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Experimental of combustion instability in NTO/MMH impinging combustion chambers

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Chinese Journal of Aeronautics 2020年第5期33卷 1476-1485页

作者： Anlong YANG Bin LI Yu YAN Shuaijie XUE Lixin ZHOU Science and Technology on liquid rocket engine Laboratory Xi’an Aerospace Propulsion InstituteXi’an 710100China

This paper presents an experimental study into dynamics of chamber pressure and heat release rate during self-excited spinning and standing azimuthal mode in NTO/MMH (nitrogen tetroxide/monomethylhydrazine) impinging combustion chambers.Nine cases including two combustion chamber configurations were conducted.The operating conditions of all unstable cases were located in the instability region according to Hewitt empirical correlation.The results show that chamber pressure oscillations keep pace with the corresponding OH*chemiluminescence intensity over the whole combustion region in the spinning and standing modes.It is indicated that the Rayleigh index is positive over the whole combustion area in all the unstable cases.A significant supersonic flame front structure of the first-order spinning mode was found in a cylindrical chamber,which means that a detonation wave could exist in the cylindrical chamber without a center body.The pressure and heat release rate oscillations at the pressure node are nonnegligible although their amplitudes are lower than those at the pressure antinode in the first-order standing mode with an annular chamber.Besides,the dominant frequency of pressure and heat release rate oscillations at the pressure node is twice as high as that at the pressure antinode.

关键词： Atomization Combustion stability Impinging jet injector Klystron effect liquid rocket engine

Numerical simulation of axial liquid film cooling in rocket combustor

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航空动力学报 2013年第2期28卷 459-465页

作者： YANG Wei SUN Bing ZHENG Li-ming School of Astronautics Beijing University of Aeronautics and Astronautics

Numerical simulation has been done for liquid film cooling in liquid rocket combustor.Multiple species of axial Navier-Stokes equations have been solved for liquid-film / hot-gas flow field,and k-εequations have been used for compressible turbulent flow.The results of the model agree well with the results of software FLUENT.The results show that :(1) liquid film can decrease the wall heat flux and temperature effectively,and the cold border area formed by the film covers the whole combustor and nozzle wall.(2) The turbulent viscosity is higher than the physical viscosity,and its biggest value is in the border area of the convergent area in nozzle.The effect of turbulent flow on the whole simulation field can not be ignored.(3) The mass fraction of kerosene at the film inlet is 1,but it decreases along the nozzle wall and achieves its lowest value at the outlet.However,the mass fraction of kerosene near the wall is the biggest at any axial location.

关键词： liquid rocket engine liquid film cooling heat flux numerical simulation turbulent flow

Periodic atomization characteristics of an impinging jet injector element modulated by Klystron effect

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Chinese Journal of Aeronautics 2018年第10期31卷 1973-1984页

作者： Anlong YANG Bin LI Shangrong YANG Yunfei XU Longfei LI Science and Technology on liquid rocket engine Laboratory Xi'an Aerospace Propulsion Institute

An experimental study on the Klystron effect of periodic injection modulated by pressure drop fluctuations on subsequent atomization is conducted. Time-resolved atomization backlit images and atomization Mie scatter images are captured by using the high speed camera. It is found that periodicity of forced atomization relies on pressure drop fluctuation amplitude and phase differences between atomization and pressure drop fluctuations relate to fluctuation frequencies. This feature of periodic atomization induced by Klystron effect corresponds to periodicities and high amplitudes of pressure fluctuations in unstable combustion chambers and chaos and low amplitudes of pressure fluctuations in stable combustions chambers. Drastically periodic varying of gross surface area of droplets with time was shown in Mie scatter images. The importance of periodic impinging jet atomization modulated by pressure drop fluctuations for acoustic liquid propellant combustion instabilities is illustrated.

关键词： Atomization Combustion stability Impinging jet injector Klystron effect liquid rocket engine Mie scatter

Periodic atomization characteristics of simplex swirl injector induced by klystron effect

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Chinese Journal of Aeronautics 2018年第5期31卷 1066-1074页

作者： Anlong YANG Shangrong YANG Yunfei XU Longfei LI Science and Technology on liquid rocket engine Laboratory Xi'an Aerospace Propulsion Institute

The atomization dynamic characteristics of a simplex swirl injector was investigated experimentally by using a hydrodynamic mechanical pulsator and the shadow photography technique. The frequency response characteristics of the fluid film and atomization fluctuations and their correlations with pressure fluctuations were obtained by using an in-house code of image processing. It is demonstrated that the klystron effect induced by periodic pressure fluctuations results in periodic liquid film fluctuation with large amplitudes, periodic superposition of droplets and reduction of the breakup length. It was found that the atomization of the simplex swirl injector only responds to the pressure fluctuation in frequency range approximately from 0 to 300 Hz, and it is particularly sensitive to pressure fluctuations at frequencies from 100 to 200 Hz. According to this experiment, the responsive frequency limitation is merely affected by injector configuration, rather than the supply line.

关键词： Atomization Combustion stability Klystron effect liquid rocket engine Simplex swirl injector

Dense core response to forced acoustic fields in oxygen-hydrogen rocket flames

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Propulsion and Power Research 2020年第3期9卷 197-215页

作者： Youhi Morii Scott Beinke Justin Hardi Taro Shimizu Hideto Kawashima Michael Oschwald Research and Development Directorate JAXASagamihara.252-5210Japan Institute of Fluid Science.Tohoku University Sendai980-8577Japan Institute of Space Propulsion DLRLampoldshausen74239Germany Research and Development Directorate JAXATsukuba305-0047Japan Institute of Jet Propulsion and Turbomachinery RWTH.Aachen52062Germany

Oscillatory combustion representative of thermo-acoustic instability in liquid rockets is simulated by experiment and LES calculation to investigate the flame behavior in detail.In particular,we focus on how the velocity and pressure fluctuations affect the behavior of the dense oxygen jet,or‘LOx core’.The test case investigated is a high pressure,multiinjector,oxygen-hydrogen combustor with a siren for acoustic excitation.First,the LES calculation is validated by the resonant frequencies and average flame topology.A precise frequency correction is conducted to compare experiment with LES.Then an unforced case,a pressure fluctuation case,and a velocity fluctuation case are investigated.LES can quantitatively reproduce the LOx core shortening and flattening that occurs under transverse velocity excitation as it is observed in the experiments.On the other hand,the core behavior under pressure excitation is almost equal to the unforced case,and little shortening of the core occurs.The LOx core flattening is explained by the pressure drop around an elliptical cylinder using the unsteady Bemoulli equation.Finally,it is shown that the shortening of the LOx core occurs because theflattening enhances combustion by mixing and increase of the flame surface area.

关键词： liquid rocket engine Combustion instability Computational fluid dynamics(CFD) Large eddy simulation(LES) Supercritical fluid

Improving the performance of LOX/kerosene upper stage rocket engines

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Propulsion and Power Research 2017年第3期6卷 157-176页

作者： Igor N.Nikischenko Raymond D.Wright Roman A.Marchan Firefly Europe B.V. Blaricum 1261 GAThe Netherlands Spacefleet Ltd DevizesWiltshireSN103APUnited Kingdom

Improved liquid rocket engine cycles were proposed and analyzed via comparison with existing staged combustion and gas-generator cycles.The key features of the proposed cycles are regenerative cooling of thrust chamber by oxygen and subsequent use of this oxygen for driving one or two oxygen pumps.The fuel pump(s)are driven in a conventional manner,for example,using a fuel-rich gas-generator cycle.Comparison with staged combustion cycle based on oxygen-rich pre-burner showed that one of the proposed semi-expander cycles has a specific impulse only on 0.4%lower while providing much lower oxygen temperature,more efficient tank pressurizing system and built-in roll control.This semi-expander cycle can be considered as a more reliable and cost-effective alternative of staged combustion cycle.Another semi-expander cycle can be considered as an improvement of gas-generator cycle.All proposed semi-expander cycles were developed as a derivative of thrust chamber regenerative cooling performed by oxygen.Analysis of existing oxygen/kerosene engines showed that replacing of kerosene regenerative cooling with oxygen allows a significant increase of achievable specific impulse,via optimization of mixture ratio.It is especially the case for upper stage engines.The increasing of propellants average density can be considered as an additional benefit of mixture ratio optimization.It was demonstrated that oxygen regenerative cooling of thrust chamber is a feasible and the most promising option for oxygen/kerosene engines.Combination of oxygen regenerative cooling and semi-expander cycles potentially allows creating the oxygen/kerosene propulsion systems with minimum specific impulse losses.It is important that such propulsion systems can be fully based on inherited and well-proven technical solutions.A hypothetic upper stage engine with thrust 19.6 kN was chosen as a prospective candidate for theoretical analysis of the proposed semi-expander cycles.The newly-developed software RECS was used for the comparative analysis of engine

关键词： Oxygen Kerosene liquid rocket engine Upper stage

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可重复使用液体火箭发动机关键技术研究

Aerospace China 2022年第4期23卷 24-34页

作者： LI Bin Academy of Aerospace Propulsion Technology Xi'an 710100

Based on current research,the development trend of reusable liquid rocket engines was analyzed.Key technologies and research focuses of the reusable liquid rocket engine have been analyzed and summarized,and then sugg... 详细信息

关键词： reusable liquid rocket engine development trend key technology

New Power for Boosting China's Aerospace Industry

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Aerospace China 2017年第1期18卷 15-20页

作者： TAN Yonghua Academy of Aerospace Propulsion Technology

China's new-generation launch vehicle LM-5 successfully completed its maiden launch in November 2016.Among the new technologies applied in the launch vehicle,four types of liquid rocket engines attracted extensive attention.These engines feature advanced concepts and technologies such as a staged combustion cycle and expander cycle.The engines are the results of hard effort of more than ten years,which is also an epitome of the development history of China's aerospace industry.This paper gives a brief introduction to the technological schemes,main parameters,development process and application of the four types of engines that powered the new-generation launch vehicle.Finally,proposals for new liquid propulsion technology development in the future in China are presented.

关键词： Launch vehicle liquid rocket engine LOX/kerosene LOX/LH2

Experiment of Cooling-film Flows in a Hot-fire Environment

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Experiment of Cooling-film Flows in a Hot-fire Environment