git.gag.com Git - sw/motorsim/blob - src/com/billkuker/rocketry/motorsim/Burn.java

   1 package com.billkuker.rocketry.motorsim;\r
   2 \r
   3 \r
   4 \r
   5 import java.util.SortedMap;\r
   6 import java.util.TreeMap;\r
   7 \r
   8 import javax.measure.quantity.Area;\r
   9 import javax.measure.quantity.Dimensionless;\r
  10 import javax.measure.quantity.Duration;\r
  11 import javax.measure.quantity.Force;\r
  12 import javax.measure.quantity.Length;\r
  13 import javax.measure.quantity.Mass;\r
  14 import javax.measure.quantity.MassFlowRate;\r
  15 import javax.measure.quantity.Pressure;\r
  16 import javax.measure.quantity.Temperature;\r
  17 import javax.measure.quantity.Velocity;\r
  18 import javax.measure.quantity.Volume;\r
  19 import javax.measure.quantity.VolumetricDensity;\r
  20 import javax.measure.unit.SI;\r
  21 \r
  22 import org.apache.log4j.Logger;\r
  23 import org.jscience.physics.amount.Amount;\r
  24 import org.jscience.physics.amount.Constants;\r
  25 \r
  26 import com.billkuker.rocketry.motorsim.fuel.KNSU;\r
  27 import com.billkuker.rocketry.motorsim.grain.BurnPanel;\r
  28 import com.billkuker.rocketry.motorsim.grain.CoredCylindricalGrain;\r
  29 import com.billkuker.rocketry.motorsim.grain.ExtrudedGrain;\r
  30 import com.billkuker.rocketry.motorsim.grain.GrainPanel;\r
  31 import com.billkuker.rocketry.motorsim.grain.MultiGrain;\r
  32 import com.billkuker.rocketry.motorsim.visual.Chart;\r
  33 \r
  34 public class Burn {\r
  35         \r
  36         private static Logger log = Logger.getLogger(Burn.class);\r
  37         protected final Motor motor;\r
  38         \r
  39         private static final Amount<Pressure> atmosphereicPressure = Amount.valueOf(101000, SI.PASCAL);\r
  40         \r
  41         \r
  42         private static double combustionEfficency = 0.97;\r
  43         \r
  44         private static double densityRatio = 0.96;\r
  45         \r
  46         public class Interval{\r
  47                 Amount<Duration> time;\r
  48                 public Amount<Length> regression;\r
  49                 public Amount<Pressure> chamberPressure;\r
  50                 Amount<Mass> chamberProduct;\r
  51                 Amount<Force> thrust;\r
  52 \r
  53                 public String toString(){\r
  54                         return time + " " + regression + " " + chamberPressure + " " + chamberProduct;\r
  55                 }\r
  56         }\r
  57         \r
  58         protected SortedMap<Amount<Duration>,Interval> data = new TreeMap<Amount<Duration>, Interval>();\r
  59         \r
  60         public SortedMap<Amount<Duration>,Interval> getData(){\r
  61                 return data;\r
  62         }\r
  63         \r
  64         public Motor getMotor(){\r
  65                 return motor;\r
  66         }\r
  67 \r
  68         public Amount<Duration> burnTime(){\r
  69                 return data.lastKey();\r
  70         }\r
  71         \r
  72         public Burn(Motor m){\r
  73                 motor = m;\r
  74         }\r
  75         \r
  76         private void burn(){\r
  77                 log.info("Starting burn...");\r
  78                 \r
  79                 Amount<Length> regStep = Amount.valueOf(0.0119904077, SI.MILLIMETER);\r
  80 \r
  81                 //if ( motor.getGrain() instanceof Grain.DiscreteRegression )\r
  82                         //regStep = ((Grain.DiscreteRegression)motor.getGrain()).optimalRegressionStep();\r
  83                 \r
  84                 Interval initial = new Interval();\r
  85                 initial.time = Amount.valueOf(0, SI.SECOND);\r
  86                 initial.regression = Amount.valueOf(0, SI.MILLIMETER);\r
  87                 initial.chamberPressure = atmosphereicPressure;\r
  88                 initial.chamberProduct = Amount.valueOf(0, SI.KILOGRAM);\r
  89                 initial.thrust = Amount.valueOf(0, SI.NEWTON);\r
  90                 \r
  91                 data.put(Amount.valueOf(0, SI.SECOND), initial);\r
  92                 \r
  93                 for ( int i = 0; i < 5000; i++ ){\r
  94 \r
  95                         Interval prev = data.get(data.lastKey());\r
  96                         log.debug(prev);\r
  97                         log.debug("Step " + i + " ==============================");\r
  98                         Interval next = new Interval();\r
  99                         \r
 100                         Amount<Velocity> burnRate = motor.getFuel().burnRate(prev.chamberPressure);\r
 101                         \r
 102                         log.debug("Burn Rate: " + burnRate);\r
 103                         \r
 104                         Amount<Duration> dt = regStep.divide(burnRate).to(Duration.UNIT);\r
 105                         \r
 106                         data.put(data.lastKey().plus(dt), next);\r
 107                         \r
 108                         log.debug("Dt: " + dt);\r
 109                         \r
 110                         next.regression = prev.regression.plus(regStep);\r
 111                         \r
 112                         log.info("Regression: " + next.regression);\r
 113                         \r
 114                         next.time = prev.time.plus(dt);\r
 115                         \r
 116                         log.debug("Vold: " + motor.getGrain().volume(prev.regression).to(SI.MILLIMETER.pow(3)));\r
 117                         \r
 118                         log.debug("Vnew: " + motor.getGrain().volume(next.regression).to(SI.MILLIMETER.pow(3)));\r
 119                         \r
 120                         //TODO Amount<Volume> volumeBurnt = motor.getGrain().volume(prev.regression).minus(motor.getGrain().volume(next.regression));\r
 121                         Amount<Volume> volumeBurnt = motor.getGrain().surfaceArea(prev.regression).times(regStep).to(Volume.UNIT);\r
 122                         \r
 123                         log.info("Volume Burnt: " + volumeBurnt.to(SI.MILLIMETER.pow(3)));\r
 124                         \r
 125                         Amount<MassFlowRate> mGenRate = volumeBurnt.times(motor.getFuel().idealDensity().times(densityRatio)).divide(dt).to(MassFlowRate.UNIT);\r
 126                         \r
 127                         log.debug("Mass Gen Rate: " + mGenRate);\r
 128                         \r
 129                         Amount specificGasConstant = Constants.R.divide(motor.getFuel().getCombustionProduct().effectiveMolarWeight());\r
 130                         Amount<Temperature> chamberTemp = motor.getFuel().getCombustionProduct().idealCombustionTemperature().times(combustionEfficency);\r
 131                         \r
 132                         Amount<MassFlowRate> mNozzle;\r
 133                         {\r
 134                                 Amount<Pressure> pDiff = prev.chamberPressure.minus(atmosphereicPressure);\r
 135                                 \r
 136                                 //pDiff = Amount.valueOf(.7342, MPA).minus(atmosphereicPressure);\r
 137                                 \r
 138                                 log.debug("Pdiff: " + pDiff);\r
 139                                 \r
 140                                 Amount<Area> aStar = motor.getNozzle().throatArea();\r
 141                                 \r
 142                                 double k = motor.getFuel().getCombustionProduct().ratioOfSpecificHeats();\r
 143                                 \r
 144                                 log.debug("K: " + k);\r
 145                                 \r
 146                                 double kSide = Math.sqrt(k) * Math.pow((2/(k+1)) , (((k+1)/2)/(k-1))); //Math.pow(2/k+1, (k+1)/(2*(k-1)));\r
 147                                 \r
 148                                 log.debug("K-Part: (good)" + kSide);\r
 149                                 \r
 150                                 \r
 151                                 \r
 152                                 //This unit conversion helps JScience to convert nozzle flow rate to\r
 153                                 //kg/s a little later on I verified the conversion by hand and\r
 154                                 //JScience checks it too.\r
 155                                 specificGasConstant = specificGasConstant.to(\r
 156                                                 SI.METER.pow(2).divide(SI.SECOND.pow(2).times(SI.KELVIN)));\r
 157                                 \r
 158                                 log.debug("Specific Gas Constant: (good)" + specificGasConstant);\r
 159                                 \r
 160                                 Amount sqrtPart = specificGasConstant.times(chamberTemp).sqrt();\r
 161 \r
 162                                 //Unit x = SI.JOULE.divide(SI.KILOGRAM).root(2);\r
 163                                 \r
 164                                 //sqrtPart = sqrtPart.times(Amount.valueOf(1, x));\r
 165                                 \r
 166                                 log.debug("Square Root Part: " + sqrtPart);\r
 167                                 \r
 168                                 mNozzle = pDiff.times(aStar).times(kSide).divide(sqrtPart).to(MassFlowRate.UNIT);\r
 169                                 \r
 170                                 log.debug("Nozzle Flow: " + mNozzle);\r
 171                                 \r
 172                                 log.debug("Nozzle Flow: " + mNozzle.to(MassFlowRate.UNIT));\r
 173                                 \r
 174                                 \r
 175                                 \r
 176                                 \r
 177                         }\r
 178                         \r
 179                         Amount<MassFlowRate> massStorageRate = mGenRate.minus(mNozzle);\r
 180                         \r
 181                         log.debug("Chamber Product rate: " + massStorageRate);\r
 182                         \r
 183                         next.chamberProduct = prev.chamberProduct.plus(massStorageRate.times(dt));\r
 184                         \r
 185                         log.debug("Chamber Product: " + next.chamberProduct);\r
 186                         \r
 187                         Amount<VolumetricDensity> combustionProductDensity = next.chamberProduct.divide(motor.getChamber().chamberVolume().minus(motor.getGrain().volume(next.regression))).to(VolumetricDensity.UNIT);\r
 188                         \r
 189                         log.debug("Product Density: " + combustionProductDensity);\r
 190                         \r
 191                         next.chamberPressure = combustionProductDensity.times(specificGasConstant).times(chamberTemp).plus(atmosphereicPressure).to(Pressure.UNIT);\r
 192                         \r
 193                         next.chamberPressure = Amount.valueOf(\r
 194                                         next.chamberPressure.doubleValue(SI.PASCAL),\r
 195                                         SI.PASCAL);\r
 196                         \r
 197                         next.thrust = motor.getNozzle().thrust(next.chamberPressure, atmosphereicPressure, atmosphereicPressure, motor.getFuel().getCombustionProduct().ratioOfSpecificHeats2Phase());\r
 198                         \r
 199                         if ( next.chamberPressure.approximates(atmosphereicPressure)){\r
 200                                 log.info("Pressure at Patm on step " + i);\r
 201                                 break;\r
 202                         }\r
 203                 }\r
 204                                 \r
 205         }\r
 206         \r
 207         public Amount<Pressure> pressure(Amount<Duration> time){\r
 208                 return data.get(time).chamberPressure;\r
 209         }\r
 210         \r
 211         public Amount<Force> thrust(Amount<Duration> time){\r
 212                 return data.get(time).thrust;\r
 213         }\r
 214         \r
 215         public Amount<Dimensionless> kn(Amount<Length> regression){\r
 216                 return motor.getGrain().surfaceArea(regression).divide(motor.getNozzle().throatArea()).to(Dimensionless.UNIT);\r
 217         }\r
 218         \r
 219         public static void main( String args[]) throws Exception{\r
 220                 Motor m = new Motor();\r
 221                 m.setFuel(new KNSU());\r
 222                 \r
 223                 CylindricalChamber c = new CylindricalChamber();\r
 224                 c.setLength(Amount.valueOf(200, SI.MILLIMETER));\r
 225                 c.setID(Amount.valueOf(30, SI.MILLIMETER));\r
 226                 m.setChamber(c);\r
 227                 \r
 228                 CoredCylindricalGrain g = new CoredCylindricalGrain();\r
 229                 g.setLength(Amount.valueOf(70, SI.MILLIMETER));\r
 230                 g.setOD(Amount.valueOf(30, SI.MILLIMETER));\r
 231                 g.setID(Amount.valueOf(10, SI.MILLIMETER));\r
 232                 m.setGrain(g);\r
 233                 \r
 234                 m.setGrain(new MultiGrain(g,2));\r
 235                 \r
 236                 //m.setGrain(new ExtrudedGrain());\r
 237                 \r
 238                 ConvergentDivergentNozzle n = new ConvergentDivergentNozzle();\r
 239                 n.setThroatDiameter(Amount.valueOf(8.500, SI.MILLIMETER));\r
 240                 n.setExitDiameter(Amount.valueOf(20.87, SI.MILLIMETER));\r
 241                 n.setEfficiency(.87);\r
 242                 m.setNozzle(n);\r
 243                 \r
 244                 Burn b = new Burn(m);\r
 245                 \r
 246                 b.burn();\r
 247                 \r
 248                 new BurnPanel(b).show();\r
 249                 /*\r
 250                 Chart<Duration, Pressure> r = new Chart<Duration, Pressure>(\r
 251                                 SI.SECOND,\r
 252                                 SI.MEGA(SI.PASCAL),\r
 253                                 b,\r
 254                                 "pressure");\r
 255                 r.setDomain(b.data.keySet());\r
 256                 r.show();\r
 257                 \r
 258                 Chart<Duration, Force> t = new Chart<Duration, Force>(\r
 259                                 SI.SECOND,\r
 260                                 SI.NEWTON,\r
 261                                 b,\r
 262                                 "thrust");\r
 263                 t.setDomain(b.data.keySet());\r
 264                 t.show();\r
 265                 \r
 266                 new GrainPanel( m.getGrain() ).show();*/\r
 267                 \r
 268         }\r
 269 }\r