CFD, NIST, Peng Robinson, Scroll Compressor
There are numerous ways of defining fluids properties for computational fluid dynamic (CFD) simulations. This paper examines three methods of defining fluid properties that are available in a commercial CFD code. Simulations were carried out for an R410a scroll compressor used in air conditioning applications and the effects are illustrated through the compression process. The first method used is the real gas property data from the National Institute of Standards and Technology (NIST). While considered the most accurate, it is not available in all CFD codes. A second method is the Peng Robinson equation of state, which approximates the real gas properties. The most widely available method, the ideal gas equation of state model, is also examined. Using the three different methods for defining fluid properties, CFD simulations of two different discharge porting schemes were analyzed. Modeling results are evaluated, and used in overall compressor performance estimates, and then compared to laboratory tests results. The results of these analyses are reviewed to illustrate the impact of the choice of property-definition methods on important design decisions. This information can also have an impact on the choice of CFD software, since not all CFD software has the fluid property options described in this paper.