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UNIVERSITY OF WEST BOHEMIA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER SYSTEM ENGINEERING. Ratkovská Katarína. JET ENGINES. HISTORY. 17.12.1903 Orvill Wright and Wilburom Wright - first controlled flight. 1935 Frank Whitley - patented principle of jet engines
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UNIVERSITY OF WESTBOHEMIAFACULTY OF MECHANICALENGINEERINGDEPARTMENT OF POWER SYSTEM ENGINEERING Ratkovská Katarína
HISTORY • 17.12.1903OrvillWright and WilburomWright - firstcontrolledflight
1935 Frank Whitley - patentedprincipleofjetengines • 27.8.1939Hans von Ohain - HeS – 3B jetengine W - 1
TYPICAL ENGINE CUTS 0 – 1 engineintake 1 – 2 compressor 2 – 3 maincombustionchamber 3 – 4 gasturbine 4 – 5 exhaustsystem
BASIC PARAMETERS • Enginethrust[N] • It's more important parameter, which ischaracterized a jet engines with direct reaction [N ] Where: - mass flow rate [] - – output gas velocity [] - – airspeed []
Enginethrust[N] mass flow rate - gas[] mass flow rate - air[] – output gas velocity [] – airspeed []
Engineperformance P[W] turbo-propengines - – propellerthrust [N] - – airspeed - – propellerefficiency [1]
TS - 21 - Turboshaftenginewithfreegasturbine. - ItisstarterofR-27F2M-300 engines.
Air mass flow rate[] • Quantity of air that flows through the engine insecond. = • m – airmass [kg] • t – time [s]
Specific engine thrust Fm [] • Hour fuel consumption [kg.] - Fuelflowrate.
Totalcompressorpressureratio • Define ratio between total pressure on compressoroutput to total pressure oncompressor input. – total air pressure on compressor input [Pa] – totalairpressure on compressoroutput [Pa]
Total absolute temperature before turbine stage[K] • is the temperature value on combustionchamber output before turbine stage. T3T = t3T+273,15 [K] • Total absolute temperature behind turbine stage [K] T4T = t4T+273,15 [K]
THERMAL CYCLE • Jet engines are reactive engines witch works with atmospheric air. Purpose of air in this case is: -Basic component of working media inthermodynamic cycle - Oxygen included in air is used during chemicalreaction of burning - Accelerated air (in case of engines with direct reaction) create trust
WORK OF IDEAL THERMAL CYCLE • In p-V diagram • In T-s diagram
EFFICIENCY OF IDEAL CYCLE -SfTJE • Quality of transformation of input heat “” to work “” is described by thermodynamic efficiency “”
CONCLUSION • Work of ideal cycle in thermodynamics is characterized by efficiency. • Thermal efficiency of cycle depend by pressure ratio π and temperature ration /
DISCUSSION QUESTIONS