combustion dynamics in sequential combustorsyju/2nd-near-limit-flames-workshop/...vitiated air + ch...

||D MAVT Department of Mechanical and Process EngineeringCAPS Combustion and Acoustics for Power & Propulsion Systems

8/14/19 1

Combustion Dynamics in Sequential combustorsNear-Limit Flames Workshop – Beijing 2019Nicolas NoirayCAPS ETH: Oliver Schulz, Markus Weilenmann, Claire Bourquard, Yuan XiongPSI: Dominik Ebi, Ulrich Doll

Noiray Nicolas

||D MAVT Department of Mechanical and Process Engineering

CAPS Combustion and Acoustics for Power & Propulsion Systems

8/14/19Oliver Schulz 2

Sequential Combustion for operational and fuel flexibility

Ansaldo GT36 gas turbineSingle cycle: 538 MW – 42.8% eff.

Operational flexibility with ultra-low NOx

for compensating renewables intermittency

and ensuring grid stability




GT36 sequential combustor

Pennell et al. „An introduction to the Ansaldo GT36 constant

pressure sequential combustor.“, ASME Turbo Expo (2017)


8/14/19Noiray Nicolas 4

Combustion tomorrow: Burn Hydrogen in large gas turbines à storage, no more CO2

Bothien et al, GT2019-90798

Demonstration of transition from 100% NG to 100% H2 at engine condition with standard GT36 hardware



Sequential combustion research at ETH

1st stage

2nd stage



The experiment and the computational domain

2.12 m

1st stage

2nd stage

Perfectly premixed fuel + air

Swirler

Fuel

Outlet

Dilution air

VGs



Combustion Dynamics in Sequential Combustor

1. From spontaneous ignition to deflagration

2. Thermoacoustic instabilities in sequential combustors

3. Sequential flame stabilization using NRP discharges




The combustion process in the sequential stage is complexCold dilution air Gas

Temperature at the inlet

of the sequential burner

decrease with increasing

dilution air.

8% decrease from 1278K to 1129K

Ebi et al.Proc. Comb. Inst. 2019



Sequential stage ignition at low and high dilution air mass flow

Time (s)



1D solutions, detailed chemistry (GRI 3.0) for 2 domain lengths

Mixing between CH4 and air-diluted vitiated flow (N2,CO2,H2O,O2)

Mixture fraction

Mixture Temperature 1450 K (atm. pressure)



Z=0.005Z=0.02

0 5 10 15Inlet velocity uin [m/s]

1D solutions, detailed chemistry (GRI 3.0) for 2 domain lengths


Transient combustion regimes (1-D flames) at elevated temperatures

Flame propagationFlame propagation

enhanced by autoignition Autoignition

lAI = u in ⌧AI<latexit sha1_base64="nndx8M0MkW4oEoCI2fAkqKs85pY=">AAACHnicbZDLSsNAFIYnXmu9RV26GSyCCymJKLoRqm50V8FeoAllMp22QyeTMHMilpAnceOruHGhiOBK38bpBbStPwx8/Occzpw/iAXX4Djf1tz8wuLScm4lv7q2vrFpb21XdZQoyio0EpGqB0QzwSWrAAfB6rFiJAwEqwW9q0G9ds+U5pG8g37M/JB0JG9zSsBYTftENFPv0AP2AOnFTZbhc5z8Olxm2YBJMtnVtAtO0RkKz4I7hgIaq9y0P71WRJOQSaCCaN1wnRj8lCjgVLAs7yWaxYT2SIc1DEoSMu2nw/MyvG+cFm5HyjwJeOj+nUhJqHU/DExnSKCrp2sD879aI4H2mW+OjBNgko4WtROBIcKDrHCLK0ZB9A0Qqrj5K6ZdoggFk2jehOBOnzwL1aOia/j2uFC6HMeRQ7toDx0gF52iErpGZVRBFD2iZ/SK3qwn68V6tz5GrXPWeGYHTcj6+gEgeqMc</latexit><latexit sha1_base64="nndx8M0MkW4oEoCI2fAkqKs85pY=">AAACHnicbZDLSsNAFIYnXmu9RV26GSyCCymJKLoRqm50V8FeoAllMp22QyeTMHMilpAnceOruHGhiOBK38bpBbStPwx8/Occzpw/iAXX4Djf1tz8wuLScm4lv7q2vrFpb21XdZQoyio0EpGqB0QzwSWrAAfB6rFiJAwEqwW9q0G9ds+U5pG8g37M/JB0JG9zSsBYTftENFPv0AP2AOnFTZbhc5z8Olxm2YBJMtnVtAtO0RkKz4I7hgIaq9y0P71WRJOQSaCCaN1wnRj8lCjgVLAs7yWaxYT2SIc1DEoSMu2nw/MyvG+cFm5HyjwJeOj+nUhJqHU/DExnSKCrp2sD879aI4H2mW+OjBNgko4WtROBIcKDrHCLK0ZB9A0Qqrj5K6ZdoggFk2jehOBOnzwL1aOia/j2uFC6HMeRQ7toDx0gF52iErpGZVRBFD2iZ/SK3qwn68V6tz5GrXPWeGYHTcj6+gEgeqMc</latexit><latexit sha1_base64="nndx8M0MkW4oEoCI2fAkqKs85pY=">AAACHnicbZDLSsNAFIYnXmu9RV26GSyCCymJKLoRqm50V8FeoAllMp22QyeTMHMilpAnceOruHGhiOBK38bpBbStPwx8/Occzpw/iAXX4Djf1tz8wuLScm4lv7q2vrFpb21XdZQoyio0EpGqB0QzwSWrAAfB6rFiJAwEqwW9q0G9ds+U5pG8g37M/JB0JG9zSsBYTftENFPv0AP2AOnFTZbhc5z8Olxm2YBJMtnVtAtO0RkKz4I7hgIaq9y0P71WRJOQSaCCaN1wnRj8lCjgVLAs7yWaxYT2SIc1DEoSMu2nw/MyvG+cFm5HyjwJeOj+nUhJqHU/DExnSKCrp2sD879aI4H2mW+OjBNgko4WtROBIcKDrHCLK0ZB9A0Qqrj5K6ZdoggFk2jehOBOnzwL1aOia/j2uFC6HMeRQ7toDx0gF52iErpGZVRBFD2iZ/SK3qwn68V6tz5GrXPWeGYHTcj6+gEgeqMc</latexit><latexit sha1_base64="nndx8M0MkW4oEoCI2fAkqKs85pY=">AAACHnicbZDLSsNAFIYnXmu9RV26GSyCCymJKLoRqm50V8FeoAllMp22QyeTMHMilpAnceOruHGhiOBK38bpBbStPwx8/Occzpw/iAXX4Djf1tz8wuLScm4lv7q2vrFpb21XdZQoyio0EpGqB0QzwSWrAAfB6rFiJAwEqwW9q0G9ds+U5pG8g37M/JB0JG9zSsBYTftENFPv0AP2AOnFTZbhc5z8Olxm2YBJMtnVtAtO0RkKz4I7hgIaq9y0P71WRJOQSaCCaN1wnRj8lCjgVLAs7yWaxYT2SIc1DEoSMu2nw/MyvG+cFm5HyjwJeOj+nUhJqHU/DExnSKCrp2sD879aI4H2mW+OjBNgko4WtROBIcKDrHCLK0ZB9A0Qqrj5K6ZdoggFk2jehOBOnzwL1aOia/j2uFC6HMeRQ7toDx0gF52iErpGZVRBFD2iZ/SK3qwn68V6tz5GrXPWeGYHTcj6+gEgeqMc</latexit>



Combustion regimes (1-D flames) at elevated temperatures 1000 K 1450 K



Application to a laboratory sequential combustor



Numerical methods• 16 and 65 millions mesh cells at 1 bar and 10 bar

• LES with AVBP

• Dynamic Thickened Flame (DTF) model

• Wall heat losses

• Analytically Reduced Chemistry (ARC) mechanism for CH4 combustion

(Gicquel et al. Comptes Rendus – Mec., 2011)

(Colin et al. Phys. Fluids 12, 2000)



Ignition of the sequential combustor (1 bar)

800 1450 2200

Pressure 1 barInlet Temperature 1450 K


Transient change of operating conditions


§ Inlet velocity = 60 m/s§ Simulated physical time = 60 ms§ Pressure 10 bar§ Inlet Temperature changed from1350 K to 1200 K




Transient change of operating conditions§ Inlet velocity = 60 m/s§ Simulated physical time = 60 ms§ Pressure 10 bar§ Inlet Temperature changed from1350 K to 1200 K




Thermoacoustic instabilities are a major obstacle to cleaner combustion

Gas turbine

combustors

Boilers, Industrial

furnaces

Power generation

Liquid Rocket

Propellant

Solid Rocket

Propellant

Aerospace

Afterburners

Aeronautics

Aero-engine combustors

Resonant feedback loop

Chamber

acoustics

Reactive flow

dynamics

p0u0

Q̇0

Pulsations-induced damages

Frequency

Time

Dynamic pressure

Frequency

Time

Structural vibrations



Thermoacoustic Instabilities1st stage flame 2nd stage flame

Complexity of pathways of thermoacoustic instabilities

Susceptibility to thermoacoustic instabilities

Complexity of numerical modeling

Prieur et al. (EM2C laboratory), J. Eng. Gas Turbines Power 140, 2018

Bonciolini et al., Royal Soc. Open Sci., 2018





P1st = 40 kW

Φ1st = 0.8

Fuel 1st : CH4

P2nd = 24 kW

Φ2nd = 0.77

Fuel 2nd : CH4 + C3H8

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2.12 m

1st stage

2nd stage

Perfectly premixed fuel + air

Swirler

Fuel

Outlet

Dilution air

VGs

Ø 40 millions mesh cellsØ 860000 CPU hoursØ TTG4A


3-D LES


q̇ = 1⇥ 109 W/m3<latexit sha1_base64="/ZYWV+B3Y5XA6kmh2ciYAFvJ7H4=">AAACCnicdVDJSkMxFM2rU61T1aWbaBFc1by20nYhFN24rGAH6ERemraheYPJfWJ5dO3GX3HjQhG3foE7/8Z0EFT0QOBwzh1yjxNIoYGQDyu2sLi0vBJfTaytb2xuJbd3qtoPFeMV5ktf1R2quRQer4AAyeuB4tR1JK85w/OJX7vhSgvfu4JRwFsu7XuiJxgFI3WS+82uD9H1+NRugnC5tkm7iJvAbyHCtWN33M52kimSLk6BDclnstkJITlykilgO02mSKE5yp3ku5nJQpd7wCTVumGTAFoRVSCY5ONEM9Q8oGxI+7xhqEfN2lY0PWWMD43SxT1fmecBnqrfOyLqaj1yHVPpUhjo395E/MtrhNArtCLhBSFwj80W9UKJwceTXHBXKM5AjgyhTAnzV8wGVFEGJr2ECeHrUvw/qWbSNknbl7lU6WweRxztoQN0hGyURyV0gcqoghi6Qw/oCT1b99aj9WK9zkpj1rxnF/2A9fYJjWKaLA==</latexit><latexit sha1_base64="/ZYWV+B3Y5XA6kmh2ciYAFvJ7H4=">AAACCnicdVDJSkMxFM2rU61T1aWbaBFc1by20nYhFN24rGAH6ERemraheYPJfWJ5dO3GX3HjQhG3foE7/8Z0EFT0QOBwzh1yjxNIoYGQDyu2sLi0vBJfTaytb2xuJbd3qtoPFeMV5ktf1R2quRQer4AAyeuB4tR1JK85w/OJX7vhSgvfu4JRwFsu7XuiJxgFI3WS+82uD9H1+NRugnC5tkm7iJvAbyHCtWN33M52kimSLk6BDclnstkJITlykilgO02mSKE5yp3ku5nJQpd7wCTVumGTAFoRVSCY5ONEM9Q8oGxI+7xhqEfN2lY0PWWMD43SxT1fmecBnqrfOyLqaj1yHVPpUhjo395E/MtrhNArtCLhBSFwj80W9UKJwceTXHBXKM5AjgyhTAnzV8wGVFEGJr2ECeHrUvw/qWbSNknbl7lU6WweRxztoQN0hGyURyV0gcqoghi6Qw/oCT1b99aj9WK9zkpj1rxnF/2A9fYJjWKaLA==</latexit><latexit sha1_base64="/ZYWV+B3Y5XA6kmh2ciYAFvJ7H4=">AAACCnicdVDJSkMxFM2rU61T1aWbaBFc1by20nYhFN24rGAH6ERemraheYPJfWJ5dO3GX3HjQhG3foE7/8Z0EFT0QOBwzh1yjxNIoYGQDyu2sLi0vBJfTaytb2xuJbd3qtoPFeMV5ktf1R2quRQer4AAyeuB4tR1JK85w/OJX7vhSgvfu4JRwFsu7XuiJxgFI3WS+82uD9H1+NRugnC5tkm7iJvAbyHCtWN33M52kimSLk6BDclnstkJITlykilgO02mSKE5yp3ku5nJQpd7wCTVumGTAFoRVSCY5ONEM9Q8oGxI+7xhqEfN2lY0PWWMD43SxT1fmecBnqrfOyLqaj1yHVPpUhjo395E/MtrhNArtCLhBSFwj80W9UKJwceTXHBXKM5AjgyhTAnzV8wGVFEGJr2ECeHrUvw/qWbSNknbl7lU6WweRxztoQN0hGyURyV0gcqoghi6Qw/oCT1b99aj9WK9zkpj1rxnF/2A9fYJjWKaLA==</latexit><latexit sha1_base64="/ZYWV+B3Y5XA6kmh2ciYAFvJ7H4=">AAACCnicdVDJSkMxFM2rU61T1aWbaBFc1by20nYhFN24rGAH6ERemraheYPJfWJ5dO3GX3HjQhG3foE7/8Z0EFT0QOBwzh1yjxNIoYGQDyu2sLi0vBJfTaytb2xuJbd3qtoPFeMV5ktf1R2quRQer4AAyeuB4tR1JK85w/OJX7vhSgvfu4JRwFsu7XuiJxgFI3WS+82uD9H1+NRugnC5tkm7iJvAbyHCtWN33M52kimSLk6BDclnstkJITlykilgO02mSKE5yp3ku5nJQpd7wCTVumGTAFoRVSCY5ONEM9Q8oGxI+7xhqEfN2lY0PWWMD43SxT1fmecBnqrfOyLqaj1yHVPpUhjo395E/MtrhNArtCLhBSFwj80W9UKJwceTXHBXKM5AjgyhTAnzV8wGVFEGJr2ECeHrUvw/qWbSNknbl7lU6WweRxztoQN0hGyURyV0gcqoghi6Qw/oCT1b99aj9WK9zkpj1rxnF/2A9fYJjWKaLA==</latexit>

q̇ = 4⇥ 108 W/m3<latexit sha1_base64="dXaaVO3FxfQblHO44N/sIbEVvDw=">AAACCnicdVDLSgMxFM34rPVVdekmWgRXNdNWWhdC0Y3LCvYBfZFJ0zY08zC5I5ahazf+ihsXirj1C9z5N2baCip6IHA45z5yjxNIoYGQD2tufmFxaTmxklxdW9/YTG1tV7UfKsYrzJe+qjtUcyk8XgEBktcDxanrSF5zhuexX7vhSgvfu4JRwFsu7XuiJxgFI3VSe82uD9H1+DTfBOFybZN2ETeB30KEa0fuuJ3rpNIkczIBNqSQzeViQvLkOFvEdoZMkEYzlDupdzOThS73gEmqdcMmAbQiqkAwycfJZqh5QNmQ9nnDUI+ata1ocsoYHxili3u+Ms8DPFG/d0TU1XrkOqbSpTDQv71Y/MtrhNArtiLhBSFwj00X9UKJwcdxLrgrFGcgR4ZQpoT5K2YDqigDk17ShPB1Kf6fVLMZm2Tsy3y6dDaLI4F20T46RDYqoBK6QGVUQQzdoQf0hJ6te+vRerFep6Vz1qxnB/2A9fYJkKSaLg==</latexit><latexit sha1_base64="dXaaVO3FxfQblHO44N/sIbEVvDw=">AAACCnicdVDLSgMxFM34rPVVdekmWgRXNdNWWhdC0Y3LCvYBfZFJ0zY08zC5I5ahazf+ihsXirj1C9z5N2baCip6IHA45z5yjxNIoYGQD2tufmFxaTmxklxdW9/YTG1tV7UfKsYrzJe+qjtUcyk8XgEBktcDxanrSF5zhuexX7vhSgvfu4JRwFsu7XuiJxgFI3VSe82uD9H1+DTfBOFybZN2ETeB30KEa0fuuJ3rpNIkczIBNqSQzeViQvLkOFvEdoZMkEYzlDupdzOThS73gEmqdcMmAbQiqkAwycfJZqh5QNmQ9nnDUI+ata1ocsoYHxili3u+Ms8DPFG/d0TU1XrkOqbSpTDQv71Y/MtrhNArtiLhBSFwj00X9UKJwcdxLrgrFGcgR4ZQpoT5K2YDqigDk17ShPB1Kf6fVLMZm2Tsy3y6dDaLI4F20T46RDYqoBK6QGVUQQzdoQf0hJ6te+vRerFep6Vz1qxnB/2A9fYJkKSaLg==</latexit><latexit sha1_base64="dXaaVO3FxfQblHO44N/sIbEVvDw=">AAACCnicdVDLSgMxFM34rPVVdekmWgRXNdNWWhdC0Y3LCvYBfZFJ0zY08zC5I5ahazf+ihsXirj1C9z5N2baCip6IHA45z5yjxNIoYGQD2tufmFxaTmxklxdW9/YTG1tV7UfKsYrzJe+qjtUcyk8XgEBktcDxanrSF5zhuexX7vhSgvfu4JRwFsu7XuiJxgFI3VSe82uD9H1+DTfBOFybZN2ETeB30KEa0fuuJ3rpNIkczIBNqSQzeViQvLkOFvEdoZMkEYzlDupdzOThS73gEmqdcMmAbQiqkAwycfJZqh5QNmQ9nnDUI+ata1ocsoYHxili3u+Ms8DPFG/d0TU1XrkOqbSpTDQv71Y/MtrhNArtiLhBSFwj00X9UKJwcdxLrgrFGcgR4ZQpoT5K2YDqigDk17ShPB1Kf6fVLMZm2Tsy3y6dDaLI4F20T46RDYqoBK6QGVUQQzdoQf0hJ6te+vRerFep6Vz1qxnB/2A9fYJkKSaLg==</latexit><latexit sha1_base64="dXaaVO3FxfQblHO44N/sIbEVvDw=">AAACCnicdVDLSgMxFM34rPVVdekmWgRXNdNWWhdC0Y3LCvYBfZFJ0zY08zC5I5ahazf+ihsXirj1C9z5N2baCip6IHA45z5yjxNIoYGQD2tufmFxaTmxklxdW9/YTG1tV7UfKsYrzJe+qjtUcyk8XgEBktcDxanrSF5zhuexX7vhSgvfu4JRwFsu7XuiJxgFI3VSe82uD9H1+DTfBOFybZN2ETeB30KEa0fuuJ3rpNIkczIBNqSQzeViQvLkOFvEdoZMkEYzlDupdzOThS73gEmqdcMmAbQiqkAwycfJZqh5QNmQ9nnDUI+ata1ocsoYHxili3u+Ms8DPFG/d0TU1XrkOqbSpTDQv71Y/MtrhNArtiLhBSFwj00X9UKJwcdxLrgrFGcgR4ZQpoT5K2YDqigDk17ShPB1Kf6fVLMZm2Tsy3y6dDaLI4F20T46RDYqoBK6QGVUQQzdoQf0hJ6te+vRerFep6Vz1qxnB/2A9fYJkKSaLg==</latexit>

p0 [Pa]<latexit sha1_base64="E92AfPB2J6GNT2RcFBOgVeH+sqw=">AAAB+HicdVDLTgJBEJzFF+ID1KOXicToicwCBrwRvXjERB7JsiGzwwATZh+Z6TXihi/x4kFjvPop3vwbhwUTNVpJJ5Wq7nR3eZEUGgj5sDIrq2vrG9nN3Nb2zm6+sLff1mGsGG+xUIaq61HNpQh4CwRI3o0Up74necebXM79zi1XWoTBDUwj7vp0FIihYBSM1C/koxPcA34HCXaa1J31C0VSOk+BDamVK5U5IVVyVq5ju0RSFNESzX7hvTcIWezzAJikWjs2icBNqALBJJ/lerHmEWUTOuKOoQH1uXaT9PAZPjbKAA9DZSoAnKrfJxLqaz31PdPpUxjr395c/MtzYhjW3UQEUQw8YItFw1hiCPE8BTwQijOQU0MoU8LcitmYKsrAZJUzIXx9iv8n7XLJJiX7ulpsXCzjyKJDdIROkY1qqIGuUBO1EEMxekBP6Nm6tx6tF+t10ZqxljMH6Aest0+G6JME</latexit><latexit sha1_base64="E92AfPB2J6GNT2RcFBOgVeH+sqw=">AAAB+HicdVDLTgJBEJzFF+ID1KOXicToicwCBrwRvXjERB7JsiGzwwATZh+Z6TXihi/x4kFjvPop3vwbhwUTNVpJJ5Wq7nR3eZEUGgj5sDIrq2vrG9nN3Nb2zm6+sLff1mGsGG+xUIaq61HNpQh4CwRI3o0Up74necebXM79zi1XWoTBDUwj7vp0FIihYBSM1C/koxPcA34HCXaa1J31C0VSOk+BDamVK5U5IVVyVq5ju0RSFNESzX7hvTcIWezzAJikWjs2icBNqALBJJ/lerHmEWUTOuKOoQH1uXaT9PAZPjbKAA9DZSoAnKrfJxLqaz31PdPpUxjr395c/MtzYhjW3UQEUQw8YItFw1hiCPE8BTwQijOQU0MoU8LcitmYKsrAZJUzIXx9iv8n7XLJJiX7ulpsXCzjyKJDdIROkY1qqIGuUBO1EEMxekBP6Nm6tx6tF+t10ZqxljMH6Aest0+G6JME</latexit><latexit sha1_base64="E92AfPB2J6GNT2RcFBOgVeH+sqw=">AAAB+HicdVDLTgJBEJzFF+ID1KOXicToicwCBrwRvXjERB7JsiGzwwATZh+Z6TXihi/x4kFjvPop3vwbhwUTNVpJJ5Wq7nR3eZEUGgj5sDIrq2vrG9nN3Nb2zm6+sLff1mGsGG+xUIaq61HNpQh4CwRI3o0Up74necebXM79zi1XWoTBDUwj7vp0FIihYBSM1C/koxPcA34HCXaa1J31C0VSOk+BDamVK5U5IVVyVq5ju0RSFNESzX7hvTcIWezzAJikWjs2icBNqALBJJ/lerHmEWUTOuKOoQH1uXaT9PAZPjbKAA9DZSoAnKrfJxLqaz31PdPpUxjr395c/MtzYhjW3UQEUQw8YItFw1hiCPE8BTwQijOQU0MoU8LcitmYKsrAZJUzIXx9iv8n7XLJJiX7ulpsXCzjyKJDdIROkY1qqIGuUBO1EEMxekBP6Nm6tx6tF+t10ZqxljMH6Aest0+G6JME</latexit><latexit sha1_base64="E92AfPB2J6GNT2RcFBOgVeH+sqw=">AAAB+HicdVDLTgJBEJzFF+ID1KOXicToicwCBrwRvXjERB7JsiGzwwATZh+Z6TXihi/x4kFjvPop3vwbhwUTNVpJJ5Wq7nR3eZEUGgj5sDIrq2vrG9nN3Nb2zm6+sLff1mGsGG+xUIaq61HNpQh4CwRI3o0Up74necebXM79zi1XWoTBDUwj7vp0FIihYBSM1C/koxPcA34HCXaa1J31C0VSOk+BDamVK5U5IVVyVq5ju0RSFNESzX7hvTcIWezzAJikWjs2icBNqALBJJ/lerHmEWUTOuKOoQH1uXaT9PAZPjbKAA9DZSoAnKrfJxLqaz31PdPpUxjr395c/MtzYhjW3UQEUQw8YItFw1hiCPE8BTwQijOQU0MoU8LcitmYKsrAZJUzIXx9iv8n7XLJJiX7ulpsXCzjyKJDdIROkY1qqIGuUBO1EEMxekBP6Nm6tx6tF+t10ZqxljMH6Aest0+G6JME</latexit>

�6000<latexit sha1_base64="Uw5Qc+MC6udv+iASTP6gTegX0VY=">AAAB7HicdVBNS8NAEN3Ur1q/qh69LBbBi2HTVltvRS8eK5i20Iay2W7apZtN2N0IJfQ3ePGgiFd/kDf/jZu0goo+GHi8N8PMPD/mTGmEPqzCyura+kZxs7S1vbO7V94/6KgokYS6JOKR7PlYUc4EdTXTnPZiSXHoc9r1p9eZ372nUrFI3OlZTL0QjwULGMHaSO7ZBUJoWK4g+zIHNKRRrdUygurovNqEjo1yVMAS7WH5fTCKSBJSoQnHSvUdFGsvxVIzwum8NEgUjTGZ4jHtGypwSJWX5sfO4YlRRjCIpCmhYa5+n0hxqNQs9E1niPVE/fYy8S+vn+ig6aVMxImmgiwWBQmHOoLZ53DEJCWazwzBRDJzKyQTLDHRJp+SCeHrU/g/6VRtB9nObb3SulrGUQRH4BicAgc0QAvcgDZwAQEMPIAn8GwJ69F6sV4XrQVrOXMIfsB6+wTQ244J</latexit><latexit sha1_base64="Uw5Qc+MC6udv+iASTP6gTegX0VY=">AAAB7HicdVBNS8NAEN3Ur1q/qh69LBbBi2HTVltvRS8eK5i20Iay2W7apZtN2N0IJfQ3ePGgiFd/kDf/jZu0goo+GHi8N8PMPD/mTGmEPqzCyura+kZxs7S1vbO7V94/6KgokYS6JOKR7PlYUc4EdTXTnPZiSXHoc9r1p9eZ372nUrFI3OlZTL0QjwULGMHaSO7ZBUJoWK4g+zIHNKRRrdUygurovNqEjo1yVMAS7WH5fTCKSBJSoQnHSvUdFGsvxVIzwum8NEgUjTGZ4jHtGypwSJWX5sfO4YlRRjCIpCmhYa5+n0hxqNQs9E1niPVE/fYy8S+vn+ig6aVMxImmgiwWBQmHOoLZ53DEJCWazwzBRDJzKyQTLDHRJp+SCeHrU/g/6VRtB9nObb3SulrGUQRH4BicAgc0QAvcgDZwAQEMPIAn8GwJ69F6sV4XrQVrOXMIfsB6+wTQ244J</latexit><latexit sha1_base64="Uw5Qc+MC6udv+iASTP6gTegX0VY=">AAAB7HicdVBNS8NAEN3Ur1q/qh69LBbBi2HTVltvRS8eK5i20Iay2W7apZtN2N0IJfQ3ePGgiFd/kDf/jZu0goo+GHi8N8PMPD/mTGmEPqzCyura+kZxs7S1vbO7V94/6KgokYS6JOKR7PlYUc4EdTXTnPZiSXHoc9r1p9eZ372nUrFI3OlZTL0QjwULGMHaSO7ZBUJoWK4g+zIHNKRRrdUygurovNqEjo1yVMAS7WH5fTCKSBJSoQnHSvUdFGsvxVIzwum8NEgUjTGZ4jHtGypwSJWX5sfO4YlRRjCIpCmhYa5+n0hxqNQs9E1niPVE/fYy8S+vn+ig6aVMxImmgiwWBQmHOoLZ53DEJCWazwzBRDJzKyQTLDHRJp+SCeHrU/g/6VRtB9nObb3SulrGUQRH4BicAgc0QAvcgDZwAQEMPIAn8GwJ69F6sV4XrQVrOXMIfsB6+wTQ244J</latexit><latexit sha1_base64="Uw5Qc+MC6udv+iASTP6gTegX0VY=">AAAB7HicdVBNS8NAEN3Ur1q/qh69LBbBi2HTVltvRS8eK5i20Iay2W7apZtN2N0IJfQ3ePGgiFd/kDf/jZu0goo+GHi8N8PMPD/mTGmEPqzCyura+kZxs7S1vbO7V94/6KgokYS6JOKR7PlYUc4EdTXTnPZiSXHoc9r1p9eZ372nUrFI3OlZTL0QjwULGMHaSO7ZBUJoWK4g+zIHNKRRrdUygurovNqEjo1yVMAS7WH5fTCKSBJSoQnHSvUdFGsvxVIzwum8NEgUjTGZ4jHtGypwSJWX5sfO4YlRRjCIpCmhYa5+n0hxqNQs9E1niPVE/fYy8S+vn+ig6aVMxImmgiwWBQmHOoLZ53DEJCWazwzBRDJzKyQTLDHRJp+SCeHrU/g/6VRtB9nObb3SulrGUQRH4BicAgc0QAvcgDZwAQEMPIAn8GwJ69F6sV4XrQVrOXMIfsB6+wTQ244J</latexit>

6000<latexit sha1_base64="UMR5jVWj1IwuB2Cg6gcEookXfvY=">AAAB63icdVDLSgMxFM34rPVVdekmWARXQ6attu6KblxWsA9oh5JJM21okhmSjFCG/oIbF4q49Yfc+TdmphVU9MCFwzn3cu89QcyZNgh9OCura+sbm4Wt4vbO7t5+6eCwo6NEEdomEY9UL8CaciZp2zDDaS9WFIuA024wvc787j1VmkXyzsxi6gs8lixkBJtMukAIDUtl5F7mgJbUK9VqRlANnVca0HNRjjJYojUsvQ9GEUkElYZwrHXfQ7HxU6wMI5zOi4NE0xiTKR7TvqUSC6r9NL91Dk+tMoJhpGxJA3P1+0SKhdYzEdhOgc1E//Yy8S+vn5iw4adMxomhkiwWhQmHJoLZ43DEFCWGzyzBRDF7KyQTrDAxNp6iDeHrU/g/6VRcD7neba3cvFrGUQDH4AScAQ/UQRPcgBZoAwIm4AE8gWdHOI/Oi/O6aF1xljNH4Aect09nCY3S</latexit><latexit sha1_base64="UMR5jVWj1IwuB2Cg6gcEookXfvY=">AAAB63icdVDLSgMxFM34rPVVdekmWARXQ6attu6KblxWsA9oh5JJM21okhmSjFCG/oIbF4q49Yfc+TdmphVU9MCFwzn3cu89QcyZNgh9OCura+sbm4Wt4vbO7t5+6eCwo6NEEdomEY9UL8CaciZp2zDDaS9WFIuA024wvc787j1VmkXyzsxi6gs8lixkBJtMukAIDUtl5F7mgJbUK9VqRlANnVca0HNRjjJYojUsvQ9GEUkElYZwrHXfQ7HxU6wMI5zOi4NE0xiTKR7TvqUSC6r9NL91Dk+tMoJhpGxJA3P1+0SKhdYzEdhOgc1E//Yy8S+vn5iw4adMxomhkiwWhQmHJoLZ43DEFCWGzyzBRDF7KyQTrDAxNp6iDeHrU/g/6VRcD7neba3cvFrGUQDH4AScAQ/UQRPcgBZoAwIm4AE8gWdHOI/Oi/O6aF1xljNH4Aect09nCY3S</latexit><latexit sha1_base64="UMR5jVWj1IwuB2Cg6gcEookXfvY=">AAAB63icdVDLSgMxFM34rPVVdekmWARXQ6attu6KblxWsA9oh5JJM21okhmSjFCG/oIbF4q49Yfc+TdmphVU9MCFwzn3cu89QcyZNgh9OCura+sbm4Wt4vbO7t5+6eCwo6NEEdomEY9UL8CaciZp2zDDaS9WFIuA024wvc787j1VmkXyzsxi6gs8lixkBJtMukAIDUtl5F7mgJbUK9VqRlANnVca0HNRjjJYojUsvQ9GEUkElYZwrHXfQ7HxU6wMI5zOi4NE0xiTKR7TvqUSC6r9NL91Dk+tMoJhpGxJA3P1+0SKhdYzEdhOgc1E//Yy8S+vn5iw4adMxomhkiwWhQmHJoLZ43DEFCWGzyzBRDF7KyQTrDAxNp6iDeHrU/g/6VRcD7neba3cvFrGUQDH4AScAQ/UQRPcgBZoAwIm4AE8gWdHOI/Oi/O6aF1xljNH4Aect09nCY3S</latexit><latexit sha1_base64="UMR5jVWj1IwuB2Cg6gcEookXfvY=">AAAB63icdVDLSgMxFM34rPVVdekmWARXQ6attu6KblxWsA9oh5JJM21okhmSjFCG/oIbF4q49Yfc+TdmphVU9MCFwzn3cu89QcyZNgh9OCura+sbm4Wt4vbO7t5+6eCwo6NEEdomEY9UL8CaciZp2zDDaS9WFIuA024wvc787j1VmkXyzsxi6gs8lixkBJtMukAIDUtl5F7mgJbUK9VqRlANnVca0HNRjjJYojUsvQ9GEUkElYZwrHXfQ7HxU6wMI5zOi4NE0xiTKR7TvqUSC6r9NL91Dk+tMoJhpGxJA3P1+0SKhdYzEdhOgc1E//Yy8S+vn5iw4adMxomhkiwWhQmHJoLZ43DEFCWGzyzBRDF7KyQTrDAxNp6iDeHrU/g/6VRcD7neba3cvFrGUQDH4AScAQ/UQRPcgBZoAwIm4AE8gWdHOI/Oi/O6aF1xljNH4Aect09nCY3S</latexit>

YO2 = 0.12<latexit sha1_base64="bAJ/pcBRUCbn8plqm3ZKexEXRIE=">AAACBXicdVC7SgNBFJ31GeMraqnFYBAsJOxuIkkKIWhjZwTzkCQss5NJMmT2wcxdMSzb2PgrNhaK2PoPdv6Nk4egogcu93DOvczc44aCKzDND2NufmFxaTm1kl5dW9/YzGxt11UQScpqNBCBbLpEMcF9VgMOgjVDyYjnCtZwh2djv3HDpOKBfwWjkHU80vd5j1MCWnIye9dO3D5qA7uF+CJxpsROkhMzZ9lOJqtb3s4Xy9jMla18uWSPSalsFo6xlTMnyKIZqk7mvd0NaOQxH6ggSrUsM4ROTCRwKliSbkeKhYQOSZ+1NPWJx1QnnlyR4AOtdHEvkLp8wBP1+0ZMPKVGnqsnPQID9dsbi395rQh6pU7M/TAC5tPpQ71IYAjwOBLc5ZJRECNNCJVc/xXTAZGEgg4urUP4uhT/T+p2ztJZXRayldNZHCm0i/bRIbJQEVXQOaqiGqLoDj2gJ/Rs3BuPxovxOh2dM2Y7O+gHjLdPPw2YZw==</latexit><latexit sha1_base64="bAJ/pcBRUCbn8plqm3ZKexEXRIE=">AAACBXicdVC7SgNBFJ31GeMraqnFYBAsJOxuIkkKIWhjZwTzkCQss5NJMmT2wcxdMSzb2PgrNhaK2PoPdv6Nk4egogcu93DOvczc44aCKzDND2NufmFxaTm1kl5dW9/YzGxt11UQScpqNBCBbLpEMcF9VgMOgjVDyYjnCtZwh2djv3HDpOKBfwWjkHU80vd5j1MCWnIye9dO3D5qA7uF+CJxpsROkhMzZ9lOJqtb3s4Xy9jMla18uWSPSalsFo6xlTMnyKIZqk7mvd0NaOQxH6ggSrUsM4ROTCRwKliSbkeKhYQOSZ+1NPWJx1QnnlyR4AOtdHEvkLp8wBP1+0ZMPKVGnqsnPQID9dsbi395rQh6pU7M/TAC5tPpQ71IYAjwOBLc5ZJRECNNCJVc/xXTAZGEgg4urUP4uhT/T+p2ztJZXRayldNZHCm0i/bRIbJQEVXQOaqiGqLoDj2gJ/Rs3BuPxovxOh2dM2Y7O+gHjLdPPw2YZw==</latexit><latexit sha1_base64="bAJ/pcBRUCbn8plqm3ZKexEXRIE=">AAACBXicdVC7SgNBFJ31GeMraqnFYBAsJOxuIkkKIWhjZwTzkCQss5NJMmT2wcxdMSzb2PgrNhaK2PoPdv6Nk4egogcu93DOvczc44aCKzDND2NufmFxaTm1kl5dW9/YzGxt11UQScpqNBCBbLpEMcF9VgMOgjVDyYjnCtZwh2djv3HDpOKBfwWjkHU80vd5j1MCWnIye9dO3D5qA7uF+CJxpsROkhMzZ9lOJqtb3s4Xy9jMla18uWSPSalsFo6xlTMnyKIZqk7mvd0NaOQxH6ggSrUsM4ROTCRwKliSbkeKhYQOSZ+1NPWJx1QnnlyR4AOtdHEvkLp8wBP1+0ZMPKVGnqsnPQID9dsbi395rQh6pU7M/TAC5tPpQ71IYAjwOBLc5ZJRECNNCJVc/xXTAZGEgg4urUP4uhT/T+p2ztJZXRayldNZHCm0i/bRIbJQEVXQOaqiGqLoDj2gJ/Rs3BuPxovxOh2dM2Y7O+gHjLdPPw2YZw==</latexit><latexit sha1_base64="bAJ/pcBRUCbn8plqm3ZKexEXRIE=">AAACBXicdVC7SgNBFJ31GeMraqnFYBAsJOxuIkkKIWhjZwTzkCQss5NJMmT2wcxdMSzb2PgrNhaK2PoPdv6Nk4egogcu93DOvczc44aCKzDND2NufmFxaTm1kl5dW9/YzGxt11UQScpqNBCBbLpEMcF9VgMOgjVDyYjnCtZwh2djv3HDpOKBfwWjkHU80vd5j1MCWnIye9dO3D5qA7uF+CJxpsROkhMzZ9lOJqtb3s4Xy9jMla18uWSPSalsFo6xlTMnyKIZqk7mvd0NaOQxH6ggSrUsM4ROTCRwKliSbkeKhYQOSZ+1NPWJx1QnnlyR4AOtdHEvkLp8wBP1+0ZMPKVGnqsnPQID9dsbi395rQh6pU7M/TAC5tPpQ71IYAjwOBLc5ZJRECNNCJVc/xXTAZGEgg4urUP4uhT/T+p2ztJZXRayldNZHCm0i/bRIbJQEVXQOaqiGqLoDj2gJ/Rs3BuPxovxOh2dM2Y7O+gHjLdPPw2YZw==</latexit>

YCH4 = 0.06<latexit sha1_base64="o4vEoZx5LBOIbDwbrYC6CRPoM+k=">AAACBnicdVDLSgMxFM34rPU16lKEYBFcSJmppa0LodhNlxXsQ9oyZNK0Dc08SO6IZZiVG3/FjQtF3PoN7vwb04egogcunJxzL7n3uKHgCizrw1hYXFpeWU2tpdc3Nre2zZ3dhgoiSVmdBiKQLZcoJrjP6sBBsFYoGfFcwZruqDLxmzdMKh74VzAOWdcjA5/3OSWgJcc8uHbizkkH2C3ElWrizFg+Sc6trFVwzIyVPSsW7FIR6/cUE3Kas+0itudKBs1Rc8z3Ti+gkcd8oIIo1batELoxkcCpYEm6EykWEjoiA9bW1CceU914ekaCj7TSw/1A6vIBT9XvEzHxlBp7ru70CAzVb28i/uW1I+iXujH3wwiYT2cf9SOBIcCTTHCPS0ZBjDUhVHK9K6ZDIgkFnVxah/B1Kf6fNHJZ28ral/lM+WIeRwrto0N0jGxURGVURTVURxTdoQf0hJ6Ne+PReDFeZ60LxnxmD/2A8fYJlnmYig==</latexit><latexit sha1_base64="o4vEoZx5LBOIbDwbrYC6CRPoM+k=">AAACBnicdVDLSgMxFM34rPU16lKEYBFcSJmppa0LodhNlxXsQ9oyZNK0Dc08SO6IZZiVG3/FjQtF3PoN7vwb04egogcunJxzL7n3uKHgCizrw1hYXFpeWU2tpdc3Nre2zZ3dhgoiSVmdBiKQLZcoJrjP6sBBsFYoGfFcwZruqDLxmzdMKh74VzAOWdcjA5/3OSWgJcc8uHbizkkH2C3ElWrizFg+Sc6trFVwzIyVPSsW7FIR6/cUE3Kas+0itudKBs1Rc8z3Ti+gkcd8oIIo1batELoxkcCpYEm6EykWEjoiA9bW1CceU914ekaCj7TSw/1A6vIBT9XvEzHxlBp7ru70CAzVb28i/uW1I+iXujH3wwiYT2cf9SOBIcCTTHCPS0ZBjDUhVHK9K6ZDIgkFnVxah/B1Kf6fNHJZ28ral/lM+WIeRwrto0N0jGxURGVURTVURxTdoQf0hJ6Ne+PReDFeZ60LxnxmD/2A8fYJlnmYig==</latexit><latexit sha1_base64="o4vEoZx5LBOIbDwbrYC6CRPoM+k=">AAACBnicdVDLSgMxFM34rPU16lKEYBFcSJmppa0LodhNlxXsQ9oyZNK0Dc08SO6IZZiVG3/FjQtF3PoN7vwb04egogcunJxzL7n3uKHgCizrw1hYXFpeWU2tpdc3Nre2zZ3dhgoiSVmdBiKQLZcoJrjP6sBBsFYoGfFcwZruqDLxmzdMKh74VzAOWdcjA5/3OSWgJcc8uHbizkkH2C3ElWrizFg+Sc6trFVwzIyVPSsW7FIR6/cUE3Kas+0itudKBs1Rc8z3Ti+gkcd8oIIo1batELoxkcCpYEm6EykWEjoiA9bW1CceU914ekaCj7TSw/1A6vIBT9XvEzHxlBp7ru70CAzVb28i/uW1I+iXujH3wwiYT2cf9SOBIcCTTHCPS0ZBjDUhVHK9K6ZDIgkFnVxah/B1Kf6fNHJZ28ral/lM+WIeRwrto0N0jGxURGVURTVURxTdoQf0hJ6Ne+PReDFeZ60LxnxmD/2A8fYJlnmYig==</latexit><latexit sha1_base64="o4vEoZx5LBOIbDwbrYC6CRPoM+k=">AAACBnicdVDLSgMxFM34rPU16lKEYBFcSJmppa0LodhNlxXsQ9oyZNK0Dc08SO6IZZiVG3/FjQtF3PoN7vwb04egogcunJxzL7n3uKHgCizrw1hYXFpeWU2tpdc3Nre2zZ3dhgoiSVmdBiKQLZcoJrjP6sBBsFYoGfFcwZruqDLxmzdMKh74VzAOWdcjA5/3OSWgJcc8uHbizkkH2C3ElWrizFg+Sc6trFVwzIyVPSsW7FIR6/cUE3Kas+0itudKBs1Rc8z3Ti+gkcd8oIIo1batELoxkcCpYEm6EykWEjoiA9bW1CceU914ekaCj7TSw/1A6vIBT9XvEzHxlBp7ru70CAzVb28i/uW1I+iXujH3wwiYT2cf9SOBIcCTTHCPS0ZBjDUhVHK9K6ZDIgkFnVxah/B1Kf6fNHJZ28ral/lM+WIeRwrto0N0jGxURGVURTVURxTdoQf0hJ6Ne+PReDFeZ60LxnxmD/2A8fYJlnmYig==</latexit>



Comparison between experiments and the LES - acoustics

Acoustic pressure sensor



Typi

cal s

elf-s

usta

ined

th

erm

o-ac

oust

ic c

ycle

(7 m

s)

OH Planar Laser Induced Fluorescence (PLIF)

OH fraction in central plane from the 3D LES

Sequential burner and chamber

Complex thermoacoustics in sequential combustors


2nd stage autoignition modeling


t/T period = 1, 2, 3, ...<latexit sha1_base64="a9o2/+YodiJtkaPDmoePqGVcuOg=">AAACC3icbVDJSgNBEO2JW4xb1KOXJkHwEMaZKOhFCHrxGCEbJCH0dCpJk56F7hoxDLl78Ve8eFDEqz/gzb+xsxw08UHB470qqup5kRQaHefbSq2srq1vpDczW9s7u3vZ/YOaDmPFocpDGaqGxzRIEUAVBUpoRAqY70moe8ObiV+/B6VFGFRwFEHbZ/1A9ARnaKRONoenlU7SKrQQHjCJQImwOx5fuQVaLNCzArVtu5PNO7YzBV0m7pzkyRzlTvar1Q157EOAXDKtm64TYTthCgWXMM60Yg0R40PWh6ahAfNBt5PpL2N6bJQu7YXKVIB0qv6eSJiv9cj3TKfPcKAXvYn4n9eMsXfZTkQQxQgBny3qxZJiSCfB0K5QwFGODGFcCXMr5QOmGEcTX8aE4C6+vExqRdt1bPfuPF+6nseRJkckR06ISy5IidySMqkSTh7JM3klb9aT9WK9Wx+z1pQ1nzkkf2B9/gBzWJiy</latexit><latexit sha1_base64="a9o2/+YodiJtkaPDmoePqGVcuOg=">AAACC3icbVDJSgNBEO2JW4xb1KOXJkHwEMaZKOhFCHrxGCEbJCH0dCpJk56F7hoxDLl78Ve8eFDEqz/gzb+xsxw08UHB470qqup5kRQaHefbSq2srq1vpDczW9s7u3vZ/YOaDmPFocpDGaqGxzRIEUAVBUpoRAqY70moe8ObiV+/B6VFGFRwFEHbZ/1A9ARnaKRONoenlU7SKrQQHjCJQImwOx5fuQVaLNCzArVtu5PNO7YzBV0m7pzkyRzlTvar1Q157EOAXDKtm64TYTthCgWXMM60Yg0R40PWh6ahAfNBt5PpL2N6bJQu7YXKVIB0qv6eSJiv9cj3TKfPcKAXvYn4n9eMsXfZTkQQxQgBny3qxZJiSCfB0K5QwFGODGFcCXMr5QOmGEcTX8aE4C6+vExqRdt1bPfuPF+6nseRJkckR06ISy5IidySMqkSTh7JM3klb9aT9WK9Wx+z1pQ1nzkkf2B9/gBzWJiy</latexit><latexit sha1_base64="a9o2/+YodiJtkaPDmoePqGVcuOg=">AAACC3icbVDJSgNBEO2JW4xb1KOXJkHwEMaZKOhFCHrxGCEbJCH0dCpJk56F7hoxDLl78Ve8eFDEqz/gzb+xsxw08UHB470qqup5kRQaHefbSq2srq1vpDczW9s7u3vZ/YOaDmPFocpDGaqGxzRIEUAVBUpoRAqY70moe8ObiV+/B6VFGFRwFEHbZ/1A9ARnaKRONoenlU7SKrQQHjCJQImwOx5fuQVaLNCzArVtu5PNO7YzBV0m7pzkyRzlTvar1Q157EOAXDKtm64TYTthCgWXMM60Yg0R40PWh6ahAfNBt5PpL2N6bJQu7YXKVIB0qv6eSJiv9cj3TKfPcKAXvYn4n9eMsXfZTkQQxQgBny3qxZJiSCfB0K5QwFGODGFcCXMr5QOmGEcTX8aE4C6+vExqRdt1bPfuPF+6nseRJkckR06ISy5IidySMqkSTh7JM3klb9aT9WK9Wx+z1pQ1nzkkf2B9/gBzWJiy</latexit><latexit sha1_base64="a9o2/+YodiJtkaPDmoePqGVcuOg=">AAACC3icbVDJSgNBEO2JW4xb1KOXJkHwEMaZKOhFCHrxGCEbJCH0dCpJk56F7hoxDLl78Ve8eFDEqz/gzb+xsxw08UHB470qqup5kRQaHefbSq2srq1vpDczW9s7u3vZ/YOaDmPFocpDGaqGxzRIEUAVBUpoRAqY70moe8ObiV+/B6VFGFRwFEHbZ/1A9ARnaKRONoenlU7SKrQQHjCJQImwOx5fuQVaLNCzArVtu5PNO7YzBV0m7pzkyRzlTvar1Q157EOAXDKtm64TYTthCgWXMM60Yg0R40PWh6ahAfNBt5PpL2N6bJQu7YXKVIB0qv6eSJiv9cj3TKfPcKAXvYn4n9eMsXfZTkQQxQgBny3qxZJiSCfB0K5QwFGODGFcCXMr5QOmGEcTX8aE4C6+vExqRdt1bPfuPF+6nseRJkckR06ISy5IidySMqkSTh7JM3klb9aT9WK9Wx+z1pQ1nzkkf2B9/gBzWJiy</latexit>



Flame stabilization using nanosecond repetitively pulsed

discharges

CH4-air

mixture

1st stage

flame

Dilution

air

2nd stage

CH4

Sequential

flame

1st stage power 30 kW

Equivalence Ratio: 0.64

Plasma

Electrode



Vitiated flow

CH4 jet

Vortex generators

Electrodes and plasma discharge

Side view sequential

burner

Vitiated flow

Quartz walls

Quartz wallsElectrodes

Plasma Discharge

40 m

m

Top view



Intensifier HSC 2

100 μs expo. OH filter

Top ViewNikon 2

5s exposure, CH filter

Nikon 1

1s exposure, no filter

HSC

1

100 μs expo, 8 kHz

About 10 ns pulses of 8 kV, Pulses repetition rate 50 kHz



Plasma-enhanced autoignition

No flame without NRPD

Electrodes and NRPD

Flame with NRPD

Vitiated Air + CH41300 K and 70 m/s

High Speed imaging after NRPD start

1.6 ms

2.1 ms

2.6 ms

40mm

CH* Intensity

(1 sec. exposure no filter)




Plasma-enhanced autoignition

No flame without NRPD

Electrodes

and NRPD

Flame with NRPD

Vitiated Air + CH41300 K and 70 m/s

High Speed imaging after NRPD start

1.6 ms

2.1 ms

2.6 ms

40mm

CH* Intensity

(1 sec. exposure no filter)

Camera settings: 0.1 millisec. exposure 8 kHz

Flame Thermal Power:

45 000 WElectric Power for Plasma:

115 W (0.25%)20 μs

(50 kHz)

10 ns

8 kV

Xiong,… , Noiray Proc. Comb. Inst. 2019



Summary§ Autoignition and flame propagation can both

govern the combustion regime in sequential combustors at relevant conditions

§ Understanding, modeling and simulating transitions between these regimes is very challenging but it is key for design of new sequential combustors

§ Thermoacoustic instabilities in these combustors involve complex pathways where flames talk to each other via acoustic, but also compositional and entropy waves

§ NRP discharges have significant impact on autoignition in sequential combustors, significant research effort is necessary to understand and model it

Exp.LES

Ebi et al., PROCI 2019

Schulz and Noiray, CNF 2019

Schulz et al., PROCI 2019

Xiong et al., PROCI 2019

combustion dynamics in sequential combustorsyju/2nd-near-limit-flames-workshop/...vitiated air + ch...

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