航空發(fā)動機綜合課程設(shè)計CFM565C發(fā)動機啟動不點火

1、航空工程學(xué)院航空發(fā)動機綜合課程設(shè)計航空發(fā)動機綜合課程設(shè)計no light up during start題 目cfm56-5ccfm56-5c 發(fā)動機啟動不點火發(fā)動機啟動不點火作者姓名賈嵩松專業(yè)名稱熱能與動力工程指導(dǎo)教師尚永鋒提交日期 答辯日期 no light up during start contentschapter 1 general.11.1 overview of the cfm56-5c turbofan engine.11.2 the technology behind the cfm56-5c turbofan engine .21.3 the subject of thi

2、s article.2chapter 2 fadec control system.42.1 fadec system introduction.42.1.1 fadec purpose.42.1.2 fadec component .42.2 electronic control unit.42.2.1 ecu distribution.42.2.2 ecu power supply.42.3 hydro-mechanical unit (hmu).52.3.1 hmu introduction.52.3.2 hmu function.52.3.3 schematic diagram of

3、hmu .62.4 process of fadec control.72.4.1 working process.72.4.2 function diagram of the fadec.82.4.3 abnormal work.8chapter 3 ignition system.103.1 general description.103.2 ignition system distribution .103.2.1 electrical power.103.2.2 ignition exciter.113.2.3 ignition leads.123.2.4 spark igniter.

4、123.3 ignition system control.133.3.1 the process of ignition.133.3.2 the control switch.143.4 principle diagram of the ignition.153.4.1 working process.153.4.2 function diagram of the ignition system.153.4.3 abnormal work.163.4 fuel nozzle.16chapter 4 fault analysis.184.1 fault analysis.184.1.1 fau

5、lt description.184.1.2 analysis of failure causes.184.1.3 fault tree .184.2 process of trouble shooting.19航空工程學(xué)院課程設(shè)計ireference.21appendix.22no light up during start iiabbreviationsegt: exhaust gas temperature ecu: electronic control unit hmu: hydro-mechanical unit fadec: full authority digital engin

6、e control pmc: power management control acc: active clearance control adiru: air data/inertial reference unit eivmu: engine interface and vibration monitoring unit vsv: variable stator vane vbv: variable bleed valve hpt: high pressure turbine lpt: low pressure turbine lptcc: low pressure turbine cas

7、e cooling hptcc: high pressure turbine case cooling racsb: rotor active clearance start bleed no light up during start 0chapter 1 general1.1 overview of the cfm56-5c turbofan enginethe cfm56-5c, the most powerful engine in the cfm56 family, is the sole cost-effective propulsion system perfectly tail

8、ored for the long-range airbus a340-200 and a340-300 aircraft (fig.1-1). fig.1-1 cfm56-5cin its class, the airbus a340/cfm56-5c offers the lowest noise signature in commercial service. supported at its entry into service in 1993 by the cfm56 familys more than 40 million engine flight hours of experi

9、ence, the cfm56-5c has an excellent reliability ratea hallmark of the cfm56 family. other versions of the cfm56 are also in service on the a320, providing airlines that operate a320/a340 mixed fleets a valuable commonality benefit due to reduced inventories and spare parts levels. to maximize overal

10、l performance and profitability for airlines, cfm offers the cfm56-5c as a total propulsion system: engine, nacelle, and exhaust systems.continuing the cfm56 engines excellent worldwide reputation, the cfm56-5c features innovative technologies, low fuel consumption, and the ability to meet all exist

11、ing environmental requirements with significant margins.航空工程學(xué)院課程設(shè)計11.2 the technology behind the cfm56-5c turbofan enginetab.1-1 related parameter of the cfm56-5cengine model：cfm56-5c2-5c3-5c4max. thrust312003250034000bypass ratio6.56.56.4so we can obtain some related general data of the cfm-5c:max.

12、 thrust (lb): 31,200 - 34,000 max climb thrust (lb):73707580max. cruise thrust (lb):69107100bypass ratio: 6.5overall pressure ratio at max climb: 37.438.3length (in):103fan diameter (in):72.3basic dry weight (lb):87961.3 the subject of this articlein the process of using the engine, generally, many

13、troubles may be happened. in this article, we focus on discussing the one of the deviant starting: no light up of starting. this failure often occurs, when the starting of the engine. namely, after the starter start, within the specified time (10 seconds after the supplying of the fuel), if the egt

14、or the indication of n2 not increase, it show that the engine is no light up. now we should close the switch of starting.by analyzing the information, we can obtain the main related component about this trouble:ecu, hmu, igniter-spark a and b.no light up during start 2in this article, we will first

15、introduce these components of this trouble, including their operating principle, some subsystem and their parts that may cause misfiring. then through these, we can obtain the fault tree of this trouble, and process or method of trouble shooting.航空工程學(xué)院課程設(shè)計3chapter 2 fadec control system2.1 fadec sys

16、tem introduction2.1.1 fadec purposethe full authority digital engine control (fadec) provides full range engine control to achieve steady state and transient engine performances when operated in combination with aircraft subsystems.fadec can take complete control of engine systems in response to com

17、mand inputs from the aircraft. it also provides information to the aircraft for flight deck indications, engine condition monitoring, maintenance reporting and trouble-shooting.the purposes of fadec follow:(a) power management control (pmc)(b) starting/shutdown ignition control(c) fuel control(d) ac

18、tive clearance control (acc)(e) variable geometry control(f) thrust reverser 2.1.2 fadec componentthe fadec system consists of:-an electronic control unit (ecu) containing two identical computers, designated channel a and channel b. the ecu electrically performs engine control calculation and monito

19、rs the engines condition.-a hydro-mechanical unit (hmu), which converts electrical signals from the ecu into hydraulic pressures to drive the engines valves and actuators.-peripheral components such as valves, actuators and sensors used for control and monitoring.refer to fig.2-1.fadec componentno l

20、ight up during start 4fig.2-1.fadec component2.2 electronic control unit2.2.1 ecu distributionthe electronic control unit (ecu) is a dual channel digital electronic control with each channel utilizing a microprocessor for main control functions, a microcontroller for pressure transducer interface fu

21、nctions and a microcontroller for arinc communication function. the ecu is a vibration-isolated single unit mounted on the fan case. refer to fig.2-2. electronic control unitthe functions of ecu follow:(a) each ecu channel receives data buses from two air data and inertial reference units (adiru) an

22、d operational commands from the engine interface vibration monitoring unit (eivmu) in the aircraft on arinc 429 data busses.(b) it also receives operating condition data from the various dedicated engine sensors such as t12, ps12, p0, n1, n2, ps3, t/p25, t3 and tc, and computes the necessary fuel fl

23、ow, vsv, vbv, hpt clearance control, lpt clearance control, rotor active clearance control valve (only applicable for cfm56-5c) and transient bleed valve (only applicable for cfm56-5c/p) positions.航空工程學(xué)院課程設(shè)計5fig.2-2 electronic control unit(c) the ecu provides the necessary current to the torque moto

24、rs in the hydro-mechanical unit to control the various modulating valves and actuators.(d) the ecu performs an on/off control of the ignition relays, starter air valve solenoid, the aircraft thrust reverser directional valve and the thrust reverser pressurizing valve.2.2.2 ecu power supplythe ecu pr

25、ovides digital data output in arinc 429 format to the aircraft for engine parameter display, aircraft flight management system and the aircraft maintenance data system. so the ecu is powered by a three-phase engine alternator. two independent coils from the alternator provide the power to the two se

26、parate ecu channels. a logic circuit within the ecu, automatically selects the correct power source：-a/c power supply. the power sources are the 115v-400hz ac transfer busses 1and 2 -control alternator. the control alternator provides two separate power sources from two no light up during start 6ind

27、ependent windings. one is hardwired to channel a, the other to channel b. the alternator is capable of supplying the necessary power above an engine speed of approximately 15% n2.refer to fig.2-3 ecu power supplyecua/c115v ac400hzcontrol alternatorchan a and bchan a and bfig.2-3 ecu power supply2.3

28、hydro-mechanical unit (hmu)2.3.1 hmu introductionthe hydro-mechanical unit (hmu) is attached to the aft section of the fuel pump unit housing. the two units make a bigger unit, or package. this package is installed on the aft side of the agb, at the left side of the horizontal drive shaft housing. r

29、efer to fig.2-4.hydro-mechanical unit. fig.2-4.hydro-mechanical unit航空工程學(xué)院課程設(shè)計72.3.2 hmu functionthe hmu has different functions: it provides internal calibration of fuel pressures. it meters the fuel flow for combustion. it provides the fuel shut-off and fuel manifold minimum pressurization levels.

30、 it bypasses unused fuel. it provides mechanical n2 over-speed protection. it delivers the correct hydraulic power source to various engine fuel equipments.refer to fig.2-5.hmu purposes.hmu fuel pressures calibration metered fuel flow for combustion-fuel shut-off-fuel manifold pressurizationexcess f

31、uel flow bypassmechanical n2 over-speed protectionfuel equipment power source supplychan a and bfig.2-5.hmu purposes2.3.3 schematic diagram of hmua general schematic of the hmu is shown in the referenced illustration. fig.2-6. schematic diagram of hmu1. fuel meteringthe fuel metering valve is hydrau

32、lically driven through a torque motor/servo valve by the ecu. the torque motor contains two electrically isolated, independent coils, one dedicated to channel a, the other to channel b of the ecu. a differential pressure regulating valve maintains a no light up during start 8constant pressure drop a

33、cross the metering valve. as a result, fuel flow varies proportionally with metering valve position. two fuel metering valve position resolvers, one dedicated to each channel in the ecu, produce an electrical feedback signal in proportion to fuel metering valve position. the ecu uses this signal to

34、compute the current required at the fuel metering valve torque motor for achieving closed loop electrical control. fig.2-6. schematic diagram of hmu2. motive flow modulationthe hmu contains 5 additional torque motors/pilot valves that modulate hydraulic signals to the following: -low pressure turbin

35、e clearance control valve (lptcc) -high pressure turbine clearance control valve (hptcc) -rotor active clearance control system (racsb) -transient bleed system -variable stator vane actuators (vsv) -variable bleed valve actuators (vbv)航空工程學(xué)院課程設(shè)計9each torque motor contains two electrically isolated,

36、independent coils. one is dedicated to channel a, the other to channel b, of the ecu. they provide flow and pressure at an hmu pressure port in response to electrical commands from the ecu.3. fuel shut-off valve the fuel shut-off valve shuts off fuel flow to the engine in response to an aircraft sup

37、plied electrical signal (28vdc) commanded by the eng/master switch. it has to be noted that the shut-off signal of the hp fuel shut-off valve also closes the lp fuel valve. 2.4 process of fadec control2.4.1 working processaccording to normal start programs, when the pilot press start switch, ecu thr

38、ough torque motor/servo valve drive hydraulically the fuel metering valve, including chan a and chan b. at the same time, a differential pressure regulating valve maintains a constant pressure drop across the metering valve, so that fuel flow varies proportionally with metering valve position. there

39、 are two resolvers that produce an electrical feedback signal in proportion to fuel metering valve position. then the ecu uses this signal to compute the current required at the fuel metering valve torque motor for achieving closed loop electrical control. refer to fig.2-7.working process.torque mot

40、or/servo valve resolvers ecuchan a and b hmufmvfuel pumpfuel manifolds p regulating valve and bypass valveadjustment proportional to the piston positionfig.2-7. working processno light up during start 102.4.2 function diagram of the fadecaccording to the subsystem and working process of the fadec, w

41、e can obtain the function diagram of the fadec. refer to fig.2-8. from it we can understand the function of fadec.fadececuhmu peripheral componentsfmvpregulating valvepressurizing and shut-off valvevalveactuatorsensorelectrical connector ecu cooling systemignition systemtmrshut-offsolenoidcontrol fi

42、g.2-8. function diagram of the fadec2.4.3 abnormal workwhen light up during start, if egt and n2 display does not increase, and the same time the flow indication also not increase, the engine will be ignition failure. this failure is called no light up during start.the process of ignition is control

43、led by ecu and hmu in fadec. so we can find possible causes in them. the ecu controls mainly the power supply in ignition. if no light up occurs, we can guess that the ignition voltage may be below 24kv. or the fuel nozzle emerges poor fuel or rich fuel conditions.no light up during start ecu igniti

44、on voltage belowhmu fuel supply abnormalecu failure lead plug loosefmv failure torque motor/servo valve failureresolver failurepressurizing valve and shut-off solenoid fig.2-9.possible failure partsin fig.2-9 possible failure parts, we show the some components that may cause the ecus and hmus abnorm

45、al working based on the reasons of the possible. from it the maintenance personnel can find the related components to shoot the trouble.no light up during start 11chapter 3 ignition system3.1 general descriptionthe ignition system consists of two independent systems a and b. each system is equipped

46、with: -one ignition exciter, the exercitation of which is controlled by the ecu, either channel a or b of the ecu. -one spark igniter -one coaxial shielded ignition lead. a. ignition exciters the 2 ignition exciters are installed on shock dampened brackets on the outer surface of the fan case. each

47、exciter has an input connector and an output connector. b. spark igniters the 2 spark igniters are installed into bosses at the 4 and 8 oclock positions on the outer surface of the combustion case. the inner tip extends, through ferrules, into the outer liner of the combustion chamber. c. ignition l

48、eads the ignition leads are constructed of insulated wire in a sealed flexible conduit having a copper inner braid and a nickel outer braid. the leads connect the spark igniters to the ignition exciters. the aft ends of the leads, from the tube bundle junction box to the spark igniters, are cooled b

49、y fan discharge air passing through the lead conduit.fig.3-1.ignition system location航空工程學(xué)院課程設(shè)計12the ignition system requires 115v, 400hz from the electrical system via the ecu. the ecu controls the operation of ignition exciters a and b. the ignition for each engine is performed by one or both exci

50、ter(s) which transform(s) the 115v-400hz power supply into high voltage pulsating current. the high voltage flows through the ignition lead (shielded and ventilated) and delivers to the spark igniter the power required to ignite the fuel/air mixture by a series of sparks. the purpose of the system i

51、s: -to produce an electrical spark to ignite the fuel/air mixture in the engine combustion chamber during the starting cycle on ground and in flight -to provide continuous ignition in the following cases: (a) when manually selected.(b) auto-matically when engine flame out is detected.3.2 ignition sy

52、stem distributionthe ignition system enables three functions: -the electrical power supply -the distribution -the switching3.2.1 electrical powerthe ignition system requires 115v, 400hz from the electrical system via the ecu. the ecu controls the operation of ignition exciters a and b. the ignition

53、exciters transform the 115v, 400hz into 20kv high voltage pulsating current. fig.3-2. electrical power aircraftupper ignition exciterlower ignition exciter115v-400hz ac115v-400hz acfig.3-2. electrical powerno light up during start 133.2.2 ignition exciterthe two ignition exciters are installed on th

54、e inlet fan case with resilient shock mounts at the 3 oclock position. a tin plated aluminum housing encloses each exciter. the components are secured to the housing mechanically or with silicone cement to protect them from vibration damage. the housing is sealed to ensure proper operation under var

55、ying environmental conditions.each ignition exciter has: -one ignition lead connector -one electrical input connector. fig.3-2. ignition exciter fig.3-2. ignition exciter3.2.3 ignition leadsan ignition lead transmits electrical energy from an ignition exciter to a spark igniter. each lead consists o

56、f a 0.28 in. (7 mm) diameter silicone insulated cable containing a no. 14 awg nickel 航空工程學(xué)院課程設(shè)計14plated copper stranded conductor. the 0.28 in. (7 mm) cable is housed within a flexible conduit which features a nickel plated copper inner braid, a nickel-iron convoluted conduit, and a nickel outer bra

57、id. fan discharge air is introduced into an enlarged diameter portion of each ignition lead conduit for cooling of the silicone insulated cable and igniter connection. refer to fig.3-3. ignition leadfig.3-3. ignition lead3.2.4 spark igniterthere are 2 spark igniters in bosses at the 4 and 8 oclock p

58、ositions, looking forward, on the combustion case assembly. the tip of the spark igniters extends, through ferrules, into the outer liner into the combustion chamber. each spark igniter is connected by a lead to an ignition exciter. the ignition exciter sends electrical energy to the spark igniter.

59、the spark igniter supplies the spark necessary for ignition of the fuel/air mixture in the combustor. fig.3-4. ignition leads and left/right spark - ignitionno light up during start 15fig.3-4. ignition leads and left/right spark ignition3.3 ignition system control3.3.1 the process of ignitionthe eng

60、ine is fitted with a dual ignition system. each system has an ignition exciter unit connected to its own spark igniter. depending on the operating mode, one or both circuit(s) is (are) selected by the ecu. the ignition exciter is of the capacitor discharge type. it requires an 115vac, 400hz input cu