ENGINE GENERAL CONCEPT<BR>The CFM56-5B engine is a high by-pass, dual rotor, axial<BR>flow turbofan. It is supported by the wing pylon and<BR>streamlined by cowlings.<BR>Air is sucked into the intake by the fan blades and split<BR>into two flow paths, the Primary and the Secondary.<BR>The primary airflow passes through the inner portion of<BR>the fan blades and is directed into a booster (LPC).<BR>The airflow then enters a High Pressure Compressor<BR>(HPC) and goes to a combustor. Mixed with fuel and<BR>ignited, the gas flow provides energy to a High Pressure<BR>Turbine (HPT) and a Low Pressure Turbine (LPT).<BR>The secondary airflow passes through the outer portion<BR>of the fan blades, the Outlet Guide Vanes (OGV’s) and<BR>exits through the nacelle discharge duct, producing<BR>approximately 80 % of the total thrust. It also plays a role<BR>in the thrust reverser system.
aircraft pylon <BR>飞机外挂架
design and operation
<P>ENGINE GENERAL CONCEPT</P>
<P>The CFM56-5B engine uses a maintenance concept<BR>called ‘On Condition Maintenance’. This means that the<BR>engine has no periodic overhaul schedules and can<BR>remain installed under the wing until something important<BR>occurs, or when lifetime limits of parts are reached.<BR>For this reason, to monitor and maintain the health of the<BR>engine, different tools are available, which are :<BR>- Engine performance trend monitoring<BR>- Borescope inspection<BR>- Lubrication particles analysis<BR>- Spectrometric Oil Analysis Program (S.O.A.P)<BR>- Engine vibration monitoring system</P>
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<P>borescope 管道镜</P>
<P>spectrometric 光谱测定的,度谱的,分光仪的,光谱仪的</P>
on condition monitoring
<P>ENGINE GENERAL CONCEPT</P>
<P>The CFM56-5B engine consists of two independent<BR>rotating systems :<BR>- The low pressure system rotational speed is<BR>designated N1.<BR>- The high pressure system rotational speed is<BR>designated N2.<BR>The engine rotors are supported by 5 bearings, identified<BR>in manuals as numbers 1 thru 5, where No. 1 is the most<BR>forward and No. 5 the most aft. These bearings are<BR>housed in 2 dry sump cavities provided by the fan and<BR>turbine frames.<BR>Engine structural rigidity is obtained with short lengths<BR>between two main structures (frames).<BR>The accessory drive system uses energy from the high<BR>pressure compressor rotor to drive the engine and<BR>aircraft accessories. It also plays a major role in starting.</P>
<P>general engine concept</P>
<P>ENGINE GENERAL CONCEPT</P>
<P>The CFM56-5B is a modular concept design engine. It<BR>has 17 different modules that are enclosed within three<BR>major modules and an accessory drive module.<BR>The 4 modules are :<BR>- The Fan Major Module<BR>- The Core Engine Major Module<BR>- The Low Pressure Turbine Major Module<BR>- The Accessory Drive Module</P>
modular design
FAN SECTION<BR>The fan section is at the front of the engine and,<BR>downstream from the air inlet cowl, the section includes<BR>the fan and booster module and fan frame module.<BR>The purposes of the fan and booster are :<BR>- to accelerate air overboard to generate thrust.<BR>- to increase the pressure of the air directed to the<BR>High Pressure Compressor (HPC).<BR>After entering the air inlet cowl, the total engine airflow<BR>passes through the fan rotor, which increases the air’s<BR>kinetic energy.<BR>Most of the airflow is ducted overboard producing<BR>approximately 80 % of the total thrust. The remainder is<BR>directed through the booster, where it is pressurized<BR>before entering the HPC.
