New sequential combustion technologies for heavy-duty gas turbines

Transcription

1 New sequential combustion technologies for heavy-duty gas turbines Conference on Combustion in Switzerland ETH Zurich Nicolas Noiray, Oliver Schulz CAPS Lab D-MAVT ETH Nicolas Noiray 07/09/17 1

2 Sequential combustors in modern gas turbines Ansaldo (formerly Alstom) General Electrics See ASME paper GT Adapted from US A1 See also ASME paper GT Sequential Combustion in H-Class gas turbines. More than 700 MW in combined cycle with approx. 62% plant efficiency Increased operational flexibility Increased fuel flexibility Lower emissions Higher CC efficiency Nicolas Noiray 07/09/17 2

3 Associated scientific challenges Technological characteristics Increased complexity of the combustors architecture and of the operating concept Auto-ignition plays a key role 1 st and 2 nd stage flames influence each others Corresponding scientific needs Adequate combustion models for accurate simulations Validation from experimental data Deep understanding of ignition, anchoring, blow-off physics Modeling and control of combustor dynamics Nicolas Noiray 07/09/17 3

4 Related research at CAPS Experiments: Generic sequential burner Nicolas Noiray 07/09/17 4

5 Related research at CAPS Experiments: 1 st stage 2 nd stage Nicolas Noiray 07/09/17 5

6 Related research at CAPS Compressible Reactive Large Eddy Simulations with autoignition chemistry Nicolas Noiray 07/09/17 6

7 Are these really autoignition fronts? Paper submitted to C&F: Combustion regimes in sequential combustors: autoignition and flame propagation at elevated temperature and pressure. O. Schulz, N. Noiray Nicolas Noiray 07/09/17 7

8 Different types of 1D flames Hot reactants propagating flame at stoichiometric condition Autoignition front Very lean condition: most reactive mixture fraction (shortest autoignition delay) Nicolas Noiray 07/09/17 8

9 From flame propagation to autoignition: residence time Critical paramters: Mixture fraction, Inlet velocity, Mixture residence time upfront of the flame Conclusions from idealized 1D perfectly premixed situations can be very informative for the practical configurations (3D partially premixed and turbulent) Nicolas Noiray 07/09/17 10

10 Sequential Combustor Configuration Operating pressure 1 and 10 bar Inlet temperature 1350 and 1450 K Nicolas Noiray 07/09/17 114

11 Numercial Methods LES with AVBP (Gicquel et al. Comptes Rendus Mec., 2011) 12 millions mesh cells Dynamic Thickened Flame (DTF) model (Colin et al. Phys. Fluids, 2000) Analytically Reduced Chemistry (ARC) scheme Wall heat loss (Schulz et al. Proc. Combust. Inst. 2016) (Jaravel et al. Proc. Combust. Inst. 2016) (Pepiot and Pitsch Combust. Flame, 2008) Nicolas Noiray 07/09/17 65

12 Autoignition versus propagation at 10 Bar 10 Bar hot inlet à Autoignition dominates 10 Bar cold inlet à Propagation dominates Nicolas Noiray 07/09/17 13

13 Ignition of sequential combustor Conditions Operating pressure 10bar Simulated time 43ms 1st stage power 300kW 2 nd stage power 300kW 2 nd stage global phi nd stage inlet T 1350K Nicolas Noiray 07/09/17 14

14 Ignition of sequential combustor Conditions Operating pressure 1bar Simulated time 90ms 1st stage power 30kW 2 nd stage power 30kW 2 nd stage global phi nd stage inlet T 1450K Autoignition driven transient evolving to propagating flame Nicolas Noiray 07/09/17 15

15 Flame stabilisation mechanism of a reactive jet in crossflow Paper submitted to C&F: Large eddy simulation of a reactive jet in hot vitiated crossflow: flame stabilisation mechanism. O. Schulz, E. Piccoli, A. Felden, G. Staffelbach, N. Noiray Nicolas Noiray 07/09/17 16

16 Premixed jet flame behavior in a hot vitiated crossflow of lean combustion products Wagner, Renfro, Cetegen, Combustion and Flame 176 (2017), Conclusions/Outlook - Windward flame anchoring closer to the crossflow suggests that auto-ignition was most likely the dominant mechanism - Further characterization of out-of- plane motion may be necessary to interpret principal strain rate behavior along the windward flame edge. Nicolas Noiray 07/09/17 17

17 Detailed experimental data available Velocity magnitude Vorticity PIV LIF CH 2 O LIF OH Heat release location deduced from LIF PLIF Nicolas Noiray 07/09/17 18

18 3-d large eddy simulation Nicolas Noiray 07/09/17 19

19 Comparison with experiments Nicolas Noiray 07/09/17 20

20 Comparison with experiments Nicolas Noiray 07/09/17 21

21 Instantaneous snapshot from LES Nicolas Noiray 07/09/17 22

22 Windward flame stabilisation due to autoignition 1. Autoignition at most reactive mixture fraction Z_mr 2. Heat transfer to higher Z Nicolas Noiray 07/09/17 23

23 3-D flame dynamics Nicolas Noiray 07/09/17 24

24 3-d flame vortex interaction Nicolas Noiray 07/09/17 25

25 Nonlinear response of auto-ignition flames to entropy waves Combustion & Flame paper under revision: O. Schulz, N. Noiray Nicolas Noiray 07/09/17 26

26 The sound of flames Power generation Aeronautics Dynamic pressure Pulsations-induced damages Aerospace Gas turbine combustors Resonant feedback loop Time Liquid Rocket Propellant Chamber acoustics u p Frequency Q Reactive flow dynamics Boilers, Industrial furnaces Aero-engine combustors Structural vibrations Solid Rocket Propellant Time Afterburners Frequency Nicolas Noiray 07/09/17 27

27 Flame Response to Temperature Fluctuations 1350 K 1450 K Gain 1.7 Gain 3.4 Nicolas Noiray 07/09/17 28

28 Flame Response to Temperature Fluctuations Nicolas Noiray 07/09/17 29

29 Decrease of inlet temperature 1450 K 1350 K Nicolas Noiray 07/09/17 30

30 0-D Autoignition Delays (CANTERA) 1350 K 1450 K Nicolas Noiray 07/09/17 31

31 Non-linear flame response to T fluctuations Nicolas Noiray 07/09/17 32

32 Conclusions and Outlook Significant progress over the last years in terms of simulations and modeling capabilities Research effort to be pursued in topics like Auto-ignition in turbulent environment at relevant conditions, Analytically Reduced Chemistry, Combustion modelling for partially premixed flames, Combustor dynamics associated with entropy waves Passive and active control of combustor dynamics Strong need for experimental data to develop and validate these combustion models Nicolas Noiray 07/09/17 33

33 Acknowledgement Nicolas Noiray 07/09/17 34