Modeling and Validation of High-Pressure Hydrogen Joule-Thomson Effect for Enhanced Hydrogen Energy System Safety

With the rapid development of hydrogen fuel cell vehicles, the research on the throttling effect of high-pressure hydrogen is crucial to the safety of hydrogen circulation systems for fuel cells. This paper studies the Joule-Thomson coefficients (${\mathsf{\mu }}_{\mathrm{J}\mathrm{T}}$) of ten gas state equations. The four equations, Van Der Waals (VDW), Redlich-Kwong (RK), Soave-Redlich-Kwong (SRK), and Beattie Bridgeman (BB), were selected for calculation. These were compared with the database of the National Institute of Standards and Technology (NIST), aiming to determine the optimal state equation under different temperature and pressure conditions. The empirical formula of the ${\mathsf{\mu }}_{\mathrm{J}\mathrm{T}}$ pressure and temperature was compounded, and the temperature rise effect was further calculated using the empirical formula of compounding. The results show that the calculated value of ${\mathsf{\mu }}_{\mathrm{J}\mathrm{T}}$ by using the VDW equation in the low-pressure range (0–2 MPa) is closer to the value in the NIST database with an error less than 0.056 $\mathrm{K}\bullet {\mathrm{M}\mathrm{P}\mathrm{a}}^{-1}$. The tendency of ${\mathsf{\mu }}_{\mathrm{J}\mathrm{T}}$ described by the RK equation corresponds to the NIST database; meanwhile, the maximum error in the SRK equation is 0.143916 $\mathrm{K}\bullet {\mathrm{M}\mathrm{P}\mathrm{a}}^{-1}$. The BB equation is more applicable within the pressure range of 20 to 50 MPa with a maximum error of 0.042853 $\mathrm{K}\bullet {\mathrm{M}\mathrm{P}\mathrm{a}}^{-1}$. The fitting error of the empirical formula is within 9.52%, and the relative error of the calculated temperature rise is less than 4%. This research might provide several technical ideas for the study of the throttling effect of hydrogen refueling stations and the hydrogen circulation system of on-board hydrogen fuel cells.