Comparison of tabulation and correlated dynamic evaluation of real fluid properties for supercritical mixing

In this study, two novel computationally efficient methods for the evaluation of real fluid properties are proposed and compared. The first one is a correlated dynamic evaluation of properties (CoDEP) method. In CoDEP, the time-space is dynamically categorized into many thermo-physical correlation zones, and the evaluation of real fluid properties only need to conduct once in each zone. The second one is a tabulation method, in which the real fluid properties are directly interpolated from a pre-generated look-up table. The two methods are applied to simulations of a liquid oxygen/methane mixing process at supercritical conditions. CoDEP accelerates the evaluation of compressibility factor by 4.8 times, thermodynamics properties by 3.3 times, and transport properties by 4.2 times. On the other hand, tabulation method reduces the computation time of property evaluation by more than 10 times. The overall computation acceleration for both methods are approximately a factor of two. They provide qualitatively similar predictions as the benchmark. CoDEP is significantly more accurate than the tabulation method for spatial distributions, but slightly less accurate for conditional statistics. In addition, the accuracy of both methods are insensitive to time, and CoDEP is insensitive to its threshold values.