下記２本の論文が，Frontiers in Heat and Mass Transfer にアクセプトされ掲載されております．
○ Relationship between Pulsation Conditions and Pin Fin Spacing for Heat Transfer Enhancement under Pulsating Flow Conditions
(Jumpei Hatakeyama, Takashi Fukue, Hidemi Shirakawa, Yasuhiro Sugimoto)
Frontiers in Heat and Mass Transfer 2026, 24(4), 2 https://doi.org/10.32604/fhmt.2026.086397
Published 31 August 2026
Abstract: 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.
○ Basic Study on Heat Transfer Enhancement in Straight Fins by Pulsating Flow
(Tomoya Kazumi, Kota Fujisawa, Kenta Emori, Takashi Fukue, Yasuhiro Sugimoto)
Frontiers in Heat and Mass Transfer https://doi.org/10.32604/fhmt.2026.088763
Published 10 September 2026
Abstract: Efficient thermal management is essential for high-heat-flux electronic devices, where increasing power density and compact packaging impose strict requirements on cooling performance with minimal pressure drop. Pulsating flow has been proposed as a technique to enhance heat transfer; however, its effects on practical heat sink geometries remain insufficiently understood. This study investigates the thermal-hydraulic characteristics of pulsating flow in a multi-straight-fin heat sink operating in the laminar and transitional flow regimes (Re = 480–2400) through a combination of heat transfer experiments and three-dimensional Computational Fluid Dynamics (CFD) analyses. The effects of pulsation frequency, amplitude, and Reynolds number on heat-transfer and pressure-drop characteristics were evaluated using the mean Stanton number, friction coefficient, and performance evaluation criteria (PEC). The CFD model was validated against experimental measurements and used to analyze phase-resolved velocity and temperature fields. The results showed that pulsating flow can either enhance or deteriorate thermal performance depending on the pulsation conditions. Higher pulsation frequencies improved both the mean Stanton number and PEC, whereas lower frequencies reduced overall performance. The enhancement was most pronounced at an intermediate Reynolds number of approximately Re = 960. Increasing pulsation amplitude increased both heat transfer and pressure drop, resulting in little variation in PEC. Local heat-transfer evaluations demonstrated that the enhancement effect became more significant in the downstream region. CFD analyses revealed that periodic disturbances of the thermal boundary layer caused by unsteady near-wall flow were responsible for the enhanced heat transfer. These findings provide fundamental insights into the thermal-hydraulic characteristics and enhancement mechanisms of pulsating flow and support its application to compact liquid-cooled heat sinks for high-heat-flux electronic devices.