Propulsion cheat sheet, Cheat Sheet of Applied Thermodynamics

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Inlet / Diffuser

• Slows the freestream to raise static pressure with minimal total-pressure loss.
• Delivers uniform, high-recovery p_t, T_t air to the compressor (or combustor in a ramjet). Compressor (axial/centrifugal)
• Adds total pressure and total temperature by doing work on the air.
• Sets the core pressure ratio that largely determines cycle efficiency and required turbine work. Combustor (burner)
• Adds heat at (nearly) constant total pressure by burning fuel; raises T_{t} to the turbine-inlet limit.
• Mixes/stabilizes the flame while keeping pressure losses and pattern factor (temperature uniformity) acceptable. Turbine
• Extracts just enough shaft work from hot gas to drive the compressor (and fan/prop/gearbox if present).
• Drops T_t and p_t across stages while aiming for high efficiency and adequate cooling. Nozzle
• Converts remaining enthalpy to jet kinetic energy; accelerates flow to produce thrust.
• Ideally expands to ambient (p_e \approx p_a); otherwise a pressure thrust term appears. Fan (turbofan only)
• Adds moderate pressure/velocity to a large bypass stream, boosting thrust via high mass flow, low exhaust speed.
• Improves propulsive efficiency and lowers TSFC at subsonic cruise; driven by an extra turbine. Propeller + Gearbox (turboprop only)
• Converts turbine shaft power into thrust by accelerating a very large air mass slightly.
• Achieves very high propulsive efficiency at low–moderate speeds; gearbox matches turbine rpm to prop. Afterburner (reheat, if installed)
• Adds heat downstream of the turbine, raising nozzle inlet T_t for big thrust boosts.
• Greatly increases fuel flow/TSFC and thermal signature; used intermittently (takeoff/accel/combat). Inter-stage Ducting & Mixer (where applicable)
• Turns, mixes, and conditions flows between modules with minimal total-pressure loss.
• In mixed-flow turbofans, blends core + bypass for a single nozzle, affecting thrust and noise. Controls & Bleeds (generic)
• Schedules fuel/variable geometry/bleeds to keep surge margins, turbine temperatures, and emissions in limits.
• Bleeds provide cooling and stability but reduce core mass flow and cycle efficienc