Laminar Condensation on a Moving Drop. Part 2. Numerical Solutions

In this paper, we investigate the problem of transient laminar condensation on a moving drop by the semianalytical series-truncation method. The objectives are to assess the validity and the accuracy of the matched-asymptotic method employed in Part 1 . The fluid flow and thermodynamic variables are expanded as complete series of Legendre polynomials. The resulting transient momentum, energy and species equations are integrated numerically. The numerical scheme basically involves a three-point central difference for the spatial derivatives and a backward difference expression for the temporal derivatives. The finite-difference equations have been solved by the strongly implicit procedure. Good agreement of the fully transient numerical results with the singular perturbation approximation results of Part 1 lends credibility to a quasi-steady treatment of the continuous phase. The computational time requirements for the fully numerical solutions increase with decreasing non-condensable gas mass fraction in the bulk environment.