Combustion chambers types?

Can

anular

cananular

Provides a structural area where the efficient burning of the fuel air ration can take place

Primary air flow- used to mix with the fuel and burn (combustion process)

secondray air- used for cooling the hot gases through dilution, insulation cools the metal, also controls shape of the flame

Adv- 1. Burners are individualy removable for inspection and maintence

2. Airflow patterns are easier to control during design

Dis- 1. design leads to large frontal area

2. Heavy weight

Advantages- less cooling air required( better heat dissapation) 

light weight

disadvantage- structurally  fragile

difficult to remove and inspect for maintence 

Radial in flow

axial flow

Impulse 

reaction

impulse reaction

Turbine?under highest stress? Can take highest stress???

True or false?

Nozzle- first row of turbine guide vanes, convert heat and pressure of the gas stream using bernoulli principal

Direct gas stream so hits strikes the turbine blades at the proper angle

Stators- nozzle guide vanes not including the first row, all attached to the engine case

Hp= specific heat of air* change in temp* Wair*778

_________________________________________

550

specific heat of air= .24

1 BTU= 778ftlbs

1 Hp= 550ftlbs/sec 

Blade use reaction principal at the tip where velocity is high, and blade gradually changes to an impulse blade at the root where the speed is low

this keeps the pressure uniform across the blade length making it the most efficient 

Your have to know the engine type to know the purpose

turboprop- useless

turbojet-main power

sub sonic uses convergent

supersonic has a convergent section then a divergent section

(how power is used/ extracted)

Turbojet-exhaust gas at highest possible velocity

turboprop/turboshaft-useless,conduct exhaust gas rearward with as little energy loss as possible

turbofan- only about 15% thrust is produced, important to extract as much a energy as possible

turbo

Case

plug

duct

nozzle 

prob

Temp prob/ thermal couple - aft of turbine gives EGT

also probes work lower temp,less likely to break 

EPR- located in exhaust,work in conjunction with probes in the intake

Supply the engine with the required mass airflow at the highest possible pressure

provide for minmum compressor stall tendencies

Rated-

duct pressure efficiency ratio- ability to convert kinetic/ dynamic pressure energy, inlet to static pressure energy at the compressor w/o a loss of total pressure

ram recovery point- A/S at which the ram pressure is equal to friction pressure,or inlet pressure is equal to total pressure

Centrifugal-impeller and diffuser

axial-rotor stator

axial-centrifugal- rotor stator impeller

Centrifugal- adv. -simple,low cost,rugged,high compression ratio per stage

dis.- efficiency limited by one or two stages, RPM limited sure to sized 80%efficient,relatively high SFC

Axial- adv.- very high compression ratio,high efficiency,low frontal  areas

dis.- suceptipal to FOD, complex and expensive, low pressure ratio per stage

Specific fuel consumption decreases with increasing pressure ratio

Inlet pressure*pressure change^number of stages=pressure change across entire sysystem

pressoff put out/ inlet pressure:1

Vfps*12*60

__________

3.14*Vfps

12*60*Vfps

_____________

3.14*diameter