A Proposal to Design and Build a Pulse-Jet Engine
Justin Marriott, Jeffrey Dennen, Matthew Skillin, Brian Melo
A Proposal to Design and Build a Pulse-Jet Engine
Submitted to
Professor Richard L. Roberts
Professor Peter S. Rourke
June 03, 2010
By
Justin Marriott
Jeffrey Dennen
Matthew Skillin
Brian Melo
WENTWORTH INSTITUTE OF TECHNOLOGY
Mech 690
Justin Marriott
(909) 994-3357
166 Hillside St. apt 1, Boston, MA 02120
Jeffrey Dennen
(508) 479-0426
98 New St. Rehoboth, MA 02769
Matthew Skillin
(617) 650-9084
15 Becket St. Dorchester, MA 02124
Brian Melo
(781) 439-1104
150 West St. Malden, MA 02148
Introduction
Did you ever hear about the buzzing of a German bomb during World War II? Well if you did you heard the first ever pulse jet engine, used on what was called the “buzz bomb”. Have you ever wondered how does a pulse jet work? How about what is the most efficient design for a pulse jet? Well Project Pulse Jet is pleased to present you with a new design of a pulse jet that will be more efficient and will have a better thrust based on the efficiency.
Problem Statement
Currently the designs of the pulse jet engines are flawed because of the lack of efficiency of the engine, not using the fuel to the full advantage. The current engines are not maximizing the thrust because they are not maximizing the fuel. We plan to maximize the fuel consumption which will also maximize the thrust capability of the jet engine.
Background Research
Apulse-jet engine(orpulsejet) is a very simple type ofjet enginein which combustion occurs inpulses. Pulsejet engines can be made with fewor no moving parts, and are capable of running statically.
The pulsejet engine was first invented in the early 1900 by a Swedish inventor Martin Wiberg. Though Wiberg was given the credit for the invention the pulsejet was mostly influenced by Paul Schmidt. Schmidt engineered the first production pulsejet during the Second World War with his flying bomb, the Argus V1. Though Schmidt had a lot of confidence in the pulsejets future the pulsejet was pushed off to the side shortly after the war with the invention of the turbofan jet engine. There has been a great deal of research on pulsejet engines recently, as more people realize the practical benefits of their capabilities. One such line of research is using pulsejet engines to study and simulate various pulse detonation engine phenomena which is much more cost-effective on a smaller scale.
A pulsejet engine is a very simple engine consisting of very little to no moving parts. The combustion cycle comprises five or six phases: Induction, Compression, (in some engines) Fuel Injection, Ignition, Combustion, and Exhaust. As air is drawn into the combustion chamber fuel is mixed in and ignited. The rapidly expanding gasses exit out of the engine and as this happens a vacuum is created in the combustion chamber which pulls in a fresh new air charge from the atmosphere, and then the whole cycle repeats itself.
There are two basic types of pulsejets. The first is known as a valved or traditional pulsejet and it has a set of one-way valves through which the incoming air passes. When the air-fuel is ignited, these valves slam shut which means that the hot gases can only leave through the engine's tailpipe, thus creating forward thrust. This was the original design that the Argus V1 Schmidt built utilized.
The second type of pulsejet is known as the valveless pulsejet. Technically the term for this engine is the acoustic-type pulsejet, or aerodynamically valved pulsejet. Most of the development work for this type of engine was done by two American engineers Lockwood and Hiller. The intake tube is responsible for the engine taking in air and mixing it with fuel to combust, and also controls the expansion of exhaust gases, as well as limiting the flow but not stopping it altogether like its valved counterpart. While the fuel-air mixture burns, a majority of the expanding gas will be forced out of the exhaust pipe section of the engine, but because the intake tube(s) also expel gas during the exhaust cycle of the engine, most valveless engines have the intakes facing backwards so that the thrust created will add to the overall thrust of the engine instead of reducing it.
The Need
Pulsejet engines theoretically are supposed to be very efficient compared to its turbofan counterpart. This has been hard to demonstrate in actual production versions of the engines and there has been various ways and ideas of how to increase its efficiency. The need to this design is that the pulsejet engine has been shown to not be as efficient as it theoretically can be and the design team is to take a focus on varies ways to increase its efficiency.
Objectives
The design team will design and fabricate a working prototype of this engine. Obtaining the highest efficiency will be the design team major focus. Testing of various designs will be compared to obtain the highest efficiency.
The following points are the design team objectives that are going to be followed to complete the project.
Ø Completed Prototype: Fully operational engine that starts up and runs for an extended time.
Ø Thorough Calculations: Methods, logic, and accuracy of the calculations required to complete a comprehensive design.
Ø Design effectiveness: Best possible design under the given conditions.
Ø Known optimization criteria: A proposed optimum engine thrust for the design, with complete calculations backing the proposal.
Ø Deliver SolidWorks models and drawings of the working prototype.
Work Plan
Budget
· Stainless steel sheet metal, with labor: $300
· Reed Valves with machining labor: $25
· Fuel pump: $0, on hand
· Fuel injector: $0 on hand
· Instrumentation: $0 on hand
· Test stand material: $40
· Fuel: $50
Total: $415
Projects Future
The future of this project is to be able to have the pulse jet operate safely and dependable enough to be equipped on a Go-cart while maintaining full drivability but achieving faster speeds. The project will continue for our own enjoyment following the conclusion of this class. Future hopes for this project will be to create more power from modifications learned throughout the project.
Qualifications
As a design team we have made it through 3.5 years of classes and will be using the knowledge of all these classes during our project to complete flow studies, calculations, SolidWorks models and thermodynamics. We will also be using professors at Wentworth to help us with any major issues that we have during our project. We have a professional welder that has agreed to so the welding on the jet engine for us.
References
1. Westberg, Fredrik, "Inside the pulsejet engine," a private study, April 2000.
2. Paxson, D.E., and John, T.W., “Conditionally Sampled Pulsejet Driven Ejector Flow Field Using DPIV,” paper#AIAA-2002-3231, 2002.
3. Logan, J. G., Jr., “Valveless pulse jet investigations, Part I, Test of small scale models,” Project SQUID Tech. Memo. No. CAL-27, Cornell Aeronaut. Lab., May 1949.
4. Lockwood, R. M., "Pulse reactor lift-propulsion system development program, final report", Advanced Research Division Report No. 508, Hiller Aircraft Company, March 1963.
5. Zinn, B. T., “Pulsating Combustion,” Advanced Combustion Methods, F. J. Weinberg, ed., Academic Press, Orlando, FL, 1986.