Changeset 644

Timestamp:

09/21/07 14:43:46 (15 months ago)

Author:

otter

Message:

unit error in gas force model in MultiBody engine example corrected. Gas parameters changed so that temperature is in a meaningful range.

Files:

• Modelica/branches/maintenance/2.2.2/Modelica/Mechanics/MultiBody/Examples/Loops/Utilities.mo (modified) (9 diffs)

Modelica/branches/maintenance/2.2.2/Modelica/Mechanics/MultiBody/Examples/Loops/Utilities.mo

@@ -226 +226 @@
     parameter SI.Length d "diameter of cylinder";
     parameter Real k0=0.01;
-    parameter Real k1=1;
-    parameter Real k=1;
+    parameter Real k1=0.005;
+    parameter Real k=0.00005;
     constant Real pi=Modelica.Constants.pi;
     constant Real PI=Modelica.Constants.pi;
@@ -270 +270 @@
             fillPattern=1)),
         Text(extent=[-100, 120; 100, 60], string="%name")));
-    
+  protected 
+    Modelica.SIunits.SpecificHeatCapacity R_air = Modelica.Constants.R/0.0289651159;
   equation 
     y = -s_rel/L;
@@ -282 +283 @@
       131.707*x^3 + 17.3438*x^2 + 17.9272*x + 2.4);
     
-    f = -1.0E5*press*pi*d^2/4;
+    f = -1.0e5*press*pi*d^2/4;
     
     V = k0 + k1*(1 - x);
-    dens = 1/V;
+    
+    dens = press/(R_air*T);
     press*V = k*T;
+    
   end GasForce;
   
@@ -296 +299 @@
     parameter SI.Length d "diameter of cylinder";
     parameter Real k0=0.01;
-    parameter Real k1=1;
-    parameter Real k=1;
+    parameter Real k1=0.005;
+    parameter Real k=0.00005;
     constant Real pi=Modelica.Constants.pi;
     constant Real PI=Modelica.Constants.pi;
@@ -365 +368 @@
 </html>"));
     
+  protected 
+    Modelica.SIunits.SpecificHeatCapacity R_air = Modelica.Constants.R/0.0289651159;
   equation 
     x = 1 - s_rel/L;
@@ -378 +383 @@
     
     V = k0 + k1*(1 - x);
-    dens = 1/V;
+    dens = press/(R_air*T);
     press*V = k*T;
     
@@ -531 +536 @@
   equation 
     
-    connect(jointRRP.frame_ia, Rod.frame_a) annotation (points=[20,-4; 49,-4;
+    connect(jointRRP.frame_ia, Rod.frame_a) annotation (points=[20,-4; 49,-4; 
           49,-1], style(
         color=10,
         rgbcolor={95,95,95},
         thickness=2));
-    connect(Mid.frame_b, jointRRP.frame_a) annotation (points=[-24,-20;
-          1.22461e-015,-20; 1.22461e-015,-8], style(
+    connect(Mid.frame_b, jointRRP.frame_a) annotation (points=[-24,-20; 
+          1.22465e-015,-20; 1.22465e-015,-8], style(
         color=10,
         rgbcolor={95,95,95},
@@ -543 +548 @@
     connect(gasForce.flange_a, jointRRP.axis) 
       annotation (points=[9,70; 16,70; 16,32],    style(color=58));
-    connect(jointRRP.bearing, gasForce.flange_b) annotation (points=[8,32; 8,52;
+    connect(jointRRP.bearing, gasForce.flange_b) annotation (points=[8,32; 8,52; 
           -20,52; -20,70; -11,70],        style(color=58));
     connect(jointRRP.frame_ib, Piston.frame_b) annotation (points=[20,28; 30,28;
@@ -551 +556 @@
         thickness=2));
     connect(jointRRP.frame_b, CylinderInclination.frame_b) annotation (points=[
-          -1.22461e-015,32; 1,32; 1,40; -24,40], style(
+          -1.22465e-015,32; 1,32; 1,40; -24,40], style(
         color=10,
         rgbcolor={95,95,95},