DME Supercritical Evaporation Numerical Simulation Based On The G~E-EOS Of Phase Equilibrium

In recent years, the engine strengthening technology are unceasing enhancement, engine cylinder pressure in the trend of increase significantly, to achieve even more than the DME critical pressure (5.37Mpa), So DME fuel in the engine cylinder are often in a state of supercritical evaporation. At present the supercritical evaporation theory is one of the key research droplets evaporate, Due to some of the assumptions in the low pressure conditions are not fit in the environment of high-pressure, Therefore need to build new characteristics of the numerical simulation model according to the droplet in supercritical conditions.By comparing the simulation results of the cubic type state equation, selected SRK equation to the basic equations after comprehensive comparison. Discussed Applicable scope of the Raoult law and phase balance principle, According to the actual situation of the pressure in the cylinder, we choose phase equilibrium calculation criteria to calculation interface in gas and liquid fuel quality score. Because of GE-EOS methods could introduced the activity coefficients for liquid to the expression of state equation (EOS), make state equation and activity coefficients model combined. The calculation results show that, the undissolved inert gas solubility enhanced markedly in high pressure environment. Raoult laws must be instead of phase balance principle because that Raoult laws can’t correctly reflect the flow characteristics.The supercritical fluid (SCF) theory and the discriminated basis are introduced. According to the specificity change of the fluid physical parameters in critical areas, this paper fixed the diffusion coefficient and partial Moore, the constant pressure than hot heat, coefficient of thermal conductivity in high pressure, establish a set of reference method to calculation the Physical parameters. Calculated results are compared with experimental data based on the theories concerned.This paper established DME in supercritical conditions of evaporation mathematical model based on the interface mobile components of conservation equation, And through the Fortran programming. Consider Soret effect and Dufour effect on the influence of the droplets evaporate. And at the same time according to the practical spray theory, this paper join secondary breakup model in the critical point. Radiation heat can speed up the temperature rising and reduce the droplet life. Analyze the influence of the life of droplet of Secondary Breakup at the actual working condition in the cylinder.