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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 - PowerPoint PPT Presentation
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UNIVERSITY OF WEST BOHEMIAFACULTY 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
• 27.8.1939 Hans von Ohain- HeS – 3B jet engine
W - 1
He - 178
TYPICAL ENGINE CUTS
0 – 1 engine intake1 – 2 compressor2 – 3 main combustion chamber3 – 4 gas turbine4 – 5 exhaust system
VK 1 engine with radial
compressor
RD 33
MiG-29
BASIC PARAMETERS
• Engine thrust [N]- It's more important parameter, which is
characterized a jet engines with direct reaction
[N ]Where:- mass flow rate []- – output gas velocity []- – air speed []
• Engine thrust [N]
mass flow rate - gas [] mass flow rate - air [] – output gas velocity [] – air speed []
• Engine performance P[W] turbo-prop engines
- – propeller thrust [N]- – air speed- – propeller efficiency [1]
Turboprop engine TP 100
TS - 21
- Turboshaft engine with free gas turbine.- It is starter of R-27F2M-300 engines.
Mig 23 - FLOGGER
• Air mass flow rate[] - Quantity of air that flows through the engine
in second.
=
• m – air mass [kg]• t – time [s]
• Specific engine thrust Fm []
• Hour fuel consumption [kg.]
- Fuel flow rate.
• Total compressor pressure ratio - Define ratio between total pressure on compressor
output to total pressure on compressor input.
– total air pressure on compressor input [Pa] – total air pressure on compressor output [Pa]
COMPRESSOR TYPESCentrifugal flow compressors
AXIAL FLOW COMPRESSORS
• Total absolute temperature before turbine stage [K]
- is the temperature value on combustion chamber 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 in thermodynamic cycle- Oxygen included in air is used during chemical reaction of burning- Accelerated air (in case of engines with direct reaction) create trust
SfJE - Ideal thermal cycle
SfJE with afterburner – ideal thermal cycle
WORK OF IDEAL THERMAL CYCLE
• In p-V diagram
• In T-s diagram
1,,. . kgJWWW adkomadexid
121. . kgJqqWid
WORK OF IDEAL THERMAL CYCLE
Ideal expansion work of gas:
1013
3
5353,
.11...11..
1..
kgJe
TcTc
TTTcTTcW
pp
ppadex
EFFICIENCY OF IDEAL CYCLE - SfTJE
• Quality of transformation of input heat “” to work “” is described by thermodynamic efficiency “”
111111..
1.1..
10
0
1
ee
eeTce
eTc
qW
p
pi
t
DEPENDENCE OF “” BY “”
WORK OF IDEAL THERMAL CYCLE - SfTJE
0
3
.
1
. TTe
opt
opt
0dedWi
1.2
0
31.2.
TT
opt
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