Mist/Steam Heat Transfer in Confined Slot Jet Impingement

Internal mist/steam blade cooling technology has been considered for the future generation of Advanced Turbine Systems (ATS). Fine water droplets about 5 μm were carried by steam through a single slot jet onto a heated target surface in a confined channel. Experiments covered Reynolds numbers from 7500 to 25000 and heat fluxes from 3 to 21 kW/m2. The experimental results indicate that the cooling is enhanced significantly near the stagnation point by the mist, decreasing to a negligible level at a distance of 6 jet widths from the stagnation region. Up to 200% heat transfer enhancement at the stagnation point was achieved by injecting only ∼1.5% of mist. The investigation has focused on the effects of wall temperature, mist concentration, and Reynolds number.© 2000 ASME