Numerical Investigation Based on CFD for Air Impingement Heat Transfer in Electronics Cooling

Air impingement cooling, as a potential air-cooling technique, has been shown to be much efficient and enabled to complement conventional forced convective air-cooling in electronics. To provide reliable references to the computational thermal analyses based on CFD for effective air-cooling technique integrated in microsystem electronics packaging, the numerical simulation based on CFD for air impingement heat transfer is conducted in the case of axisymmetric impinging jet by adopting various turbulence models and wall functions. The results indicate that the inherent disadvantage of the overpredictions of the turbulent kinetic energy and heat transfer rate in the stagnation region for the standard and realizable k-epsiv turbulence models primarily depends on the improper modeling of the source term in the transport equation of the turbulent energy dissipation rate, rather than the isotropic eddy viscosity assumption and high pressure gradient in the vicinity of the stagnation point. The RNG k-epsiv turbulence model greatly improves the prediction accuracy of the turbulent viscosity and heat transfer rate in the stagnation region and seems to be preferable not only to the standard and realizable k-epsiv turbulence models but also to advanced Reynolds stress turbulence model to some extent in respect to the prediction capability with respect to the turbulence and heat transfer characteristics for such an axisymmetric impinging jet