HEAT-TRANSFER BETWEEN AN IMPINGING AIR-JET AND AN IMPINGED WATER-SURFACE

Impingement of producer gas obtained from rice-husk gasification onto a water surface has been found to be very effective in removing tar an d ash from the gas. Correlations to estimate tar-and dust-removal effi ciencies have been developed. An advantage of impingement is that the hot gas jet is cooled. Here, we describe experiments to study heat tra nsfer when heated ambient air impinges on the water surface. An equati on to estimate the overall heat-transfer coefficient has been derived. This coefficient is expressed in terms oi Nu and is correlated with t he following dimensionless groups: v(a)/v(w), H-n/D-n, D-c/D-n, and Re . The correlation obtained by minimizing the absolute error is Nu = 0. 0148 (v(a)/v(w))(-0.16) x (H-n/D-n)(-1.3) (D-c/D-n)(-1/2) Re-1.2. (C) 1998 Elsevier Ltd. All rights reserved.