Heat Transfer From Low Aspect Ratio Pin Fins

Abstract

The performance of many engineering devices from power electronics to gas turbines is limited by thermal management. Pin fins are commonly used to augment heat transfer by increasing surface area and increasing turbulence. The present research is focused on but not limited to internal cooling of turbine airfoils using pin fins. Although the pin fins are not limited to a single shape, circular cross-sections are most common.The present study examines heat transfer from a single row of circular pin fins with the row oriented perpendicular to the flow. The configurations studied have spanwise spacing to pin diameter ratios of two, four, and eight. Low aspect ratio pin fins were studied whereby the channel height to pin diameter was unity. The experiments are

Endwall heat transfer and pressure drop in rectangular channels with attached and detached circular pin-fin array

“…As compared in Fig. 6, the comparison of Nu derived by Lyall et al [35] with present Nu at Re = 30,000 yields 7% lower values of present Nu than those reported by Lyall et al [35]; whereas the comparison of present Nu with Nu derived by Chyu et al [34] at Re = 18000 results in 17% lower values of present Nu. These discrepancies can be attributed to differences in channel aspect ratio, pin pitch ratio, experimental setup and boundary conditions.…”

“…For the purpose of validation, Fig. 6 also collects the endwall heat transfer data reported in [27,34,35] for the channels with attached pin-fins which share the similar test configurations with the present study. As compared in Fig.…”

“…5. Y-wise Nu profiles at various X locations for pin-fin channels with C/d pin-fin (C/d=0) Detached pin-fin (C/d=1/4) Detached pin-fin (C/d=2/4) Detached pin-fin (C/d=3/4) Chyu et al [34]Lyall et al[35] Comparison of endwall area-averaged Nu values for the pin-fin channels with C/d…”

Multi-scale pin fins: Scale analysis and mathematical optimization of micro-pin fins arranged in rows

“…Figure 3a show that the thermal conductivity ratio has no e ect on the pin-ndiameter ratio and height ratio. Their aspect ratio is less than or equal to one as predicted in Equations (16), (17) and (18). Figure 3b shows that the maximized rate of heat transfer increases as the thermal conductivity ratio increases.…”

“…Manufacturing Restraint: Pin-n manufacturing and size constraint allows for typical aspect ratios in the range of 0.5 and 4 [17,18]. Considering fabrication techniques, inter n spacing is limited to 50 microns [19,20].…”