Impingement heat transfer from rib roughened surface within two-dimensional arrays of circular jet with initial crossflow has been investigated experimentally. The configurations considered are intended to simulate the impingement cooled midchord region of the gas turbine airfoils in case where an initial crossflow is present. Many factors affect the heat transfer. The relative positions of the jet hole to the ribs and the geometric parameters have the significant effect on the heat transfer characteristics and have been experimentally studied. The investigation on the effect of the relative position of the jet hole to the ribs has been presented in an other paper. The effects of the geometric parameters such as jet hole spacing, jet-to-surface spacing, rib pitch-to-height ratio and rib height-to-hole diameter ratio on the heat transfer characteristics are considered in this paper. The experimentation is conducted under the conditions of Reynolds number 7,000–15,000 and the crossflow-to-jet mass flux ratio based on each channel/jet hole area 0∼0.5. With three jet hole spacing to jet hole diameter ratios, five jet-to-surface spacings, three rib pitch-to-height ratios and three rib height-to-hole diameter ratios, a great number of experimental data has been obtained. Based on this, the effects of the geometric parameters on the heat transfer characteristics have been obtained qualitatively and quantitatively. It can be used for evaluating the efficiency of the impingement heat transfer.
Numerical simulation on impingement heat transfer characteristics in ultra fast cooling
