To Create a Combustion Chamber for a Prototype Jet

EngineEoin Robinson

Design Specification

To create combustion chamber and a housing for a jet engine prototype.

Has a capacity to operate and withstand temperature of approximately 540- 630°C.

Combine with Turbine section and fuel supply sections.

Design and operation

Images acquired from Jet engine prototype book and www.designtechnology.org

Operation

The operation of a jet engine combustion chamber is similar to that of a four stroke cylinder combustion chamber.

Image acquired from www.salvatoreaiello.com

Combustion chamber components

Components

Front sectionFront part (9.2)Hooked tubes (x 6 ) (9.3)Air jets ( x 6) (9.4)Jacket (Middle section)Sleeve (8.1)Rear (8.2)Outlet (8.3)Housing (outer section)The housing jacket (17.1)Pressure nipples (18)Fuel pipe (17.1)

Index courtesy of the Jet engine book

Finished Design * Note : All components shown in this drawing were made on Creo/Pro-E . Air compressor not part of this project.

Fuel intake

For combustion to be successful:The chamber will have to accommodate

Kerosene fuel being burned at temperatures reaching from 540- 630°C.

Must be raised to a pressure of 1 – 3 bar .Outer casing must have apertures for the

manometer, kerosene tube and propane tube (for ignition).

Must maintain an air to fuel ratio of at least 1:10.

The Flame tube

The purpose of the flame tube is to regulate the amount of air being fed into the combustion chamber.

The holes provide gradual increase of air into the combustion jacket.

It is very important that the air speed is not too fast because if it is the flame will be snuffed out or the fuel will simply be blown away.

Primary, secondary and Tertiary zones

Primary Zone: the area in which the fuel igniters come into contact with the air.

Secondary Zone + Tertiary : larger diameter holes which provides remaining colder air to mix with.

Completed assembley

Primary zone Secondary zone

Tertiary zone

Materials Needs

Issues with materials & manufacture

Welding equipment not designed to work with stainless steel. (Highly specialized)

Lack of filler materials Cutting equipment not designed for

complex shapes.(Bandsaw)Bending Austenitic steel very difficult E =

190 Gpa.FAS facility unworkable

Materials Analysis

Austenitic stainless steel 304/314

There are many factors contributing to the selection of austenitic stainless steels. The main factors were:

Easy to acquire / ubiquitous ( with the exception of 321) Can operate at high temperatures ( AISI 304, 316, 316L, 321

can all withstand the anticipated operating temperature of 650°C)

Can be welded Not magnetic Relatively cheap (AISI 304, 316, 316L could each be acquired

for less than 100€ for 1000mm x1000 x .5mm sheet Highly ductile Strength and Hardness can be increased by Cold working. Solution Annealing increases tensile strength

Bill of materials

Stainless Steel families

Austenitic Ferritic Duplex Martensitic Precipitation hardening

Source: Azom.com

Methods of Manufacture

Brazing Annealing Bending (for the sheet Steel)DrillingCutting

Shift Focus

Deficiencies in manufacturing equipment and expertise on my part meant this project could not be constructed form AISI 304/314.

Alternative manufacturing equipment SLS/RPD Machine .

SLS /RPD Machine

The SLS machined takes a design rendered on CAD and builds it slowly by layers and layers of polymer dust.

Model

Tasks completed

Pro-E Drawings Requisition sheets Polymer model of the Combustion

chamber and outer casing prototypeFinal Report

Thank you !Any questions