Thermal performance difference of ideal gas model and van der Waals gas model in gas-loaded accumulator

Abstract

Real gas that considering intermolecular force and molecular volume shows difference compared with the assumption as ideal. While designing accumulator or quantitatively evaluating working state of accumulator in hydraulic circuit, charged in gas-loaded accumulator, the gas properties involves pressure, temperature and stored energy are assumed by the first law of thermodynamics and gas equation of state. The discrepancy of thermodynamic behaviours of real gas from ideal gas should be highlighted. In this paper, the well-known van der Waals equation was employed as real gas model to compare with ideal gas model. The gas behaviours have shown different trends during compression and expansion by mathematically analysis and being confirmed in both isothermal and adiabatic operations. A detailed pressure deviation between ideal gas model and van der Waals model was displayed.