The Propellant Properties input tab is shown in the following figure. Every value except the Ambient Temperature was already set. These values all came from the NIOSH-AA-2 section of the Rocket Grain Reference book which were retrieved during the Rocket Motor Sizing section of this tutorial. The only value which we had to enter here was the 70 degrees F.
Below the screen capture all of the inputs are fully defined.
The following input categories for Propellant Properties are shown:
- Physical Properties
- Burn Rate Parameters
Under the Physical Properties category on the left hand side of the input tab are the following propellant characteristics:
- The Propellant Name is the nomenclature of the rocket motor propellant.
- The Ambient Temperature is the conditioning temperature of the rocket motor grain prior to start of combustion.
- The Density is the mass per unit volume of the energetic material that comprises the rocket motor grain.
- The Molecular Weight is the molecular weight of the propellant.
- The Specific Heat Ratio is the Specific Heat Ratio (Pressure/Volume) of the propellant grain combustion products.
On the right hand side of the Propellant Properties input tab are the parameters which determine the burn rate, pressure, etc. of the propellant grain. These inputs are:
- Burn Rate is the velocity at which the propellant burning surface regresses at a known pressure.
- Burn Rate Exponent the "a" burn exponent in the Bp^a burn rate equation; B is the burn rate coefficient, and p is the pressure.
- Press @ Burn Rate Meas is the Reference pressure for the propellant.
- Temp @ Burn Rate Meas is the Reference temperature for the propellant.
- Pi K is the percent burn rate change per degree temperature change (temperature sensitivity) of the propellant.
- Flame Temp is the Adiabatic Flame Temperature of the propellant combustion gases.
- 2nd Burn Rate Exponent is a secondary burn rate exponent when and where there is a distinctive change in propellant burn characteristics.
- Pressure @ 2nd Burn Rate is used as a Reference Pressure when and where there is a distinctive change in propellant burn characteristics.
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