A modified equation of state for water for a wide range of pressure and the concept of water shock tube

Abstract

An equation of state (EOS) for compressible water is presented for the application over a wide range of pressure. The proposed EOS is a modified form of the Noble Abel Stiffened Gas equation (NASG) which is originally developed for the prediction of saturation properties of water. Three well-known EOS for water viz., the Tait EOS, the Stiffened Gas EOS, and the NASG EOS are used in the comparative study of the proposed EOS. Accuracy of the density estimates of the modified EOS is quantified by comparing with the published NIST data. The evaluative study of the EOS is performed over the pressure range of 1×105 Pa to 1×109 Pa and temperature range of 280 K–370 K. The analysis reveals the supremacy of the modified version of the NASG EOS over the original version for its improved accuracy and suggests its applicability over a wide range of pressure. The problem of water shock tube is selected in the study as an application of the EOS and to demonstrate the robustness of the modified EOS. The superiority of the modified NASG EOS over the Tait EOS in modelling non-isothermal flow problems with high accuracy is also revealed in the study.