Local Heat/Mass Transfer and Friction Loss Measurement in a Rotating Matrix Cooling Channel

Abstract

The present investigation provides detailed local heat/mass transfer and pressure drop characteristics in a matrix cooling channel, under rotating conditions. The matrix channel had cooling subpassages with crossing angles of 45 deg. The detailed heat/mass transfer coefficients were measured via the naphthalene sublimation method, and pressure drops were also obtained. The experiments were conducted for various Reynolds numbers (10,500 to 44,000) and rotation numbers (0.0 to 0.8). In the stationary case, the heat transfer characteristics were dominated by turning, impinging, and swirling flow, induced by the matrix channel geometry. Average heat/mass transfer coefficients on the leading and trailing surfaces in the stationary channel were approximately 2.1 times greater than those in a smooth channel. In the rotating cases, the effect of rotation on heat/mass transfer characteristics differed from that of typical rotating channels with radially outward flow. As the rotation number increased, the Sherwood number ratios increased on the leading surfaces but changed only slightly on the trailing surfaces. The thermal performance factors increased with rotation number due to the increased Sherwood number ratios and decreased friction factor ratios.