排序方式: 共有32条查询结果,搜索用时 15 毫秒
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相干anti-Stokes Raman散射(coherent anti-Stokes Raman scattering,CARS)技术作为一种非接触测量手段,已广泛应用于多种发动机模型燃烧室温度测量及地面试验.然而,目前的工作主要集中在稳态燃烧场温度的测量,缺乏用高分辨率的单脉冲来测量瞬变的燃烧火焰温度及组分浓度的研究.基于CARS理论,结合多参数拟合算法,开发了基于MATLAB的CARS光谱计算和拟合程序CARSCF;利用McKenna平面火焰炉在不同工况下进行了温度测量,并与DLR测量结果进行对比,结果显示开发的CARSCF具有较高的测量重复性和准确性;最后将CARS技术应用于测量超燃冲压发动机点火过程中的温度测量,获取了点火过程中的温度.结果显示,在来流Mach数为3的条件下,H2/air点火过程中温度呈现急剧上升然后缓慢下降,而CARS信号则呈现急剧上升然后急剧下降随后又缓慢上升的趋势,并且在点火过程中最高温度为1 511 K. 相似文献
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利用磁流体五波模型对低磁雷诺数下压缩管道中磁流体流动进行数值模拟。该模型由带有电磁作用强制项的Navier-Stokes方程组与电势Poisson方程组成,数值格式分别采用严格保证熵条件的熵条件格式和中心差分格式。数值模拟对不同磁作用数下的不同几何外形管道进行数值模拟研究,结果表明在磁流体压缩管道中,由于发生器模式提取... 相似文献
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激波风洞内超燃冲压发动机三面压缩进气道流场实验观测 总被引:2,自引:0,他引:2
主要进行了超燃冲压发动机三面压缩进气道的实验观测。利用来流马赫数4.5的直通式激波风洞,考察了三组具有不同压缩角度的进气道模型内部的流场情况。实验观测手段为油流法、丝线法和高速纹影,同时,辅以数值模拟以有助于流场细节分析。纹影照片展示了进气道内部以激波边界层相互作用为主要影响因素的流场复杂结构,数值模拟也显示了相近的结果。油流技术与丝线法显示了近壁面处的流动图像,照片中可见激波、分离线、再附线等分界线位置。根据实验结果,可以推测唇口激波与进气道内边界层的相互作用及其引起的壁面分离是影响进气道内流动的主要因素。同时,尝试了利用抽吸方法减弱激波与边界层相互作用诱发的壁面流动分离,并取得一定结果。 相似文献
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High order numerical simulation of the thermal load on a lobed strut injector for scramjet applications 下载免费PDF全文
In this paper, the thermal load on an actively cooled lobed strut injector for scramjet (supersonic combustion ramjet) applications is investigated numerically. This requires coupled simulations of the strut internal and external flow fields together with the heat conduction in the solid injector body. In order to achieve a fast mixing, the lobed strut is positioned at the channel axis to inject hydrogen into the core of a Mach 3 air stream. There it is exposed to the extremely high temperatures of the high speed flow. While the external air and hydrogen flows are supersonic, the strut internal hydrogen flow is mainly subsonic, in some regions at very low Mach numbers. To enable a simulation of the internal flow field which ranges from very low to very high Mach numbers (approximately Mach 2.25 at the nozzle exit), a preconditioning technique is employed. The compressible finite‐volume scheme uses a spatially fourth order multi‐dimensional limiting process discretization, which is used here for a first time to simulate a geometrically and fluid mechanically highly complex problem. It will be demonstrated that besides its high accuracy the multi‐dimensional limiting process scheme is numerically stable even in case of demanding practical applications. The coupled simulation of the lobed strut injector delivers unique insight into the flow phenomena inside and outside the strut, the heat fluxes, the temperature distribution in the solid material, the required hydrogen mass flux with respect to cooling requirements and details concerning the conditions at the exit of the injector. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Lu Tian Li-Hong Chen Qiang Chen Feng-Quan Zhong Xin-Yu Chang 《Acta Mechanica Sinica》2016,32(1):75-82
A dual-mode scramjet can operate in a wide range of flight conditions. Higher thrust can be generated by adopting suitable combustion modes. Based on the net thrust, an analysis and preliminary optimal design of a kerosene-fueled parameterized dual-mode scramjet at a crucial flight Mach number of 6 were investigated by using a modified quasi-one-dimensional method and simulated annealing strategy. Engine structure and heat release distributions, affecting the engine thrust, were chosen as analytical parameters for varied inlet conditions(isolator entrance Mach number: 1.5–3.5). Results show that different optimal heat release distributions and structural conditions can be obtained at five different inlet conditions. The highest net thrust of the parameterized dual-mode engine can be achieved by a subsonic combustion mode at an isolator entrance Mach number of 2.5. Additionally, the effects of heat release and scramjet structure on net thrust have been discussed. The present results and the developed analytical method can provide guidance for the design and optimization of high-performance dual-mode scramjets. 相似文献
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Estimation of energetic efficiency of heat supply in front of the aircraft at supersonic accelerated flight. Part 1. Mathematical models 总被引:1,自引:1,他引:0
A. F. Latypov 《Thermophysics and Aeromechanics》2008,15(4):537-548
Fuel economy at boost trajectory of the aerospace plane was estimated during energy supply to the free stream. Initial and
final flight velocities were specified. The model of a gliding flight above cold air in an infinite isobaric thermal wake
was used. The fuel consumption rates were compared at optimal trajectory. The calculations were carried out using a combined
power plant consisting of ramjet and liquid-propellant engine. An exergy model was built in the first part of the paper to
estimate the ramjet thrust and specific impulse. A quadratic dependence on aerodynamic lift was used to estimate the aerodynamic
drag of aircraft. The energy for flow heating was obtained at the expense of an equivalent reduction of the exergy of combustion
products. The dependencies were obtained for increasing the range coefficient of cruise flight for different Mach numbers.
The second part of the paper presents a mathematical model for the boost interval of the aircraft flight trajectory and the
computational results for the reduction of fuel consumption at the boost trajectory for a given value of the energy supplied
in front of the aircraft. 相似文献
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Kinetic analysis of n-decane–hydrogen blend combustion in premixed and non-premixed supersonic flows
Alexander M. Starik Leonid V. Bezgin Valery I. Kopchenov Nataliya S. Titova Sergey A. Torokhov 《Combustion Theory and Modelling》2016,20(1):99-130
Numerical analysis of ignition and combustion of an n-decane–hydrogen fuel blend in a premixed supersonic flow and in a model scramjet duct is performed using a reduced reaction mechanism built especially to describe the oxidation of blended n-C10H22–H2 fuel in air at the temperature T0 > 900–1000 K in the pressure range P0 = 0.1–13 atm. The developed kinetic mechanism involves the principal reactions responsible for chain mechanism development both for n-decane and for hydrogen oxidation. It has been shown that using blended n-C10H22–H2 fuel makes it possible to enhance the ignition and combustion both in premixed and in non-premixed supersonic fuel–air flows compared to burning pure hydrogen–air and n-decane–air mixtures. This allows high combustion completeness in the scramjet duct at the distance of ~1 m even at extremely low air temperature T0 = 1000 K and pressure P0 = 0.3 atm. This is due to the interaction of kinetics of the formation of highly reactive atoms and radicals, carriers of chain mechanism, in H2–air and n-C10H22–air mixtures. 相似文献