Formulation of the Equation of State for Light Water Substance(1st Report, Second Vihal Coefficient and Isobaric Specific Heat Capadity at Zero Pressure)

For light water substance, the 1967 IFC [International Formulation Committee] Formulation for Industrial Use should be revised in accordance with the International Practical Temperature Scale of 1968 and the New International Skeleton Table recommended by the IAPS [International Association for the Properties of Steam] in 1985. The purpose of the present study is to formulate the virial equation of state for light water substance. As the first step, correlating equations of the second virial coefficient, B0 and of isobaric specific heat capacity at zero pressure, cp0 were obtained for light water substance. The new correlating equations have the following functional form: where T is the absolute temperature and the coefficients of these correlating equations, bi and ci were determined to meet the following requirements, respectively. (1) Values of the second virial coefficient satisfy sufficiently the standard values and tolerances which have been proposed by Le Fevre et al. using the correlation formulated by including the data of throttling experiments in the low-temperature range together with the P-v-T data. (2) Values of the isobaric specific heat capacity at zero pressure are based on the most reliable values obtained theoretically from quantum-statistical theory by Woolley. For light water substance, the values of the second virial coefficient given by the new correlation agree well with the standard values by Le Fevre et al. and the deviation in the isobaric specific heat capacity at zero pressure between the values calculated from the new correlation and the standard values given by Woolley are within ±0.03% in the range from 270K to 1300K