Turbulent heat transfer study of inclined impinging jets

The heat transfer coefficient of impinging jet is several times higher than that of cross flow conditions, which makes it an attractive cooling solution for high power electronics enclosure or space constrained system. A number of parameters affect jet impingement heat transfer such as nozzle exit-to-target spacing, inclination angle, and Reynolds number. Numerical simulations for a two-dimensional air jet have been created using six well-known turbulent models. The objective of this exercise is to assess the capability of these models as it relates to jet impingement heat transfer. Four different cases were created and compared to the experimental results of Beitelmal et al. (2000). The deviation of the numerical results from the experimental ones varied between 1% to 50% with an average deviation of about 24%. None of the turbulence models used in this study showed any superior capabilities when dealing with jet impingement heat transfer application. However the current results showed that both one-equation Spalart-Allmaras and the RNG k-ε models gave the best estimates for normally impinging jet with a percent deviation ranging between 3% and 32% and average deviation of 22% from the experimental results. The SST k-ω model results gave a better approximation in case of inclined jet heat transfer with an average deviation of 18% from the experimental results.