Learn
How a Jet Engine Works?
A jet engine converts fuel into thrust using four continuous stages: intake, compression, combustion, and expansion.
The thermodynamic cycle behind it is the Brayton cycle, and understanding it is essential for aerospace, mechanical, and propulsion engineering.
This interactive simulation lets you drag an airflow position slider through a turbojet cross-section and watch what happens to the air at every stage.
The top panel shows a schematic engine with compressor blades, combustion flames, turbine blades, and a converging nozzle.
The bottom panel traces a live T-s (temperature vs entropy) diagram that builds in real time as you move through the engine. Pressure, temperature, velocity, and thermal efficiency update at every position.
A pressure ratio slider (4:1 to 30:1) lets you see how modern high-pressure-ratio engines achieve better efficiency than older designs.
Each stage is color-coded: blue for intake, orange for compressor, red for combustion, green for turbine, purple for nozzle.
Tap any stage button to jump directly to that section with a full explanation of the physics.
Built for aerospace and mechanical engineering students, GATE and interview prep, turbine design fundamentals, and anyone curious about what happens inside the engine every time they board a flight.
Try this simulation yourself
Start with the slider at the far left. You're at the inlet. Air enters at 288 K, 101 kPa, moving at flight speed. The dot on the T-s diagram sits at point 1 in the bottom left. Nothing has happened to the air yet.
Slowly drag the slider into the compressor (orange zone). Watch the pressure metric climb from 101 kPa toward 1200+ kPa. Temperature rises too, from 288 K to over 600 K. On the T-s diagram, the dot climbs vertically along the 1→2 isentropic line. Entropy stays constant because compression is (ideally) reversible. The compressor blades in the top panel are doing all this work.
Continue into the combustion chamber (red zone). Fuel burns at constant pressure. Temperature rockets from ~600 K to 1500 K. This is the hottest point in the entire engine. On the T-s diagram, the dot sweeps right along the 2→3 curve. Entropy increases because you're adding heat. The flame dots in the cross-section light up.
Move into the turbine (green zone). Hot gas expands through the turbine blades, spinning the shaft that drives the compressor. Pressure and temperature drop. The T-s dot falls vertically along 3→4. The turbine extracts just enough energy to power the compressor. Everything left in the gas is for thrust.
Drag into the nozzle (purple zone). Remaining energy accelerates the gas to exhaust speed. The velocity metric jumps to 500+ m/s. This velocity difference between inlet and exhaust creates thrust: F = mass flow × (V_exit - V_inlet). That's Newton's third law turning heat into forward motion.
Now drag the pressure ratio slider from 12 up to 25. Watch efficiency climb from 45% to over 53%. The T-s diagram stretches taller because higher compression means higher peak temperature for the same heat input. This is exactly why modern engines like the GE9X use pressure ratios above 27.
Drop the pressure ratio to 4. Efficiency falls to 33%. The T-s cycle area shrinks, meaning less net work per unit of heat added. Low pressure ratio engines waste more energy in the exhaust. You can see the difference in the cycle shape immediately.
Tap the stage buttons (Inlet, Compressor, Combustion, Turbine, Nozzle) to jump directly to each section. The info bar explains exactly what's happening physically at that stage, what's happening thermodynamically on the T-s diagram, and where this stage fits in real engine design.