峰值波长法快速检测煤粉炉火焰温度的研究

基于维恩位移定律和普朗克定理,提出了根据光纤光谱仪测得的相对火焰辐射光谱快速确定煤粉炉火焰温度的峰值波长法,研究了煤粉炉火焰中辐射率函数对该方法测量温度的影响,并以300 MW和350 MW煤粉炉火焰辐射光谱为基础,给出了适用于电站煤粉炉火焰温度光谱法测量的峰值波长温度测量公式.结果表明:对于煤粉炉火焰这类非灰体温度火焰,利用峰值波长法可以快速得到火焰温度,且最大测量误差小于1.60%.     

KIVA程序在固体火箭发动机内流场数值模拟中的应用

本文以ＫＩＶＡ程序为研究起点，结合固体火箭发动机燃烧室内流场的特点，新增了边界种类和推进剂燃烧反应模型，用非正交的计算网格实现了对推进剂燃面的动态跟踪，采用ＡＬＥ法求解气相流场。算例为三维短管型装药的燃烧室内轴对称可压流场。数值模拟的结果揭示了燃烧室内瞬态流动的细节，为固体火箭发动机的跨音速内流场仿真提供了一个直接求解的新思路     

发射率结合辐射光强实时测量高温辐射源2维温度场

提出了一种由光纤光谱仪与黑白CCD相机构成的新型实时在线高温温度场测量系统.该系统用光纤光谱仪和黑白CCD相机同时测得高温辐射源的真实发射率和光强场,然后根据发射率和光强场计算得到高温辐射源的温度场.利用该系统对高温发光物体——卤素灯灯丝的温度场进行测量,得到了不同电压值下卤素灯灯丝的温度场分布图,并将所得温度场的最高温度与相应工况下发射光谱法测量得到的最高温度进行比较.结果表明:两者相对偏差在5%以内;所提出的测量方法既弥补了发射光谱法不能获得场分布的缺陷,又避免了比色法测温中单色波长带宽和发射率瞬时变化带来的误差,是一种有效的温度场测量方法.     

弹用发动机技术特点及应用前景展望

以燃气轮机的结构类型作为论题切入点,介绍了涡轮喷气发动机、涡轮风扇发动机、冲压发动机及超燃冲压发动机等几类常见的航空发动机（空气喷气发动机）,以及固体火箭发动机与液体火箭发动机等几类常见的火箭发动机的技术特点,重点对几类相关发动机在导弹领域的应用进行了研究,并对其前景进行了展望。     

基于热电偶扫描的炭烟火焰温度场测量

提出了一种热电偶扫描快速测量炭烟火焰温度场的方法,并对McKenna燃烧器形成的乙烯/空气平面炭烟火焰温度场进行测量.结果表明:在1450～1700 K火焰温度时,由炭烟沉积导致热电偶热辐射损失的修正温度偏差为200～240 K,修正后的火焰温度测量值与其他测温方法结果吻合良好,证实了该方法可以快速测量炭烟火焰温度场;...     

基于火焰图像分析的1000 MW电站锅炉炉膛温度及发射率同时测量研究

文中提出了一种基于线性发射率模型的电站锅炉煤粉火焰温度及发射率检测技术,并利用自主设计的便携式炉膛温度检测系统测量了1 000 MW超超临界锅炉炉膛上、中、下三层(37 m、27 m、23 m)燃烧器区域的火焰温度及发射率(535 nm),测量结果与基于灰性假设的温度和发射率测量结果进行了比较。测量结果表明:锅炉在710 MW负荷下煤粉火焰的温度范围为1 799～1 992 K,发射率范围为0.32～0.66;煤粉燃烧火焰在可见光波段内并非灰性,光谱发射率随波长的增大而减小,因此,测温过程中不宜采用灰性发射率假设。现场实验结果表明:燃烧器对冲布置煤粉炉前后墙两侧燃烧器出口附近的火焰温度与发射率高于远离燃烧器出口的炉膛中间区域,前墙燃烧器出口附近的平均发射率随高度增加而增加;燃烧区最高平均温度、最高温度、最高平均发射率和最高发射率均出现在上层前墙燃烧器出口附近,分别为1 951 K、1 992 K、0.56和0.66。     

数据挖掘在液体火箭发动机故障检测中的应用北大核心CSCD

液体火箭发动机作为航天领域中广泛应用的动力系统，其工作环境恶劣且复杂，成为当前航天机械故障的多发地。液体火箭发动机在执行任务时发生故障具有巨大的破坏性，保障其工作可靠性是航天器系统可靠性工程的重要任务。液体火箭发动机故障是指发动机在工作状态中出现非正常现象或与原始工况不相符的新工况。液体火箭发动机故障检测是指通过传感器等测量仪器，获取能够反映当前工况的测量数据，通过数据处理后的结果分析液体火箭发动机工作状态的可靠性。受高温、高压等恶劣工作环境的影响，     

激光诱导磷光测温技术在缸内温度测量中的应用

将激光诱导磷光测温技术应用到发动机缸内气体的二维温度测量中.其原理是利用Dy:YAG磷光剂受355 nm波长的激光激发后辐射的458 nm和494 nm磷光强度比进行温度测量,实验在一台侧向换气的光学发动机上进行,测试了该发动机压缩行程的二维温度分布,与由缸压计算的缸内平均温度比较,误差均小于5%.     

火花点火发动机末端混合气自燃化学的实验研究

本文介绍碳氢燃料的自燃化学过程的实验研究结果。试验研究是在一台倒拖发动机上进行的。实验中研究了进气温度、燃料辛烷值、发动机转速和压缩比对燃料氧化和自燃的影响。对实验中的燃料自燃变化规律以及自燃从无到有的连续循环间的放热过程进行了总结，并对实验中的一些特殊现象进行了可能的解释，指出焰前反应中间产物的某些特性及其对焰前反应的重要影响。     

激光脉冲热导仪测试半球向全发射率的探讨

测试半球向全发射率的方法很多。我们对激光脉冲热导仪稍作改进,用来测试样品背面的温度曲线和半球向全发射率ε_H(从室温到高温)。 卡计法通过测量样品加热后的冷却曲线,由下式可计算得到ε_H:     

Regenerative Cooling for Liquid Rocket Engines

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Flame plasma and the microwave determination of solid propellant regression rates

The microwave determination of detonation wave velocities in explosives and regression rates of solid rocket propellants was initially based on the firm belief of the original workers that the incident microwave in an explosive or propellant strand is totally reflected by the highly conductive flame plasma. Subsequent investigations have shown that the microwave conductivity of flame plasmas is of no consequence in microwave reflection from the strand-flame interface, the flame behaving actually as a medium of refractive index close to unity. This paper reviews the development of ideas in this field and adds new experimental evidence that rocket solid propellant flames are nonreflecting plasmas for frequencies in the microwave region. Microwave measurements are a powerful tool in solid rocket propellant studies and yield a complete regression rate versus pressure curve in a single experiment, thus substituting for many Crawford bomb tests, in fact in improved conditions of combustion, and it appears to be important to absolve the method of criticism relative to flame plasma reflection, of which no experimental evidence was ever produced, and which actually only was a working hypothesis of the inventors of the method.     

Internal Flow Simulation of High-Performance Solid Rockets using a k-ω Turbulence Model

For technological reasons many high-performance solid rocket motors are made from segmented propellant grains with non-uniform port geometry. In this paper parametric studies have been carried out to examine the geometric dependence of transient flow features in solid rockets with non-uniform ports. Numerical computations have been carried out in an inert simulator of solid propellant rocket motor with the aid of a standard k-ω turbulence model. It was seen that the damping of the temperature fluctuation is faster in solid rocket with convergent port than with divergent port geometry. We inferred that the damping of the flow fluctuations using the port geometry is a meaningful objective for the suppression and control of the instability and/or pressure/thrust oscillations during the starting transient of solid rockets.     

Review of engineering solutions applicable in tests of liquid rocket engines and propulsion systems employing hydrogen as a fuel and relevant safety assurance aspects

The review presents the author's papers on specific features of experimental development of oxygen-hydrogen liquid rocket engines (LRE), namely the 11D56, 11D57, RD0120, KVD1, and a number of propulsion units and power plants, as well as compares some data on propulsion development activities with relevant data obtained abroad. Also has been shown a role of model studies, component-level tests of engine units and systems, including those performed at simulated flight conditions, and integrated tests in support of experimental development of advanced engines and propulsion systems designed for rocket upper stages. There have been considered techniques and equipment intended to ensure safety of ground testing of rocket engines and power plants involving the use of effective diagnostic systems and emergency protection systems.     

A Tool for Predicting the Thermal Performance of a Diesel Engine

This paper presents a thermal network model for the simulation of the transient response of diesel engines. The model was adjusted by using experimental data from a completely instrumented engine run under steady-state and transient conditions. Comparisons between measured and predicted material temperatures over a wide range of engine running conditions show a mean error of 7°C. The model was then used to predict the thermal behavior of a different engine. Model results were checked against oil and coolant temperatures measured during engine warm-up at constant speed and load, and on a New European Driving Cycle. Results show that the model predicts these temperatures with a maximum error of 3°C.     

发动机氧涡轮喷嘴叶栅气动特性的试验研究

对一个用于大推力液体火箭发动机氧涡轮泵的复速级涡轮的喷嘴叶栅进行了试验研究，以考察喷嘴叶栅的气动特性，验证喷嘴叶栅的气体设计。该复速级喷嘴叶栅采用先进的后加载流动控制技术，以减弱叶机的二次流损失，对喷嘴叶栅进行了四个进气口流角，三个出口等熵马赫数条件下的平面叶栅吹风试验，测取了型面压力分布，出口气流角以及叶栅损失等重要气动特性参数，试验研究表明氧涡轮的喷嘴叶栅的设计是成功的，具有良好的气动特性，可以有效地应用于液体火箭发动机的涡轮中，本研究也为该类喷雾叶栅的设计提供了有用的实验数据和指导意义的结论。     

Genetic algorithm to optimize the design of main combustor and gas generator in liquid rocket engines

A genetic algorithm was used to develop optimal design methods for the regenerative cooled combustor and fuel-rich gas generator of a liquid rocket engine. For the combustor design, a chemical equilibrium analysis was applied, and the profile was calculated using Rao＇s method. One-dimensional heat transfer was assumed along the profile, and cooling channels were designed. For the gas-generator design, non-equilibrium properties were de- rived from a counterflow analysis, and a vaporization model for the fuel droplet was adopted to calculate resi- dence time. Finally, a genetic algorithm was adopted to optimize the designs. The combustor and gas generator were optimally designed for 30-tonf, 75-tonf, and 150-tonf engines. The optimized combustors demonstrated su- perior design characteristics when compared with previous non-optimized results. Wall temperatures at the nozzle throat were optimized to satisfy the requirement of 800 K, and specific impulses were maximized. In addition, the target turbine power and a burned-gas temperature of 1000 K were obtained from the optimized gas-generator design.     

Numerical analysis of gaseous hydrogen/liquid oxygen flamelet at supercritical pressures

Supercritical conditions are typically encountered in high-pressure combustion devices such as liquid propellant rockets and gas turbine engines. Significant real fluid behaviors including steep property variations occur when the fluid mixtures pass through the thermodynamic transcritical regime. The laminar flamelet concept is a robust and reliable approach that correctly accounts for real fluid effects, the large variation in thermophysical properties, and the detailed chemical kinetics for turbulent flames at transcritical and supercritical conditions. In the present study, the flamelet equations in the mixture fraction space are extended to treat the flame field of general fluids over transcritical and supercritical states. Flamelet computations are carried out for gaseous hydrogen and cryogenic liquid oxygen flames under a wide range of thermodynamic conditions. Based on numerical results, the detailed discussions are made for the effects of real fluid, pressure, and differential diffusion on the local flame structure and the characteristics encountered in liquid propellant rocket engines.     

The effect of clove oil and diesel fuel blends on the engine performance and exhaust emissions of a compression-ignition engine

Diesel engines provide the major power source for transportation in the world and contribute to the prosperity of the worldwide economy. However, recent concerns over the environment, increasing fuel prices and the scarcity of fuel supplies have promoted considerable interest in searching for alternatives to petroleum based fuels. Based on this background, the main purpose of this investigation is to evaluate clove stem oil (CSO) as an alternative fuel for diesel engines. To this end, an experimental investigation was performed on a four-stroke, four-cylinder water-cooled direct injection diesel engine to study the performance and emissions of an engine operated using the CSO–diesel blended fuels. The effects of the CSO–diesel blended fuels on the engine brake thermal efficiency, brake specific fuel consumption (BSFC), specific energy consumption (SEC), exhaust gas temperatures and exhaust emissions were investigated. The experimental results reveal that the engine brake thermal efficiency and BSFC of the CSO–diesel blended fuels were higher than the pure diesel fuel while at the same time they exhibited a lower SEC than the latter over the entire engine load range. The variations in exhaust gas temperatures between the tested fuels were significant only at medium speed operating conditions. Furthermore, the HC emissions were lower for the CSO–diesel blended fuels than the pure diesel fuel whereas the NO_x emissions were increased remarkably when the engine was fuelled with the 50% CSO–diesel blended fuel.     

流固耦合仿真技术在发动机稳态传热计算中的应用

为解决发动机传热研究中冷却水与缸套、机体之间的流动与传热问题,将有限元软件中提供的流固耦合仿真技术应用到发动机稳态传热计算中。建立了发动机活塞组-缸套-冷却水-机体流固耦合传热模型,该模型既包括了固体与固体之间的接触传热,也包括了流体与固体之间的耦合传热。同时,零件之间的传热边界条件也变得既简单又合理。以某型号柴油机为例进行了有限元仿真计算,并与活塞和缸套的温度场测量数据进行了对比分析。结果表明：仿真结果与试验测量数据误差较小,应用流固耦合仿真方法可以较好的模拟发动机稳态传热状态。