Dynamics of (C 6 H 12 O 6 ) n Propulsion During Alkane Combustion in an Adiabatic Reactor What makes the spud fly?

Who Are These People? Those who take all precautions to minimize bodily risk? Those who take all precautions to minimize bodily risk? No No Voted “Most Likely to be Maimed” by their classmates? Voted “Most Likely to be Maimed” by their classmates? Maybe Maybe Organ Donors? Organ Donors? Someday Someday

Combustion Kinetics (The Chemistry of Boom)

Simple Combustion of Methane (Natural Gas) CH 4 + 2O 2  CO 2 + 2H 2 O + Energy CH 4 + 2O 2  CO 2 + 2H 2 O + Energy Can be Autocatalytic Under Proper Circumstances Can be Autocatalytic Under Proper Circumstances

Combustion Kinetics Reactions Can be Autocatalytic if: Reactions Can be Autocatalytic if: Heat of Reaction is High Enough Heat of Reaction is High Enough Rate of Reaction is Fast Enough to Heat Up Surrounding Gas Rate of Reaction is Fast Enough to Heat Up Surrounding Gas Heat of Reaction is Determined by Chemistry Heat of Reaction is Determined by Chemistry Rate of Reaction Can be Controlled Rate of Reaction Can be Controlled

Simple Combustion of Methane CH 4 + 2O 2  CO 2 + 2H 2 O + Energy CH 4 + 2O 2  CO 2 + 2H 2 O + Energy If CH 4 << 2O 2, Reaction is Slow If CH 4 << 2O 2, Reaction is Slow Autocatalysis Unlikely Autocatalysis Unlikely If CH 4 >> 2O 2, Reaction is also Slow If CH 4 >> 2O 2, Reaction is also Slow Autocatalysis Unlikely Autocatalysis Unlikely Need Proper Proportion of Fuel and Oxygen Need Proper Proportion of Fuel and Oxygen

Combustion Terms Lower Explosion Limit Lower Explosion Limit Volume Percent of Fuel in Air Where Autocatalysis Begins (Minimum Lean) Volume Percent of Fuel in Air Where Autocatalysis Begins (Minimum Lean) Upper Explosion Limit Upper Explosion Limit Volume Percent of Fuel in Air Where Autocatalysis Ends (Maximum Rich) Volume Percent of Fuel in Air Where Autocatalysis Ends (Maximum Rich) Stoichiometric Proportion Stoichiometric Proportion Volume Percent of Fuel in Air Where Oxygen and Fuel are in Exact Combustion Proportion Volume Percent of Fuel in Air Where Oxygen and Fuel are in Exact Combustion Proportion

General Fuel Energy Methane CH 4 – 890 KJ/mole Methane CH 4 – 890 KJ/mole Propane C 3 H 8 – 2220 KJ/mole Propane C 3 H 8 – 2220 KJ/mole Acetylene C 2 H 2 – 1299 KJ/mole Acetylene C 2 H 2 – 1299 KJ/mole

Calculating the Energy Release Calculate the Volume of Gas in Chamber: Calculate the Volume of Gas in Chamber: V = pi (D 2 /4) L V = pi (D 2 /4) L Inject a Volume V f of Fuel in Chamber Inject a Volume V f of Fuel in Chamber Volume of Air in Chamber: Volume of Air in Chamber: V air = V – V f V air = V – V f Calculate Moles of Air and Fuel: Calculate Moles of Air and Fuel: N f = P V f /(RT) Ideal Gas Law N f = P V f /(RT) Ideal Gas Law

Calculate Energy Release Calculate Moles of Oxygen in Chamber Calculate Moles of Oxygen in Chamber N oxygen = 0.21 N air N oxygen = 0.21 N air Determine if Oxygen or Fuel is Limiting Reagent: Determine if Oxygen or Fuel is Limiting Reagent: C 3 H O 2  3CO 2 + 4H 2 O C 3 H O 2  3CO 2 + 4H 2 O Calculate Maximum Amount of Fuel Reacted Calculate Maximum Amount of Fuel Reacted Calculate Energy Released Calculate Energy Released

Rules of Experiment Safety, Safety, Safety Safety, Safety, Safety Vary Volume of Fuel and Measure Distance Potato Traveled Vary Volume of Fuel and Measure Distance Potato Traveled Determine Kinetic Energy of Potato Leaving the Barrel of Cannon Determine Kinetic Energy of Potato Leaving the Barrel of Cannon Compare with Combustion Energy Compare with Combustion Energy