Aircraft Air Conditioning And Pressurisation System
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Transcript of Aircraft Air Conditioning And Pressurisation System
AIRCRAFT AIR CONDITIONING AND
PRESSURISATION SYSTEMCahit Kutay Uysal
WHAT IS PRESSURISATION?
• Basically, pressurize means to increase the pressure of any specific area.• Most of the commercial aircrafts need to pressurization systems. Because,
the higher the altitude means the lower the air pressure. • The lower air pressure makes it more difficult for human to breathe normally. • This can cause several difficulties to the human body such as HYPOXIA,
TRAPPED GAS and DECOMPRESSION SICKNESS.
AIRCRAFT STRUCTURES
• If an aircraft is to be pressurised, the pressurised section must be strong enough to operational stresses
• In general, the maximum altitude at which an aircraft can fly is limited by the maximum allowable cabin differential pressure • Light aircraft – approx. 3-5 psi • Large reciprocating-engine aircraft – approx. 5.5 psi • Turbine-powered transport aircraft – approx. 9psi
AIR CONDITIONING SYSTEM
AIR CYCLE MACHINE
CONTROLLING THE CABIN PRESSURE AND SOURCES OF PRESSURISATION
- Pressurisation air from the compressor of the engine turbocharger- Hot air cooled by the intercooler- Discharge: Controlled and uncontrolled- Controlled; flows through outflow valve or safety valve- Uncontrolled; air that escapes around door and window seals, cables or other openings- Outflow valve; primary cabin pressure control, regulates the amount of pressurized air that is
allowed to exit the cabin- Safety valve (Positive pressure relief valve); will open in case of a malfunction in the
outflow valve- Dump valve; Releases all cabin pressure when aircraft lands - Negative pressure relief valve; Prevents cabin pressure from going below that of the ambient
air
MODES OF PRESSURISATION
- Unpressurised mode; cabin pressure is same with the atmosperic pressure
- Isobaric mode; the pressure in the cabin remains constant as the flight altitude changes
- The outflow valve is closed to maintain selected cabin altitude- The outflow valve modulates on flight altitude change
- Constant differential mode; the cabin pressure limited by a setted differential pressure value
THANK YOU FOR LISTENING
ANY QUESTIONS?