Influence of novel equilaterally staggered jet impingement over a concave surface at fixed pumping power

A new cooling configuration is proposed for the leading edge cooling of turbine vane by using five equilaterally staggered air jets. Two configurations, having one central and four neighboring jet impingement pipes (JIP), are tested. One configuration has all JIP of circular section and in the second, all four neighboring JIP are provided with 45° chamfer. The chamfered exit of JIP faces the concave target surface. Experimental data of Nusselt number and thermal performance factors (TPF) for chamfered configuration is compared with the non-chamfered configuration, both operated at a constant pumping power. It is found that for the fixed pumping power condition the chamfered configuration performs better than the non-chamfered configuration showing: (i) significant increase in the cooling coverage area (ii) increase in heat transfer and (iii) reduction in coolant requirement. In the range of experimental condition used in the present work, the thermal performance factor of the chamfered configuration is 8–24% better than that of the non-chamfered configuration. The effect of jet-to-plate spacing is found to be mild. The average Nusselt number correlations developed for both the chamfered and non-chamfered configurations are given by- Nu¯chamfered=0.409×Re0.6×(H/d)0.053 Nu¯non-chamfered=0.351×Re0.6×(H/d)0.06