Heat Transfer and Fluid Flow on Dimpled Surface With Bleed Flow

Abstract

This study investigates the effects of bleed flow on heat transfer and fluid flow on a dimpled surface in a rectangular channel. The heat transfer on a dimpled surface with bleed flow is compared with that on a dimpled surface without bleed flow. The height of the channel is 15.0 mm. The dimples are arrayed in staggered on the bottom surface of the channel with a pitch of 15.0 mm. The dimple depth is 3.75 mm and the dimple footprint diameter is 13.0 mm. The bleed hole is installed on the inner surface of the dimple and the diameter of the hole is 1.3 mm. The tests were conducted with varying Reynolds numbers from 1000 to 10,000 and 0.5% of total mass flow is flowing out through a bleed hole. A numerical method was employed to determine the detailed heat transfer coefficients. Commercial computational fluid dynamics software, ANSYS CFX 13.0, is adopted and the Shear Stress Transport model is set to turbulent model. As a result, the overall heat transfer rate on dimpled surface with bleed flow is 10–20% higher than that without bleed flow.