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

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Experimental study of engine-like turbulent combustion 500 Piston position (mm) 400 300 200 Updraft Dow ndraft Methane 100 0 90 100 110 120 130 140 150 160 170 180 190 200 Time (ms) (a) 500 tel-00623090, version 1 - 13 Sep 2011 Piston position (mm) Piston position (mm) Updraft 400 Dow ndraft Methane 300 200 100 0 90 100 110 120 130 140 150 160 170 180 190 200 Time (ms) (b) 500 Updraft Dow ndraft 400 Methane 300 200 100 0 90 100 110 120 130 140 150 160 170 180 190 200 Time (ms) (c) Figure 5.14-Piston position for various fuels and ignition timings. (a) 5 ms BTDC; (b) 7.5 ms BTDC; (c) 12.5 ms BTDC. 152
Chapter 5 tel-00623090, version 1 - 13 Sep 2011 From figure 5.13 it is observed that the compression stroke is independent of the ignition timing. The TDC position is reached at 137 ms and is kept during around 4 ms to 141 ms. The measured compression stroke duration is about 44 ms. Expansion stroke is indeed slightly influenced by the ignition timing, which become slower when the ignition is made far from TDC. However, as seen in the figure 5.13 the ignition timings of 5 ms BTDC and 7.5 ms BTDC could be considered to have the same piston displacement along time. The 12.5 ms BTDC ignition timing is the one with lower displacement for every fuel under study. Therefore, considering a criterion of 1.0 mm for the final piston position the duration of the expansion stroke is around 49 ms for ignition timing of 5 ms and 7.5 ms BTDC and 51 ms for 12.5 ms BTDC ignition timing. This could be explained by the fact that when the combustion starts to earlier in relation to TDC (12.5 ms BTDC) a large part of heat is released when the piston is still moving up. Therefore, when the ignition is made close to TDC the heat released is available on the expansion stroke to push the piston down. Thus, it is expected that some influence of the fuel type on the expansion stroke exists (figure 5.14). From figure 5.14 it is observed that both syngas compositions show similar time evolution of the piston position. However, methane shows a different time evolution of the piston position in the expansion stroke to the whole igniting timings. This is explained by the combustion time of the mixtures that are lower for methane, followed by the downdraft and finally by updraft. Thus, the heat released is not so much available on the expansion stroke for methane as it is for updraft syngas. This also indicates that the turbulent burning velocity of methane should be higher than the syngas compositions ones. 5.2.1.2 Equivalent rotation speed The compression stroke is imposed by the RCM hydraulic system; the expansion stroke is a function of the heat release of the mixture being burned. Thus, the equivalent rotation speed is not constant and its variation should be evaluated taking into account the fuel and the ignition timing. Figure 5.15 shows the average of the piston velocity during various experiments without combustion and different spark times and after TDC synchronization. 153
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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
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Bibliographic revision Circulating
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Bibliographic revision or eliminate
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Bibliographic revision established
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Bibliographic revision Hydrogen Hyd
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Bibliographic revision of low moist
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Bibliographic revision scrubbing an
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Bibliographic revision suggests tha
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Bibliographic revision 1 d( δ A) 1
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Bibliographic revision Since n is
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Bibliographic revision 2 ( rsr ) 2
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Bibliographic revision This evoluti
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Bibliographic revision The burning
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Bibliographic revision δVG = − a
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Bibliographic revision 2 1 − −
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Bibliographic revision where the su
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Bibliographic revision the stretche
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Bibliographic revision burning velo
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Experimental set ups and diagnostic
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Chapter 4 CHAPTER 4 EXPERIMENTAL AN
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Chapter 4 4.1 Laminar burning veloc
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Chapter 4 4.1.1.1 Flame morphology
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Chapter 4 P i = 1.0 bar, Ti = 293 K
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Chapter 4 Figure 4.5 shows schliere
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Chapter 4 P i = 2.0 bar, T i = 293
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Chapter 4 Sn (m/s) 3.0 2.5 2.0 1.5
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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)
Page 131 and 132: Chapter 4 tel-00623090, version 1 -
Page 133 and 134: Chapter 4 are tested and discussed.
Page 135 and 136: Chapter 4 7 500 Pressure (bar) 6 5
Page 137 and 138: Chapter 4 Pressure (bar) 7 6 5 4 3
Page 139 and 140: Chapter 4 4.2.3.4 Quenching distanc
Page 141 and 142: Chapter 4 10000 Quenching distance
Page 143 and 144: Chapter 5 CHAPTER 5 EXPERIMENTAL ST
Page 145 and 146: Chapter 5 30 10 25 8 Pressure (bar)
Page 147 and 148: Chapter 5 30 Piston position (mm) 2
Page 149 and 150: Chapter 5 5.1.1.4 In-cylinder press
Page 151 and 152: Chapter 5 estimation of various par
Page 153 and 154: Chapter 5 TDC 1.25 ms 2.5 ms 3.75 m
Page 155: Chapter 5 Piston position (mm) 500
Page 159 and 160: Chapter 5 From figure 5.15 is possi
Page 161 and 162: Chapter 5 From figure 5.16 is obser
Page 163 and 164: Chapter 5 80 Pressure (bar) 70 60 5
Page 165 and 166: Chapter 5 80 10 Pmax (bar) 70 60 50
Page 167 and 168: Chapter 5 -5.0 ms -3.75 ms -2.5 ms
Page 169 and 170: Chapter 5 observation emphasis the
Page 171 and 172: Chapter 6 CHAPTER 6 NUMERICAL SIMUL
Page 173 and 174: Chapter 6 centered at the spark plu
Page 175 and 176: Chapter 6 H 2 O, (3) N 2 , (4) O 2
Page 177 and 178: Chapter 6 For all the above express
Page 179 and 180: Chapter 6 motions within the cylind
Page 181 and 182: Chapter 6 tel-00623090, version 1 -
Page 183 and 184: Chapter 6 Heat transfer Wei et al.,
Page 185 and 186: Chapter 6 The calibration coefficie
Page 187 and 188: Chapter 6 6.3.2.2 In-cylinder volum
Page 189 and 190: Chapter 6 40 Experimental 30 Numeri
Page 191 and 192: Chapter 6 80 70 60 Numerical Experi
Page 193 and 194: Chapter 6 downdraft syngas than for
Page 195 and 196: Chapter 6 80 23º BTDC 60 29.5º BT
Page 197 and 198: Chapter 6 with experimental results
Page 199 and 200: Conclusions CHAPTER 7 CONCLUSIONS 7
Page 201 and 202: Conclusions radius and time for syn
Page 203 and 204: Conclusions conditions, therefore s
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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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