A study on microchip cooling performance increment by using air jet impingement with one and double rows

Abstract

The impinging jet technique is a high-performance cooling technology for microchips which are basic elements of computer systems and have high heat generation rates in small volumes. In this study, the improvement of heat transfer of the desktop microchips used in all technological products today by air-impinging jet flow was examined. For this purpose, numerical research was carried out on the cooling of copper plate surfaces with two different patterns, concave and roof shaped having 1000 W/m2 constant heat flux in rectangular cross-sectional ducts by one and double air jets with distances of Dh and 2 Dh between them. Numerical analysis was performed steady and in three dimensions with the k– ε turbulence model by the Ansys–Fluent program. The obtained results were compared with the numerical and experimental results of the study in the literature and it was seen that they are determined to be compatible. The results were presented as the mean Nu number for each of both patterned surfaces and the mean outlet temperature of the jet flow ( Tmoj) and the mean Nu number ( Num) of all patterned surfaces in single and double jet channels with different distances. Besides, pressure drop (Δ P), friction factor ( f), thermal resistance ( Rt) and thermo-hydraulic performance (THP) of concave and roof-patterned surfaces in the channels with different jet setup configurations were analyzed. Streamline and temperature contour distributions of the jet flow along the channel for different H/ Dh ratios and jet numbers were evaluated for both patterned surfaces. In H/ Dh  =  4 and at Re  =  7000, the average Nu number for roof-patterned surfaces was found to be 30.52% higher than concave patterned surfaces in the case of double jets with a distance of Dh. Rt reduction values of the roof and concave pattern surfaces with a double jet arrangement having 2 Dh distance at Re  =  5000 and H/ Dh  =  8 are 163.7% and 36.23% when compared to single jet, respectively.