Prague Czech Republic March 7-9, 2016 Combustion calibration in a Methane port fuel injection engine with the STAR-CD ISSIM embedding the ECFM-3Z model
INDEX 1. PROBLEM PROPOSED 2. ANALYTICAL & NUMERICAL MODELS 3. ISSIM PARAMETERS 4. CALIBRATION POINT 5. RESULTS 6. CONCLUSION Contact: juan.sanprimitivo@polito.it sergio.tosi@polito.it
1. PROBLEM PROPOSED
PROBLEM PROPOSED Engine main parameters Name TJET 1.4 Number of Cylinders 4 Injection Port fuel Fuel Methane Stroke 84 mm Bore 72 mm Rod Length 129 mm CR 9.8 Operation Points Velocity (rpm) load 2000 3 2000 3.6 2000 4.4 2000 6 2570 7.9 3000 8 3500 6 Calibration point
2. ANALYTICAL & NUMERICAL MODELS
FUNDAMENTAL EQUATIONS Conservation of mass Conservation of momentum Conservation of energy Dρ Dt = 0 Du Dt = F p ρ Dh Dt = Dp + k T + Φ Dt Combustion CH 4 + 2O 2 CO 2 + 2H 2 O + Q
NUMERICAL SOLVER - MESHER ES-ICE Total number of cells Cells inside cylinder Cells for refinement for Combustion Cells in runners 1.1 Mln 0.8 Mln 0.1 Mln 0.3 Mln
NUMERICAL SOLVER FLUID DYNAMICS STAR Turbulence model Combustion model Ignition model Wall treatment Laminar flame Speed K-ε Realizable ECFM-3Z ISSIM Algelberger Metghalchi Correlation
3. ISSIM PARAMETERS
SECONDARY CIRCUIT Secondary Circuit Rs Resistance (Rs): Electrical resistance in the Secondary Circuit [Default value=9000 Ohm] Inductance (Ls): Coil inductance in the Secondary Circuit [Default value=31 mh] Energy (En): Energy in the Secondary Circuit [Default value=0.05 J] FACTEGRVOLT: modification factor of the Voltage according to EGR
SECONDARY CIRCUIT Pressure Analysis Ref. Test Peak [bar] 43.3 +0.4% Angle [º] 370.1 +0.1 Analysis of Secondary Circuit Parameter Reference Test Energy [J] 0.05 0.2 Resistance [kohm] 9 20 Inductance [mh] 31 60 Mass flow burnt Ref. Test 10% 354.7 +0.3 50% 362.7 +0.1 90% 372.6 +0.2
FACTEGRVOLT1 Pressure Analysis Ref. Test 1 Test 2 Peak [bar] 43.3 +0.2% +0.1% Angle [º] 370.1 +0.1 0 Analysis of FACTEGRVOLT1 Reference 4 Test 1 2 Test 2 8 Mass flow burnt Ref. Test 1 Test 2 10% 355.2-0.1 0 50% 362.8-0.1 0.1 90% 372.9-0.1 0
LAMINAR SPEED CORRESPONDING TO ISSIM S L corr = 0.5 1 4δ L 0 l spk + = 4δ L 0 l spk 1 2 + 4 4δ L 0 ign 1 + T b l spk 400 S L eff = S L 0 1 + S L corr 1 e 2 x x spk l spk SPINFEXT2 T b ign = Min E b c p b m b, TEMPMAXLCORR SPINFEXT2: Proportional coefficient to adjust the size of the influence sphere for effective laminar flame speed [Default value=1] TEMPMAXCORR: Maximum admissible temperature taken into account for SL correction due to energy provided by spark plug [Default value=5000]
SPINFEXT2 Pressure Analysis Ref. Test 1 Test 2 Peak [bar] 43.12-2.6% 2.62% Angle [º] 370.3 +0.9-1.1 Analysis of SPINFEXT2 Reference 8 Test 1 4 Test 2 16 Mass flow burnt Ref. Test 1 Test 2 10% 355.2 +0.8-1.4 50% 362.8 +1.3-1.3 90% 372.9 +1.3-1.4
LAMINAR SPEED CORRESPONDING TO METGHALCHI PRTRANSL: Transition pressure for application of ULAM3 or ULAM3BELOW in the laminar flame speed correlation [Default value=0] ULAM3: Adjustment of pressure ifluence in laminar flame speed correlation for P>PRTRANSL [Default value=40] ULAM3BELOW: adjustment of pressure influence in laminar flame speed correlation for P<PRTRANSL [Default value=60]
ULAM3BELOW Pressure Analysis Ref. Test 1 Test 2 Peak [bar] 36.33 +18.7% -4.3% Angle [º] 373.5-3.2 +0.6 Analysis of ULAM3BELOW Reference 6.5 Test 1 6 Test 2 10 Mass flow burnt Ref. Test 1 Test 2 10% 356.9-1.7 +0.5 50% 367.4-4.6 +1.4 90% 382.7-9.8 +2.2
CALIBRATION SETTING
4. CALIBRATION POINT (2000@3 bar)
2000 rpm @ 3 bar 2000x3 U3B=4.6 SPIN2FEXT=6 Experimental Relative Error Max_P (bar) 19.83 19.58 1.28% Intake mass (g) 0.160 0.161 0.62% Mbf 10 359.2 (25.2) 358.7 (24.7) 0.5 Mbf 50 370.6 (36.6) 370.9 (36.9) 0.3 Mbf 90 385.1 (51.1) 384.9 (50.9) 0.2 T_SA (K) 695.7 711.4 2.21% P_SA (bar) 5.32 5.28 0.75% 120 (intake phase) IMEP Net (bar) IMEP gross (bar) 3.35 3.51 4.56% 4.04 4.08 0.98%
2000 rpm @ 3 bar
2000 rpm @ 3 bar CH 4-6 24 4 34 14 44
5. RESULTS
ULAM3BELOW March 7 9 2000 rpm @ 3 bar 8.5 8 7.5 7 6.5 6 5.5 5 4.5 4 4,6 @ 2000 rpm 2 3 4 5 6 7 8 9 LOAD [BAR]
ULAM3BELOW March 7 9 2000 rpm @ 6 bar 8.5 8 7.5 7 6.5 6,5 @ 2000 rpm 6 5.5 5 4.5 4 4,6 @ 2000 rpm 2 3 4 5 6 7 8 9 LOAD [BAR]
ULAM3BELOW March 7 9 3500 rpm @ 6 bar 8.5 8 7.5 7,25 @ 3500 rpm 7 6.5 6,5 @ 2000 rpm 6 5.5 5 4.5 4 4,6 @ 2000 rpm 2 3 4 5 6 7 8 9 LOAD [BAR]
ULAM3BELOW March 7 9 3000 rpm @ 8 bar 8.5 8,25 @ 3000 rpm 8 7.5 7,25 @ 3500 rpm 7 6.5 6,5 @ 2000 rpm 6 5.5 5 4.5 4 4,6 @ 2000 rpm 2 3 4 5 6 7 8 9 LOAD [BAR]
SPINFX2 ULAM3BELOW March 7 9 ALL RESULTS 8.5 8,25 @ 3000 rpm 8 7.5 7,25 @ 3500 rpm 7,9 @ 2570 rpm 7 6.5 6,5 @ 2000 rpm 6 5.5 5 4.5 4 5,2 @ 2000 rpm 4,8 @ 2000 rpm 4,6 @ 2000 rpm 1 2 3 4 5 6 0.5 7 8 9 LOAD [BAR] 0 2000 2250 2500 2750 3000 3250 3500 RPM 4.5 4 3.5 3 2.5 2 1.5 RPM vs SPINFX2
SUMMARY RESULTS Error in Intake Mass Error in Pressure at Spark Advance 5% 5% 4% 4% 3% 2% 1% 0% 2.3% 1.9% 1.6% 1.1% 0.6% 0.8% 1.0% 2000x3 2000x3.6 2000x4.4 2000x6 2570x7.9 3000x8 3500x6 3% 2% 1% 0% 2.2% 2.0% 0.8% 0.8% 0.9% 0.2% 0.0% 2000x3 2000x3.6 2000x4.4 2000x6 2570x7.9 3000x8 3500x6 5.00% Error in Peak Pressure 5.00% Error in Temperature at Spark Advance 4.00% 4.00% 3.00% 3.00% 2.00% 1.00% 0.00% 1.28% 1.06% 0.74% 0.56% 0.04% 0.15% 2000x3 2000x3.6 2000x4.4 2000x6 2570x7.9 3000x8 1.21% 3500x6 2.00% 1.00% 0.00% 1.28% 1.06% 0.74% 0.56% 0.04% 0.15% 2000x3 2000x3.6 2000x4.4 2000x6 2570x7.9 3000x8 1.21% 3500x6
6. CONCLUSION
CONCLUSIONS 1- Development of a model to solve stoichiometric combustion of methane for different operation points.: #Case α u3b spin2 Max peak pressure θ max peak pressure θ 10 θ 50 θ 90 Error Peak Pressure [%] Error θ Peak Pres. [deg] Error θ 10 [deg] Error θ 50 [deg] Error θ 90 [deg] 2000x3 1,6 4,6 6 19,83 375,8 359,2 370,6 385,1 1,28-0,2 0,5-0,3 0,2 2000x3.6 1,6 5,2 4 23,85 374,5 357,8 368,7 382,5-0,04-0,3 0,5 0,0 0,8 2000x4.4 1,6 4,8 4 24,3 377,1 360,6 372,5 388,1-1,06-0,5 0,1 0,1 2,2 2000x6 1,6 6,5 4 34,94 374,7 358,5 369,1 383,9-0,74-0,5-0,1 0,0 2,7 2570x7.9 1,6 7,9 1 43,39 374,8 358,6 369,3 385,1 0,56-0,1 0,2 0,5 2,9 3000x8 1,6 8,25 0,1 48,15 372 354,9 365,4 382,4 0,15-0,8-0,9-0,4 4,8 3500x6 1,6 7,25 0,1 36,64 373,4 356,9 367,3 383-1,21-0,8-0,3-0,3 3,7
FUTURE DEVELOPMENT 1- Introduce new model for laminar speed, DARS: Laminar speed 1.1- Availability to have more accurate results for stoichiometric simulations; possibility of mantaining all parameters (ULAM3BELOW and SPINFEXT2) constant for all operation points. 1.2- Solve combustion for lean mixtures. 2- Extrapolate the results for other engines for similar operation points. 3- Be able to predict the combustion for new engines without experimental sets.
DÍKY