Analysis of real gas equation of state for CFD modelling of twin screw expanders with R245fa, R290, R1336mzz(Z) and R1233zd(E)

Abstract Positive displacement expanders are widely investigated and theirs models commonly use the REFPROP database to evaluate fluid properties. However, estimating procedures in CFD using result heavy of CPU time. Therefore, a study has been carried out determine if simpler methods for property estimation suitable. The ANSYS CFX solver used includes number cubic equations state, namely, Redlich Kwong, Soave Aungier Kwong Peng Robinson. To their suitability, performance simulations were with each them, on twin screw expander 4/5 rotor configuration an “N” profile, operating R245fa, R290, R1336mzz(Z) R1233zd(E). For considered equation, expander's results deviation from those obtained is evaluated. These show that ideal gas equation state gives predictions flow power deviate significantly determined REFPROP. alternatively available give far better agreement. Of these, RK highest deviation, although it differs by only 2.2% maximum values. PR yields closest agreement order 0.8%, while both SRK ARK less than 1.1% maximum, practically negligible. Apart good obtained, real equations, place REFPROP, resulted saving approximately 43% time obtain same level convergence solver.