💧 Steam Tables Calculator
Calculate thermodynamic and transport properties of water and steam using NBS/NRC high-precision formulations.
📝 Configuration
NBS/NRC Steam Formulation:
Based on the Haar-Gallagher-Kell Helmholtz free energy model, which is numerically consistent across liquid, gas, and mixture regions.
Region Definitions:
• Subcooled Liquid: $T \lt T_{sat}$
• Saturated Mixture: $T = T_{sat}$, 0 ≤ $x$ ≤ 1
• Superheated Vapor: $T \gt T_{sat}$
• Supercritical Fluid: $P \gt 22.055$ MPa
Based on the Haar-Gallagher-Kell Helmholtz free energy model, which is numerically consistent across liquid, gas, and mixture regions.
Region Definitions:
• Subcooled Liquid: $T \lt T_{sat}$
• Saturated Mixture: $T = T_{sat}$, 0 ≤ $x$ ≤ 1
• Superheated Vapor: $T \gt T_{sat}$
• Supercritical Fluid: $P \gt 22.055$ MPa
📊 Results & Visualization
Configure inputs and click Calculate to view steam properties.
📘 Calculation Methodology
Mathematical Model & Theory
Thermodynamic properties of water and steam are modeled using the IAPWS-IF97 industrial formulation, which divides the state space into 5 regions, mapping Helmholtz free energy equations $a( ho, T)$ and Gibbs free energy equations $g(P, T)$ to obtain pressure, volume, temperature, enthalpy, and entropy.
Worked Engineering Example
Problem Statement:
Find the enthalpy and quality of water at $P = 1$ MPa and $T = 179.88$°C (saturation conditions) if its entropy is $s = 5.0$ kJ/(kg·K). (At 1 MPa, $s_f = 2.138$, $s_g = 6.585$ kJ/(kg·K), $h_f = 762.6$, $h_g = 2777.1$ kJ/kg).
Step-by-step Solution:
1. Calculate quality $x$ from entropy:
$$x = \frac{s - s_f}{s_{fg}} = \frac{5.0 - 2.138}{6.585 - 2.138} = \frac{2.862}{4.447} = 0.6436$$ 2. Calculate mixture enthalpy $h$:
$$h = h_f + x(h_g - h_f) = 762.6 + 0.6436 \times (2777.1 - 762.6) = 2059.2 \text{ kJ/kg}$$
Final Result:
Steam quality is 0.644 and enthalpy is 2059.2 kJ/kg.
Find the enthalpy and quality of water at $P = 1$ MPa and $T = 179.88$°C (saturation conditions) if its entropy is $s = 5.0$ kJ/(kg·K). (At 1 MPa, $s_f = 2.138$, $s_g = 6.585$ kJ/(kg·K), $h_f = 762.6$, $h_g = 2777.1$ kJ/kg).
Step-by-step Solution:
1. Calculate quality $x$ from entropy:
$$x = \frac{s - s_f}{s_{fg}} = \frac{5.0 - 2.138}{6.585 - 2.138} = \frac{2.862}{4.447} = 0.6436$$ 2. Calculate mixture enthalpy $h$:
$$h = h_f + x(h_g - h_f) = 762.6 + 0.6436 \times (2777.1 - 762.6) = 2059.2 \text{ kJ/kg}$$
Final Result:
Steam quality is 0.644 and enthalpy is 2059.2 kJ/kg.