What is Critical Pressure of Water – Definition

At pressure, that is higher than the critical pressure of water, water is in special state, that is known as supercritical fluid state. Critical pressure is Pcr = 22.09 MPa. Thermal Engineering

Critical Pressure of Water

Phase diagram of water
Phase diagram of water.
Source: wikipedia.org CC BY-SA

At pressure, that is higher than the critical pressure,  water is in special state, that is known as supercritical fluid state. A supercritical fluid is a fluid that is at pressures higher than its thermodynamic critical values. At the critical and supercritical pressures a fluid is considered as a single-phase substance in spite of the fact that all thermophysical properties undergo significant changes within the critical and pseudocritical regions.

For water, the critical  parameters are the following:

  • Pcr = 22.09 MPa
  • Tcr = 374.14 °C (or 647.3 K)
  • vcr = 0.003155 m3/kg
  • uf = ug = 2014 kJ/kg
  • hf = hg = 2084 kJ/kg
  • sf = sg =4.406 kJ/kg K

See also: Critical Point of Water

See also: Supercritical Fluid

Reactor Physics and Thermal Hydraulics:
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