Thermal and Thermodynamic analyses of impingement cooling system with turbulent jet arrays
In the present study, a multi-objective optimization procedure
combining finite element modeling of turbulent convection,
Non-linear regression and Multi-Objective Genetic Algorithm (MOGA) is demonstrated, to obtain an optimum configuration for jet impingement cooling system. For the purpose, equations governing conservation of mass, momentum and energy are solved in a Cartesian framework using Streamline Upwind Petrov-Galerkin (SUPG) Finite Element Method (FEM). Turbulent kinetic energy and its dissipation rate are modeled using k - ε turbulence model with standard wall functions. The effect of velocity ratio (V R), Reynolds number (Re) and channel height (H/L) on fluid flow pattern, heat transfer and entropy generation are presented and discussed. A counter-rotating recirculation bubbles are formed in the neighborhood of confinement surface in the vicinity of both jet inlets due to shear driven interaction by high velocity jets on ambient fluid. Also, in the regions of shear interaction, turbulent kinetic energy is found to be high due to dominance of turbulent production. The magnitude of overall Nusselt number (Nuov) and global total entropy generation (Stot,Ω) is found to increase
with increasing V R and Re and decreasing H/L. Finally, Multi-Objective Genetic Algorithm (MOGA) has been implemented to obtain optimum configurations of impingement cooling system, where a trade-off between two performance parameters, Nuov and Stot,Ω is obtained.