comparison of the equations of state from joule-thomson coefficient

in the present work, we have examined the ability of some different equations of state in predicting the joule-thomson coefficient, ?j-t, of different fluids. for dense fluids, for which density is greater than the boyle density, ?b, two appropriate equations of state, namely the linear isotherm regularity, lir, and the dense system equation of state, dseos, have been examined. the results show that the dseos is in better agreement with the experimental data than the lir. however, only at very high pressures the lir gives a better result. for low densities, densities lower than the boyle density, twelve equations of state namely the van der waals, dieterici, bertholet, deiters, virial, adachi-lu-sugie, kubic-marthin, yu-lu, twu-coon-cunningham, song-mason, ihm-song-mason, and the extended linear isotherm regularity, elir, have been examined. the results show that the virial, song-mason, ihm-song-mason and elir are in a better agreement than the others. finally we have recommended an appropriate equation of state (elir) from which the joule-thomson coefficient can be calculated. in this way we found that two harmless refrigerants, r-152a and r-32, have the largest value of ?j-t, which is in accordance with the experimental observations.