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Chinese Physics B 2022年第10期31卷 436-443页

作者：康杨李宁黄孝龙翁春生 National Key Laboratory of Transient Physics Nanjing University of Science and TechnologyNanjing 210094China

Acoustic characteristics of the detonation sound wave generated by a pulse detonation engine with an annular nozzle,including peak sound pressure, directivity, and A duration, are experimentally investigated while utilizing gasoline as fuel and oxygen-enriched air as oxidizer. Three annular nozzle geometries are evaluated by varying the ratio of inner cone diameter to detonation tube exit diameter from 0.36 to 0.68. The experimental results show that the annular nozzles have a significant effect on the acoustic characteristics of the detonation sound wave. The annular nozzles can amplify the peak sound pressure of the detonation sound wave at 90° while reducing it at 0° and 30°. The directivity angle of the detonation sound wave is changed by annular nozzles from 30° to 90°. The A duration of the detonation sound wave at 90° is also increased by the annular nozzles. These changes indicate that the annular nozzles have an important influence on the acoustic energy distribution of the detonation sound wave, which amplify the acoustic energy in a direction perpendicular to the tube axis and weaken it along the direction of the tube axis.

关键词： pulse detonation engine annular nozzle detonation sound wave acoustic characteristics

A numerical study of two-and three-dimensional detonation dynamics of pulse detonation engine by the CE/SE method

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Acta Mechanica Sinica 2005年第1期21卷 32-39页

作者： ChunshengWeng JayP.Gore SchoolofPowerengineering NanjingUniversityofScience&TechnologyNanjing210094China SchoolofPowerengineering NanjingUniversityofScience&TechnologyNanjing210094China//SchoolofMechanicalEngineenngPurdueUniversityIN47907USA

In this paper, the CE/SE method is developed to simulate the two- and three-dimensional flow-field of pulse detonation engine (PDE). The conservation equations with stiff source terms for chemical reaction are solved in two steps. The detailed analysis of computational results of a PDE with a single detonation tube and a PDE with five detonation tubes are given in this paper. Complex wave systems are observed inside and outside a PDE. For a PDE with 5 detonation tubes, there is a big bow shock produced from a number of little shocks near the open ends of tubes. A lot of vortexes interact with shocks and a large expansion wave propagates forward and backward with respect to the PDE in a semi-oval shape.

关键词： pulse detonation engine detonation shock numerical simulation CE/SE method

Acoustic characteristics of pulse detonation engine sound propagating in enclosed space

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Chinese Physics B 2020年第1期29卷 378-386页

作者：康杨李宁翁春生黄孝龙 National Key Laboratory of Transient Physics Nanjing University of Science and Technology

Acoustic characteristics of pulse detonation engine(PDE)sound propagating in enclosed space are numerically and experimentally investigated.The finite element software LS-DYNA is utilized to numerically simulate the PDE sound propagating in enclosed space.Acoustic measurement systems are established for testing the PDE sound in enclosed space,and the time-frequency characteristics of PDE sound in enclosed space are reported in detail.The experimental results show that the sound waveform of PDE sound in enclosed space are quite different from those in open space,and the reflection and superposition of PDE sound on the walls of enclosed space results in the sound pressure oscillating obviously.It is found that the peak sound pressure level(PSPL)and overall sound pressure level(OASPL)of PDE sound in enclosed space are higher than those in open space and their difference increases with the rise of propagation distance.The results of the duration of PDE sound indicate that the A duration of PDE sound in enclosed space is higher than that in open space except at measuring points located at 2-m and 5-m while the B duration is higher at each of all measuring points.Results show that the enclosed space has a great influence on the acoustic characteristic of PDE sound.This research is helpful in performing PDE experiments in enclosed laboratories to prevent the PDE sound from affecting the safety of laboratory environment,equipment,and staffs.

关键词： pulse detonation engine acoustics characteristics enclosed space

Thrust measurement method verification and analytical studies on a liquid-fueled pulse detonation engine

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Chinese Journal of Aeronautics 2014年第3期27卷 497-504页

作者： Lu Jie Zheng Longxi Wang Zhiwu Peng Changxin Chen Xinggu School of Power and Energy Northwestern Polytechnical University

In order to test the feasibility of a new thrust stand system based on impulse thrust mea- surement method, a liquid-fueled pulse detonation engine （PDE） is designed and built. Thrust per- formance of the engine is obtained by direct thrust measurement with a force transducer and indirect thrust measurement with an eddy current displacement sensor （ECDS）. These two sets of thrust data are compared with each other to verify the accuracy of the thrust performance. Then thrust data measured by the new thrust stand system are compared with the verified thrust data to test its feasibility. The results indicate that thrust data from the force transducer and ECDS system are consistent with each other within the range of measurement error. Though the thrust data from the impulse thrust measurement system is a litter lower than that from the force transducer due to the axial momentum losses of the detonation jet, the impulse thrust measurement method is valid when applied to measure the averaged thrust of PDE. Analytical models of PDE are also discussed in this paper. The analytical thrust performance is higher than the experimental data due to ignoring the losses during the deflagration to detonation transition process. Effect of equivalence ratio on the engine thrust performance is investigated by utilizing the modified analytical model. Thrust reaches maximum at the equivalence ratio of about 1.1.

关键词： Analytical model Equivalence ratio Impulse method Liquid fuel pulse detonation engine Thrust measurements

Acoustic characteristics of pulse detonation engine with ellipsoidal reflector

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Chinese Physics B 2018年第10期27卷 413-423页

作者：康杨李宁翁春生王传位 National Key Laboratory of Transient Physics Nanjing University of Science and Technology

Acoustic characteristics of a pulse detonation engine（PDE） with and without an ellipsoidal reflector are numerically and experimentally investigated. A two-dimensional（2 D） non-splitting unstructured triangular mesh Euler solver based on the space-time conservation element and solution element（CE/SE） method is employed to simulate the flow field of a PDE.The numerical results clearly demonstrate the external flow field of the PDE. The effect of an ellipsoidal reflector on the flow field characteristic near the PDE exit is investigated. The formation process of reflected shock wave and reflected jet shock are reported in detail. An acoustic measurement system is established for the PDE acoustic testing. The experimental results show that the ellipsoidal reflector changes the sound waveform and directivity of PDE sound. The reflected shock wave and reflected jet shock result in two more positive pressure peaks in the sound waveform. The ellipsoidal reflector changes the directivity of PDE sound from 20 to 0. It is found that the peak sound pressure level（PSPL） and overall sound pressure level（OASPL） each obtain an increment when the PDE is installed with a reflector. The maximum relative increase ratio of PSPL and OASPL are obtained at the focus point F2, whose values are 6.1% and 6.84% respectively. The results of the duration of the PDE sound indicate that the reflecting and focusing wave generated by the reflector result in the increment of A duration and B duration before and near focus point F2. Results show that the ellipsoidal reflector has a great influence on the acoustic characteristic of PDE sound. The research is helpful for understanding the influence of an ellipsoidal reflector on the formation and propagation process of PDE sound.

关键词： pulse detonation engine ellipsoidal reflector acoustic characteristics experiments and simulations

Computational Fluid Dynamics Analysis of Shock Propagation and Reflection in a pulse detonation engine Combustor

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Computational Fluid Dynamics Analysis of Shock Propagation a...

作者： Win Myo Nyunt 南京理工大学

学位级别：硕士

The pulse detonation engine consists of an initiation chamber and main combustion chamber. In the operation process, a deflagration is initiated in an initiation chamber filled with fuel-air mixture. Then, the deflagration rapidly transformed to detonation and finally, the detonation wave transition from the initiation chamber to the main combustion chamber. The combustor model used the same initial conditions with the pressure of 1atm and temperature of 300K. Hydrogen 2%and Air with Oxygen 22% are filled in the initiator and main combustor. In this paper, the flow fields of the PDE with a stoichiometric hydrogen-air mixture are numerically simulated. Effort is also expended to study the flow dynamics with low and high ignition energy in the initiation chamber, and the detonation wave propagation in main combustion chamber of PDE. The effects of shock wave propagation and reflection studied by fixing the dimensions of combustion chambers, initial conditions, outlet conditions and varying the pressure and temperature of ignition source of initiation chamber in single step and multi-steps reactions. At higher temperature and pressure, ignition is strong, or sharp. A single reaction center causes the abrupt appearance of a secondary shock induced by the explosive reaction. At lower temperature and pressure, the ignition is weak, or mild. The location of reaction centers where chemical reactions begin, appear behind the shock, and they gradually develop into an explosion. A high energy igniter can play an important role in rapid initiation techniques, but only as a means of initially creating a highly turbulent flame. The acceleration of that flame to detonation still consumes a considerable distance. The time of detonation depended on DDT length reduced, so that the ignition energy is very important for detonation process in the PDE combustion chamber. The multi-steps models are viewed as being more realistic than the traditional one-step models. The multi-step reaction models included initiation, br

关键词： deflagration detonation transition laminar flame turbulent flame shock wave pulse detonation engine detonation wave

The Feasibility of Applying AC Driven Low-Temperature Plasma for Multi-Cycle detonation Initiation

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Plasma Science and Technology 2016年第11期18卷 1110-1115页

作者：郑殿峰 Department of Aeronautics and Astronautics School of Engineering Peking University

Ignition is a key system in pulse detonation engines （PDE）. As advanced ignition methods, nanosecond pulse discharge low-temperature plasma ignition is used in some combustion systems, and continuous alternating current （AC） driven low-temperature plasma using dielectric barrier discharge （DBD） is used for the combustion assistant. However, continuous AC driven plasmas cannot be used for ignition in pulse detonation engines. In this paper, experimental and numerical studies of pneumatic valve PDE using an AC driven low-temperature plasma igniter were described. The pneumatic valve was jointly designed with the low-temperature plasma igniter, and the numerical simulation of the cold-state flow field in the pneumatic valve showed that a complex flow in the discharge area, along with low speed, was beneficial for successful ignition. In the experiments ethylene was used as the fuel and air as oxidizing agent, ignition by an AC driven low-temperature plasma achieved multi-cycle intermittent detonation combustion on a PDE, the working frequency of the PDE reached 15 Hz and the peak pressure of the detonation wave was approximately 2.0 MPa. The experimental verifications of the feasibility in PDE ignition expanded the application field of AC driven low-temperature plasma.

关键词： pulse detonation engine low-temperature plasma ignition detonation combustion

Acceleration of DDT by non-thermal plasma in a single-trial detonation tube

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Chinese Journal of Aeronautics 2018年第5期31卷 1012-1019页

作者： Dianfeng ZHENG Bing WANG College of engineering Peking University School of Aerospace engineering Tsinghua University

This paper compares the flame acceleration in single-trial dual-detonation tubes triggered by a spark plug and non-thermal plasma igniter. The low-temperature plasma was generated by an in-house novel AC-driven dielectric barrier discharge igniter, which reduces the power supply requirements and was applied in the quiescent ignition of a single-trial detonation tube. Three different types of detonation mixtures were tested with flame propagation tracked by ion probes and pressure waves recorded by high-frequency pressure transducers. The flame propagation speeds were calculated and compared based on signals from the ion probes. The detonation combustion succeeded in the dual tubes, but the deflagration-to-detonation transition could be significantly accelerated by the plasma for all mixtures, as it was shortened by more than 50% compared to that of the spark plug. The present study provides a suitable technological approach for igniters of PDEs.

关键词： AC driven Deflagration-to-detonation transition Dielectric barrier discharge Non-thermal plasma pulse detonation engine

Interaction Dynamics Characteristics of detonation Waves with Coolant Flow in a Hydrogen Fuelled detonation Chamber

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Transactions of Nanjing University of Aeronautics and Astronautics 2016年第6期33卷 -页

作者： Li Jianzhong Yuan Li Wang Jiahua Jiangsu Province Key Laboratory of Aerospace Power System Nanjing University of Aeronautics and Astronautics School of National Defense engineering PLA University of Science and Technology

To analyze the dynamic interaction between detonation waves and coolant flow in a hydrogen fuelled detonation chamber,a hydrogen fuelled detonation chamber with a cooled liner was designed and a simulation model was established.An explicit high-resolution total variation diminishing(TVD)scheme was developed to solve the two-dimensional Euler equations implemented with an augmented reduced mechanism of the hydrogen/air mixture.A point-implicit method was used to solve the numerical stiffness of the chemical reaction source term.The interaction between detonative was and coolant flow were presented.The interaction dynamics between detonation waves and coolant flow in a detonation chamber were investigated.The results indicated that there were some negative interaction effects between detonation waves and coolant flow.

关键词： pulse detonation engine detonation wave augmented reduced mechanism numerical simulation

Numerical simulations of cellular detonation diffraction in a stable gaseous mixture

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Propulsion and Power Research 2016年第3期5卷 177-183页

作者： Jian Li Jianguo Ning Charles B.Kiyanda Hoi Dick Ng State Key Laboratory of Explosion Science&Technology Beijing Institute of TechnologyBeijing 100081China Department of Mechanical and Industrial engineering Concordia UniversityMontréalQCH3G 1M8Canada

In this paper,the diffraction phenomenon of gaseous cellular detonations emerging from a confined tube into a sudden open space is simulated using the reactive Euler equations with a two-step Arrhenius chemistry model.Both two-dimensional and axisymmetric configurations are used for modeling cylindrical and spherical expansions,respectively.The chemical parameters are chosen for a stable gaseous explosive mixture in which the cellular detonation structure is highly regular.Adaptive mesh refinement(AMR)is used to resolve the detonation wave structure and its evolution during the transmission.The numerical results show that the critical channel width and critical diameter over the detonation cell size are about 1371 and 2571,respectively.These numerical findings are comparable with the experimental observation and confirm again that the critical channel width and critical diameter differ essentially by a factor close to 2,equal to the geometrical scaling based on front curvature theory.Unlike unstable mixtures where instabilities manifested in the detonation front structure play a significant role during the transmission,the present numerical results and the observed geometrical scaling provide again evidence that the failure of detonation diffraction in stable mixtures with a regular detonation cellular pattern is dominantly caused by the global curvature due to the wave divergence resulting in the global decoupling of the reaction zone with the expanding shock front.

关键词： detonations Diffraction pulse detonation engine Stable mixture Adaptive mesh refinement(AMR)