Calculate the mass flow rate of steam based on pipe diameter, velocity, and specific volume.
Note: Specific volume varies with steam pressure (e.g., Sat. steam at 10 bar abs ≈ 0.194 m³/kg).
Calculation Results
Mass Flow Rate (kg/h):0 kg/h
Mass Flow Rate (kg/s):0 kg/s
Cross-Sectional Area:0 m²
function calculateSteamFlow() {
var d = parseFloat(document.getElementById('pipeDiameter').value);
var v = parseFloat(document.getElementById('steamVelocity').value);
var sv = parseFloat(document.getElementById('specificVolume').value);
if (isNaN(d) || isNaN(v) || isNaN(sv) || sv <= 0 || d <= 0) {
alert("Please enter valid positive numbers for all fields.");
return;
}
// Convert diameter mm to meters
var d_m = d / 1000;
// Calculate Cross Sectional Area (m2) = PI * (D/2)^2
var area = Math.PI * Math.pow((d_m / 2), 2);
// Calculate Volumetric Flow (m3/s) = Velocity * Area
var volumetricFlow = v * area;
// Calculate Mass Flow (kg/s) = Volumetric Flow / Specific Volume
var massFlowS = volumetricFlow / sv;
// Calculate Mass Flow (kg/h)
var massFlowH = massFlowS * 3600;
document.getElementById('resKgh').innerText = massFlowH.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resKgs').innerText = massFlowS.toLocaleString(undefined, {minimumFractionDigits: 4, maximumFractionDigits: 4});
document.getElementById('resArea').innerText = area.toLocaleString(undefined, {minimumFractionDigits: 5, maximumFractionDigits: 5});
document.getElementById('steamResult').style.display = 'block';
}
Understanding Steam Flow Rate Calculations
Accurately calculating the steam flow rate is essential for sizing piping systems, choosing control valves, and ensuring the efficiency of thermal processes. If the flow rate is underestimated, the system may suffer from excessive pressure drops; if overestimated, the equipment will be unnecessarily expensive and may perform poorly at low loads.
The Mass Flow Formula
The calculation used in this tool is based on the fundamental continuity equation for fluid mechanics. The formula for mass flow rate ($ \dot{m} $) is:
ṁ = (V × A) / v
ṁ: Mass Flow Rate (kg/s)
V: Velocity of the steam (m/s)
A: Cross-sectional area of the pipe ($m^2$)
v: Specific volume of the steam ($m^3/kg$)
Typical Design Velocities for Steam
To avoid erosion, noise, and excessive pressure drop, engineers typically design systems within these velocity ranges:
Steam Type
Recommended Velocity (m/s)
Saturated Steam
20 – 30 m/s
Superheated Steam
40 – 60 m/s
Exhaust Steam (Low Pressure)
50 – 70 m/s
Why Specific Volume Matters
Unlike water, steam is a compressible gas. Its density (and therefore its specific volume) changes dramatically with pressure. For example, saturated steam at 1 bar (absolute) has a specific volume of approximately 1.69 $m^3/kg$, whereas at 10 bar (absolute), it occupies only 0.194 $m^3/kg$. When using this calculator, ensure you obtain the correct specific volume from a Steam Table based on your operating pressure.
Example Calculation
Imagine you have a pipe with an internal diameter of 80mm carrying saturated steam. If your design velocity is 25 m/s and the steam is at a pressure where the specific volume is 0.24 $m^3/kg$: