 2 involving P r = 7.2 . In the lower cavity, the average Nusselt number of the bottom wall ( N u b ¯ ) is higher at R e = 100 , G r = 10 3 for the case 1, and at Re → 0, G r = 10 5 for the case 2 involving P r = 7.2 .