Choked nozzle and thrust correction - turbojet, Other Engineering

Assignment Help:

Choked Nozzle

Considering the formula for thrust under "choked" nozzle conditions:
Thrust =(P-P0 )A + WVj /g    

Where: P = Pressure
P = Ambient Pressure
A = Area
W = Mass Flow
V = Velocity

It can be seen that the thrust can be further affected by a change in the mass flow rate of air through the engine and by a change in jet velocity. An increase in mass airflow may be obtained by using water injection to cool the air and increases in jet velocity by using after-burning.

Changes in ambient pressure and temperature considerably influence the thrust of the engine. This is because of the way they affect the air density and hence the mass of air entering the engine for a given engine rotational speed.

Thrust Correction - Turbojet

To enable the performance of similar engines to be compared when operating under different climatic conditions, or at different altitudes, correction factors must be applied to the calculations to return the observed values to those which would be found under I.S.A. conditions. For example, the thrust correction for a turbo-jet engine is:


Thrust (lb) (corrected) = thrust (lb) (observed) x 30/Po
• Where P0 = atmospheric pressure in inches of mercury (in Hg) (observed) 

30 = I.S.A. standard sea level pressure (in Hg)

 


Related Discussions:- Choked nozzle and thrust correction - turbojet

Aerodynamics-flow model diagram , We will need to use several different flo...

We will need to use several different flow models as we go along. It is crucial to understand the simplifications used to obtain these models because these limit the validity of th

System dynamics , System Dynamics  Crucial to the development of a guid...

System Dynamics  Crucial to the development of a guidance system is an understanding of the dynamics of the system. In particular, it is necessary to understand how the acceler

Net present value method: npv, Discounted cash flow methods Net present val...

Discounted cash flow methods Net present value method: NPV It is one of the classic methods of evaluating the investment project. Here each potential projects value is find out its

Hot section inspections of aircraft, Hot Section Inspections (HSI's) Th...

Hot Section Inspections (HSI's) The hot section includes all components in the combustion and turbine sections of the engine. Scheduled inspections may involve visual inspectio

Levelling Theory and Computation, Two readings i.e., 1.64m, and 0.73m, were...

Two readings i.e., 1.64m, and 0.73m, were taken during leveling procedure to define the slope of centerline of a bridge at points A, and B. If distance AB = 50m, find the slope of

Equivalent shaft horsepower - aircraft maintenance , Equivalent Shaft Horse...

Equivalent Shaft Horsepower (EHP) In practice there is always a certain amount of jet thrust in the total output of the turbo-propeller engine and this must be added to the s.h

Fundamentals of lift and drag , Lift and drag are merely the resolved compo...

Lift and drag are merely the resolved components in specific directions of a resultant aerodynamic force caused by the relative velocity V of the vehicle through the air. If al

Diffusion, distingush between short range and long range diffusion

distingush between short range and long range diffusion

Avionic systems design- stability derivatives, The idea of stability deriva...

The idea of stability derivatives is to approximate the general functional relationship between any force ormoment variable and the dynamic or control variables as a Taylor series

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd