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Diagnosing ratio of electron density to collision frequency of plasma surrounding scaled model in a shock tube using low-frequency alternating magnetic field phase shift

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Chinese Physics B 2024年第5期33卷 519-530页

作者：吴明兴谢楷刘艳徐晗张宝田得阳 School of Aerospace science and technology Xidian UniversityXi'an 710071China hypervelocity aerodynamics institute China Aerodynamics Research and Development CenterMianyang 621000China

A non-contact low-frequency(LF)method of diagnosing the plasma surrounding a scaled model in a shock tube is *** method utilizes the phase shift occurring after the transmission of an LF alternating magnetic field through the plasma to directly measure the ratio of the plasma loop average electron density to collision *** equivalent circuit model is used to analyze the relationship of the phase shift of the magnetic field component of LF electromagnetic waves with the plasma electron density and collision *** applicable range of the LF method on a given plasma scale is *** upper diagnostic limit for the ratio of the electron density(unit:m^(-3))to collision frequency(unit:Hz)exceeds 1×10^(11),enabling an electron density to exceed 1×10^(20)m^(-3)and a collision frequency to be less than 1 *** this work,the feasibility of using the LF phase shift to implement the plasma diagnosis is also *** experiments on shock tube equipment are conducted by using both the electrostatic probe method and LF *** comparing the diagnostic results of the two methods,the inversion results are relatively consistent with each other,thereby preliminarily verifying the feasibility of the LF *** ratio of the electron density to the collision frequency has a relatively uniform distribution during the plasma *** LF diagnostic path is a loop around the model,which is suitable for diagnosing the plasma that surrounds the ***,the causes of diagnostic discrepancy between the two methods are *** proposed method provides a new avenue for diagnosing high-density enveloping plasma.

关键词： low-frequency alternating magnetic field phase shift shock-tube plasma diagnosis electron density collision frequency

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Design and experimental study of a practical Osculating Inward Cone Waverider Inlet

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Chinese Journal of Aeronautics 2016年第6期29卷 1582-1590页

作者： He Xuzhao Zhou Zheng Qin Si Wei Feng Le Jialing science and technology on scramjet laboratory Hypervelocity Aerodynamics Institute of CARDC

A design method based on tip to tail streamline tracing and osculating inward cone methods is discussed for designing the integrated Osculating Inward Cone Waverider Inlet（OICWI）. A practical geometrical constrained experimental model of OICWI is designed based on the validated design method. It has a total contraction ratio of 4.61 and inner contraction ratio is 2.0. Wind-tunnel tests have been conducted for the OICWI model at free stream Mach number（Ma） of 4.0, 3.5 and 3.0 respectively. The experimental results show that the OICWI has high flow capture ratio and compression abilities. It can self-start at Ma= 3.5 and 4.0 and its flow capture ratio is 0.73 at Ma= 4.0, and Angle of Attack（AOA） 0°. The research results show that the OICWI has advantages of inward cone waverider and streamline tracing inlet. Present OICWI is a novel approach for waverider inlet integration studies and it will promote the use of waverider inlet integration configuration in the studies of airbreathing hypersonic vehicles.

关键词： Inlet Integration design Inward turning cone Waverider Wind tunnel experiment

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Effects of temperature and pressure on OH laser-induced fluorescence exciting A-X (1,0) transition at high pressures

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Chinese Physics B 2020年第9期29卷 295-301页

作者： Xiaobo Tu Linsen Wang Xinhua Qi Bo Yan Jinhe Mu Shuang Chen science and technology on scramjet laboratory Hypervelocity Aerodynamics InstituteChina Aerodynamics Research and Development CenterMianyang 621000China China aerodynamics Research and Development Center Mianyang 621000China

The effects of temperature and pressure on laser-induced fluorescence(LIF)of OH are numerically studied under the excitation of A-X(1,0)transition at high pressures.A detailed theoretical analysis is carried out to reveal the physical processes of *** is shown that high pressure LIF measurements get greatly complicated by the variations of pressure-and temperature-dependent parameters,such as Boltzmann fraction,absorption lineshape broadening,central-frequency shifting,and collisional *** at high pressures require a careful choice of an excitation line,and the Q1(8)line in the A-X(1,0)band of OH is selected due to its minimum temperature dependence through the calculation of Boltzmann *** absorption spectra of OH become much broader as pressure increases,leading to a smaller overlap integral and thus smaller excitation *** central-frequency shifting cannot be omitted at high pressures,and should be taken into account when setting the excitation *** fluorescence yield is estimated based on the LASKIN ***,OH-LIF measurements were conducted on flat stoichiometric CH4/air flames at high *** both the numerical and experimental results illustrate that the pressure dependence of fluorescence yield is dominated,and the fluorescence yield is approximately inversely proportional to *** results illustrate the physical processes of OH-LIF and provide useful guidelines for high-pressure application of OH-LIF.

关键词： laser-induced fluorescence OH high pressure numerical analysis

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An Inverse Design Method for Non-uniform Flow Inlet with a Given Shock Wave

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Acta Mathematicae Applicatae Sinica 2019年第2期35卷 287-304页

作者： Wen-you QIAO An-yuan YU Yu-hui WANG Research Center of Combustion aerodynamics Southwest University of Science And Technology science and technology on scramjet laboratory of hypervelocity aerodynamics institute CARDC Airbreathing Hypersonic technology Research Center of CARDC

For the hypersonic inlet and fore-body integrated design, the non-uniform incoming flow generated by the fore-body will bring a relatively big challenge to the inward-turning inlet design. To make the inlet match the non-uniform incoming flow, this paper, based on previous studies, develops a cross-stream marching plus(CSMP) method, by which an aerodynamic surface used to generate a given shock shape can be *** method can correct such solution points as may give rise to grid distortions or flow-field abnormity and overcome the shortcoming of the insufficient stability of previous methods. Numerical simulation results of the conical supersonic flowfield show that the error obtained from the proposed CSMP method drops with the reduction of the grid dimension and the marching step, being less than 0.05% for reducing the marching step to 10%; that with this method the maximum relative error of the pressure on the profile is less than 0.23%. In the design process of the inward-turning inlets that match the fuselage fore-body, it's found that in comparison with the results of the inviscid CFD results, the aerodynamic surface designed with the CSMP method can fully generate the given shock wave shape. Thus, the CSMP method provides a new direction for the inlet/fore-body integrated design.

关键词： inverse method of characteristics gradient direction derivative inlet non-uniform incoming flow

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Numerical analysis of quantitative measurement of hydroxyl radical concentration using laser-induced fluorescence in flame

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Chinese Physics B 2016年第6期25卷 157-164页

作者：陈爽苏铁郑尧邦陈力刘亭序李仁兵杨富荣 science and technology on scramjet laboratory China Aerodynamics Research and Development Center Hypervelocity Aerodynamics Institute Mianyang 621000 China China aerodynamics Research and Development Center Mianyang 621000 China

The aim of the present work is to quantitatively measure the hydroxyl radical concentration by using LIF（laserinduced fluorescence） in *** detailed physical models of spectral absorption lineshape broadening,collisional transition and quenching at elevated pressure are *** fine energy level structure of the OH molecule is illustrated to understand the process with laser-induced fluorescence emission and others in the case without radiation,which include collisional quenching,rotational energy transfer（RET）,and vibrational energy transfer（VET）.Based on these,some numerical results are achieved by simulations in order to evaluate the fluorescence yield at elevated *** results are useful for understanding the real physical processes in OH-LIF technique and finding a way to calibrate the signal for quantitative measurement of OH concentration in a practical combustor.

关键词： laser-induced fluorescence hydroxyl radical quenching quantitative measurement

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Quantitative measurement of hydroxyl radical(OH) concentration in premixed flat flame by combining laser-induced fluorescence and direct absorption spectroscopy

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Chinese Physics B 2016年第10期25卷 89-95页

作者：陈爽苏铁李中山白菡尘闫博杨富荣 science and technology on scramjet laboratory Hypervelocity Aerodynamics Institute of China Aerodynamic Research and Development Center China aerodynamics Research and Development Center Division of Combustion Physics Lund University

An accurate and reasonable technique combining direct absorption spectroscopy and laser-induced fluorescence（LIF）methods is developed to quantitatively measure the concentrations of hydroxyl in CH;/air flat laminar flame. In our approach, particular attention is paid to the linear laser-induced fluorescence and absorption processes, and experimental details as well. Through measuring the temperature, LIF signal distribution and integrated absorption, spatially absolute OH concentrations profiles are successfully resolved. These experimental results are then compared with the numerical simulation. It is proved that the good quality of the results implies that this method is suitable for calibrating the OH-PLIF measurement in a practical combustor.

关键词： laser-induced fluorescence(LIF) direct absorption spectroscopy hydroxyl radical(OH) quantitative measurement

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Validation of a RANS transition model using a high-order weighted compact nonlinear scheme

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science China(Physics,Mechanics & Astronomy) 2013年第4期56卷 805-811页

作者： TU GuoHua DENG XiaoGang MAO MeiLiang State Key laboratory of aerodynamics China Aerodynamics Research & Development Center science and technology on scramjet laboratory Hypervelocity Aerodynamics Institute of CARDC National University of Defense technology Computational aerodynamics institute China Aerodynamics Research & Development Center

A modified transition model is given based on the shear stress transport (SST) turbulence model and an intermittency transport equation. The energy gradient term in the original model is replaced by flow strain rate to saving computational costs. The model employs local variables only, and then it can be conveniently implemented in modern computational fluid dynamics codes. The fifth-order weighted compact nonlinear scheme and the fourth-order staggered scheme are applied to discrete the governing equations for the purpose of minimizing discretization errors, so as to mitigate the confusion between numerical errors and transition model errors. The high-order package is compared with a second-order TVD method on simulating the transitional flow of a flat plate. Numerical results indicate that the high-order package give better grid convergence property than that of the second-order method. Validation of the transition model is performed for transitional flows ranging from low speed to hypersonic speed.

关键词： hypersonic boundary layer transition transition model intermittency factor high-order schemes

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Experimental Study on the Penetration of Diesel and Biodiesel Spray Liquid Emerging from an Equilateral Triangular Orifice under Evaporative Conditions

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Journal of Thermal science 2022年第5期31卷 1565-1574页

作者： YIN Bifeng YE Ze JIA Hekun YU Shenghao DENG Weixin School of Automotive and Traffic Engineering Jiangsu UniversityZhenjiang212013China science and technology on scramjet laboratory Hypervelocity Aerodynamics Institute of CARDMianyang621000China

This paper reports the results of an experimental study on the liquid phase characteristics of the biodiesel and diesel discharged from an equilateral triangular orifice and a circular orifice under different injection conditions by Mie-scattering *** results revealed that the biodiesel liquid penetration length was longer than that of diesel under the same injection *** addition,the increase of the chamber pressure was expected to enhance the interaction between air and fuel,resulting in the acceleration of the liquid phase breakup ***,with increasing chamber temperature,the liquid penetration of biodiesel was reduced less than that of *** was due to the high surface tension and viscosity of biodiesel which inhibited the chamber air entrainment and suppressed the liquid breakup ***,the higher probability of shorter diesel liquid penetration length indicated better air-fuel mixing than that of ***,the triangular orifice liquid length was shorter than that of the circular *** the stabilized liquid cone angle from the circular orifice was larger than that from the triangular orifice,indicating that using an equilateral triangular orifice has the potential to improve the air-fuel mixing process.

关键词： equilateral triangular orifice liquid penetration length biodiesel diesel

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Tomography system for measurement of gas properties in combustion flow field

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Chinese Journal of Aeronautics 2017年第5期30卷 1697-1707页

作者： Junling SONG Yanji HONG Mingyuan XIN Guangyu WANG Zhaoran LIU State Key laboratory of Laser Propulsion & Application Space Engineering University Beijing 101416 China science and technology on scramjet laboratory Hypervelocity Aerodynamics Institute CARDC Mianyang 621000 China

This paper describes a self-designed fiber-coupled tomography system and its application in combustion diagnostics. The tomographic technique, which combines tunable diode laser spectroscopy and algebraic reconstruction technique, enables the simultaneous reconstruction of temperature and gas concentration with both spatial and temporal resolutions. The system measures a maximum diameter of 35 cm in a circular area with a minimum spatial resolution of 1 mm×1 mm and temporal response of up to 1 kHz. Simulations validate the effects of the beam arrangement and discrete grid on reconstruction accuracy, and give the optimal beam arrangements. Experiments are made to demonstrate the tomography method, and systems are constructed in laboratory and on engineering test benches.

关键词： Absorption Combustion diagnostics Spectroscopy Temperature Tomographic image

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Experimental investigation on aero-heating of rudder shaft within laminar/turbulent hypersonic boundary layers

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Chinese Journal of Aeronautics 2019年第5期32卷 1215-1221页

作者： Qiang LI Liang NIE Kouli ZHANG Yu LI Suyu CHEN Guangsheng ZHU hypervelocity aerodynamics institute China Aerodynamics Research and Development Center science and technology on Space Physics laboratory China Academy of Launch Vehicle Technology

The aero-heating of the rudder shaft region of a hypersonic vehicle is very harsh, as the peak heat flux in this region can be even higher than that at the stagnation point. Therefore, studying the aero-heating of the rudder shaft is of great significance for designing the thermal protection system of the hypersonic vehicle. In the wind tunnel test of the aero-heating effect, we find that with the increase of the angle of attack of the lifting body model, the increasement of the heat flux of the rudder shaft is larger under laminar flow conditions than that under turbulent flow conditions. To understand this, we design a wind tunnel experiment to study the effect of laminar/turbulent hypersonic boundary layers on the heat flux of the rudder shaft under the same wind tunnel freestream conditions. The experiment is carried out in the ?2 m shock tunnel(FD-14 A) affiliated to the China aerodynamics Research and Development Center(CARDC). The laminar boundary layer on the model is triggered to a turbulent one by using vortex generators, which are 2 mm-high diamonds. The aero-heating of the rudder shaft(with the rudder) and the protuberance(without the rudder) are studied in both hypersonic laminar and turbulent boundary layers under the same freestream condition. The nominal Mach numbers are 10 and 12, and the unit Reynolds numbers are2.4 × 10~6 m^(-1) and 2.1 × 10~6 m-1. The angle of attack of the model is 20°, and the deflection angle of the rudder and the protuberance is 10°. The heat flux on the model surface is measured by thin film heat flux sensors, and the heat flux distribution along the center line of the lifting body model suggests that forced transition is achieved in the upstream of the rudder. The test results of the rudder shaft and the protuberance show that the heat flux of the rudder shaft is lower in the turbulent flow than that in the laminar flow, but the heat flux of the protuberance is the other way around,i.e., lower in the laminar flow than in th

关键词： Heat flux Hypersonic boundary layer Rudder Shock tunnel Transition Vortex generator

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