Evaluating Multi-Component Pressure Dependence of Mixture Rules for Multi-Well Multi-Channel Reacting Systems

摘要

A substantial fraction of reactions in combustion are controlled by collisional energy transfer between reactants and surrounding bath gas. While the majority of fundamental research focuses on systems with single-collider bath gases, all practical combustion situations involve significant fractions of multiple components - thus requiring a mixture rule to extrapolate from kinetic data for pure bath gases to multi-component bath gases. Therefore, understanding the accuracy of mixture rules to be implemented, and ensuring their ability to represent multi-component pressure dependence properly, are of great significance to combustion modelling. The present paper evaluates various mixture rules for representing multi-component pressure dependence for multi-well multi-channel reactions by comparing their performance against master equation calculations. The master equation calculations reveal deviations from mixture rules implemented in current combustion codes of up to a factor of 10. Similar to our previous work on single-well, single channel-reactions, the present results indicate that newly proposed mixture rules based on the reduced pressure are substantially more accurate than those using the absolute pressure (reducing maximum deviations from a factor of 10 to ～3%). The present results continue to generalize and validate improved mixture rules of general applicability for different reaction classes and characteristics for their incorporation in combustion codes.