This simulation shows constant enthalpy, entropy, temperature, and quality curves on a log pressure versus log volume diagram for water. The phase envelope is a thick black line. Toggle property curves on or off by clicking the appropriate checkbox above the plot. Toggle grid lines on and off using the "gridlines" checkbox.

The thick black line on the pressure-volume diagram represents the phase envelope. Inside the phase envelope is the two-phase region where vapor and liquid are in equilibrium. Outside of the phase envelope, only one phase is present (liquid, vapor, or supercritical fluid). For a constant temperature curve (an isotherm), pressure is constant inside the phase envelope. The constant-property curves were compiled using steam tables that can be downloaded as an Excel spreadsheet or in other formats here.

This simulation was created in the Department of Chemical and Biological Engineering, at University of Colorado Boulder for LearnChemE.com by Neil Hendren under the direction of Professor John L. Falconer. Address any questions or comments to learncheme@gmail.com. All of our simulations are open source, and are available on our LearnChemE Github repository.

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