Study substance transitions with dependable thermodynamic estimates. Review saturation pressure, boiling point, and region behavior. Create clearer engineering reports using graphs, summaries, and exports.
| Fluid | Temperature (°C) | Pressure (kPa) | Expected Region | Reason |
|---|---|---|---|---|
| Water | 25 | 101.325 | Subcooled or compressed liquid | Pressure exceeds water saturation pressure at 25 °C. |
| Water | 120 | 101.325 | Superheated vapor | Atmospheric pressure is below saturation pressure at 120 °C. |
| Carbon Dioxide | 35 | 8000 | Supercritical fluid | Both temperature and pressure exceed critical values. |
| Ammonia | -90 | 50 | Solid region | Temperature is below the approximate fusion boundary. |
Reduced properties
Tr = T / Tc
Pr = P / Pc
Ambrose-Walton vapor pressure correlation
ln(Psat/Pc) = f0(Tr) + ωf1(Tr)
The calculator uses the fluid acentric factor, critical pressure, and critical temperature to estimate the vapor-pressure curve.
Boiling point at selected pressure
The boiling point is found iteratively by solving for the temperature where Psat(T) = Pin.
Approximate fusion line
Tfusion(P) = Ttriple + m × (P - Ptriple)
This linear boundary is a practical estimate for identifying solid-side conditions. It is intentionally simplified for quick engineering checks.
It estimates the likely phase region of a pure substance from temperature, pressure, and fluid constants. It also reports saturation pressure, boiling point, reduced properties, and a plotted pressure-temperature state point.
Use it for screening, education, and preliminary engineering checks. Final design work should rely on validated equations of state, trusted thermodynamic databases, or specialist simulation packages.
That happens when the entered pressure is very close to the estimated saturation pressure at the chosen temperature. The tolerance field controls how close the point must be before the calculator calls it a boundary.
The acentric factor measures how much a fluid’s vapor-pressure behavior departs from simple spherical molecules. It helps the vapor-pressure correlation better match real substances.
The fusion slope provides a simple way to estimate how the solid-liquid boundary shifts with pressure. It is a practical approximation, not a full experimental phase-boundary model.
Yes. Choose the custom fluid option and enter the triple point, critical point, acentric factor, and fusion slope. This lets you adapt the calculator to many pure-substance engineering studies.
If your selected pressure is above the critical pressure or outside the practical search range, a normal saturation boiling point may not exist. In that case the calculator returns no boiling-point estimate.
The chart shows the estimated liquid-vapor saturation curve, a simplified fusion trend, triple and critical markers, and your calculated state point. It helps you see where the operating condition lies.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.