Twofluid theory of the condensation and evaporation effects in fluid flow
Abstract
A twofluid theory for the effects of condensation and evaporation in the fluid flow has been formulated. Attention is given to a mixture of two fluids of which fluid 1 is a perfect gas while fluid 2 may exist in its liquid, vapor or a mixture of a liquid and its own vapor state. A dryness fraction lambda is introduced. When lambda = 1, fluid 2 is in gaseous state; when lambda = 0, fluid 2 is in liquid state and when lambda is greater than 0 and less than 1, fluid 2 is a mixture of a liquid and its own vapor. A relaxation time tlambda characterizes the relaxation process of evaporation or condensation. With this formulation an investigation may be conducted of the relaxation zone in the condensation shock in a supersonic wind tunnel as well as the unsteady flow region due to condensation and evaporation when the mass concentration of water in moist air is very high. The general fundamental equations of this twofluid theory are given. A special case of onedimensional unsteady nozzle flow with condensation and evaporation is discussed in details. Finally, the sound speed of fluid 2 is briefly analyzed.
 Publication:

Archiv of Mechanics, Archiwum Mechaniki Stosowanej
 Pub Date:
 1982
 Bibcode:
 1982ArMeS..34..661P
 Keywords:

 Condensation;
 Evaporation;
 Flow Theory;
 Fluid Flow;
 Two Fluid Models;
 Acoustic Velocity;
 Atmospheric Circulation;
 Inviscid Flow;
 Nozzle Flow;
 Supersonic Wind Tunnels;
 Unsteady Flow;
 Fluid Mechanics and Heat Transfer