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

   1 package com.billkuker.rocketry.motorsim;\r
   2 \r
   3 import java.awt.Shape;\r
   4 import java.awt.geom.AffineTransform;\r
   5 import java.awt.geom.GeneralPath;\r
   6 import java.awt.geom.Line2D;\r
   7 \r
   8 import javax.measure.quantity.Area;\r
   9 import javax.measure.quantity.Dimensionless;\r
  10 import javax.measure.quantity.Force;\r
  11 import javax.measure.quantity.Length;\r
  12 import javax.measure.quantity.Pressure;\r
  13 import javax.measure.unit.SI;\r
  14 \r
  15 import org.jscience.physics.amount.Amount;\r
  16 \r
  17 public class ConvergentDivergentNozzle extends MotorPart implements Nozzle {\r
  18 \r
  19         private Amount<Length> throatDiameter;\r
  20         \r
  21         private Amount<Length> exitDiameter;\r
  22         \r
  23         private double efficiency = 1.0;\r
  24         \r
  25         \r
  26         public Amount<Area> throatArea() {\r
  27                 return throatDiameter.divide(2).pow(2).times(Math.PI).to(Area.UNIT);\r
  28         }\r
  29         \r
  30         public Amount<Area> exitArea() {\r
  31                 return exitDiameter.divide(2).pow(2).times(Math.PI).to(Area.UNIT);\r
  32         }\r
  33 \r
  34 \r
  35         public Amount<Length> getThroatDiameter() {\r
  36                 return throatDiameter;\r
  37         }\r
  38 \r
  39 \r
  40         public void setThroatDiameter(Amount<Length> throatDiameter) {\r
  41                 if ( exitDiameter != null && throatDiameter.isGreaterThan(exitDiameter))\r
  42                         throw new IllegalArgumentException("Throat > Exit");\r
  43                 Amount<Length> old = this.throatDiameter;\r
  44                 this.throatDiameter = throatDiameter;\r
  45                 firePropertyChange("throatDiameter", old, throatDiameter);\r
  46         }\r
  47         \r
  48 \r
  49         public Amount<Length> getExitDiameter() {\r
  50                 return exitDiameter;\r
  51         }\r
  52 \r
  53 \r
  54         public void setExitDiameter(Amount<Length> exitDiameter) {\r
  55                 if ( throatDiameter != null && exitDiameter.isLessThan(throatDiameter))\r
  56                         throw new IllegalArgumentException("Throat > Exit");\r
  57                 Amount<Length> old = this.exitDiameter;\r
  58                 this.exitDiameter = exitDiameter;\r
  59                 firePropertyChange("exitDiameter", old, exitDiameter);\r
  60         }\r
  61         \r
  62         public Amount<Force> thrust(Amount<Pressure> Po, Amount<Pressure> Pe, Amount<Pressure> Patm, final double k ){\r
  63                 double cF = thrustCoefficient(Po, Pe, Patm, k);\r
  64                 return Po.times(throatArea()).times(cF).to(Force.UNIT);\r
  65         }\r
  66 \r
  67         public double thrustCoefficient(Amount<Pressure> Po, Amount<Pressure> Pe, Amount<Pressure> Patm, final double k ){\r
  68                 double pRatio = Pe.divide(Po).to(Dimensionless.UNIT).doubleValue(Dimensionless.UNIT);\r
  69 \r
  70                 double a = (2*k*k)/(k-1);\r
  71                 \r
  72                 double b = Math.pow(2/(k+1), (k+1)/(k-1) );\r
  73                 \r
  74                 double c = 1.0 - Math.pow(pRatio, (k-1)/k);\r
  75                 \r
  76                 Amount<Pressure> pDiff = Pe.minus(Patm);\r
  77                 \r
  78                 double d = pDiff.times(exitArea()).divide(Po.times(throatArea())).to(Dimensionless.UNIT).doubleValue(Dimensionless.UNIT);\r
  79                 \r
  80                 double Cf = efficiency * Math.sqrt(a*b*c)+d;\r
  81                 \r
  82                 return Cf;\r
  83         }\r
  84 \r
  85         public double getEfficiency() {\r
  86                 return efficiency;\r
  87         }\r
  88 \r
  89         public void setEfficiency(double efficiency) {\r
  90                 double old = this.efficiency;\r
  91                 this.efficiency = efficiency;\r
  92                 firePropertyChange("efficiency", old, efficiency);\r
  93         }\r
  94 \r
  95         public Shape nozzleShape(Amount<Length> chamberDiameter){\r
  96                 GeneralPath s = new GeneralPath();\r
  97                 double throatR = throatDiameter.divide(2).doubleValue(SI.MILLIMETER);\r
  98                 double exitR = exitDiameter.divide(2).doubleValue(SI.MILLIMETER);\r
  99                 double cR;\r
 100                 if (chamberDiameter == null)\r
 101                         cR = exitR;\r
 102                 else\r
 103                         cR = chamberDiameter.divide(2).doubleValue(SI.MILLIMETER);\r
 104                 \r
 105                 double diff = exitR-throatR;\r
 106                 double cDiff = cR-throatR;\r
 107                 \r
 108                 s.append(new Line2D.Double(0,0,diff,diff*3), false);\r
 109                 s.append(new Line2D.Double(0,0,cDiff,-cDiff), true);\r
 110                 \r
 111                 s.transform(AffineTransform.getScaleInstance(-1, 1));\r
 112                 s.transform(AffineTransform.getTranslateInstance(-throatR, 0));\r
 113                 \r
 114                 s.append(new Line2D.Double(0,0,diff,diff*3), false);\r
 115                 s.append(new Line2D.Double(0,0,cDiff,-cDiff), true);\r
 116                 \r
 117                 //a.add(new java.awt.geom.Area( new Ellipse2D.Double(0,0,5,5)));\r
 118                 \r
 119                 return s;\r
 120         }\r
 121 }\r