principles of gas turbine/reciprocating operations

nozzle

shape of the opening increases the velocity and decreases pressure

diffuser

increases pressure and decreases velocity

subsonic nozzle and diffuser shape

N= convergent

D= divergent

supersonic nozzle and diffuser shapes

N= divergent

D= convergent

gas generator

produces the high-energy airflow necessary for creating thrust

all gas turbine engines at minimum have a

compressor, combustion chamber, and a turbine

brayton cycle

4 events that happen simultaneously: intake, compression, combustion, exhaust

otto cycle

same as brayton but happen sequentially and within a single piston

thrust

develops as a result of many pressure, temperature, and velocity changes as airflow passes through an engine

gross thrust

measurement of thrust due solely from the velocity of the exhaust gases produced by a stationary engine

net thrust eq

mass of air *(Vf-Vi/t)

when will net thrust and gross thrust be equal

inlet velocity is zero and atmospheric conditions are standard

factors that affect thrust

temperature, altitude, pressure, engine rpm, ram effect

describe ram effect

at increased speeds more air is being rammed into the inlet, increasing mass and pressure of inlet air

increase in engine rpm results in

increase in thrust

at high rpm a small increase in ______ will produce a large increase in thrust

throttle

engine pressure ratio gauges

indicates the pressure ratio between the inlet and exhaust airflow

Torquemeter

indicates shaft horsepower available to drive a propeller or rotor

tachometer

determines engine performance and indicates engine speed