Inputs
Example data table
| Case | Method | Key inputs | Typical output |
|---|---|---|---|
| A | Energy | Load 500 kW, h_in 2785 kJ/kg, h_out 419 kJ/kg, η 0.95, SF 1.10 | ≈ 867 kg/h |
| B | Pipeline | 300 kPa gauge, 180°C, x=1.00, ID 50 mm, v 25 m/s | ≈ 46 kg/h (approx.) |
| C | Pipeline | 500 kPa gauge, 200°C, x=0.95, ID 80 mm, v 20 m/s | ≈ 160 kg/h (approx.) |
Examples are illustrative and depend on assumed properties.
Formula used
Energy method
Steam mass flow is estimated from heating demand and enthalpy drop.
- ṁ = Q / (Δh · η)
- Q = thermal load (kW = kJ/s)
- Δh = h_in − h_out (kJ/kg)
- η = efficiency (0–1), then multiply by safety factor
Velocity method
Steam mass flow is estimated from density, pipe area, and velocity.
- ṁ = ρ · A · v
- A = π·D²/4
- ρ_v ≈ P_abs /(R·T) using R = 461.5 J/kg·K
- Wet steam: 1/ρ ≈ x/ρ_v + (1−x)/ρ_l (simple mixture model)
How to use this calculator
- Select a method based on available data.
- For heating, enter load and enthalpies from tables.
- For pipelines, enter pressure, temperature, diameter, and velocity.
- Choose an output unit and press Calculate.
- Download CSV or PDF for records and reports.
Professional guide for steam flow estimation
1) Why steam flow matters on site
Steam supports curing, cleaning, sterilizing, temporary heating, and process assistance. Correct mass flow keeps temperatures stable and avoids waste. Undersupply causes slow warm-up and uneven heat. Oversupply increases fuel use, venting, and trap losses. This tool provides checks for planning.
2) Two practical calculation paths
The energy method converts a known heat duty into steam flow using the enthalpy drop between inlet steam and outlet condensate. The pipeline method estimates flow from pipe area, velocity, and density when you are checking an installed line. Pick the method that matches what you can measure reliably.
3) Property data and typical ranges
Steam properties change with pressure, temperature, and dryness. For accurate work, pull enthalpy from trusted steam tables. As a practical reference, saturated dry steam around 3 bar(g) is often near 2720 to 2800 kJ/kg, and condensate near 100 C is about 419 kJ/kg. Use your actual set points for final values.
4) Efficiency and safety factor selection
Efficiency represents distribution losses and control margin. Short insulated runs may justify 0.90 to 0.98, while long outdoor runs or intermittent service may be lower. Safety factor commonly falls between 1.05 and 1.25 for peaks and uncertainty. Avoid extreme factors that hide design problems.
5) Velocity checks for piping
Velocity screening helps reduce noise, erosion, and water hammer risk. Designers typically confirm velocity alongside pressure drop and drainage layout. Here, density uses a simple vapor ideal-gas estimate and an optional wet-steam mixture model, so treat results as an approximation for comparison and reporting.
6) Quality and wet steam effects
Quality is the dry mass fraction. A value of 1.00 indicates all vapor, while 0.90 means 10% liquid by mass. Wet steam can reduce predictable heat delivery, increase condensate loading, and raise hammer risk at low points. Improving separation and drainage often stabilizes performance.
7) Field workflow for construction teams
Define the duty, record pressure type and set point, estimate condensate return temperature, and run the energy method. Compare the result to regulator capacity and valve selection. For installed lines, verify inside diameter, estimate velocity, and use the pipeline method to cross-check the expected order of magnitude.
8) Documentation and handover
Export CSV for handover sheets and PDF for commissioning packs. Capture date, operating mode, and any condensate issues. Repeat after insulation repairs or control tuning to quantify improvements and keep performance targets aligned across stakeholders.
FAQs
1) Which method should I choose?
Use the energy method when you know required heat duty and enthalpies. Use the pipeline method when you have pipe size and an estimated or measured velocity for a quick check.
2) Where do I get inlet and outlet enthalpy?
Use steam tables for your pressure and condition. Inlet enthalpy depends on pressure and dryness or superheat. Outlet enthalpy often matches condensate return temperature and pressure.
3) What efficiency value is reasonable?
For short insulated runs and stable loads, 0.90 to 0.98 is common. For long outdoor piping, intermittent service, or poor insulation, use a lower value and verify on site.
4) Does pipe velocity alone confirm a good design?
No. Velocity is only one check. Also review pressure drop, noise, erosion risk, dryness, and condensate drainage. Final sizing should confirm regulator capacity, valve sizing, and trapping layout.
5) How does steam quality affect results?
Lower quality increases mixture density and can change estimated mass flow for the same velocity. Wet steam also reduces usable heat and can raise water hammer risk with poor drainage.
6) Why does the pipeline method mention ideal gas?
It uses an ideal-gas estimate for vapor density to stay simple. Real steam deviates more at higher pressures. For accuracy-critical work, use verified properties from steam tables.
7) What should I include in commissioning records?
Log pressure type, set points, temperature, pipe size, assumed quality, and operating mode. Save the exports with date and notes about insulation, traps, and observed condensate behavior.