MEMOIRS OF SHONAN INSTITUTE OF TECHNOLOGY Vol. 42, No. 1, 2008 * Evolution of Novel Studies on Thermofluid Dynamics with Combustion Hiroyuki SATO* This paper mentions the recent development of combustion control technology and describes some results on the active combustion control system for suppressing flame instabilities. As for the combustion control technology, there are three typical elements including their coupling effects; thermoacoustic, heat release and fluid dynamics. In this research, development of the active combustion control system is carried out experimentally, which is based on a thermoacoustic control and a flame structure control. As the thermoacoustic approach, a feedback control system using a loudspeaker is developed, and furthermore a flame structure control system is also investigated using a secondary injection method. Both results of the thermoacoustic and the flame structure control show a good performance of suppressing the pressure oscillation. Key words: Active Combustion Control, Oscillatory Combustion, Noise, Pressure Oscillation 1 NOx NOx 1) 7) 2000 5 8) Fig. 1 2 * 19 11 5 Fig. 1. A schematic diagram showing the elements for combustion control. 19
42 1 Fig. 2. Schematic diagram of experimental apparatus. (Active Noise Control; ANC) 3 Fig. 3. PLIF measurement system. 3.1 125 125 600 mm 30 60 kw Fig. 2 OH PLIF (Planar Laser Induced Fluorescence) Fig. 3 OH* OH A 2 Í X 2 20
(1, 0) Q 1 (7) l 283.222 nm Double Pulse ND: YAG Spectra-Physics PIV400-10 (l 355 nm) Dye Laser; Lamda Physics Scanmate UV 567 nm SHG (l 283 nm) PLIF OH* ICCD LaVision Nanostar OH OH* ICCD nsec. 3.2 ANC H 2 H 9),10) H 2 Fig. 4 9),10) Fig. 5 y w Fig. 4. Schematics of H 2 control theory. Fig. 5. Block diagram of H 2 control system. Z 21 Z 22 w W i (i 1, 2) Fig. 5 G(s) 11) (System Identification; S. I.) G m H( f ) 12) P H( f) P xy xx ( f) ( f) (1) 21
42 1 P xy ( f ) P xx ( f ) G p ( jw) e T ( jw), T L/a (2) T L a G 0 G m G m G m ( jw) G p ( jw) G 0 ( jw) (3) Fig. 6. Schematics of H control theory. (3) G m (1) G p (2) G 0 G 0 12) G G m G( ω) n r 1 Ur jvr Ur jvr j( ω ω ) σ j( ω ω ) σ r w r s r U r V r (4) 12) (3) (4) G m (3) G m ( jw) G 0 ( jw) G( jw) (5) H 2 (6) u(t ) r r r (4) Fig. 7. Block diagram of H 2 / H control system. T T J u W1u x W2x dt ( ) 0 (6) u x W i T (u T W 1 u) (x T W 2 x) K (s) MATLAB/Simulink Fig. 5 G (s) W 1 (s) W 2 (s) w Z 22 H 2 (6) K (s) H Fig. 6 H 2 /H Fig. 7 H 2 /H W 1 (s) (10 200 Hz, 4th order Butterworth) G (s) 22
w Z 21 H w Z 22 H 2 3.3 30 mm H 2 Fig. 8 Fig. 9 Fig. 8 Fig. 9 Q f 2.5 l/min 0.95 35 db feedback 180 Hz 15 db H 2 ANC 3.4 Fig. 2 Fig. 2 Fig. 8. System identification for H 2 controller. Fig. 9. Performance of developed H 2 control system. 60 deg. jet Fig. 10 Fig. 11 H 2 /H feedback Fig. 10 Fig. 11 23
42 1 Fig. 12. Effect of SFI on p rms and NOx emissions. Fig. 10. System identification for H 2 /H controller. Fig. 11. Performance of developed H 2 /H control system. sin H H 2 80 Hz Q s 3.0 l /min 3.5 V 5V feedback D p 3Pa D p 0.19 Pa 1 19.6 db 2 25.2 db 3.5 NOx NOx NOx 45 deg. 90 deg., (Secondary Fuel Injection; SFI) Q mf Q sf Q sf /(Q mf Q sf ) NOx Fig. 12 45 deg. 90 deg. 3% 0.5 kpa NOx 20% Whitelaw 13) NOx NOx 24
Fig. 13. Effect of SAI on p rms and NOx emissions. NO NO NOx (Secondary Air Injection; SAI) Q ma Q sa Q sa /(Q ma Q sa ) NOx Fig. 13 90 deg. 45 deg. 22.2% 7dB NOx 45 deg. 15 ppm 90 deg. 12.2% 30% NOx NOx 45 deg. NOx 90 deg. 3.6 f 0.85 Q f 16 l/min Q a 180 l/min PLIF Fig. 14. Phase-locked OH* chemiluminescence images of the self-excited oscillation. Fig. 14 OH* OH* a h Fig. 15 6.25% 90 deg. OH-PLIF OH intensity mol Fig. 13 Fig. 16 22.2% 45 deg. OH-PLIF Fig. 13 25
42 1 Fig. 17. Rayleigh index of the self-excited oscillation (f 0.85). Fig. 15. OH-PLIF images for non-effective case (a 90 deg., Q sa /Q ma Q sa 6.25%). Fig. 18. Results of Rayleigh index; (left side) effective case (a 45 deg. Q sa /Q ma Q sa 22.2%), (right side) non-effective case (a 90 deg. Q sa /Q ma Q sa 12.2%). OH-PLIF 150 R.I. p T 1 Rxy (, ) p ( t) qoh ( t, x, y) dt T (7) Fig. 16. OH-PLIF images for effective case (a 45 deg., Q sa /Q ma Q sa 22.2%). Rayleigh Index (R.I.) R.I. (7) 14) 1/4 OH PLIF Rayleigh 15) t p/2 t p/2 Fig. 17 f 0.85 Q f 16 l/ min Q a 180 l/min R.I. R.I. Fig. 18 45 deg. 90 deg. 26
R.I. 90 deg. (Fig. 17) 45 deg. 4 1) S. Candel, Proc. Combust. Inst.: 29, pp. 1 28, 2002. 2) S. S. Evesque et al., Proc. R. Soc. Lond., A: 459, pp. 1709 1749, 2003. 3) A. Coker et al., AIAA-2003-1009, 2003. 4) I. Emiris et al., Combust. Sci. Tech., vol. 175, pp. 157 184, 2003. 5) W. p. Shih, et al., Proc. Combust. Inst.: 26, pp. 2771 2778, 1996. 6) A. F. Ghoniem, et al., Proc. Combust. Inst.: 30, 2004 (in press). 7) J. H. Uhm et al., Combust. Flame, vol. 139, pp. 106 125, 2004. 8) 2 vol. 46, no. 138, pp. 251 259, 2004. 9) I. Kajiwara, M. Fukuda, H. Shimojima, JSME Trans. C (in Japanese), vol. 64, no. 621, pp. 192 199, 1998. 10) H. Shimijima, Y. Matsunaga, S. Koike, I. Kajiwara, JSME Trans. C (in Japanese), vol. 65, no. 633, pp. 115 122, 1999. 11) S. Adachi System Identification for Control (in Japanese), Tokyo Denki University Press, pp. 1 14, 2002. 12) Editorial board of Modal Analysis, Handbook on Modal Analysis (in Japanese), CORONA Publishing Co., Ltd., pp. 68 132, 2000. 13) S. R. N. D, Zilwa, et al., Experiments in Fluid vol. 32, pp. 453 457, 2002. 14) J. G. Lee, et al., Proc. Combust. Inst. 28, pp. 739 746, 2000. 15) L. Rayleigh, The Theory of Sound, vol. 2, pp. 226, 1945. 27