Exploratory Investigation of Laminar Boundary Layer Heat Transfer Characteristics of Gas Liquid-Spray Systems

摘要

On the basis of an assumed two-dimensional model for the two-phase boundary layer on a body exposed to a gas stream containing liquid drops, an approximate analysis is made of the surface effects occuring with laminar flow. Some of the findings are: (1) Surface rates of heat transfer in an air stream may be increased more than thirtyfold by water drop injection. (2) The surface friction and heat transfer rate always decrease initially with increasing liquid 'catch' rates. (3) When the impinging drops have retained at least a little of the local free stream tangential velocity and/or temperature level, minima and maxima occur in the surface friction and/or heat transfer rate, respectively as the liquid 'catch' rate increases. (4) The minima in the surface boundary layer characteristics are so close to unity and occur at such infinitesimal, corrected 'catch' rates for the liquids studied, that, in effect, they don't exist for practical purposes. Instead, the surface characteristics seem to initially increase linearly with the liquid ingestion rate. (Author)