Troels Dyhr Pedersen.indd - Solid Mechanics

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- 4 - - 11.5.3 Filtering of sample data for frequency analysis 48 11.6 Representation of acoustic measurements 48 11.6.1 Sound pressure 48 11.6.2 Sound pressure level 48 11.6.3 Time domain representation 49 11.6.4 Frequency domain representation 50 11.6.5 Frequency spectrum analysis in the time domain 51 11.7 Theory of cylinder acoustics 53 11.7.1 Circumferential modes 53 11.7.2 Radial modes 53 11.7.3 Axial modes 54 11.8 Calculation of resonance frequencies 54 11.9 COMSOL calculations of cylinder acoustic resonance 55 12 SIMULATION OF DETONATION PHENOMENA 58 12.1 Background 58 12.2 Explosions 59 12.2.1 Uniform explosion 59 12.2.2 Non uniform explosions and pressure wave amplification 59 12.3 Detonations 60 12.3.1 Introduction 60 12.3.2 Detonation waves 61 12.3.3 Shock wave 61 12.3.4 Reference for velocitities 61 12.3.5 Conservation equations 63 12.3.6 The Rayleigh relation 63 12.3.7 The Hugoniot relation 64 12.3.8 Determination of the Chapman Jouget velocity 67 12.3.9 Results for the stationary solution 70 12.4 Detonation study in CFD 71 12.4.1 Problem setup in STAR-CD 71 12.4.2 Simulation results 73 12.5 Observations of detonation in HCCI combustion 76 12.5.1 Experimental setup 76 12.5.2 Pressure trace 77 13 SUMMARY AND CONCLUSION 79 14 REFERENCES 81 15 APPENDIX A: REDUCED SCHEME FOR LEAN PREMIXED DME COMBUSTION 84
- 5 - - 16 APPENDIX B: DETONATION MODEL IN EES 86 17 PAPER I : THE EFFECT OF COMPRESSION RATIO, EQUIVALENCE RATIO AND ENGINE SPEED ON HCCI COMBUSTION OF DIMETHYL ETHER 86 18 PAPER II: CONTROLLING THE HEAT RELEASE OF DME HCCI COMBUSTION WITH METHANOL AND EGR 89 19 PAPER III: REDUCING HCCI COMBUSTION NOISE THROUGH PISTON DESIGN 90
Page 1: Homogeneous Charge Compression Igni
Page 4 and 5: - 2 - - Table of contents 1 FOREWOR
Page 8 and 9: - 6 - - 1 Foreword The work describ
Page 10 and 11: 3 Résumé - 8 - - This thesis is b
Page 12 and 13: 4 Resumé (dansk) - 10 - - Denne af
Page 14 and 15: 5 Introduction - 12 - - 5.1 About H
Page 16 and 17: - 14 - - 5.3 Scope of investigation
Page 18 and 19: 6 The basics of HCCI combustion - 1
Page 20 and 21: - 18 - - the cylinder. In HCCI comb
Page 22 and 23: 7 Combustion of DME - 20 - - 7.1 Co
Page 24 and 25: - 22 - - 8 Description of experimen
Page 26 and 27: - 24 - - 8.1.3 Piston modifications
Page 28 and 29: - 26 - - combustion event is often
Page 30 and 31: - 28 - - however not possible, sinc
Page 32 and 33: - 30 - - (excess air ratio 3) of ai
Page 34 and 35: dQ dt = h ⋅ A ⋅ - 32 - - ( T
Page 36 and 37: - 34 - - In addition, many reaction
Page 38 and 39: - 36 - - Arrows in the scheme indic
Page 40 and 41: - 38 - - formaldehyde (CH2O) and fo
Page 42 and 43: Figure 12: Termination of the low t
Page 44 and 45: - 42 - - The non-carbon radical act
Page 46 and 47: 10.7 List of species Radicals of hy
Page 48 and 49: - 46 - - If a frequency analysis of
Page 50 and 51: - 48 - - 11.5.3 Filtering of sample
Page 52 and 53: - 50 - - The SPL of the cylinder pr
Page 54 and 55: Figure 17: Intensity chart for cyli
Page 56 and 57:
- 54 - - 11.7.3 Axial modes Axial w
Page 58 and 59:
- 56 - - A case was set up to make
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12 Simulation of detonation phenome
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- 60 - - provided more ideal condit
Page 64 and 65:
- 62 - - positive in the x- directi
Page 66 and 67:
3,0 x 10 6 2,5 x 10 6 2,0 x 10 6 1,
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- 66 - - A detailed drawing of the
Page 70 and 71:
- 68 - - In the expressions above,
Page 72 and 73:
( 21) ( 22) - 70 - - The mach numbe
Page 74 and 75:
( 25) - 72 - - Δt v = u ⋅ Δx wh
Page 76 and 77:
- 74 - - Figure 29: Development in
Page 78 and 79:
- 76 - - 12.5 Observations of deton
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- 78 - - On figure 34, the individu
Page 82 and 83:
- 80 - - • The engine load obtain
Page 84 and 85:
- 82 - - 15. Takayugi Tsuchiya, Yos
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- 84 - - 15 Appendix A: Reduced sch
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16 Appendix B: Detonation model in
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- 88 - - 17 Paper I: The Effect of
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- 90 - - 19 Paper III: Reducing HCC
Page 94 and 95:
DESCRIPTION OF THE EXPERIMENT OBJEC
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Engine modification To obtain a low
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Pressure [Mpa] 6 5 4 3 2 1 lambda 2
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Pressure [Mpa] 6 5 4 3 2 1 lambda 4
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At lambda 4, IMEP peaks at a compre
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CONCLUSION • It was possible to a
Page 107 and 108:
close to the lean limit. HC is comp
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Reactions do however not stop entir
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METHANOL TEST PROCEDURE In the firs
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Page 8 of 22 0 -5 -10 -15 -20 -25
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With EGR there was a notable change
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Page 12 of 22 9 8 7 6 5 4 3 2 MEOH
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Page 14 of 22 250 200 150 100 50 40
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EMISSIONS The emissions in table 6
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Page 18 of 22 15 12 9 6 3 0 1000 RP
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REFERENCES 1. Mingfa Yao: An Invest
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PM: Particulate matter THC: Total H
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Coupling of pressure waves and reac
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chambers which often have this flat
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The two piston crowns with chambers
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Page 8 of 21 Figure 10: Steel plate
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Page 10 of 21 16.7 kW @ 3000 rpm 17
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v v, ref T T ref with T and Tref be
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dB higher than the 8 cylindrical ch
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Page 16 of 21 Flat chamber 7 BTDC 3
Page 145 and 146:
Page 18 of 21 diesel type chamber 3
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CONCLUSION HCCI combustion generate
Page 150:
DTU Mechanical Engineering Section
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Troels Dyhr Pedersen.indd - Solid Mechanics

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