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Aerothermal characteristics of bleed slot in hypersonic flows

Science China(Physics,Mechanics & Astronomy) 2015年第10期58卷 46-59页

作者： yue lianjie LU HongBo XU Xiao CHANG XinYu State Key Laboratory of High Temperature Gas Dynamics Institute of Mechanics Chinese Academy of Sciences

Two types of flow configurations with bleed their aerodynamic thermal loads and related in two-dimensional hypersonic flows flow structures at choked conditions. are numerically examined to investigate One is a turbulent boundary layer flow without shock impingement where the effects of the slot angle are discussed, and the other is shock wave boundary layer in- teractions where the effects of slot angle and slot location relative to shock impingement point are surveyed. A key separation is induced by bleed barrier shock on the upstream slot wall, resulting in a localized maximum heat flux at the reattachment point. For slanted slots, the dominating flow patterns are not much affected by the change in slot angle, but vary dramatically with slot location relative to the shock impingement point. Different flow structures are found in the case of normal slot, such as a flow pattern similar to typical Laval nozzle flow, the largest separation bubble which is almost independent of the shock position. Its larger detached distance results in 20% lower stagnation heat flux on the downstream slot corner, but with much wider area suffering from severe thermal loads. In spite of the complexity of the flow patterns, it is clearly revealed that the heat flux generally rises with the slot location moving downstream, and an increase in slot angle from 20° to 40° reduces 50% the heat flux peak at the reattachment point in the slot passage. The results further indicate that the bleed does not raise the heat flux around the slot for all cases except for the area around the downstream slot corner. Among all bleed configurations, the slot angle of 40° located slightly upstream of the incident shock is regarded as the best.

关键词： boundary layer control boundary layer heat flow shock wave interactions separated flows

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Flow characteristics of hypersonic inlets with different cowl-lip blunting methods

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Science China(Physics,Mechanics & Astronomy) 2014年第4期57卷 741-752页

作者： LU HongBo yue lianjie CHANG XinYu State Key Laboratory of High Temperature Gas Dynamics Institute of Mechanics Chinese Academy of Sciences

Under hypersonic flight conditions,the sharp cowl-lip leading edges have to be blunted because of the severe aerodynamic *** paper proposes four cowl-lip blunting methods and studies the corresponding flow characteristics and performances of the generic hypersonic inlets by numerical simulation under the design conditions of a flight Mach number of 6 and an altitude of 26 *** results show that the local shock interference patterns in the vicinity of the blunted cowl-lips have a substantial influence on the flow characteristics of the hypersonic inlets even though the blunting radius is very small,which contribute to a pronounced degradation of the inlet *** Equal Length blunting Manner(ELM)is the most optimal in that a nearly even reflection of the ramp shock produces an approximately straight and weak cowl reflection *** minimal total pressure loss,the lowest cowl drag,maximum mass-capture and the minimal aeroheating are achieved for the hypersonic *** the other blunting manners,the ramp shock cannot reflect evenly and produces more curved cowl reflection *** Type V shock interference pattern occurs for the Cross Section Cutting blunting Manner(CSCM)and the strongest cowl reflection shock gives rise to the largest flow loss and *** cowl-lip blunted by the other two blunting manners is subjected to the shock interference pattern that transits with an increase in the blunting ***,the peak heat flux does not fall monotonously with the blunting radius ***,the cowl-lip surface suffers from severe aerothermal load when the shear layer or the supersonic jet impinges on the wall.

关键词： hypersonic inlet cowl-lip bluntness flow characteristics shock pattern shock interference

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Parameters for evaluating the efficiency of inlet compression

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Chinese Journal of Aeronautics 2021年第12期34卷 51-56页

作者： Keting CHEN lianjie yue Xinyu ZHANG State Key Laboratory of High Temperature Gas Dynamics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering and Science University of Chinese Academy of ScienceBeijing 100049China

The efficiency parameters are studied in this paper for evaluating the compression quality of the inlets with different compression degrees and assessing different design *** is proposed for the efficiency parameters,based on two mathematically derived efficiency parameters,entropy rise coefficient and compression quality *** efficiency parameters are then examined for equal intensity shocks system to show their capabilities in characterizing the quality of compression system with different compression degrees,and representing the average compression efficiency of the entire *** the process efficiency and compression quality efficiency are compared in the Mollier diagram to afford a clear understanding of their difference in evaluating the overall and the local compression efficiency.

关键词： Airbreathing engine Compression efficiency Compression quality Inlet Self-consistency

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Theoretical analysis of effects of boundary layer bleed on scramjet thrust

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Science China(Physics,Mechanics & Astronomy) 2013年第10期56卷 1952-1961页

作者： yue lianjie XU XianKun CHANG XinYu State Key Laboratory of High Temperature Gas Dynamics Institute of MechanicsChinese Academy of Sciences

The effects of boundary layer bleed on the scramjet thrust are studied in the present paper.A theoretical model is developed to evaluate the thrust increment and influencing *** thrust increment resulting from the bleed is dominated by the rise in total pressure recovery and bleed mass flow *** bleed mass flow rate exerts stronger impact on the engine thrust than the total *** to current bleed design,it is a severe challenge for the engine to enhance its total pressure to maintain the original thrust when there is no ***,the initial total pressure recovery,fuel mass addition,combustion efficiency and area ratio of engine exit to entrance can affect the contributions of the bleeding to the thrust *** scramjet needs a higher rise in total pressure recovery to counteract the negative effect of bleed mass loss at higher initial total pressure recovery or larger area ratio of engine exit/*** heat release results in a little lower demand on the rise in total pressure recovery for maintaining the scramjet *** results will aid in understanding the fundamental mechanism of bleeding on engine thrust.

关键词： scramjet boundary layer bleed theoretical analysis engine thrust

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Numerical investigation on flow nonuniformity-induced hysteresis in scramjet isolator

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Chinese Journal of Aeronautics 2020年第12期33卷 3176-3188页

作者： Tinglong HUANG lianjie yue Shenghu MA Qifan ZHANG Peng ZHANG Xinyu CHANG State Key Laboratory of High-temperature Gas Dynamics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China Department of Mechanical Engineering the Hong Kong Polytechnic UniversityHong KongChina

Numerical simulation and theoretical analysis were conducted to study the hysteresis inside scramjet isolator during the reciprocating process of back pressure *** is revealed that only a regular reflection is theoretically possible for two leading shocks when the inflow Mach number is greater than 2.0,and no hysteresis can occur in the transition between shock reflection ***,wall suction,gas injection,and background waves cause non-uniformity of the incoming flow and would make hysteresis *** the classical hysteresis in the transition between shock reflection,new kinds of hysteresis were found in both the deflection angle of separated boundary layer and the location of the shock ***,the occurrence of hysteresis in the deflection angle of the separated boundary layer is accompanied with the shock reflection *** the case with background waves or gas injection,hysteresis in the starting position of leading shock was observed *** back pressure decreases,the leading shock does not follow the same path as that as the back pressure increases,and it is anchored at the location where the background shock or the injection interacts with the leading *** is inferred that,if two strong adverse pressure gradient regions move towards and interact with each other,hysteresis will take place when they start to separate.

关键词： Adverse pressure gradient Back pressure Hysteresis effects Non-uniform flow Shock train

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Thermochemical non-equilibrium flow characteristics of high Mach number inlet in a wide operation range

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Chinese Journal of Aeronautics 2023年第12期36卷 164-184页

作者： Chunliang DAI Bo SUN lianjie yue Shengbing ZHOU Changfei ZHUO Changsheng ZHOU Jianyi YU School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China State Key Laboratory of High Temperature Gas Dynamics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China College of Aerospace Engineering Chongqing UniversityChongqing 400044China Beijing System Design Institute of Electro-mechanic Engineering Beijing 102308China

The high-temperature non-equilibrium effect is a novel and significant issue in the flows over a high Mach number(above Mach 8)air-breathing ***,this study attempts to investigate the high-temperature non-equilibrium flows of a curved compression two-dimensional scramjet inlet at Mach 8 to 12 utilizing the two-dimensional non-equilibrium RANS ***,the thermochemical non-equilibrium gas model can predict the actual high-temperature flows,and the numerical results of the other four thermochemical gas models are only used for comparative ***,the thermochemical non-equilibrium flow fields and work performance of the inlet at Mach 8 to 12 are ***,the influences of high-temperature non-equilibrium effects on the starting characteristics of the inlet are *** results reveal that a large separation bubble caused by the cowl shock/lower wall boundary layer interaction appears upstream of the shoulder,at Mach *** separation zone size is smaller,and its location is closer to the downstream area while the thermal process changes from frozen to non-equilibrium and then to *** the increase of inflow Mach number,the thermochemical non-equilibrium effects in the whole inlet flow field gradually strengthen,so their influences on the overall work performance of the high Mach number inlet are more *** vibrational relaxation or thermal non-equilibrium effects can yield more visible influences on the inlet performance than the chemical non-equilibrium *** inlet in the thermochemical non-equilibrium flow can restart more easily than that in the thermochemical frozen *** work should provide a basis for the design and starting ability prediction of the high Mach number inlet in the wide operation range.

关键词： Non-equilibrium Scramjet inlet Starting ability Thermochemical Work performance

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Experimental study of hysteresis and catastrophe in a cavity-based scramjet combustor

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Chinese Journal of Aeronautics 2022年第10期35卷 118-133页

作者： Xu ZHANG Qifan ZHANG Zhenjie WU lianjie yue Zhanbiao GAO Weihang LUO Hao CHEN State Key Laboratory of High Temperature Gas Dynamics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China Innovation Academy for Light-duty Gas Turbine Chinese Academy of SciencesBeijing 100190China

Hystereses and catastrophes were experimentally investigated in a cavity-based scramjet *** inflow Mach number was *** Equivalence Ratio(ER)was continuously regulated with multi-steps to explore influences of historical regulation directions on combustion *** divided hysteresis loops with catastrophes were *** 1-D flow estimations,the first loop occurred with shock-free/separated scramjet mode transitions,while the second kept in the separated scramjet *** breaks through the traditional knowledge that hysteresis and catastrophe were certainly related to ramjet/scramjet mode *** first hysteresis and catastrophes were attributed to flame stabilization mode transitions between the cavity shearlayer stabilized and the jet-wake stabilized,with flow separation establishment/vanishment upstream the *** obvious variations of flame and shock/separation structures meant large wall-pressure changes in the expansive duct,and generated obvious thrust ***,transition ER and catastrophe were larger in historical ER-increasing path because combustion efficiency became obviously larger as flow separation *** of critical transition ERs meant the first *** second hysteresis and catastrophes in the jet-wake stabilized mode were attributed to flame/shock interaction mode transitions between the flame/shock weak interaction mode and intensive interaction *** transition caused slightly stronger/weaker flame interacting with slightly larger/smaller flow separation,which meant small wall-pressure changes in the expansive duct,and thus thrust catastrophe was *** occurred as the critical transition ER was slightly higher in historical ER-increasing path because of slightly lower combustion efficiency under slightly smaller separation.

关键词： Catastrophe Cavity-based scramjet Flame stabilization Flame/shock interaction Hysteresis

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Flow and Leakage Characteristics in Sealing Chamber of a Variable Geometry Hypersonic Inlet

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Transactions of Nanjing University of Aeronautics and Astronautics 2022年第6期39卷 663-671页

作者： XIA Feng SUN Bo YU Jianyi yue lianjie GAO Yu DAI Chunliang College of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094P.R.China Beijing System Design Institute of Electro-mechanic Engineering Beijing 100190P.R.China State Key Laboratory of High-Temperature Gas Dynamics Beijing 100190P.R.China

When the variable geometry hypersonic inlet is sealed with ceramic wafers,the cavity flows inside the sealing chamber can be affected by the boundary layer near the side *** study the influence of the boundary layer thickness near the side wall on the flow and leakage characteristics in sealing chamber,the numerical calculation of the cavity flow in the sealing chamber under different inflow boundary layer thicknesses is carried *** results show that three-dimensional cavity flow structures are close to being asymmetric,and the entrance pressure of the leakage path can also be affected by asymmetry;with the increase of the thickness of the boundary layer,the pressure at the cavity floor and the seal entrance ***,the existing leakage prediction model is modified according to the distribution rule of the cavity floor and the flow properties in the leakage path.

关键词： variable geometry inlet ceramic wafer seal vortex structure leakage rate asymmetry three-dimensional cavity flow

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斜爆轰波的波角和法向速度-曲率关系初探

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航空学报 2020年第11期41卷 170-180页

作者：杨理岳连捷张新宇北京理工大学宇航学院北京100081 中国科学院力学研究所高温气体动力学国家重点实验室北京100190 中国科学院大学工程科学学院北京100049

为研究斜劈诱导斜爆轰波的波阵面弯曲效应,以期为斜爆轰的不稳定性及其演化规律提供新的见解,基于加权本质无振荡(WENO)格式空间离散和附加Runge-Kutta方法时间离散的求解器,针对不同的化学反应参数(释热量、放热速率和化学反应区参考长... 详细信息

为研究斜劈诱导斜爆轰波的波阵面弯曲效应,以期为斜爆轰的不稳定性及其演化规律提供新的见解,基于加权本质无振荡(WENO)格式空间离散和附加Runge-Kutta方法时间离散的求解器,针对不同的化学反应参数(释热量、放热速率和化学反应区参考长度)条件,开展斜爆轰波的数值计算研究。结果表明斜爆轰波沿波阵面的波角变化可分为3个区域:区域Ⅰ,波角平滑减小;区域Ⅱ,波角跃升后衰减;区域Ⅲ,波角有规律振荡。波阵面法向速度-曲率关系在区域Ⅰ呈现准垂直直线变化趋势,并伴随着爆轰波强度的不断衰减;在区域Ⅲ则呈现出"D"形曲线,即由极曲线段、光滑水平变化段和拟线性变化段组成,为类胞格结构的周期性演变;区域Ⅱ可认为是以上两个区域特征的耦合。不同的化学反应参数对斜爆轰波波阵面的弯曲效应影响存在较大差别。

关键词：数值计算斜爆轰波爆轰不稳定性类胞格结构波角法向速度-曲率关系

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基于动态分区概念的高超声速燃烧大涡模拟

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力学学报 2022年第4期54卷 954-974,I0003页

作者：姚卫刘杭张政肖雅彬岳连捷中国科学院力学研究所高温气体动力学国家重点实验室北京100190 中国科学院大学工程科学学院北京100049

本文基于动态分区概念开展了亿级网格的高马赫数全尺寸超燃冲压发动机内外流耦合一体化改进延迟分离涡(IDDES)模拟研究.研究建立了包括动态分区火焰面湍流燃烧模型(DZFM)、分区自适应化学(ZDAC)和分区并行自适应建表(Z-ISAT)的完整动态... 详细信息

本文基于动态分区概念开展了亿级网格的高马赫数全尺寸超燃冲压发动机内外流耦合一体化改进延迟分离涡(IDDES)模拟研究.研究建立了包括动态分区火焰面湍流燃烧模型(DZFM)、分区自适应化学(ZDAC)和分区并行自适应建表(Z-ISAT)的完整动态分区燃烧模拟框架,并通过1.15亿网格的马赫数12 REST标准高超声速燃烧室模型初步验证了分区模拟框架的保真性.DZFM通过分区解耦的思想既准确表征了当地湍流化学交互作用关系,又有效提升了整场湍流燃烧的计算效率.Z-DAC和Z-ISAT通过在分区框架内对化学反应机理进行动态实时简化和建表查询,可进一步提升当前分区内化学反应的求解效率.基于1.25和1.4亿网格动态分区框架对比分析了马赫数10条件下中心支板(strut)和壁面撑挡型(pylon)两类构型氢气高超声速燃烧室特性.支板或撑挡结构均诱发了明显的边界层分离和头部回流区,由此两种燃烧室均出现了较长区域的喷注点前部燃烧现象.基于Borghi图的数值分析表明当前氢气高超声速燃烧室中广泛存在扩散控制为主的火焰面模式,效率提升的瓶颈在于高效增混.壁面撑挡燃烧室具有较高的穿透深度和近场混合效率,因而燃烧效率高于净推力准则80%,相应的比冲1234 s也远高于中心支板燃烧室的437 s.分区自适应化学方法在将近一半的计算域上降低了反应求解计算代价,特别是在无燃料区反应机理的简化幅度更加明显.相比与传统的有限速率PaSR模型,DZFM模型实现了高达11倍的加速比.

关键词：高超声速燃烧动态分区火焰面分区自适应化学分区并行自适应建表改进延迟分离涡模拟

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