Combustion process, Other Engineering

Assignment Help:

Combustion process:

Air from the engine compressor enters the combustion chamber at a velocity up to 500 feet per second, but because at this velocity the air speed is far too high for combustion, the first thing that the chamber must do is to diffuse it, i.e. decelerate it and raise its static pressure. Because the speed of burning kerosene at normal mixture ratios is only a few feet per second, any fuel lit even in the diffused air stream, which now has a velocity of about 80 feet per second, would be blown away. A region of low axial velocity has therefore to be created in the chamber, so that the flame will remain alight throughout the range of engine operating conditions.

In normal operation, the overall air/fuel ratio of a combustion chamber can vary between 45:1 and 130:1. Kerosene, however, will only burn efficiently at, or close to, a ratio of 15:1, so the fuel must be burned with only part of the air entering the chamber, in what is called a primary combustion zone. This is achieved by means of a flame tube (combustion liner) that has various devices for metering the airflow distribution along the chamber.

 

834_combustion proces.png

Approximately 20 per cent of the air mass flow is taken in by the snout or entry section. Immediately downstream of the snout are swirl vanes and a perforated flare, through which air passes into the primary combustion zone. The swirling air induces a flow upstream of the centre of the flame tube and promotes the desired recirculation. The air not picked up by the snout flows into the annular space between the flame tube and the air casing.

Through the wall of the flame tube body, adjacent to the combustion zone, are a selected number of holes through which a further 20 per cent of the main flow of air passes into the primary zone. The air from the swirl vanes and that from the primary air holes interacts and creates a region of low velocity recirculation. This takes the form of a toroidal vortex similar to a smoke ring, and has the effect of stabilising and anchoring the flame. The recirculating gases hasten the burning of freshly injected fuel droplets by rapidly bringing them to ignition temperature.


Related Discussions:- Combustion process

Financial Econometrics, In this assignment you are asked to demonstrate you...

In this assignment you are asked to demonstrate your understanding of both exploratory and statistical inference techniques described in class to investigate how the currency marke

Electron gun, Electron gun: The electron gun consists of the following:...

Electron gun: The electron gun consists of the following: 1.  Cathode:  An indirectly heated cathode (negatively biased w.r.t. the screen). 2.  Grid:          A cylindric

The pitch change mechanism , THE PITCH CHANGE MECHANISM : The cylinder...

THE PITCH CHANGE MECHANISM : The cylinder backplate . The disc shaped backplate provides a mounting for the pitch change cylinder. This backplate fits in front of the propel

Civil engineering, how to prepare assignment note on culverts in between 4 ...

how to prepare assignment note on culverts in between 4 to 6 pages

How do comets get their tails, How do comets get their tails? - Most comet...

How do comets get their tails? - Most comets stay frozen in the outer solar system. Only a few enter the inner solar system where they can grow tails. - When a comet nears the sun

Microbiology, Explain the following observations: cells of Escherichia coli...

Explain the following observations: cells of Escherichia coli fermenting glucose grow faster when NO3 - is supplied to the culture and then grow even faster when the culture is hig

Fire risk assessment in uk - fire protection engineering, Fire risk assessm...

Fire risk assessment in UK: In the UK FRAs are required by law in all commercial premises.  But the FRAs are not the same as described in NFPA 551.  The principles remain the

Hot and cold working, advantages and disadvantages of cold and hot working

advantages and disadvantages of cold and hot working

Determine payback and npv, Payback & NPV Julia Corp. is in the business o...

Payback & NPV Julia Corp. is in the business of making sugar cookies. The company is considering the purchase of a new cookie making machine which will improve its manufacturing

flow solver, Flow Solver The flow solver of FP utilises data produced ...

Flow Solver The flow solver of FP utilises data produced by the grid generator, together with data read from an input file named FLOW.DAT, and proceeds to calculate the solutio

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