Numerical investigation of heat transfer and pressure drop of in-line array of heated obstacles cooled by jet impingement in cross-flow

A computational study of cooling in-line array of heated obstacles simulating electronic components by jet impingement in cross-flow (JICF) has been investigated using RNG k-ε turbulence model. The jet position has been changed to impinge each obstacle consecutively at different jet-to-channel Reynolds number ratios, Rej/Rec = 1, 2, and 4. The main flow structure, the static pressure, local and average Nusselt numbers as well as the thermal enhancement factor have been investigated. The results show that there is a significant variation between the flow structures around an obstacle when subjected to JICF or CF. The friction factor for JICF is greater than that for cross-flow only (CF) by 88% at the first jet position and Rej/Rec = 4. The irregular distribution of local Nusselt number (Nu) on the impinged obstacle is moderated by increasing the Reynolds number ratios. Increasing Reynolds number ratio increases the average Nusselt number (Nu‾) of the downstream obstacles and decreases it for the upstream obstacles. The increment of Nu‾ for whole array for JICF than CF is about 26% at JP3 and Rej/Rec = 4. Moreover, the highest value of thermal enhancement factor is attained at JP3 and it equals 12% for Rej/Rec = 4