Calculation of combustion in the engine cylinder

Update: January 30, 2018
OpenFOAM 4.x

Case directory

$FOAM_TUTORIALS/combustion/engineFoam/kivaTest

Summary

We calculates the combustion in a piston engine cylinder operating the crank angle from -180° to 60°. The mesh file is prepared in KIVA format and we convert it to OpenFOAM format for using. The model geometry consists of three regions: cylinderHead (green), liner (red), and piston (white) as shown in the figure below.

Model geometry (upper) Model geometry (upper)
Model geometry (lower) Model geometry (lower)

The engine specifications are defined in the file "constant/engineGeometry" as follows.

engineMesh      layered;
conRodLength    conRodLength [0 1 0 0 0 0 0] 0.147;
bore            bore [0 1 0 0 0 0 0] 0.092;
stroke          stroke [0 1 0 0 0 0 0] 0.08423;
clearance       clearance [0 1 0 0 0 0 0] 0.00115;
rpm             rpm [0 0 -1 0 0 0 0] 1500;	

The settings, ignition position, etc. of the equations for combustion reaction are defined in the file "constant/combustionProperties", and the fuel, oxidant, and products of combustion are defined in the file "constant/thermophysicalProperties" as "fuel", "oxidant", and "burntProducts", respectively.

The meshes are as follows, and the number of mesh is 27544.

Meshes (upper) Meshes (upper)
Meshes (lower) Meshes (lower)
Mesh Meshes (XY-plane)
Mesh Meshes (XZ-plane)

The calculation result is as follows.

Temperature distribution in the engine cylinder (T, volume rendering)

The flow velocity, pressure, and temperature distributions at a crank angle of 60° in the XY plane (Z=0.07) and XZ plane (Y=0) are shown below. A sphere in the figure indicates the ignition position.

Flow velocity at Z=0.07 plane (U) Flow velocity at Z=0.07 plane (U)
Flow velocity at Y=0 plane (U) Flow velocity at Y=0 plane (U)
Pressure at Z=0.07 plane (p) Pressure at Z=0.07 plane (p)
Pressure at Y=0 plane (p) Pressure at Y=0 plane (p)
Temperature at Z=0.07 plane (T) Temperature at Z=0.07 plane (T)
Temperature at Y=0 plane (T) Temperature at Y=0 plane (T)

And the average pressure and temperature at each crank angle are output to The file "logSummary.-180.dat".

Average pressure (p) Average pressure (p)
Average temperature (T) Average temperature (T)
Average of (k * 2/3)^1/2 Average of (k * 2/3)1/2
1 - (Average of b) 1 - (Average of b)

Commands

cp -r $FOAM_TUTORIALS/combustion/engineFoam/kivaTest kivaTest
cd kivaTest

kivaToFoam -file otape17
engineFoam

paraFoam

gnuplot
gnuplot>plot "logSummary.-180.dat" using 1:2 lc rgb "gray"
gnuplot>plot "logSummary.-180.dat" using 1:3 lc rgb "gray"
gnuplot>plot "logSummary.-180.dat" using 1:4 lc rgb "gray"
gnuplot>plot "logSummary.-180.dat" using 1:5 lc rgb "gray"

We use the utility "kivaToFoam" to convert the KIVA format (KIVA-3V format) mesh file "otape17" into OpenFOAM format.

Calculation time

21 minutes 33.99 seconds *Single, Inter(R) Core(TM) i7-2600 CPU @ 3.40GHz 3.40GHz

Reference