Calculate steam flow based on pipe size, velocity, and pressure.
Typical range: 15-40 m/s
Calculation Results
Est. Steam Density:–
Pipe Cross-Sectional Area:–
Volumetric Flow Rate:–
Mass Flow Rate (kg/hr):–
Mass Flow Rate (kg/s):–
Understanding Steam Mass Flow Rate
Accurately calculating the steam mass flow rate is fundamental for the proper sizing of steam pipes, control valves, and orifice plates in industrial process engineering. Unlike liquids, steam is a compressible fluid, meaning its density changes significantly with pressure and temperature. Therefore, calculating the mass flow rate ($\dot{m}$) requires not just the velocity and pipe area, but also an accurate determination of the steam's density at operating conditions.
The Continuity Equation
This calculator utilizes the fundamental Continuity Equation for fluid mechanics. While more complex methods exist for metering (such as differential pressure across an orifice), the general sizing equation is:
$\dot{m} = A \times v \times \rho$
$\dot{m}$: Mass Flow Rate (kg/s)
$A$: Cross-sectional Area of the pipe (m²)
$v$: Velocity of the steam (m/s)
$\rho$: Density of the steam (kg/m³)
Key Parameters Explained
1. Steam Pressure & Density
The most critical variable in steam calculations is density. Saturated steam at 1 bar gauge has a significantly different specific volume compared to steam at 10 bar gauge. This calculator estimates the density of saturated steam based on the gauge pressure input using a high-fidelity power-law approximation. If you have superheated steam, it is recommended to input the exact Specific Volume directly if known.
2. Velocity Constraints
When designing steam systems, velocity is kept within specific ranges to prevent erosion, noise, and water hammer.
Saturated Steam: Typically 15 m/s to 30 m/s.
Superheated Steam: Can range higher, typically 30 m/s to 60 m/s depending on pipe size.
Exhaust Steam: Usually lower, around 15 m/s to 20 m/s.
Why Mass Flow Matters Over Volumetric Flow
In energy transfer applications, the heat content is directly related to the mass of the steam, not its volume. A boiler produces a certain mass of steam per hour (kg/hr), and heat exchangers consume steam by mass. Volumetric flow (m³/hr) is useful for determining velocity inside the pipe, but mass flow is required for energy balances and thermodynamic efficiency calculations.
Common Conversion Factors
1 kg/s = 3600 kg/hr
1 bar = 100,000 Pascals = 14.5 PSI
Density ($\rho$) = 1 / Specific Volume ($v_g$)
function calculateSteamFlow() {
// 1. Get Inputs
var diameterInput = document.getElementById('pipeDiameter').value;
var velocityInput = document.getElementById('steamVelocity').value;
var pressureInput = document.getElementById('steamPressure').value;
var specVolInput = document.getElementById('specificVolume').value;
// 2. Validate Numbers
var d_mm = parseFloat(diameterInput);
var v_ms = parseFloat(velocityInput);
var p_bar_g = parseFloat(pressureInput);
var vol_custom = parseFloat(specVolInput);
if (isNaN(d_mm) || d_mm <= 0) {
alert("Please enter a valid positive Pipe Diameter.");
return;
}
if (isNaN(v_ms) || v_ms 0) {
density_kgm3 = 1 / vol_custom;
} else {
if (isNaN(p_bar_g) || p_bar_g < 0) {
alert("Please enter a valid Steam Pressure or Specific Volume.");
return;
}
// Approximate Saturated Steam Density from Pressure
// Formula approximation for range 0-30 bar:
// Absolute Pressure P_abs = P_gauge + 1.01325
var p_abs = p_bar_g + 1.01325;
// Empirical fit for saturated steam density (approximate)
// Density ~= 0.536 * (P_abs ^ 0.94) is a decent approximation for general process engineering
// For higher accuracy in JS without a full steam table, we use this power law.
density_kgm3 = 0.52 * Math.pow(p_abs, 0.94);
}
// 5. Calculate Flow Rates
// Volumetric Flow Q (m3/s) = A * v
var volFlow_m3s = area_m2 * v_ms;
var volFlow_m3h = volFlow_m3s * 3600;
// Mass Flow m_dot (kg/s) = Q * density
var massFlow_kgs = volFlow_m3s * density_kgm3;
var massFlow_kgh = massFlow_kgs * 3600;
// 6. Display Results
document.getElementById('resDensity').innerHTML = density_kgm3.toFixed(3) + " kg/m³";
document.getElementById('resArea').innerHTML = area_m2.toFixed(5) + " m²";
document.getElementById('resVolFlow').innerHTML = volFlow_m3h.toFixed(2) + " m³/h";
document.getElementById('resMassFlowHour').innerHTML = massFlow_kgh.toLocaleString('en-US', {maximumFractionDigits: 1}) + " kg/hr";
document.getElementById('resMassFlowSec').innerHTML = massFlow_kgs.toFixed(3) + " kg/s";
// Show result box
document.getElementById('results').style.display = 'block';
}
function resetSteamCalc() {
document.getElementById('pipeDiameter').value = '';
document.getElementById('steamVelocity').value = '';
document.getElementById('steamPressure').value = '';
document.getElementById('specificVolume').value = '';
document.getElementById('results').style.display = 'none';
}