Image Credits and References:
http://www.wimp.com/vortexcannon/ is a video from BBC America showing the Vortex Cannon
http://www.youtube.com/watch?v=GteGbZeKsOI is a Vortex/Hail Cannon in Worcestershire, UK
http://www.youtube.com/watch?v=463WI03jiwY is from Highvoltagefeathers Creations showing a handheld acetylene Vortex Cannon
The task is to design and build a full-scale vortex cannon powered by a stoichiometric mixture of acetylene and air. The high-pressure combustion reactants are forced through a converging nozzle and then rapidly expanded at the inlet of the cone to allow the escaping gas to accelerate as its pressure field is drastically reduced. The diffuser cone expands at a 5° to 7° angle, which allows the gas to slow and the pressure to rise until it equals the atmosphere. A portion of the escaping gas is converted into a 200 mile-per-hour ring vortex that holds its shape and propagates up to 150 feet down range. Care must be taken to specify and build the combustion chamber to withstand the transient pressure within ample safety factors. Remote operation of the machine includes the control of an electronic ignition, valves for fuel and air, plus a nitrogen flush for safety. Experiments will include various “trip” rings at the muzzle to start the vortex rotation.
Level of Difficulty: High
nozzle, muzzle, stoichiometric, detonation, deflagration, First Law of Thermodynamics, internal energy of combustion, enthalpy, adiabatic, pulse detonation engine
“Vortex Ring Generator,” by George K. Lucey, Jr. (ARL)
“History of Hail Cannons,” by Sasha Khokha (NPR), http://www.thelivingmoon.com/45jack_files/03files/Hail_Cannons.html
Electrical Engineer (2) – Electrical Engineers on the project are responsible for the high-voltage ignition system. The EEs will also design and build a trailer-mounted power system that provides 120-Vac utility power for the igniter, gas control valves, fuel-line heating, general lighting, and diagnostic equipment in the field. The trailer’s power system is a 12-V car battery/inverter source.
Mechanical Engineer (2) – Mechanical Engineers on the project are responsible for the design of the combustion chamber, reducer section, and the long diffuser cone. Modeling and calculations will be employed in the design to guarantee the chamber can withstand the pressure impulse of combustion. Construction of the cannon will include the installation of gas injectors and pressure diagnostic ports that must not compromise vessel integrity.
Chemist (1) – The chemist on the project is responsible for the air/fuel/nitrogen injection system. The fuel/air injectors assure a stoichiometric mixture of acetylene and air for each shot. The nitrogen injectors flush the machine after each shot for safety and system repeatability. The Chemist designs the machine’s operating space to avoid a deflagration-to-detonation transition.
Aerospace Engineer (1) – The Aerospace Engineer is responsible for modeling the combustion product flow from the nozzle restriction to the muzzle exit at the diffuser cone. The goal is to match the flow field pressure to the atmospheric pressure at the exit. Additionally, the Aerospace Engineers conduct the tripping ring experiments to enhance vortex formation.
Computer Scientist (2) – Computer Scientists on the project are responsible for the control and diagnostic system that guarantees the safe and reliable operation of the machine from a distance. Diagnostic measurements include transient pressure samples at the combustion chamber, nozzle and muzzle. The control system governs the correct sequence of gas-fire-flush operations.
Designer (2) – Designers on the project direct the fabrication of all difficult/large components by other businesses with proper drawing and design packages. Designers are also responsible for integrating the machine, controls, power, and diagnostics into a trailer transport system that is legally qualified for Colorado roads.
Journalist (1) — The Journalist documents the project’s progress on the website, communicates with the local media, and is responsible for a final report. The whole project is your project.
Multimedia Artist (1) – The Multimedia Artist is responsible for bringing the machine’s operation in the field to life for community, family, and sponsors with sophisticated production videos. The whole project is your project.
Business Manager (1) – The Business Manager is responsible for reporting the project’s progress against a predetermined schedule, determines critical path items to completion, and tracks project spending to assure that costs remain within a fixed budget. The whole project is your project.