• Title/Summary/Keyword: mixing chamber

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Study on the statistical turbulence characteristics of cross jets in the cylinder by on-line computer system (온라인 컴퓨터 시스템에 의한 실린더내 충돌분류의 통계학적 난류특성 연구)

  • 노병준;박종호
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.12 no.4
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    • pp.876-891
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    • 1988
  • This study was carried out to investigate the mixing flow of a turbulent cross jet in a cylindrical chamber. A study on the turbulent mixing flow of a cross jet at 45.deg. with respect to each other in the free atmospheric condition was conducted before this study and has given us some fundamental experimental results. Present data have been analyzed and compared with semi-empirical equations for a round and a plane jets. Interests on this kind of cross jets (flows) have been increasing during the past several years for the purpose of the analysis of mixing flows and their applications. In this study, a turbulent cross jet of air in a cylindrical chamber has been conducted and the turbulent characteristics in the mixing region have been analyzed experimentally. The experimental data were discussed by comparing with the semi-empirical equations of Hinze and Gortler. From the experimental curve, the semi-empirical equations of mean velocities and Reynolds stresses have been derived. Three dimensional data acquisitions and the statistical treatments of turbulence characteristics were carried out by on-line computer measurement system connected with the constant temperature type 2-channel hot-wire anemometer system.

A Mixing Head Integrated, Multi-Ignition Device for Liquid Methane Engine (액체메탄엔진용 믹싱헤드 일체형 다중점화장치)

  • Lim, Byoungjik;Lee, Junseong;Lee, Keejoo;Park, Jaesung
    • Journal of the Korean Society of Propulsion Engineers
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    • v.26 no.3
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    • pp.54-65
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    • 2022
  • We are developing a compact ignition device that can provide a multi-ignition capability for an upper stage methane engine of a two staged small satellite launch vehicle. Firstly, the multi-ignition device is designed and built as an integral part of an additively manufactured mixing head. Secondly, the ignition device requires no separate high-pressure vessels to store ignition propellants as they are branched out from the main feed lines for the mixing head. We performed experiments at various levels, including igniter autonomous tests, thrust chamber ignition and combustion tests on the new compact ignition device which is integrated in the thrust chamber of one-tonf class liquid oxygen/liquid methane engine, and confirmed stable ignition performance.

DEVELOPMENT OF A METHOD FOR CONTROLLING GAS CONCENTRATION FOR USE IN C.A EXPERIMENTS

  • Yun, H.S.
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 2000.11c
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    • pp.662-669
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    • 2000
  • Based on the viscous flow characteristics of gas through capillary tube, a simple and low cost system was developed for controlling gas concentration for use in C.A experiments. The gas flow rate through capillary tube had a linear relationship with pressure, $(length)^{-1}$ and $(radius)^4$ of capillary tube, which agreed well with Hagen-Poiseuille's law. The developed system could control the gas concentration in storage chamber within ${\pm}0.3%$ deviation compared to the preset concentration. The required time for producing target gas concentration in storage chamber was exactly predicted by the model used in this study, and it required much longer time than the calculated time which divided the volume of chamber by flow rate. Therefore, for producing target gas concentration as quickly as possible, it needs to supply higher flow rate of gas during the initial stage of experiment when gas concentration in storage chamber has not reached at target value. It appeared that the developed system was very useful for C.A experiments. Because one could decide a desired flow rate by the prediction model, control flow rate freely and easily by changing pressure in the pressure-regulating chamber and the accuracy was high.

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Study on Two-Phase Flow generated by Two Jets with Height Difference (높이차가 존재하는 두 분류의 2상유동에 관한 연구)

  • 박상규;양희천;이용호
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.1
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    • pp.88-93
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    • 2000
  • In this study, the mixing process of two-phase flow generated by two jets with height difference is analyzed. The primary jet is jetted on the condition of the state mixed pulverized solid particles with air. The height difference between the main jet and the secondary jet is changed into three kinds(0, 32.5, 47.5mm). The velocity vector field, concentration field and turbulent properties of solid particles are measured by using 3-Dimensional Particles Dynamics Analyzer. As the height difference of two jets through the two nozzles increases, the solid particle recirculation zone and the dense zone in the combustion chamber become large. The solid particle concentration at the center of the combustion chamber gets dense because the particle velocity remains slow due to the existence of the solid particle recirculation zone. The particle concentration in the combustion chamber can also be influenced by the hight difference of two jets.

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A Cold Flow Experiment for the Incinerator Shape Design (소각로의 형상설계를 위한 냉간유동실험)

  • 류창국;김숭기;최상민
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.8
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    • pp.2184-2193
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    • 1994
  • A flow visualization experiment using water-table models was performed. The water-table models simulated the two-dimensional cold flow fields inside the combustion chambers of incinerators. The flow were visualized by small but neutrally bouyant particles photographed by an overhead camera. The experimentally simulated flow fields apparently showed distinct features of two combustion chamber shapes; counter and parallel flow types. The significance of the secondary air injection on the mixing of combustion gases were clearly observed. The effects of the recirculation zones, which were present in the secondary chamber, were discussed by considering the importance of them for optimal combustion.

A CFD Study on Thermo-Acoustic Instability of Methane/Air Flames in Gas Turbine Combustor

  • Sohn, Chae-Hoon;Cho, Han-Chang
    • Journal of Mechanical Science and Technology
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    • v.19 no.9
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    • pp.1811-1820
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    • 2005
  • Thermo-acoustic instability of methane/ air flames in an industrial gas-turbine combustor is numerically investigated adopting CFD analysis. The combustor has 37 EV burners through which methane and air are mixed and then injected into the chamber. First, steady fuel! air mixing and flow characteristics established by the burner are investigated by numerical analysis with single burner. And then, based on information on the flow data, the burners are modeled numerically via equivalent swirlers, which facilitates the numerical analysis with the whole combustion system including the chamber and numerous burners. Finally, reactive flow fields within the chamber are investigated numerically by unsteady analysis and thereby, spontaneous instability is simulated. Based on the numerical results, scaling analysis is conducted to find out the instability mechanism in the combustor and the passive control method to suppress the instability is proposed and verified numerically.

Evaluation of turbulent SGS model for large eddy simulation of turbulent flow inside a sudden expansion cylindrical chamber (급 확대부를 갖는 실린더 챔버 내부 유동에 관한 LES 난류모델의 평가)

  • 최창용;고상철
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.3
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    • pp.423-433
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    • 2004
  • A large eddy simulation (LES) is performed for turbulent flow in a combustion device. The combustion device is simplified as a cylindrical chamber with sudden expansion. A flame holder is attached inside a cylindrical chamber in order to promote turbulent mixing and to accommodate flame stability. The turbulent sub-grid scale models are applied and validated. Emphasis is placed on the evaluation of turbulent model for the LES of complex geometry. The simulation code is constructed by using a general coordinate system based on the physical contravariant velocity components. The calculated Reynolds number is 5000 based on the bulk velocity and the diameter of inlet pipe. The predicted turbulent statistics are evaluated by comparing with the LDV measurement data. The Smagorinsky model coefficients are estimated and the utility of dynamic SGS models are confirmed in the LES of complex geometry.

Experimental study of combustion stability assesment of injector (액체로켓엔진 안정성 예측을 위한 시험적 기법 연구)

  • Lee, Kwang-Jin;Seo, Seong-Hyeon;Moon, Il-Yoon;Han, Yeoung-Min;Seol, Woo-Seok;Lee, Soo-Yong
    • 한국연소학회:학술대회논문집
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    • 2003.12a
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    • pp.145-152
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    • 2003
  • The objective of the present study is to develop methodology for the assesment of combustion stability of liquid rocket injectors. To simulate actual combustion occurring inside of a thrust chamber, a full-scale injector has been employed in the study, which burns gaseous oxygen and mixture of methane and propane. The main idea of the experiment is that the mixing mechanism is considered as a dominant factor significantly affecting combustion instability in a full-scale thrust chamber. Single & multi split triplet injectors have been used with an open-end cylindrical combustion chamber. The characteristics revealed by excited dynamic pressures in gaseous combustion show degrees of relative acoustic damping depending on operating conditions. Upon test results, the direct comparison between various types of injectors can be realized for the selection of the best design among prospective injectors.

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Combustion Characteristics of High Pressure Thrust Chamber with Single Coaxial Swirl Injector (이중와류 분사기를 적용한 고압 모델 연소기의 연소 특성 연구)

  • Seo, Seong-Hyeon;Lee, Kwang-Jin;Han, Yeoung-Min;Kim, Seung-Han;Kim, Jong-Gyu;Seol, Woo-Seok
    • 한국연소학회:학술대회논문집
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    • 2003.12a
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    • pp.131-136
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    • 2003
  • Experimental study on combustion characteristics of double swirl coaxial injectors has been conducted for the assessment of critical design parameters of injectors. A subscale thrust chamber has been fabricated with a water-cooled copper nozzle, which allows a chamber to be reused without replacing parts. Two different designs of injectors have been tested for the understanding of the effects of recess length on combustion. Clearly, the recess length drastically affects the combustion efficiency and hydraulic characteristics of the injector. Internal mixing of propellants in the injector with the recess number of two increases a combustion efficiency and reveals sound combustion although a pressure drop required for the similar amount of mass flow rates increases compared with the injector of the recess number of one.

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Optimal Design and Test of Fuel-Rich Gas Generator

  • Lee, Changjin;Kwon, Sun-Tak
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2004.03a
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    • pp.560-564
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    • 2004
  • The optimal design and combustion analysis of the gas generator for Liquid Rocket Engine (LRE) were performed. A fuel-rich gas generator in open cycle turbopump system was designed for 10ton$_{f}$ in thrust with RP-1/Lox propellant. The optimal design was done for maximizing specific impulse of main combustion chamber with constraints of combustion temperature and power matching required by turbopump system. Design variables were selected as total mass flow rate to gas generator, O/F ratio in gas generator, turbine injection angle, partial admission ratio, and turbine rotational speed. Results of optimal design show the dimension of length, diameter, and contraction ratio of gas generator. Also, the combustion test was conducted to evaluate the performance of injector and combustion chamber. And the effect of the turbulence ring was investigated on the mixing enhancement in the chamber.r.

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