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1、航空发动机的种类与结构Aircraft Engine Types And Construction,1,PPT课件,活塞式 燃气涡轮式 冲压式,三大种类,2,PPT课件,活塞式航空发动机早期在飞机或直升机上应用的航空发动机，用于带动螺旋桨或旋翼。大型活塞航空发动机的功率可达 500千瓦。后来为功率大、高速性能好的燃气涡轮发动机所取代。但小功率的活塞式航空发动机仍广泛地用于轻型飞机、直升机及超轻型飞机。燃气涡轮发动机应用最广。包括涡轮喷气发动机、涡轮风扇发动机、涡轮螺旋桨发动机和涡轮轴发动机，都具有压气机、燃烧室和燃气涡轮。涡轮螺旋桨发动机主要用于时速小于800千米的飞机；涡轮轴发动机主要用作直
2、升机的动力；涡轮风扇发动机主要用于速度更高的飞机；涡轮喷气发动机主要用于超声速飞机。冲压发动机冲压发动机特点是无压气机和燃气涡轮，进入燃烧室的空气利用高速飞行时的冲压作用增压。它构造简单、推力大，特别适用于高速高空飞行。由于不能自行起动和低速下性能欠佳，限制了应用范围，仅用在导弹和空中发射的靶弹上。,3,PPT课件,The Heat Engine,Converts chemical energy (fuel) into heat energy.Heat energy is then converted into mechanical energy.The heat energy is rele
3、ased at a point in the cycle where the pressure is high, relative to atmospheric.,4,PPT课件,The Heat Engine,Divided into groups or types depending upon:The working fluid used.The means of compression.The Propulsive working fluid.,5,PPT课件,Types Of Heat Engines,6,PPT课件,Types Of Heat Engines,TurbojetMean
4、s of compression: Turbine-driven compressorEngine working fluid: Fuel/air mixturePropulsive working fluid: Fuel/air mixture,7,PPT课件,Types Of Heat Engines,TurbopropMeans of compression: Turbine-driven compressorEngine working fluid: Fuel/air mixturePropulsive working fluid: Ambient Air,8,PPT课件,Types
5、Of Heat Engines,RamjetMeans of compression: Ram compression Engine working fluid: Fuel/air mixturePropulsive working fluid: Fuel/air mixture,9,PPT课件,Types Of Heat Engines,Pulse-JetMeans of compression: Compression due to combustionEngine working Fluid: Fuel/air mixturePropulsive working Fluid: Fuel/
6、air mixture,10,PPT课件,Types Of Heat Engines,RocketMeans of compression: Compression due to combustionEngine working fluid: Oxidizer/fuel mixturePropulsive working fluid: Oxidizer/fuel mixture,11,PPT课件,Types Of Heat Engines,ReciprocatingMeans of compression: Reciprocating action of pistonsEngine worki
7、ng fluid: Fuel/air mixturePropulsive working fluid: Ambient air,12,PPT课件,Engine Requirements,13,PPT课件,Engine Requirements,EfficiencyPower and Weight: If the specific weight of an engine is decreased, the performance of the aircraft will increase.Reciprocating engines produce approximately 1 HP for e
8、ach pound of weight.,14,PPT课件,Engine Requirements,Fuel EconomyThe basic parameter for describing the fuel economy of aircraft engines is specific fuel consumption.Specific fuel consumption for reciprocating engines is the fuel flow (lbs/hr) divided by brake horsepower.,15,PPT课件,Engine Requirements,D
9、urability and ReliabilityDurability is the amount of engine life obtained while maintaining the desired reliability.Reliability and durability are built into the engine by the manufacture.Continued reliability is determined by the maintenance, overhaul, and operating personnel,16,PPT课件,Engine Requir
10、ements,Operating FlexibilityThe ability of an engine to run smoothly and give desired performance at all speeds from idling to full-power.The engine must also function efficiently through all variations in atmospheric conditions.,17,PPT课件,Engine Requirements,CompactnessTo effect proper streamlining
11、and balancing of an aircraft, the shape and size of the engine must be compact.In a single engine aircraft, the shape and size of the engine will affect the view of the pilot.,18,PPT课件,Engine Requirements,Powerplant Selection,?,19,PPT课件,Reciprocating Engine,For aircraft whose cruising speeds will no
12、t exceed 250 MPH the reciprocating engine is the usual choice.Chosen for its excellent efficiency.Turbocharged or supercharged for high altitude use.- Turbo-use exhaust- Super-use accessory drive,20,PPT课件,Turboprop Engine,For cruising speeds from 180 to 350 MPH the turboprop engine performs better.D
13、evelops more power per pound then reciprocating.Operate most economicallyat high altitudes.,21,PPT课件,Turbojet/Turbofan Engines,Intended to cruise from high subsonic speeds up to Mach 2.0.Operates most efficiently at high altitudes.Less instrumentation andcontrols required.,22,PPT课件,Types Of Reciproc
14、ating Engines,23,PPT课件,In-Line Engines,Generally has even number of cylinders.Liquid or air cooled.Has only one crankshaft.,24,PPT课件,In-Line Engines,Small Frontal area, better adapted to streamlining.When mounted inverted, it offers the added advantages of a shorter landing gear.High weight to horse
15、power ratio.,25,PPT课件,V-type Engines,Cylinders are arranged in two in-line banks generally set 30-60 apart.Even number of cylinders and are liquid or air cooled.,26,PPT课件,Radial Engines,Consists of a row, or rows, of cylinders arranged radially about a center crankcase.The number of cylinders compos
16、ing a row may be either three, five, seven, or nine.,27,PPT课件,Radial Engines,Proven to be very rugged and dependable.High horsepower.,28,PPT课件,Rotary-Radial,Used during World War I by all of the warring nations.Cylinders mounted radially around a small crankcase and rotate with the propeller.,29,PPT
17、课件,Rotary-Radial,Torque and gyro effect made aircraft difficult to control.Problems with carburetion, lubrication, and exhaust.,30,PPT课件,Opposed Or O-type Engines,Two banks of cylinders opposite each other with crankshaft in the center.Liquid or air cooled, air cooled version used predominantly in aviation.,31,PPT课件,Opposed Or O-type Engines,Has low weight-to-horsepower ratio.Its narrow silhouette makes it ideal for installation on wings.Little vibration.,32,PPT课件,33,PPT课件,34,PPT课件,
