맥동류의 연소소음 연구
Study on Combustion Noise of Unsteady Flow
양영준
․도승주*
Yang Young Joon and Do Seung Ju
Key Words :Unsteady Combustion(비정상연소), Forced Pulsating Mixture Supply(강제맥동류),
Premixed Combustion(예혼합연소), Combustion Oscillation(연소진동)
ABSTRACT
The usefulness of unsteady combustion was experimentally investigated using confined premixed flames stabilized by a rearward-facing step. For this purpose, apparatus of forced pulsating mixture supply, which could be modulated its amplitude and frequency, was designed. The unsteady combustion used in this experiment plays an important role in controlling self-excited combustion oscillations and furthermore it exhibits desirable performance, from a practical point of view, such as high load combustion and reduction of pollutant emission like nitric oxide. 1. 서 론 . , . . . , , (self-excited combustion oscillation) . Rayleigh . E = ∮p'q'dt > 0 (1) , p' q' . τ -π/2<τ<π/2 . (passive control) (feedback) (active control) . . 2. 실험장치 및 방법 Fig. 1 . 147 L/min 한국소음진동공학회 2014년 추계학술대회 355
Air water
Exhaust duct Inlet duct
Combustion
Fluctuating unit water Fuel(C3H8)
Air rotameter Fuel
Venturi mixer (I)
Step height 28 Cooling Cooling Spark plug unit : mm 55 50 193 280 25 40 rotameter chamber AAir rotameter
Venturi mixer (II) Fuel(C3H8) (22) Air water Exhaust duct Inlet duct Combustion
Fluctuating unit water Fuel(C3H8)
Air rotameter Fuel
Venturi mixer (I)
Step height 28 Cooling Cooling Spark plug unit : mm 55 50 193 280 25 40 rotameter chamber AAir rotameter
Venturi mixer (II) Fuel(C3H8)
(22)
Fig. 1 Experimental apparatus.
0 0.2 0.4 0.6 0.8 1 70 95 120 145 170 195 220 Air flowrate L/min
70 80 90 100 110 70 95 120 145 170 195 220 Air flowrate L/min ■ ● combustion oscillation no combustion oscillation 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 Ld [mm] 450 600 900 ■ ▲ ●
(a) Pressure fluctuation (b) Sound pressure level
Fig. 2 Variations of pressure fluctuation and sound pressure level with respect to air flow rate (Ld=600mm).
Fig. 3 Variations of rms of pressure fluctuations with respect to equivalence ratio.
. Ⅰ Ⅱ 2 . Ⅰ , , 1 2 . 1 , 2 (Hitachi, 0.2 OP-5T) 1 . . . 0.5 MPa, 50 mm, 18 mm 1 . , , 3 . 3. 실험결과 및 고찰 Fig. 2 . . (φ=1.0) . , . Fig. 3 rms . (stoichiometric ratio) 450 mm 0.9 , 600 mm 0.8 , 900 mm 0.75 . 356
. (1) ( ) . ( ) . 4. 결 론 . . . 참 고 문 헌
(1) T. Bai, X. C. Cheng, B. R. Daniel, J. I. Jagoda and B. T. Zinn, "Performance of a Gas Burning Rijke Pulse Combustor with Tangential Reactants Injection," Combust. Sci. and Tech. 94, 1993, pp. 1-10.
(2) Y. Neumeier, B. T. Zinn and J. I. Jagoda, "Frequency Domain Analysis of the Performance of a Valved Helmholtz Pulse Combustor," Combust. Sci. and Tech. 94, 1993, pp. 295-316.
(3) J. E. Dec and J. O. Keller, "Pulse
Combustor Tail-Pipe Heat-Transfer Dependence on Frequency, Amplitude and Mean Flow Rate," Combustion and Flame 77, 1989, pp. 357-374.
(4) J. O. Keller, P. A. Eibeck, T. T. Bramlette and P. K. Barr, "Pulse Combustion: Tailpipe Exit Jet Characteristics," Combust. Sci. and
Tech. 94, 1993, pp. 167-192.
