03 START HERE
Liquid leaves the condenser
Heat has been removed. The working fluid is mostly liquid water at low pressure.
LOW PRESSURE · LIQUID
01 / THE BIG PICTURE
A power plant is a loop.
Heat makes steam. Steam turns a turbine. The turbine turns a generator. Then the steam cools back into water so the cycle can start again.
Aha
The turbine does not “make energy.” It converts part of the steam’s energy into rotation. The generator converts much of that shaft work into electricity.
02 / FOLLOW THE WATER
Four moments make one cycle.
These state numbers are the landmarks engineers use to calculate what the fluid gains and gives up.
04 PUMP
The pump raises pressure
A small amount of work pushes the liquid to boiler pressure. Pressurizing liquid takes far less work than compressing steam.
HIGH PRESSURE · LIQUID
01 BOILER
Heat makes hot steam
The boiler adds heat. If temperature rises above the boiling point at that pressure, the steam is superheated.
HIGH PRESSURE · HOT VAPOR
02 TURBINE
Steam expands and spins
Pressure falls through the turbine. The steam gives up enthalpy and leaves with less energy per kilogram.
LOW PRESSURE · EXHAUST
02 → 03
The condenser removes leftover heat so exhaust vapor returns to liquid. Then the pump closes the loop.
03 / WHERE THE ENERGY GOES
Every output has a boundary.
Start with heat supplied to the cycle. Some becomes net shaft work; the rest leaves as heat from the condenser.
ONE CYCLE ENERGY BUDGET BALANCED
Heat added→net work + heat rejectedQ̇in = Ẇnet + Q̇out
Generator loss is a second, nested split of shaft work. Do not add it again to the first heat-input split.
Ẇt = ṁ(h1 − h2)
Mass flow multiplied by the enthalpy drop gives turbine power.
Ẇp ≈ ṁvΔP
Pressurizing liquid needs work. In this cycle it is small, but it is counted.
η = Ẇnet / Q̇in
Net cycle work divided by heat supplied to the working fluid.
Open the full calculation chain
1 · Estimate the inlet: use saturated vapor properties at boiler pressure, then add a simple superheat correction.
h₁ ≈ hᵍ + cₚ(T₁ − Tₛₐₜ)2 · Find an ideal outlet: expand at constant entropy to condenser pressure.
s₂ₛ = s₁ → h₂ₛ from condenser-pressure properties3 · Apply turbine efficiency:
h₂ = h₁ − ηₜ(h₁ − h₂ₛ)4 · Complete the cycle balance:
Ẇnet = Ẇt − Ẇp · Q̇in = ṁ(h₁ − h₄) · Q̇out = Q̇in − ẆnetSteam quality is calculated from h₂ only when the outlet is inside the saturated liquid–vapor region.
04 / READ THE INSTRUMENTS
Numbers tell different stories.
Power, efficiency and exhaust quality are connected, but they answer different questions.
Electric output
How much electricity right now? More steam flow usually increases power because more kilograms pass through each second.
FLOW ↑ → POWER ↑
Thermal efficiency
How much heat became net work? For the same cycle conditions, changing flow scales heat and work together, so efficiency stays similar.
WORK ÷ HEAT IN
Steam quality
How much of a wet mixture is vapor? Lower quality means more liquid droplets. Quality is not defined for superheated steam.
x = vapor mass fraction
The cycle plots
Where is the working fluid? T–s plots temperature vs entropy; P–v plots pressure vs specific volume. The diagrams are teaching sketches.
READ THE AXES FIRST
Healthy rangex ≥ 0.90
Watch moisture0.85 ≤ x < 0.90
Wet-steam warningx < 0.85
These are classroom indicators used by this simulation, not universal turbine operating limits.
05 / YOUR EXHIBITION EXPERIMENT
Change one dial. Explain the trade-off.
A short, repeatable investigation helps the audience see that the simulator is a model of cause and effect.
01
Pressure vs. moisture
Start from the default setup. Pin it with Compare. Move boiler pressure from 5 MPa to 15 MPa, then 20 MPa.
Run this experiment02
Observe together
- Does electric output rise at every step?
- Does efficiency keep rising at the same rate?
- What happens to the exit-quality marker and warning?
- Which result is a trade-off rather than a simple win?
03
Record what you find
Write each value down before moving the next dial. Reset between experiments.
| Pressure | Power | Efficiency | Exit state | What changed? |
|---|---|---|---|---|
| 5 MPa | ||||
| 15 MPa | ||||
| 20 MPa |
Explain it: “When I changed ___, the model showed ___. I think this happened because ___.”
Exhibition challenge
Can you find a setup that produces more power without triggering the wet-steam warning? What did you have to trade away?
06 / QUESTIONS, DEFINITIONS & SOURCES
Stay curious. Check the model.
Use these answers to guide discussion. The full property calculations used by real engineers are more detailed than this classroom simulator.
Why doesn't higher pressure always mean more power?
Power depends on energy extracted per kilogram and steam flow. Pressure changes both the inlet and exhaust states. In this model, high pressure can also lower exit quality. The exact curve is model-dependent.
Why can the quality display say “DRY”?
Quality describes a saturated liquid–vapor mixture only. Superheated vapor is outside that region, so calling it 100% quality would be misleading.
Why might a low quality concern engineers?
A wetter exhaust contains more liquid droplets. In real turbines, droplets can erode blades. The simulation's red line at 85% is an educational alert, not a universal design limit.
Why does more flow raise power but not efficiency?
At fixed thermodynamic conditions, both heat input and work output grow in proportion to mass flow. Their ratio therefore remains about the same.
What does “isentropic” mean?
It describes an idealized expansion at constant entropy. Turbine efficiency compares the real enthalpy drop with this ideal reference.
QUICK GLOSSARY
Useful language
Enthalpy · h
Energy per unit mass used to track energy changes in flowing steam.
Entropy · s
A thermodynamic property used to describe the ideal constant-entropy expansion.
Superheat
Steam temperature above the boiling temperature at the same pressure.
Specific volume · v
Volume occupied by one kilogram of the working fluid.
Net shaft work
Turbine work after subtracting the work required by the pump.
Sankey diagram
A flow diagram where band width represents the amount of energy.
Megawatt · MW
One million joules of energy transferred every second.
What this simulator leaves out
TurbineLab uses rounded saturation values, simple superheat and pump equations, a fixed generator efficiency, and schematic diagrams. It does not model supercritical steam, reheat, turbine stages, or each power source's full plant. Use the results to explore trends, not to design or operate equipment.
See the model assumptions
- The property table is sparse and linearly interpolated; it is not a complete IAPWS calculation.
- Superheated steam uses approximate heat capacity. Real properties vary with pressure and temperature.
- Boiler pressure is limited to 20 MPa; supercritical operation is outside this model.
- Pump work uses constant liquid specific volume. Generator efficiency is fixed at 98%.
- RPM is mapped from power for the animation, not calculated from turbine design or grid speed.
- The T–s dome, P–v path, and plant scenario cards are teaching illustrations.
- The 85% wet-steam alert is a classroom threshold, not a universal operating limit.
TRUSTED STARTING POINTS
Where real steam properties come from
Engineering calculations use validated property formulations rather than the simplified correlations in this demo.
PROJECT NOTES
What changed in TurbineLab
- Cycle calculations use a turbine enthalpy drop, pump work, and an explicit energy balance.
- Superheated exhaust no longer receives an invented steam-quality number.
- Cycle diagrams and RPM are identified as teaching visuals where they are schematic.
- The guide adds a learning path, glossary, experiment sheet, answers, and authoritative property references.
Built in phases:Core model→Visuals→Exhibition learning