Heat transfer of confined impinging air-water mist jet

This paper describes the detailed heat transfer distributions of an atomize d air-water mist jet impinging orthogonally onto a confined tal-gst plate w ith various water-to-air mass-flow ratios. A transient technique was used t o measure the full field heat transfer coefficients of the impinging surfac e. Results showed that the high momentum mist-jet interacting with the wate r-film and wall-jet flows created a variety of heat transfer contours on th e impinging surface. The trade-off between the competing influences of the different heat transfer mechanisms involving in an impinging mist jet made the nonlinear variation tendency of overall heat transfer against the incre ase of water-to-air mass-flow ratio and extended the effective cooling regi on, With separation distances of 10, 8, 6 and 4 jet-diameters, the spatiall y averaged heat transfer values on the target plate could respectively reac h about 2.01, 1.83, 2.43 and 2.12 times of the equivalent air-jet values, w hich confirmed the applicability of impinging mist jet for heat transfer en hancement. The optimal choices of water-to-air mass-flow ratio for the atom ized mist jet required the considerations of interactive and combined effec ts of separation distance, air-jet Remolds number and the water-tu-air mass -flow ratio into the atomized nozzle.