Bekaert Sa · EURONEXT:BEKB
Bekaert Sa — Technical Presentation (October 2014)
30 slides from Bekaert Sa's technical presentation, Oct 9, 2014
Slide 1: Numerical Investigations of the Response of a Simplified Burner-heat exchanger System
Numerical Investigations of the Response of a Simplified Burner-heat exchanger System to Inlet Velocity Excitations Naseh Hosseini, Viktor Kornilov, Joan Teerling, Ines Lopez Arteaga and Philip de Goey COMBURA '14 Combustion Research and Application Kontakt der Kontinenten, Soesterberg, The Netherla
Slide 2: Thermoacoustics
Introduction Numerical Model Results Conclusions Acknowledgement - Thermoacoustics 2
Slide 3: Challenges
Introduction Numerical Model Results Conclusions Acknowledgement - Challenges • Thermoacoustic noise is currently an issue in domestic heating systems • Closer burner and heat exchanger in compact condensing boilers • The industry’s need for design rules to make thermoacoustically stable systems 3
Slide 4: Goal
Introduction Numerical Model Results Conclusions Acknowledgement - Goal • The physics of the interactions between a burner and a heat exchanger from a hydrodynamic and thermoacoustic point of view • In this presentation the method of modelling, implementation of CFD setup, validation of the simulati
Slide 5: Numerical domain
Introduction Numerical Model Results Conclusions Acknowledgement - Numerical domain • Flat multi-slit burner • Plane 2D symmetric • Dimensions in mm 5
Slide 6: The model
Introduction Numerical Model Results Conclusions Acknowledgement - The model • ANSYS Fluent CFD code • Laminar flow with energy equation • Species conservation t Yi . vYi .J i Ri Si • Single step reaction CH 4 2 O2 3.76 N2 CO2 2H 2O 7.52 N2 • Arrhenius formulat
Slide 7: Verifications
Introduction Numerical Model Results Conclusions Acknowledgement - Verifications • Pseudo-1D model (0.02 35mm) • Grid independency 26.50 26.25 26.27 26.24 26.13 26.00 SL (CM/S) 25.75 25.83 25.50 25.25 25.00 0.020 SQR 0.025 SQR 0.050 SQR 0.100 SQR ELEMENT SIZE AND TYPE (MM) 7
Slide 8: Verifications
Introduction Numerical Model Results Conclusions Acknowledgement - Verifications • Pseudo-1D model (0.02 35mm) • Grid independency • Equivalence ratio sensitivity 40 35 This Study Lange (1992) 30 Dyakov (2001) Kishore (2008) 25 Sl (cm/s) 20 15 10 5 0 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 Equiva
Slide 9: Verifications
Introduction Numerical Model Results Conclusions Acknowledgement - Verifications • Pseudo-1D model (0.02 35mm) • Grid independency • Equivalence ratio sensitivity 90 80 This Study • Unburnt temperature sensitivity 70 Sharma (1981) 60 Brown (2003) Sl (cm/s) 50 40 30 20 10 0 150 200 250 300 350 400
Slide 10: 2D grid, using 1D conclusions, 165,000 elements
Introduction Numerical Model Results Conclusions Acknowledgement - 2D grid, using 1D conclusions, 165,000 elements 10
Slide 11: Flame transfer function
Introduction Numerical Model Results Conclusions Acknowledgement - Flame transfer function • Velocity perturbation as input and heat release rate as output • Step increase of 5% with assumed linearity, 40ms relaxation time • The (complex) flame transfer function defined as relative flame response di
Slide 12: Case studies
Introduction Numerical Model Results Conclusions Acknowledgement - Case studies Distance between Burner Deck Inlet Velocity (cm/s) and Heat Exchanger (mm) 25 50 5 Hex05-V25 Hex05-V50 10 Hex10-V25 Hex10-V50 15 Hex15-V25 Hex15-V50 N/A NoHex-V25 NoHex-V50 12
Slide 13: Left: inlet velocity 25cm/s - Right: inlet velocity 50cm/s
Introduction Numerical Model Results Conclusions Acknowledgement - Left: inlet velocity 25cm/s - Right: inlet velocity 50cm/s • Reaction rate (kmol/m3s) • Temperature (K) 17
Slide 14: Flow field through flame and around heat exchanger
Introduction Numerical Model Results Conclusions Acknowledgement - Flow field through flame and around heat exchanger 18
Slide 15: Normalized Heat Release Rate
Introduction Numerical Model Results Conclusions Acknowledgement V50-NoHex V50-Hex15 V50-Hex10 V50-Hex05 V25-NoHex V25-Hex15 V25-Hex10 V25-Hex05 2.8 1.07 2.7 1.06 2.6 1.05 2.5 1.04 2.4 V50 1.03 V50 2.3 1.02 Normalized Heat Release Rate 2.2 1.01 Heat Release Rate (kW) 2.1 1.00 2.0 0.99 1.9 1.07 1.8 1
Slide 16: Normalized Heat Release
Introduction Numerical Model Results Conclusions Acknowledgement - Offset for Hex05V50 1.07 1.06 Normalized Heat Release 1.05 1.04 1.03 1.02 NoHex 1.01 Hex15 1.00 Hex10 Hex05 0.99 0 5 10 15 20 25 30 35 40 Time (ms) 20
Slide 17: Response to square excitation
Introduction Numerical Model Results Conclusions Acknowledgement - Response to square excitation 1.06 1.05 Normalized Heat Release 1.04 1.03 1.02 1.01 1.00 0.99 0 5 10 15 20 25 30 35 40 Time (ms) 21
Slide 18: Case Studies with Heat Exchanger
Introduction Numerical Model Results Conclusions Acknowledgement 2.5 Deck Hex Flame Element Heat Transfer Rate (kW) 2.0 1.5 1.0 0.5 0.0 HEX05 HEX10 HEX15 HEX05 HEX10 HEX15 V25 V50 Case Studies with Heat Exchanger 22
Slide 19: ReacTF - V25
Introduction Numerical Model Results Conclusions Acknowledgement NoHex Hex15 Hex10 Hex05 NoHex Hex15 Hex10 Hex05 1.0 1 Gain Gain 0.8 0.1 0.6 Gain Gain 0.01 0.4 0.001 0.2 0.0 0.0001 0 100 200 300 400 500 600 700 800 900 1000 0 100 200 300 400 500 600 700 800 900 1000 Frequency (Hz) Frequency (Hz) Rea
Slide 20: ReacTF - V25
Introduction Numerical Model Results Conclusions Acknowledgement NoHex Hex15 Hex10 Hex05 NoHex Hex15 Hex10 Hex05 1.0 1 Gain Gain 0.8 0.1 0.6 Gain Gain 0.01 0.4 0.001 0.2 0.0 0.0001 0 100 200 300 400 500 600 700 800 900 1000 0 100 200 300 400 500 600 700 800 900 1000 Frequency (Hz) Frequency (Hz) Rea
Slide 21: ReacTF - V50
Introduction Numerical Model Results Conclusions Acknowledgement NoHex Hex15 Hex10 Hex05 NoHex Hex15 Hex10 Hex05 1.6 1.4 Gain 1 Gain 1.2 1.0 Gain Gain 0.1 0.8 0.6 0.01 0.4 0.2 0.0 0.001 0 100 200 300 400 500 600 700 800 900 1000 0 100 200 300 400 500 600 700 800 900 1000 Frequency (Hz) Frequency (Hz
Slide 22: HexTF - V25
Introduction Numerical Model Results Conclusions Acknowledgement Hex15 Hex10 Hex05 Hex15 Hex10 Hex05 1.0 1 Gain Gain 0.8 0.6 Gain Gain 0.1 0.4 0.2 0.0 0.01 0 100 200 300 400 500 600 700 800 900 1000 0 100 200 300 400 500 600 700 800 900 1000 Frequency (Hz) Frequency (Hz) HexTF – V25 Hex15 Hex10 Hex0
Slide 23: HexTF - V50
Introduction Numerical Model Results Conclusions Acknowledgement Hex15 Hex10 Hex05 Hex15 Hex10 Hex05 1.0 1 Gain Gain 0.8 0.6 Gain Gain 0.1 0.4 0.2 0.0 0.01 0 100 200 300 400 500 600 700 800 900 1000 0 100 200 300 400 500 600 700 800 900 1000 Frequency (Hz) Frequency (Hz) HexTF - V50 Hex15 Hex10 Hex0
Slide 24: DeckTF - V25
Introduction Numerical Model Results Conclusions Acknowledgement NoHex Hex15 Hex10 Hex05 NoHex Hex15 Hex10 Hex05 1.6 1.4 Gain 1 Gain 1.2 1.0 Gain Gain 0.8 0.6 0.4 0.2 0.0 0.1 0 100 200 300 400 500 600 700 800 900 1000 0 100 200 300 400 500 600 700 800 900 1000 Frequency (Hz) Frequency (Hz) DeckTF –
Slide 25: DeckTF - V50
Introduction Numerical Model Results Conclusions Acknowledgement NoHex Hex15 Hex10 Hex05 NoHex Hex15 Hex10 Hex05 2.5 Gain Gain 2.0 1 1.5 Gain Gain 1.0 0.5 0.0 0.1 0 100 200 300 400 500 600 700 800 900 1000 0 100 200 300 400 500 600 700 800 900 1000 Frequency (Hz) Frequency (Hz) DeckTF - V50 NoHex He
Slide 26: The possibility of calculating a total transfer function
Introduction Numerical Model Results Conclusions Acknowledgement - The possibility of calculating a total transfer function Q flame Qhex Q TFflame TFhex deck TFdeck Qinput Qinput Qinput Qhex TFflame TFhex Q flame Qhex TFtotal TFflame TFhex Q flame Hex Transfer Function Total Flame Deck - C
Slide 27: The possibility of calculating a total transfer function
Introduction Numerical Model Results Conclusions Acknowledgement - The possibility of calculating a total transfer function Hex Total Flame Deck 31
Slide 28: Experimental setup
Introduction Numerical Model Results Conclusions Acknowledgement - Experimental setup 32
Slide 29: Conclusions
Introduction Numerical Model Results Conclusions Acknowledgement - The model accurately predicts combustion properties - Absolute heat release changes with approaching hex, but normalized values and flame transfer function don’t - Impingement causes intense flame cooling, counter phase behavior, and
Slide 30: Acknowledgement
Introduction Numerical Model Results Conclusions Acknowledgement The presented work is part of the Marie Curie Initial Training Network Thermo-acoustic and Aero-acoustic Nonlinearities in Green Combustors with Orifice Structures (TANGO). We gratefully acknowledge the financial support from the Europ