Thermal Management Using Pulsating Jet Cooling Technology

The existing methods of heat removal from compact electronic devises are known to be deficient as the evolving technology demands more power density and accordingly better cooling techniques. Impinging jets can be used as a satisfactory method for thermal management of electronic devices with limited space and volume. Pulsating flows can produce an additional enhancement in heat transfer rate compared to steady flows. This article is part of a comprehensive experimental and numerical study performed on pulsating jet cooling technology. The experimental approach explores heat transfer performance of a pulsating air jet impinging onto a flat surface for nozzle-to-surface distances 1 ≤ H/D ≤ 6, Reynolds numbers 1,300 ≤ Re ≤ 2,800 pulsation frequency 2Hz ≤ f ≤ 65Hz, and Strouhal number 0.0012 ≤ Sr = fD/U_m ≤ 0.084. The time-resolved velocity at the nozzle exit is measured to quantify the turbulence intensity profile. The numerical methodology is firstly validated using the experimental local Nusselt number distribution for the steady jet with the same geometry and boundary conditions. For a time-averaged Reynolds number of 6,000, the heat transfer enhancement using the pulsating jet for 9Hz ≤ f ≤ 55Hz and 0.017 ≤ Sr ≤ 0.102 and 1 ≤ H/D ≤ 6 are calculated. For the same range of Sr number, the numerical and experimental methods show consistent results.