Project Pulse-Jet Group 4. Jeffrey Dennen Justin Marriott Brian Melo Matthew Skillin. What is Project Pulse–Jet? . Project Pulse – Jet is an analytical study of how a pulse-jet engine works. Our Goals To design, build and test a pulse-jet engine. Plan of Action
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Project Pulse-Jet Group 4 Jeffrey Dennen Justin Marriott Brian Melo Matthew Skillin
What is Project Pulse–Jet? • Project Pulse – Jet • is an analytical study of how a pulse-jet engine works. • Our Goals • To design, build and test a pulse-jet engine. • Plan of Action • Research and design a prototype of a pulse-jet engine. • Build the prototype based on our design. • Test the prototype against the theoretical analysis.
History of the pulsejet • The pulsejet engine was first invented in the early 1900 by a Swedish inventor Martin Wiberg • Paul Schmidt, who engineered the first production pulsejet during the Second World War with his flying bomb, the Argus V1. • Nicknamed the “buzz” bomb because of the low hum it admitted during flight. • Used by the Germans to bomb London from 1944-1945 • Over 9,000 V-1 were fired on England during WW2 • The pulsejet took a backseat in the engineering world when the turbofan jet engine was invented • Has returned to the engineering scene as of late because of the interest in Pulse Detonation Engines (PDE).
How does it work? • A pulsejet engine is a very simple jet 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. • 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 fro m the atmosphere, and then the whole cycle repeats itself.
Types of Pulse Jets • There are two basic types of pulsejets. • valve or traditional pulsejet • valve-less pulsejet. • The Argus V1 Schmidt was a valve pulsejet • Most of the development work for the valve-less engines are done by two American engineers Lockwood and Hiller. • Types of Valves • Petal • High Efficiency Petal • Valve Grid
Design Research • The Lenoir cycle is an idealized thermodynamic cycle often used to model a pulse-jet engine. • Comprises of 3 cycles: • Heat added at constant volume. • Adiabatic Expansion. • Exhaust of the hot gasses at a constant pressure. • Thrust can be directly calibrated on the basis that the cycle is completed over two working strokes.
Design Research • C.E. Tharratt • Discovered a surprising result that the ratio of duct volume to effective length had a linear relationship to the maximum static thrust or: • V/L = 0.00316F • This relationship has been compared to all known pulse-jets from the large V-1 “flying bomb” of over 500 lb. thrust to the miniature Dyna-jets of 4-5 lbs. thrust. • Thrust = 2.2 x Cross-Sectional area or F = 2.2A
Sample Calculations • . • . • . • . • .
Pulse-Jet Body Exploded Taper Combustion Chamber Exhaust Pipe
Design Matrix for valves • Ranked on a 1 to 10 scale (1 being the worst and 10 being the best)
Valve Design • Sample Calculation. • Valve area = (0.23 x mean cross-sectional area) / 0.6 assuming the valves are going to be 60% efficient. • Valve Area = (0.23 x 7.72)/0.6 = 2.96 in
Valve Component Explode Valve Body Diffuser Reed Valve
Final Design Exploded Valve Assembly Body Assembly
Building and Testing • Materials • Pulse-Jets Main body. • Rolled and seem welded using 0.063” Stainless Steel Sheet Metal. • Stainless Selected because of its higher resistance to heat then mild steel. • Valve Body • CNC machined (Mill and Lathe) from 6061 Aluminum. • Aluminum used for its light weight and its machinability. • Reed Valve • 0.006” Spring Steel. • low alloy, medium carbon steel or high carbon steel with a very high yield strength. This allows objects made of spring steel to return to their original shape despite significant bending or twisting.
Fuel and Fuel Delivery • Fuel • Propane • Easily obtained. • Boiling Point below room temperature. • Being a gas allows for easier starting. • Fuel Delivery System • Propane Tank • Propane lines • Gas Fitting Nozzle • Needle Valve
Testing • Prototype will be tested to verify thrust output. • Test Stand will be constructed to secure Pulse-Jet safely. • Digital scale will be attached to frame to calculate thrust
Budget • Stainless steel sheet metal, with labor: $150 • Valve Body: $0 on hand • Reed Valves with machining labor: $25 • Propane Tank: $0, on hand • Fuel Delivery System: $0 on hand • Instrumentation: $0 on hand • Test stand material: $0 on hand • Fuel: $50 • Total: $175
Project’s Future • Continue testing on prototype to gain further knowledge of its operating cycle. • Construct larger Jet using the knowledge gained from this smaller prototype. • Use larger engine to power to propel a manned vehicle.
Thank You • Group 4 would like to thank • Professor Roberts • Professor Rourke • Mechanology Inc. (Attleboro, MA) • Wayne’s Sheet Metal • Paul’s Custom Exhaust • Project’s Lab Staff • Machine Shop Staff
Bibliography • Simpson Bruce “The Enthusiasts' Guide to Pulsejet Engines” • http://www.aardvark.co.nz/pjet/ • http://www.zachmiers.com/pulsejetbook/ • http://www.pulse-jets.com/ • Roy, Gabriel “Combustion processes in propulsion control, noise, and pulse detonation”