CONDENSATION OF VAPOR ON A VERY COLD LIQUID STREAM

A liquid stream of isoamyl acetate exposed for ∼0.001 second at about -65° C. was used to condense supplied vapor of the same material for which it formed an absolute sink. Condensation rates were measured for various pressures of vapor fed to the cold liquid steam. The maximum rate observed simulated the flow of vapor through an orifice having the same area as the condensing surface and opposing nil downstream pressure and equaled approximately the maximum condensation rate prediced by Schrage's “modified theory.” Schrage's “simple theory” is also satisfactory for this extreme case, if sonic velocity is assumed for vapor approaching the interface and values of temperature and pressure at a Mach number of unity are used in the calculation. Under these conditions of complete condensation, and when the distance between the evaporator and condenser is much longer than the mean free path of the vapor, the rate of condensation or evaporation appears to be limited by the fastest rate the vapor can flow, perhaps by the speed of sound. © 1969, American Chemical Society. All rights reserved.