1. University of Wisconsin -- Engine Research Center slide 1 Investigation of Heat Transfer Correlations for HCCI Engines Eric Gingrich, Christopher Gross, and Varun Ramesh Computer Project ME 769 Advanced Combustion 04/30/2013

2. University of Wisconsin -- Engine Research Center slide 2Outline Introduction  HCCI  Engine Heat Transfer Correlations  Project  CANTERA  Experimental setup Results Summary Conclusion

3. University of Wisconsin -- Engine Research Center slide 3 Introduction: HCCI HCCI combustion is described as a controlled auto- ignition combustion process Governed by chemical kinetics Heat transfer processes change the in-cylinder conditions Dominant heat transfer mechanism is forced convection from bulk gas to the wall www-pls.llnl.gov

4. University of Wisconsin -- Engine Research Center slide 4 Introduction: Engine Heat Transfer Correlations Caton, ICEF2011-60017 Chang et.al., SAE 2004-0102996

5. University of Wisconsin -- Engine Research Center slide 5 Introduction: Project Woschni, Hohenberg, and Chang correlations have all been applied to a 0-D chemical kinetics solver For simulations a reduced PRF mechanism was used (47 species & 142reactions) Three engine cases were modeled: Mode 3Mode 5Mode 7 Speed (RPM)149019002300 Load IMEPg (bar)5.35.7 Intake Temperature (C)485150 Intake Pressure (bar)1.291.241.16 Percent n-heptane7912 Percent iso-octane939188 Dempsey et.al., CST

6. University of Wisconsin -- Engine Research Center slide 6 What is CANTERA and why use it? “Cantera is a suite of object-oriented software tools for problems involving chemical kinetics, thermodynamics, and/or transport processes.” Developed David Goodwin’s group at Caltec Can be used as a 0-D kinetics solver similar is CHEMKIN Open source (free) Easy to preform parametric studies MATLAB interface code.google.com/p/cantera/

7. University of Wisconsin -- Engine Research Center slide 7 Development of CANTERA “Engine” CANTERA reactor allows for changing volume, area, and heat transfer coefficient Changing volume accomplished by creating a moving wall and specifying a wall velocity Wall velocity must be specified using a Fourier series At IVO initial temperature, pressure and mole fractions are specified V, A, h, T 0, P 0, X 0 Wall velocity

8. University of Wisconsin -- Engine Research Center slide 8 Experimental Setup Base Engine Single-cylinder version of GM 1.9L 4-cylinder DI Diesel Bore x Stroke82.0 mm x 90.4 mm Connecting Rod Length 145.54 mm Displacement0.477 L Compression Ratio16.7:1 Intake Valve Opening/Closing 344°/-132° aTDC Exhaust Valve Opening/Closing 112°/388° aTDC Swirl Ratio1.5 – 2.3 Piston Bowl TypeRe-entrant bowl

9. University of Wisconsin -- Engine Research Center slide 9 Wireless Telemetry System

10. University of Wisconsin -- Engine Research Center slide 10 Results: Mode 3

11. University of Wisconsin -- Engine Research Center slide 11 Results: Mode 5

12. University of Wisconsin -- Engine Research Center slide 12 Results: Mode 7

13. University of Wisconsin -- Engine Research Center slide 13Summary

14. University of Wisconsin -- Engine Research Center slide 14Conclusion 0-D chemical kinetics only captures SOC and not combustion duration For most cases the heat transfer coefficient is only accurate within an order of magnitude 0-D heat transfer correlations are difficult to create over a large range of speeds, loads, and require much tuning In order to match SOC the Woschni and Hohenberg correlations require non-physical IVC temperatures (Woschni does not ignite)

15. University of Wisconsin -- Engine Research Center slide 15 Questions?

16. University of Wisconsin -- Engine Research Center slide 16References https://www-pls.llnl.gov/?url=science_and_technology-chemistry- combustion Canton, J., “Comparisons of Global Heat Transfer Correlations for Conventional and High Efficiency Reciprocating Engines”,ASME ICEF2011-60017 Chang, J., et. al, “New Heat Transfer Correlation for HCCI Engine Derived from Measurements of Instantaneous Surface Heat Flux”, SAE 2004-01-2996 Dempsy, Walker, Gingrich, Reitz, “Comparison of Lower Temperature Combustion Strategies for Advanced Compression Ignition Engines with Focus on Controllability”, Submitted to: Combustion Science and Technology https://code.google.com/p/cantera/