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MotorSim 0.2

Download Here and open the jar file. If you do not have Java installed on your computer it won't run.


New Features

  • KNER
  • KNDX
  • Editable Fuel
  • Non-SI Unit option
  • Max Thrust, Pressure
  • Average Thrust
  • Motor Rating
  • Moon Burner
  • Rod & Tube

Example Motors

Moon Burner




Moon Burner, KN - Erythritol

<object-stream>
  <com.billkuker.rocketry.motorsim.Motor>
    <chamber class="com.billkuker.rocketry.motorsim.CylindricalChamber">
      <ID>30 mm</ID>
      <length>200 mm</length>
    </chamber>
    <fuel class="com.billkuker.rocketry.motorsim.fuel.KNER"/>
    <grain class="com.billkuker.rocketry.motorsim.grain.Moonburner">
      <ID>10 mm</ID>
      <OD>29 mm</OD>
      <aftEndInhibited>true</aftEndInhibited>
      <coreOffset>6 mm</coreOffset>
      <foreEndInhibited>true</foreEndInhibited>
      <length>200 mm</length>
    </grain>
    <name>Moon Burner</name>
    <nozzle class="com.billkuker.rocketry.motorsim.ConvergentDivergentNozzle">
      <efficiency>0.85</efficiency>
      <exitDiameter>9 mm</exitDiameter>
      <throatDiameter>5 mm</throatDiameter>
    </nozzle>
  </com.billkuker.rocketry.motorsim.Motor>
</object-stream>

Rod & Tube Grain


Rod & Tube, KN - Dextrose

<object-stream>
  <com.billkuker.rocketry.motorsim.Motor>
    <chamber class="com.billkuker.rocketry.motorsim.CylindricalChamber">
      <ID>30 mm</ID>
      <length>150 mm</length>
    </chamber>
    <fuel class="com.billkuker.rocketry.motorsim.fuel.KNDX"/>
    <grain class="com.billkuker.rocketry.motorsim.grain.RodAndTubeGrain">
      <aftEndInhibited>false</aftEndInhibited>
      <foreEndInhibited>true</foreEndInhibited>
      <length>150 mm</length>
      <od>30 mm</od>
      <rodDiameter>10 mm</rodDiameter>
      <tubeID>20 mm</tubeID>
    </grain>
    <name>Rod and Tube Motor</name>
    <nozzle class="com.billkuker.rocketry.motorsim.ConvergentDivergentNozzle">
      <efficiency>0.85</efficiency>
      <exitDiameter>13 mm</exitDiameter>
      <throatDiameter>9 mm</throatDiameter>
    </nozzle>
  </com.billkuker.rocketry.motorsim.Motor>
</object-stream>

C-Slot & End Burner


I included some example motor buttons, an end burner and a c-slot. While I don't have a way to edit them yet, I put them in to show what I hope to support soon.

Editable Fuel

You can replace the fuel section of a motor with the following XML, and then edit the numbers. Note that A and N have different values depending on the units you use to characterize the fuel. If you work in inches per second and psi set the type to NONSI. If you work in mm per second and MPA set the type to SI. The values below are for KNSU.

Editable Fuel

    <fuel class="com.billkuker.rocketry.motorsim.fuel.EditableFuel">
      <a>0.0665</a>
      <combustionEfficiency>0.97</combustionEfficiency>
      <combustionProduct class="com.billkuker.rocketry.motorsim.fuel.EditableFuel$EditableCombustionProduct">
        <effectiveMolarWeight>0.04197999999999999 kg/mol</effectiveMolarWeight>
        <idealCombustionTemperature>1720 K</idealCombustionTemperature>
        <ratioOfSpecificHeats>1.133</ratioOfSpecificHeats>
        <ratioOfSpecificHeats2Phase>1.044</ratioOfSpecificHeats2Phase>
      </combustionProduct>
      <densityRatio>0.96</densityRatio>
      <idealDensity>1889.0 kg/m³</idealDensity>
      <n>0.319</n>
      <type>NONSI</type>
    </fuel>

Performance, Quality, Bugs


I compute the surface area and volume of the fancy grains using geometry. The code is not as fast as it could be, and for some reason I have not tracked down there seem to be little blips and spikes in the output. The curves look OK overall.

In some circumstances the burn will oscillate wildly. I know it is related to the pressure being too high or low relative to the regression step. If you change the default motor to KNER, which needs a higher Kn to work, the simulation does poorly.

Updates

I don't want to spam the mailing list anymore. If you use this and want to know when a new version comes out mail me, or watch this page.

ċ
MotorSim-0.2.jar
(4104k)
Bill Kuker,
Apr 23, 2009, 10:20 AM
ą
Bill Kuker,
Apr 23, 2009, 10:29 AM
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