Convegni ATI - Accesso riservato soci CTI

Autore: A.,Torres, J.B. Cazalbou, P. Chassaing

Collana: CA - 49 - Perugia 1994

Note:
The numerical method presented in this paper has been designed for the analysis of the two-phase flow in a modern heat axchager (cool air and a fully atomized spray of water droplets are injected at the inlet) and for the improvement of its thermal efficiency. In this study, we examine the influence of the Sauter Mean Diameter of the spray in order to give guidelines for the improvement of the system. Because the geometry of the heat exchanger is very simple, the equations are solved in a square-cross-section channel, considered as an "average" channel. In our analysis, the temperature, pressure and velocity field are obtained from the solution of the three-dimensional Navier Stockes equations. The motion of the droplets is computed within a Langrangian reference frame, using a fourth-order Runge-Kutta integration applied to a finite number of droplet sizes representing the distribution within the spray. The size distribution used at the inlet of the channel follows a log-normal law. The diameter of the droplets varies along their trajectories and the amount of evaporation provides discrete sinks for the temperature equation but does not influence the dinamycs of the gas phase.