Hydraulics of a channel with a linear jet array

Hydraulic drag was investigated in channels with length/width ratios of 25 and 41.8 in order to quantify the heat transfer coefficient enhancement produced by longitudinal transpiration cooling in the presence of pressure drops. Experiments were performed using channels of different heights to identify optimal Euler numbers for jet injection cooling on the inlet edges of turbine blades. Varying numbers of jets in linear arrays on the channel walls were studied. The pressure drop penalty in the channels was found to be moderate, while the heat transfer coefficients were doubled with the transpiration cooling. Alternatively, the pressure drop reduction was doubled for a given heat transfer coefficient. Temperature was also shown to effect the pressure drop.