• Title/Summary/Keyword: 배플간극

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Simulating Combustion Tests for the Verification of Baffle Gap of Optimal Damping Characteristics in Liquid Rocket Combustors (로켓연소기에서 최적의 감쇠특성을 보이는 분사기형 배플의 간극 검증을 위한 상압모사연소시험)

  • Kim, Hong-Jip;Lee, Kwang-Jin;Choi, Hwan-Seok
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.36 no.2
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    • pp.179-185
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    • 2008
  • Simulating combustion tests have been performed to elucidate the effect of baffle gaps on the optimal damping characteristics in liquid rocket combustors where coaxial injectors are installed. Amplitude of pressure oscillation in model combustion chamber and the combustion stability margin are used to quantify the damping capacitance of baffles. Satisfactory agreement has been achieved with the results of cold acoustic tests. Present results have shown that the optimal gap for high acoustic damping capacity has also the large combustion stability margin in simulating combustion tests. Therefore, the present results can be utilized to determine the baffle length and optimal gap in full-scaled rocket combustors.

Cold Acoustic Tests for the Elucidation of the Gap of Optimal Damping Capacity of Baffled Injectors in Liquid Rocket Combustors (로켓연소기에서 분사기형 배플의 간극에 따른 감쇠특성 파악을 위한 상온음향시험)

  • Kim, Hong-Jip;Lee, Kwang-Jin;Choi, Hwan-Seok
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.35 no.8
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    • pp.720-725
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    • 2007
  • Cold acoustic tests have been performed to elucidate the effect of baffle gaps on the optimal damping characteristics in a liquid rocket combustor where coaxial injectors are installed. For several axial baffle lengths, an optimal acoustic damping capacitance has been achieved in a certain gap range. Cold acoustic tests for simulating fluid viscosity by changing the pressure in a model chamber have been done to study the main mechanism of optimal damping. Experimental data have shown that the optimal gap for high damping capacity exists mainly due to the viscosity near the gap of baffles. Therefore, axial baffle length can be reduced by using the optimal baffle gap, providing a possible solution of thermal cooling problems. Also, these optimum characteristics can be some guidelines for manufacturing and assembling injectors in full-scaled rocket combustors.

A Numerical Study on Acoustic Damping Induced by Gap between Baffled Injectors in a Model Rocket Combustor (모형 로켓 연소실에서 배플형 분사기의 간극에 의한 음향 감쇠 효과에 관한 수치적 연구)

  • Sohn, Chae-Hoon;Lee, Jung-Yun
    • Journal of the Korean Society of Propulsion Engineers
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    • v.11 no.3
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    • pp.35-42
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    • 2007
  • Acoustic damping induced by gap width between baffled injectors is investigated numerically, which are installed to suppress pressure oscillations in a model rocket combustor. The previous work reported that the baffled injectors show larger acoustic damping with the gap width between injectors. It is simulated numerically and its mechanism is examined. Damping factors are calculated as a function of gap width and it is found that the optimum gap is 0.1 mm or so. For understanding of the improved damping induced by the gap, dissipation rate of turbulent kinetic energy and vorticity are calculated as a function of the gap. Both parameters have their maximum values at the specific gap and especially, the dissipation rate has the same profile as that of damping factor. It verifies that the improved damping made by the gap is attributed to the increased acoustic-energy dissipation.

A Study on the Combustion Stability Evaluation of Double Swirl Coaxial Injector (이중 와류 동축형 분사기의 연소안정성 평가에 관한 연구)

  • ;;;Kim, Hong-Jip;Choe, Hwan-Seok;Lee, Su-Yong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.12
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    • pp.41-47
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    • 2006
  • A liquid rocket thrust chamber should have a high confidence in its combustion performance and combustion stability. Expecially, the injector of which function is spraying and mixing propellants plays an important role in getting the confidence. This study was carried out to evaluate combustion stability of a double swirl coaxial injector by using the model similarity method. Besides, in case of a baffle which was used to improve combustion stability, the length and gap effects of the baffle were investigated.

Study on the Model Similarity Method for evaluating the Combustion Stability of Coaxial Swirl Injector (동축 와류 분사기의 연소안정성 평가를 위한 모델 상사 기법 연구)

  • Lee Kwang-Jin;Seo Seong-Hyeon;Kim Hong-Jip;Ahn Kyu-Bok;Choi Hwan-Seok;Lee Soo-Yong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2006.05a
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    • pp.257-263
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    • 2006
  • Liquid rocket combustion chamber must have high confidence in combustion performance and combustion stability. Expecially, an injector playing a part in the mixing of propellants is an important parameter to determine it. The present study was carried out in the viewpoint of combustion stability to evaluate the combustion stability characteristics of Coaxial Swirl Injector, using a model similarity method. Besides, in case of baffle applied to improve combustion stability, the effectiveness getting from changing the axial length and the gap of baffle was investigated.

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