Why Are Rocket Nozzles Bell-Shaped? Propulsion | Aerospace engineering | GATE | Viru Sir IITian

[00:00:00]Have you ever noticed that most of rocket engines [music] have bell-shaped nozzle? That shape is not chosen for appearance. It is [music] carefully designed to produce maximum thrust.

[00:00:12]Inside a rocket engine, hot gases are generated at [music] extremely high pressure and temperature. These gases first pass through a narrow section called throat.

[00:00:22]At the throat, gas reaches the speed of sound.

[00:00:26]As the gas moves beyond the [music] throat and enters the wider bell-shaped section, it expands rapidly. [music] This expansion converts pressure energy into velocity. The bell shape guides [music] the expanding gases smoothly in the desired direction. As the exhaust becomes supersonic, it leaves [music] the nozzle at extremely high speed. The faster the exhaust leaves the rocket, the greater the thrust [music] produced.

[00:00:53]A simple straight nozzle would waste energy and produce less thrust. A bell-shaped [music] nozzle, also known as converging-diverging nozzle, extracts more useful energy from the exhaust while keeping the nozzle shorter and lighter. That's why the bell-shaped nozzle [music] became one of the most important innovations in rocket engineering. Without it, modern space missions would be far less efficient.