OGS
[case] WaterVapourLatentHeatWithCriticalTemperature

A latent heat model of vaporisation of water considering the critical temperature.

The model uses an equation for a general expression of the latent heat of vaporisation of water in the vicinity of and far away from the critical temperature, which was presented by Torquato and Stell in [38].

Denoting the critical temperature as $$T_c$$, and introducing a dimensionless variable $$\tau=(T_c-T)/T_c$$ associated with temperature $$T$$, the equation is given by

$L(\tau) = a_1 \tau^{\beta}+a_2 \tau^{\beta+\Delta} +a_4 \tau^{1-\alpha+\beta} +\sum_{n=1}^{M}(b_n \tau^n),\,\text{[kJ/kg]},$

where the parameters of $$b_n$$ are obtained by the least square method by fitting the equation with the experiment data.

In this model, the parameter set of $$M=5$$ is taken for a high accuracy. All parameters are given below:

• $$\alpha=1/8,\,\beta=1/3,\, \Delta=0.79-\beta$$,
• $$a_1=1989.41582,\, a_2=11178.45586, a_4=26923.68994$$,
• $$b_n:=\{-28989.28947, -19797.03646, 28403.32283, -30382.306422, 15210.380\}$$.

The critical temperature is 373.92 $$^{\circ}$$C.

A comparison of this model with the model of MaterialPropertyLib::LinearWaterVapourLatentHeat is given in the following figure.