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Thermodynamic Principles Operating on a Spud Gun. George Bucşan: Aerospace Engineering, 2014 Marco Romero: Aerospace Engineering, 2014 . Thermodynamic Principles Operating on a Spud Gun. Some background information and motivation. Design, Construction, Theory. ΔU N.
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Thermodynamic Principles Operating on a Spud Gun George Bucşan: Aerospace Engineering, 2014 Marco Romero: Aerospace Engineering, 2014
Thermodynamic Principles Operating on a Spud Gun Some background information and motivation Design, Construction, Theory ΔUN Experimental Calculations and Results
Thermodynamic Principles Operating on a Spud Gun The basic idea for our project came about while were questioning the accuracy and deadliness of cannons.
Thermodynamic Principles Operating on a Spud Gun Due to a variety of safety and liability issues, we will be experimenting with a spudgun and analyze its thermodynamic behavior, which in turn will give us a greater insight into real cannons.
Thermodynamic Principles Operating on a Spud Gun A crucial part in the development of our experiment was testing the designed cannon.
Thermodynamic Principles Operating on a Spud Gun • In order to carry our experiment further we had to make some quick assumptions: • the burn process occurs extremely fast • the gas expands adiabatically until the projectile leaves the barrel • the chemical energy is divided into thermal and kinetic energies
Thermodynamic Principles Operating on a Spud Gun Oxidizing the chemical fuel – lighter fluid: 2C5H12 + 2C6H14 + 35 O2 → 22 CO2 + 26 H2O (@433K) 1g naphtha →0.2 moles of carbon dioxide and water Energy lost in heating the resulting gas and vapors: ΔT = 433K – 293K = 140K ΔUf = cv*n*R*ΔT = 0.698 kJ/g
Thermodynamic Principles Operating on a Spud Gun Energy lost in heating the N2 in the barrel: n = V * ρair * cN2 / µN2 = 43 moles N2 ΔUN= cv*n*R*ΔT = 75.075 kJ Total energy available (per ml. of fuel – “n”): ΔU = n*0.502 + 75.075 [kJ] H = 48.77 kJ/g E = 33.81*n – 75.08 [kJ]
Thermodynamic Principles Operating on a Spud Gun Muzzle velocity: v =
Thermodynamic Principles Operating on a Spud Gun Drag: Fd= 0.5 * Cd * ρair * V2 * π * r2
Thermodynamic Principles Operating on a Spud Gun Experimental data vs. Theoretical data: Experimental data – red, Theoretical data - green
Thermodynamic Principles Operating on a Spud Gun • Why the differences? • Final temperature lower due to adiabatic expansion • Incomplete fuel vaporization (due to saturation) • 273K ambient temperature (assumed – 293K) • Approximations on potato shape, mass, Cd • Final adjustments: • E = α*33.81*n – β* 75.08 [kJ] • α = 0.85 & β = 0.67
Thermodynamic Principles Operating on a Spud Gun Finally: Experimental data – red, Initial theoretical data – green, Adjusted theoretical data - blue
Thermodynamic Principles Operating on a Spud Gun References: "Cannon." Wikipedia, the Free Encyclopedia. Web. 01 Feb. 2012. <http://en.wikipedia.org/wiki/Cannon>. Clymer, Jeffrey. "Heat of Combustion & Respiratory Quotient Calculation." Fuse.net. 22 July 2009. Web. Jan.-Feb. 2012. <http://home.fuse.net/clymer/rq/hoctable.html>. "Drag Coefficient." Wikipedia, the Free Encyclopedia. 1 Feb. 2012. Web. 10 Feb. 2012. <http://en.wikipedia.org/wiki/Drag_coefficient>. "Fort Moultrie: How Does a Cannon Work." nps.gov. National Park Service U.S. Department of the Interior. Web. 20 Jan. 2012. <http://www.nps.gov/fosu/planyourvisit/upload/how_does_a_cannon_work.pdf>. "HowStuffWorks "How Spud Guns Work"" HowStuffWorks "Home and Garden" Web. 24 Jan. 2012. <http://home.howstuffworks.com/spud-gun1.htm>. "Material Safety Data Sheet Ronsonol Lighter Fluid." May 2000. Web. 3 Feb. 2012. <http://www.local510.org/msds_sheets/Ronsonol_MSDS.pdf>. The Spudgun Technology Center - Your Source for Spudgun Parts, Information, and More! Web. 24 Jan. 2012. <http://www.spudtech.com/content.asp?id=5>.
Thermodynamic Principles Operating on a Spud Gun Questions ? Krupp Dora (Germany, 1941) This is “the” gun!