A CALCULATION OF THERMODYNAMIC PARAMETERS FOR MIXED CELLS IN GAS DYNAMICS

Yu.A. Bondarenko, Yu.V. Yanilkin
VANT. Ser.: Mat. Mod. Fiz. Proc 2000. Вып.4. С. 12-25.

The techniques of closing differential equations of Lagrangian gas dynamics for multi-component medium in mixed cells are studied when a method of concentrations or similar methods are used for gas-dynamic calculations. Along with a much used assumption of component compressibility equality an assumption of component pressure equality is considered in detail. In addition to these two closing techniques a new technique is proposed, derived from the assumption of component pressure increments equality. As to accuracy the latter technique turned out to be not worse than the technique, based on assumption of total pressures equality, but it is more economical and much better than one, based on the assumption of component compressibility equality. Special attention is paid to explicit difference schemes with precalculated pressure, but main results can be transferred to other difference schemes.

A new model of heat conduction for multi-component medium is proposed. This model does not suggest components temperature equality in mixed cells. The model is founded on accounting intragrid heat exchange between components in mixed cells which is performed in the same manner as that in the normal heat conduction. An essentially higher accuracy of the method proposed as compared with the method using an assumption of components temperature equality is shown.