15.1 PRINCIPLE

http://part66.blogspot.com/

ENERGY

• Energy : Capacity to do work (Joule)• Potential Energy : Result from influence of

gravity on mass due to its position

PE = mass x gravity x height• Kinetic Energy : Result from motion of mass

KE = 1/2mv2

NEWTON LAW

• 1ST Law : A body will continue its state of rest or uniform motion

unless external force changing it.

2nd Law :Rate of change of momentom of a body is proportional to

the applied force.

3rd Law :In every action there will be equal and opposite reaction

BRAYTON CYCLE

• Brayton cycle : – The process of converting heat to do the work in

jet engine.– Air is compress,heat and accelerate due to air

molecule expand to produce the reaction force

RELATION

• Application to Jet engine :u = 0m/smair= 260kg/s v=500m/s

F = maF =260 x 500Thrust = 130kN

Acc = (V–U) ÷ tAcc =(500 – 0) ÷ 1sAcc = 500 m/s2

Work = F x DWork = EnergyKE = ½(mv2)KE = ½(260)(500)2

KE = 32.5MJ

Power = Work/TimePow = 32.5/1sPow = 32.5Mwatt

TURBO JET

TURBOFAN

TURBOSHAFT

TURBOPROP