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

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Chapter 3 regulated for pressures up to 40 bar. The dynamic response of the sensor is 2 µs. The signal acquisition is made by a digital oscilloscope with memory (Tektronix TDS 420A). The acquisition frequency may be varied from 10-200 kHz depending on the duration of the phenomena. Pressure measurements are used to evaluate the quality of the combustion and the burning velocity in the constant volume method. 3.1.4 Rapid compression machine A rapid compression machine (RCM) is an instrument to simulate a single cycle of an internal combustion engine, thus also allowing the study of spontaneous ignition under more comparable conditions than those existing in real engines (Strozzi et al., 2008). tel-00623090, version 1 - 13 Sep 2011 The rapid compression machine of the Institute Pprime used in this work has the following configuration (Fig.3.3). All the characteristics of the RCM are summarized in Table 3.1. Cylinder volume (cm 3 ) Table 3.1 – Geometric and kinematic characteristics of the RCM. Stroke (cm) Square piston (cm) Cylinder section (cm 2 ) Compression time (ms) Dead volume (cm 3 ) Compression ratio (ε) 1043 41.9 5.63 24.89 44 58.5-128.5 9.1 – 18.8 This experimental set up is well-suited for optical visualization purposes. It features both large lateral and vertical optical accesses. 1 2 5 6 7 9 8 4 3 Figure 3.3 – RCM scheme. (1) cylinder/combustion chamber, (2) return cylinder, (3) guiding wheel, (4) Brake system, (5) Piston, (6) Connecting rod, (7) Cam, (8) hydraulic cylinder, (9) lever (Strozzi, 2008). 65
Experimental set ups and diagnostics Running principle Compression of reactive mixtures is obtained as follows. A hydraulic cylinder sets a cam into motion. The horizontal translation is transformed into a vertical motion via a guiding wheel. The RCM is equipped with a return cylinder to maintain the contact between the cam and the guiding wheel; this ensures that the volume of the chamber is well stabilized at top dead center (TDC). RCM generally carry out the compression at constant piston velocity. In opposite, the cam of the Institute Pprime RCM has been designed in such a manner that the piston velocity evolves similarly as it does in a real engine. Acceleration and deceleration are moderate and the effect of the compression stroke becomes perceptible only several milliseconds after bottom dead center (BDC). tel-00623090, version 1 - 13 Sep 2011 The RCM is fitted with a heating system in the chamber walls to vary the initial temperature at BDC between 293 and 373 ±1.5K. Moreover, by changing the clearance volume, volumetric compression ratio of the RCM can be varied from ε =9.1 to ε=18.8. The RCM features a square cross/section with rounded corners piston (50×50, r=3.6 mm), allowing flat windows to be mounted on lateral sides of the chamber; this enables direct visualizations and planar laser sheet measurements within the whole dead volume. The windows are sealed with specifically designed square flat rings and circular rings are used for the cylinder head. The piston is equipped with a squared sealing ring but also with a square shaped guiding ring, to avoid asymmetric formation of corner vortex. Moreover the RCM features a long compression stroke (S=419 mm), providing a wider visualization window at TDC for a given compression ratio. Mechanical part of RCM The mechanical part of the RCM is based on the principle of the catapult. A cylinder, commanded by a high-speed servo valve (response time of approximately 5 ms) and supplied with a hydro-electric power station allowing a flow of 400 l/min, drives a steel rod of large dimensions (length 775 mm, thickness 50 mm, H section) which in turns drive a carriage of 40 kg at high speed installed horizontally on rails. This carriage is equipped with a cam whose profile actuates a roller that supports the piston vertical movement. The profile is calculated to reproduce the movement of an engine running at around 700 rpm. It was necessary to install hydraulic brakes (ordered in a 66
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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
Page 17 and 18: Introduction proves to have higher
Page 19 and 20: Introduction Chapter 3 - Experiment
Page 21 and 22: Bibliographic revision CHAPTER 2 BI
Page 23 and 24: Bibliographic revision point today
Page 25 and 26: Bibliographic revision - Boudouard
Page 27 and 28: Bibliographic revision Table 2.1 -
Page 29 and 30: 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 67: 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
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Chapter 4 0.5 0.4 φ=1.2 Su (m/s) 0
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Chapter 4 0.3 φ=0.8 Su (m/s) 0.2 0
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Chapter 4 a minimum pressure to exp
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Chapter 4 Notice the similar behavi
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Chapter 4 A very good agreement bet
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Chapter 4 ( ) Q = h T − T (4.21)
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Chapter 4 tel-00623090, version 1 -
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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 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 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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