Development and implementation of multicomponent liquid wall film evaporation model for internal combustion engine applications

Abstract

Various environmental regulations put ever stringent requirements on the automotive industry as a part of solution to the problem of global warming and climate change. Engine emissions are influenced, among others, also with quality of fuel and air mixing process. Auto ignitability of fuel in cylinder depends on detailed chemical composition of the fuel as well as on the evolution of the thermal and compositional state of the fuel mixture. The evaporation of wall film, formed by spray/wall impingement has strong effects on engine emission. This works aims at further development of the numerical model of liquid wall film by implementation and validation of mathematical models of multicomponent wall film evaporation. Two multicomponent liquid film evaporation models were developed, the first one on the basis of analogy between momentum and mass transfer, and the second one employing modified wall functions which take into account influence of the evaporation on boundary layer above liquid film. Particular scientific contribution is in implementation of the UNIFAC method for activity coefficients calculation. Finally, implemented models were compared with available experimental data in order to confirm their validity