Etude de la combustion de gaz de synthèse issus d'un processus de ...

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Chapter 3 A zone of high velocities (5 to 8 m/s), where the flow is turbulent, that come in the center of the clearance volume 5 ms after. The laminar flow of this zone becomes twodimensional and diverging to the walls. The turbulent zone reaches TDC and occupies a large part of the chamber at that moment. The flow in this zone is structured by two counter-rotating vortices, which is consistent with the literature where the movement of the piston brings the gas from the side wall toward the center of the chamber, forming vortices on the corners. These vortices then move to the side walls and after down the chamber. Simultaneously, the maximum velocity of the flow gradually decreases, and the size of the 'laminar' zone observed at the end of compression decreases. The disappearance of this zone occurs approximately 17 ms after TDC, although some low velocity zones remain. 40 ms after TDC, the corner vortices are replaced by a fragmented and highly three-dimensional flow. tel-00623090, version 1 - 13 Sep 2011 The coexistence of laminar and turbulent regions is characteristic of MCR flat piston flow, where the gases are at rest before compression. One can observe a certain asymmetry in vortices velocity, with lower values at TDC and close to the walls (figure 3.14). This asymmetry reflects the exchange of kinetic energy that occurs in the strain layer between the vortex and the zone of lower flow. The velocity gradient direction at the zone interface may also be parallel to the mean flow, as is in the case of few milliseconds before TDC. In this case, if the inertia of the high speed zone regrowth clearly the core zone, the turbulent nature of the flow at the interface is also likely to accelerate the decrease in the extent of the core zone. This emphasis the existence of two ranges of scales associated with mixing phenomenon: those of the overall movement, and those of turbulence. Moreover, the overall velocity of the movement decreases rapidly if the flow stops. Thus, reflecting the kinetic energy transfer from large scales to the turbulent scales. 79
Experimental set ups and diagnostics -10 ms -5 ms tel-00623090, version 1 - 13 Sep 2011 TDC 10 ms 5 ms 20 ms 30 ms 40 ms Figure 3.14 – Inert compression velocity fields (m/s) in the RCM (reprinted from Strozzi, 2008). 80
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THÈSE Pour l’obtention du Grade
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Acknowledgements Acknowledgements T
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Résumé __________________________
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Nomenclature Nomenclature Roman tel
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Nomenclature Subscripts tel-0062309
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Contents tel-00623090, version 1 -
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Contents 6.4. SYNGAS FUELLED-ENGINE
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Introduction CHAPTER 1 INTRODUCTION
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Introduction proves to have higher
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Introduction Chapter 3 - Experiment
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Bibliographic revision CHAPTER 2 BI
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Bibliographic revision point today
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Bibliographic revision - Boudouard
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Bibliographic revision Table 2.1 -
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Bibliographic revision Biomass Dryi
Page 31 and 32: Bibliographic revision Circulating
Page 33 and 34: Bibliographic revision or eliminate
Page 35 and 36: Bibliographic revision established
Page 37 and 38: Bibliographic revision Hydrogen Hyd
Page 39 and 40: Bibliographic revision of low moist
Page 41 and 42: Bibliographic revision scrubbing an
Page 43 and 44: Bibliographic revision suggests tha
Page 45 and 46: Bibliographic revision 1 d( δ A) 1
Page 47 and 48: Bibliographic revision Since n is
Page 49 and 50: Bibliographic revision 2 ( rsr ) 2
Page 51 and 52: Bibliographic revision This evoluti
Page 53 and 54: Bibliographic revision The burning
Page 55 and 56: Bibliographic revision δVG = − a
Page 57 and 58: Bibliographic revision 2 1 − −
Page 59 and 60: Bibliographic revision where the su
Page 61 and 62: Bibliographic revision the stretche
Page 63 and 64: Bibliographic revision burning velo
Page 65 and 66: Experimental set ups and diagnostic
Page 81: Experimental set ups and diagnostic
Page 89 and 90: Chapter 4 CHAPTER 4 EXPERIMENTAL AN
Page 91 and 92: Chapter 4 4.1 Laminar burning veloc
Page 93 and 94: Chapter 4 4.1.1.1 Flame morphology
Page 95 and 96: Chapter 4 P i = 1.0 bar, Ti = 293 K
Page 97 and 98: Chapter 4 Figure 4.5 shows schliere
Page 99 and 100: Chapter 4 P i = 2.0 bar, T i = 293
Page 101 and 102: Chapter 4 Sn (m/s) 3.0 2.5 2.0 1.5
Page 103 and 104: Chapter 4 5 ms 10 ms 15 ms 20 ms 25
Page 105 and 106: Chapter 4 behaviour of the curves r
Page 107 and 108: Chapter 4 1.50 Sn (m/s) 1.25 1.00 0
Page 109 and 110: Chapter 4 0.5 0.4 φ =1.0 Su (m/s)
Page 111 and 112: Chapter 4 variation of the normaliz
Page 113 and 114: Chapter 4 4.1.1.6 Comparison with o
Page 115 and 116: Chapter 4 The values of laminar bur
Page 117 and 118: Chapter 4 Pressure (bar) 7 6 5 4 3
Page 119 and 120: Chapter 4 0.5 0.4 φ=1.2 Su (m/s) 0
Page 121 and 122: Chapter 4 0.3 φ=0.8 Su (m/s) 0.2 0
Page 123 and 124: Chapter 4 a minimum pressure to exp
Page 125 and 126: Chapter 4 Notice the similar behavi
Page 127 and 128: Chapter 4 A very good agreement bet
Page 129 and 130: Chapter 4 ( ) Q = h T − T (4.21)
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Chapter 4 are tested and discussed.
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Chapter 4 7 500 Pressure (bar) 6 5
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Chapter 4 Pressure (bar) 7 6 5 4 3
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Chapter 4 4.2.3.4 Quenching distanc
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Chapter 4 10000 Quenching distance
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Chapter 5 CHAPTER 5 EXPERIMENTAL ST
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Chapter 5 30 10 25 8 Pressure (bar)
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Chapter 5 30 Piston position (mm) 2
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Chapter 5 5.1.1.4 In-cylinder press
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Chapter 5 estimation of various par
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Chapter 5 TDC 1.25 ms 2.5 ms 3.75 m
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Chapter 5 Piston position (mm) 500
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Chapter 5 tel-00623090, version 1 -
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Chapter 5 From figure 5.15 is possi
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Chapter 5 From figure 5.16 is obser
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Chapter 5 80 Pressure (bar) 70 60 5
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Chapter 5 80 10 Pmax (bar) 70 60 50
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Chapter 5 -5.0 ms -3.75 ms -2.5 ms
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Chapter 5 observation emphasis the
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Chapter 6 CHAPTER 6 NUMERICAL SIMUL
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Chapter 6 centered at the spark plu
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Chapter 6 H 2 O, (3) N 2 , (4) O 2
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Chapter 6 For all the above express
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Chapter 6 motions within the cylind
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Chapter 6 tel-00623090, version 1 -
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Chapter 6 Heat transfer Wei et al.,
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Chapter 6 The calibration coefficie
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Chapter 6 6.3.2.2 In-cylinder volum
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Chapter 6 40 Experimental 30 Numeri
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Chapter 6 80 70 60 Numerical Experi
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Chapter 6 downdraft syngas than for
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Chapter 6 80 23º BTDC 60 29.5º BT
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Chapter 6 with experimental results
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Conclusions CHAPTER 7 CONCLUSIONS 7
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Conclusions radius and time for syn
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Conclusions conditions, therefore s
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Conclusions tel-00623090, version 1
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References References tel-00623090,
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References tel-00623090, version 1
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Appendix A - Overdetermined linear
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Appendix A - Overdetermined linear
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Appendix B- Syngas-air mixtures pro
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Appendix C -Rivère model Heat flux
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Appendix C -Rivère model The work
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tel-00623090, version 1 - 13 Sep 20
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