检索结果-南通市图书馆

Back Pressure Characteristics for Turbine Channel of External-Parallel TBCC Inlet

在线全文

学校读者我要写书评

暂无评论

Transactions of Nanjing University of Aeronautics and Astronautics 2019年第5期36卷 808-816页

作者： SUN Bo XIANG Cuiling zhuo changfei Department of Aerospace Engineering Nanjing University of Science and TechnologyNanjing 210094P.R.China Shanxi North Xing'an Chemical Indutry Co. Ltd.Taiyuan 030008P.R.China.

For investigating the back pressure characteristics of turbine channel of an external-parallel turbine-based combined cycle(TBCC)inlet during the mode transition with the freestream air Mach number of 1.8,wind tunnel tests and numerical simulations are carried out.The results show that the critical back pressure of the turbine channel decreases linearly with the decrease of the open degree of splitter plate.The turbine channel has self-starting capacity when the open degree of the turbine channel is 100%.The total pressure recovery coefficient increases with the increase of back pressure when turbine channel is at supercritical and critical state.The mass capture ratio,total pressure recovery coefficient and outlet pressure ratio decrease obviously when turbine channel is at subcritical state.Results of the research would provide scheme reference and technology storage for TBCC propulsion evolution.

关键词： turbine-based combined cycle inlet turbine channel mode transition back pressure wind tunnel test

Development process of muzzle flows including a gun-launched missile

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2015年第2期28卷 385-386页

作者： zhuo changfei Feng Feng Wu Xiaosong School of Mechanical Engineering Nanjing University of Science and Technology

Numerical investigations on the launch process of a gun-launched missile from the muz- zle of a cannon to the free-flight stage have been performed in this paper. The dynamic overlapped grids approach are applied to dealing with the problems of a moving gun-launched missile. The high-resolution upwind scheme （AUSMPW ＋） and the detailed reaction kinetics model are adopted to solve the chemical non-equilibrium Euler equations for dynamic grids. The development process and flow field structure of muzzle flows including a gun-launched missile are discussed in detail. This present numerical study confirms that complicated transient phenomena exist in the shortly launching stages when the gun-launched missile moves from the muzzle of a cannon to the free- flight stage. The propellant gas flows, the initial environmental ambient air flows and the moving missile mutually couple and interact. A complete structure of flow field is formed at the launching stages, including the blast wave, base shock, reflected shock, incident shock, shear layer, primary vortex ring and triple point.

关键词： Blast flow field Chemical reaction Computational fluiddynamics Dynamic overlapped grids Gun-launched missile Muzzle flows

在线全文

学校读者我要写书评

暂无评论

内流激波边界层干扰非对称特性研究综述

气动研究与试验

气动研究与试验 2024年第3期2卷 52-59页

作者：孙波卓长飞南京理工大学江苏南京210094

当内流中(喷管和隔离段)出现激波诱导边界层分离时,可能出现非对称流动现象,即使边界条件是对称的,这一令人费解的现象几十年前便引起研究人员的注意,然而至今对其机理仍未完全揭示。本文对国内外过膨胀喷管和隔离段内非对称激波边界层... 详细信息

当内流中(喷管和隔离段)出现激波诱导边界层分离时,可能出现非对称流动现象,即使边界条件是对称的,这一令人费解的现象几十年前便引起研究人员的注意,然而至今对其机理仍未完全揭示。本文对国内外过膨胀喷管和隔离段内非对称激波边界层干扰流动的相关研究进行了综述,总结了非对称流动的典型现象、特征和模式,对近期提出的流动偏转角混合层卷吸模型进行了介绍。

关键词：激波边界层干扰非对称喷管激波串边界层分离 Coanda效应

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

在线全文

学校读者我要写书评

暂无评论

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 vehicle.Thus,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 calculations.Notably,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 analysis.Firstly,the thermochemical non-equilibrium flow fields and work performance of the inlet at Mach 8 to 12 are analyzed.Then,the influences of high-temperature non-equilibrium effects on the starting characteristics of the inlet are investigated.The results reveal that a large separation bubble caused by the cowl shock/lower wall boundary layer interaction appears upstream of the shoulder,at Mach 8.The 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 equilibrium.With 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 obvious.The vibrational relaxation or thermal non-equilibrium effects can yield more visible influences on the inlet performance than the chemical non-equilibrium reactions.The inlet in the thermochemical non-equilibrium flow can restart more easily than that in the thermochemical frozen flow.This 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

Self-ignition characteristics of the high-speed ramjet kinetic energy projectile in the launch process

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2019年第4期32卷 851-860页

作者： changfei zhuo Haotian CHEN Wenjin YAO Xiaoming WANG School of Mechanical Engineering Nanjing University of Science and Technology

To research the self-ignition characteristics of high-speed ramjet kinetic energy projectile in the launch process, the self-ignition process based on the solid fuel of polyethylene was numerically simulated by using the dynamic grid technology. The effect of different muzzle velocity on the self-ignition performance, and the effect of opening the blockage at different times on the flow field stability of the combustion chamber and the flow field characteristics after the solid fuel ramjet stabilized were analyzed. The results show that the occurrence of self-ignition is not only related to the pressure, temperature in the combustion chamber, and the muzzle velocity, but also to the content of C_2H_4 and its degree of mixing with air in the combustion chamber. After the kinetic energy projectile gets out of the muzzle and before the blockage opens, there is oscillation occurring in the combustion chamber. The higher the muzzle velocity of the kinetic energy projectile, the more prone to the occurrence of the self-ignition and the negative effects can be avoided due to the pressure oscillation in the combustion chamber. The effect of opening the blockage at different times on the flow field stability after the self-ignition occurs in a period of time is weak. After the blockage opens, the solid fuel ramjet can reach a stable working condition quickly.

关键词： Dynamic grid Kinetic energy projectile Muzzle velocity Self-ignition Solid fuel ramjet

在线全文

学校读者我要写书评

暂无评论

超声速流动中底部排气形式对减阻性能的影响

航空学报 2014年第8期35卷 2144-2155页

作者：卓长飞武晓松封锋南京理工大学机械工程学院江苏南京210094

为了研究超声速流动中底部排气减阻技术,采用AUSMPW+迎风格式、k-ω剪切应力输运(SST)湍流模型、8组分12反应化学动力学模型和二阶矩湍流燃烧模型求解三维带化学反应的Navier-Stokes方程。数值研究了超声速流动中底部排气流场,分析了底... 详细信息

为了研究超声速流动中底部排气减阻技术,采用AUSMPW+迎风格式、k-ω剪切应力输运(SST)湍流模型、8组分12反应化学动力学模型和二阶矩湍流燃烧模型求解三维带化学反应的Navier-Stokes方程。数值研究了超声速流动中底部排气流场,分析了底部排气形式对底部流场和减阻特性的影响规律和机理。计算结果表明:从减阻性能来看,随着排气参数的增大,采用边缘型排气得到的底压比呈增大趋势,而采用中心型排气得到的底压比呈先增大后减小的趋势;从流场结构来看,随着排气参数的增大,采用中心型排气的流场结构发生较大变化,前、后滞止点位置发生明显改变以至最后消失,初始回流区逐渐被后推以至消失,而采用边缘型排气的流场结构基本无重大变化,前滞止点位置始终不变,后滞止点位置后移,初始回流区始终存在。该文研究可为底排技术的工程应用提供参考。

关键词：超声速流动底部排气技术底部排气形式底压比减阻性能

在线全文

学校读者我要写书评

暂无评论

隔舱式双脉冲发动机金属膜片打开压强研究

兵器装备工程学报 2022年第2期43卷 9-13页

作者：李赛赛余陵张彤卓长飞甘语怀南京理工大学机械工程学院航空宇航系南京210094 北方华安工业集团有限公司黑龙江齐齐哈尔161006

根据双脉冲固体火箭发动机的要求,设计一种隔舱金属膜片式的级间隔离装置,装置包括预制缺陷槽的金属膜片和支撑架,利用有限元法对隔舱金属膜片进行数值模拟研究。仿真结果表明在支撑架的作用下,金属膜片的承压能力大幅提高,能够满足Ⅰ... 详细信息

根据双脉冲固体火箭发动机的要求,设计一种隔舱金属膜片式的级间隔离装置,装置包括预制缺陷槽的金属膜片和支撑架,利用有限元法对隔舱金属膜片进行数值模拟研究。仿真结果表明在支撑架的作用下,金属膜片的承压能力大幅提高,能够满足Ⅰ脉冲承压要求。在Ⅱ脉冲40 ms建压15 MPa的条件下,厚度t=2 mm、凹槽深度h=1 mm的金属膜片经过8.2 ms打开,打开压强为3.075 MPa,初始裂痕大致沿着预置缺陷槽。通过四组不同建压时间仿真发现,增长建压时间,膜片打开时间变长,打开压强增大0.4 MPa后稳定在3.4 MPa左右;随着凹槽深度的增加,打开压强近似呈线性减小。

关键词：双脉冲固体火箭发动机隔舱金属膜片数值模拟打开压强

固体火箭发动机装药设计的一种燃面推移方法研究

在线全文

学校读者我要写书评

暂无评论

固体火箭技术 2021年第3期44卷 321-330页

作者：王栋刘登航卓长飞南京理工大学机械工程学院南京210094

固体火箭发动机装药设计是固体火箭发动机设计的核心内容之一,找到一种针对复杂三维装药的通用燃面推移计算方法具有重要的工程应用价值。研究使用UG NX二次开发平台工具SNAP和Block UIStyler编写装药设计建模程序,并采用射线摇摆旋转... 详细信息

固体火箭发动机装药设计是固体火箭发动机设计的核心内容之一,找到一种针对复杂三维装药的通用燃面推移计算方法具有重要的工程应用价值。研究使用UG NX二次开发平台工具SNAP和Block UIStyler编写装药设计建模程序,并采用射线摇摆旋转相交法(IRSR)进行装药表面离散;然后,依照几何燃烧定律用C++编写与一维内弹道耦合的装药燃面推移计算程序,得到装药在整个燃烧过程中的内流场参数变化情况。该计算程序以链表为基础结构交织成网状数据结构来管理装药燃面的离散点信息,并配以相应的面积计算方法,在指定步长的迭代计算过程中,可判定识别并处理点奇异、点过密或者过稀、面交汇的情况,避免计算失真。结果表明,此基于燃面推移的设计方法可准确捕捉装药燃烧过程中的复杂拓扑结构变化,与实际情况吻合较好,适用于非槽平端单通道装药或者实心装药。

关键词： UG NX二次开发装药离散燃面推移一维内弹道

在线全文

学校读者我要写书评

暂无评论

圆盘结构下旋转爆震波的不稳定传播特性

航空学报 2018年第2期39卷 39-50页

作者：夏镇娟马虎卓长飞周长省南京理工大学机械工程学院南京210094

为研究圆盘结构下旋转爆震波的不稳定传播特性,以2H2+O2+3.76N2为反应混合物,开展该结构下的二维数值研究。详细分析了旋转爆震波不稳定传播模态的流场特征,以及爆震波参数、出口流场参数和增压比的变化。结果表明,不稳定传播模态下,旋... 详细信息

为研究圆盘结构下旋转爆震波的不稳定传播特性,以2H2+O2+3.76N2为反应混合物,开展该结构下的二维数值研究。详细分析了旋转爆震波不稳定传播模态的流场特征,以及爆震波参数、出口流场参数和增压比的变化。结果表明,不稳定传播模态下,旋转爆震波重复进行"解耦—再起爆"过程,内圆扩张曲面的发散作用,使出口附近的爆震波首先解耦,解耦区域逐渐往流场内部扩张;反射激波与前导激波的碰撞产生局部热点,促使爆震波重新起爆;爆震波的压力、温度以及传播速度皆随爆震波的解耦及再起爆过程发生变化;旋转爆震波的不稳定传播对出口速度分量及马赫数的影响很小;出口增压比受不稳定传播的影响较大,随时间呈周期性变化,变化幅值较高且不稳定。出口增压比的循环周期与爆震波"解耦—再起爆"的周期一致,稳定后两者的循环频率约为21.6kHz。

关键词：旋转爆震波数值模拟圆盘结构不稳定传播爆震参数