TY  - EJOU
AU  - Hatakeyama, Jumpei 
AU  - Fukue, Takashi 
AU  - Shirakawa, Hidemi 
AU  - Sugimoto, Yasuhiro 

TI  - Relationship between Pulsation Conditions and Pin Fin Spacing for Heat Transfer Enhancement under Pulsating Flow Conditions
T2  - Frontiers in Heat and Mass Transfer

PY  - 2026
VL  - 24
IS  - 4
SN  - 2151-8629

AB  - This paper describes a pin fin spacing designed to maximize forced convection heat transfer performance by combining pulsating flow with a pin fin array. With the recent miniaturization and high-density packaging of electronic equipment, thermal management has become a critical issue due to the increasing heat generation density. To address this challenge, we have focused on pulsating flow, commonly observed in blood circulation systems, and investigated its potential to enhance heat transfer. Previous studies have shown that pulsating flow enhances the overall heat transfer around heating elements and ribs by supplying low-temperature coolant to the rear surfaces of the objects during the deceleration period. This heat transfer enhancement is attributed to the mixing of stagnant coolant in the separation region, driven by pulsation-induced secondary flow. Therefore, it is considered that there is a relationship between the generated secondary flow and the arrangement of heat transfer enhancement devices to maximize cooling performance. Quantifying this relationship remains a critical issue for practical applications. In this study, we investigated the optimal conditions for three pin fins mounted in a rectangular cooling channel to maximize heat transfer under pulsating flow. The test pin fins were arranged in a single row along the flow direction. As key parameters, the fin spacing and the pulsating Strouhal number were examined. The proposed pulsating Strouhal number is derived from the time-averaged Reynolds number, pulsation frequency, flow channel dimensions, and coolant velocity. The results showed that the heat transfer performance increased with increasing fin spacing, while the rate of increase gradually decreased at larger spacings. Furthermore, regarding the pulsating Strouhal number, the flow pattern around the pin fins transitioned at 0.3, at which point the heat transfer performance reached its maximum.
KW  - Pulsating flow; forced convection; pin fin array; heat transfer enhancement; Strouhal number

DO  - 10.32604/fhmt.2026.086397