Heat Transfer Characteristics Within the Matrix Cooling Channels

Abstract

Matrix or latticework cooling has become a new area of research due to its advantage of providing a structural rigidity to the fragile structures like gas turbine blades, electronic components or circuitries, and compact heat exchangers. In this article, the heat transfer characteristics in matrix cooling channels with different rib angles have been studied using liquid crystal thermography. A total of three matrix models with rib angles 35 deg, 45 deg, and 55 deg having a common subchannel aspect ratio 0.8 have been studied. The results are evaluated in terms of local and average augmentation Nusselt numbers for different regions of the matrix. The augmentation Nusselt number has been found to increase in each region as the angle increases from 35 deg to 45 deg and the same has been found to decrease slightly upon the further increase in angle from 45 deg to 55 deg. The highest percentage increase in augmentation Nusselt number up to 50% has been observed in entry region, whereas the same remained nearly 26–30% in middle and exit regions in streamwise directions, i.e., the effect of the matrix rib angle is more prominent in the entry region. The higher resistance offered by the greater number of ribs for angle 55 deg is believed to be responsible for the decrease in augmentation Nusselt number for Re ≤ 9000.