用稳流试验台和等折射率技术进行内燃机气缸和燃烧室中紊流运动…

本文报导了利用等折射率技术和激光多普勒测速技术在稳态流动模拟试验装置上对直喷式柴油机气缸和燃烧室内的紊流运动所进行的研究。由于在这种情况下激光束在透明材料制成的燃烧室内表面上不再受折射或反射，所以可以在复杂形状燃烧室内的任一部位进行测量，并可保持高的有效数据率。     

柴油机燃烧室内气流及紊流的研究

本文介绍用热线风速仪测量架油机燃烧室中的气流及紊流的結果。用联机计算机及统计方法完成了试验数据的采集及信息处理,测量了工作循环中气缸和燃烧室内的气流平均速度、紊流强度及紊流尺度等参数。试验结果表明,气缸内的紊流强度在进气行程中期达到最大值,在其后的压缩和膨胀行程期间,紊流强度一直在衰减;但在压缩上止点附近,由于挤流作用,燃烧室内的紊流强度达到另一峄值。本文还分析了气缸内气体压力和温度波动对瞬时气流速度的影响,并建议,在求发动机气缸内气流的紊流参数时,宜采用时间平均法。     

内燃机气缸和燃烧室中紊流运动的测量和紊流参数的计算

摘要本文介绍了用热线风速仪测量内燃机气缸及燃烧室中的紊流运动的方法和数据的采集及处理过程.对紊流参数的计算方法进行了分析比较,讨论了平均速度和紊流强度的不同求法,探讨了采样频率的时窗宽度对计算紊流参数的影响,并对全方位测量及三维测量方法进行了比较.     

应用PDA研究ω燃烧室的气缸内紊流场

介绍了应用三维粒子动态分析对两种ω燃烧室的气缸内紊流场的测量结果，给出了在进气和压缩过程气缸内相平均速度和紊流强度的分布，分析燃烧室结构和偏心，气门偏置及转速对气缸内紊流场的分布和变化规律的影响。     

汽油机射流燃烧室内挤流运动的研究

本文介绍采用二维水模拟试验方法对汽油机射流燃烧室内流体运动的特征进行的研究,并与浴盆型燃烧室进行了比较,拍摄出流体的流谱照片。这项工作有助于确切了解在射流燃烧室内挤压产生的紊流情况。试验结果表明:由于射流燃烧室具有独特的结构,在挤流和逆挤流过程中,在燃烧室和主室内形成强烈的紊流运动,这对于提高汽油机的燃烧速度,实现高压缩比、大幅度地提高热效率和抑制爆燃是极为有利的。     

直喷式柴油机气缸内各向异性紊流模拟和试验研究

本文发展了一种模拟直喷式柴油机气缸内各向异性紊流的方法。在建立雷诺应力表达式中，没有采用标准的ｋ－ε紊流模型所做的各向同性假设，从紊流的随机性质出发导出适合于各向异性紊流的雷诺应力表达式，对一个轴对称缩口形燃烧室在压缩过程中的流动情况进行了模拟和实际测量。计算与实测结果的对比表明，预测模型及方法有较好的精度。文中还对缸内紊流分布的特点进行讨论。     

直喷式柴油机缸内紊流及其对柴油机性能影响的研究

本介绍了由不同几何形状的进气扰动片和燃烧室产生的进气紊流和挤压紊流对直喷式柴油机性能影响的研究。缸内紊流测量是用热线风速仪在倒拖发动机试验台上进行的。试验表明：由进气扰动片产生的进气紊流不能保持到进气终了，因此进气扰动片对柴油机性能的影响是由于进气涡流的变化所致；由燃烧室形状增强的挤压紊流可使柴油机烟度明显改善，但对燃油经济性几乎没有影响。     

直喷式柴油机气缸内空气流动能量转换及紊流场变化规律的研究

在直喷式柴油气机气缸及燃烧室中用线热风速仪研究了紊流场的发展变化规律。结果表明：在压缩行程的初期和中期，缸内的流场可近似当做均匀各向同性紊流场；在循环的大部分时间内，缸内和燃烧室中的紊流场则是非均匀，各向异性的。通过对压缩过程中缸内空气流动能量的转换分析，导出了估算压缩终了燃烧室内涡流转速的公式，计算结果与实验结果基本相符，并指出了燃烧室内涡流和紊流强度增强的原因及影响因素。     

扰动紊流对中小型柴油机性能的影响

本文强调，在柴油机燃烧室内组织有序的空气涡流运动的基础上，再组织无序的空气扰动紊流，并使二者合理匹配，对改进燃烧室内的油气混合，加快燃烧及提高发动机性能有着重大的作用。还通过几种燃烧室的分析和试验数据对比，对这种观点进行了论证。     

EQ6100—1汽车发动机新型燃烧室紊流场的LDA测量

本介绍了作对自行开发的几个东风ＥＱ６１００－１汽车汽油发动机燃烧室其中之一的“双浴盆式”新型燃烧室流场的ＬＤＡ测量。在拖动状态下，通过二维测量分析了新型“双浴盆式”燃烧室中的速度场、紊流强度分布。结果显示：在压缩终了附近，这种新型燃烧室中的紊流场具有高的紊流强度。     

汽油机气缸中滚动气流运动对发动机性能的影响

本文通过调整导气屏气阀位置产生大范围变化的缸内气流运动形式，用传统的稳流试验台和作者最近研制的测缸内滚流运动的稳流试验台对各种气流运动形式进行稳流试验，用二维激光多普勒测速仪在反拖的发动机缸内紊流运动的发展变化并用着火发动机的性能实验结果来分析各种气流形式的涡流、滚流和紊流特性。试验结果表明，在气缸中产生较强的横轴涡流即滚动或接近滚动气流运动时，燃烧室内的紊流强度可获得较大的提高，性能也有明显的改     

Numerical simulation of hydrogen combustion process in rotary engine with laser ignition system

In this paper the combustion and ignition process in the hydrogen-fueled peripheral-ported rotary engine with single and dual laser ignition systems was studied numerically. The computational method was established for the process simulation including interaction between turbulence and chemical reactions. The detailed chemical kinetic model of hydrogen combustion was used. It was shown that the ignition and combustion process in the H₂-fueled rotary engine is highly transient with specific distortion and stretching of the combustion front in the combustion chamber due to complex motion of the rotor relative to the engine housing. The single and dual laser ignition systems were simulated to compare the ignition efficiency and the rate of hydrogen burning out. The evaluation of pressure in the combustion chamber was performed and compared with the experimental data obtained for the rotary engine fueled by natural gas. It was shown that the H₂-fueled rotary engine with the dual laser ignition system has potential application in alternative automotive industry due to high efficiency and near-zero carbon-based emission.     

柴油机涡流室内空气流动特性的LDA测试及数学模型

本报导了采用激光多普勒测速仪（ＬＤＡ）首次在实机上对柴油机涡流室内空气运动规律测试的研究结果。研究表明：涡流室内涡流在一定的半径范围内是刚体涡流，在涡流室周边区域可近似看作势涡流。     

进气道和燃烧室形状对大缸径天然气发动机缸内流动和燃烧的影响

为了提升采用当量燃烧的大缸径天然气发动机的指示热效率,提出了组织弱涡流、强滚流、高湍流强度的缸内气流运动的理念,据此设计了不同形状的进气道和燃烧室,并采用三维数值模拟的方法研究了进气道和燃烧室形状对缸内流动和燃烧的影响。研究发现:与原机相比,当将原螺旋进气道改为直进气道并配合原缩口型、新的直口型、敞口型和半球型燃烧室时,缸内涡流运动显著减弱,滚流运动明显增强,在压缩冲程中最大滚流比分别可达0.76、0.83、1.03和1.71;点火时刻缸内平均湍动能分别增加了35.27%、36.26%、50.33%和135.99%,燃烧速率逐渐加快,指示热效率逐渐增加。综上,半球型燃烧室配合直进气道更有利于缸内强滚流的形成和点火时刻湍流强度的提高,指示热效率也由原机的39.51%提高到42.14%。     

The influence of turbulence on the structure and propagation of enclosed flames

This investigation was undertaken to examine the influence of turbulence on burning velocity and on the physical structure of the flame surface under flow conditions similar to those experienced in turbojet afterburner systems. Uniform propane-air mixtures were supplied to a combustion chamber 12 in. long and of 4 in. × 4 in. cross section. Control over the turbulence level was achieved by means of grids located at entry to the chamber. Schlieren photographs were taken through transparent side walls at turbulence levels ranging from 2 to 14 per cent and at velocities up to 250 ft/sec. These photographs provided the basic data for the investigation. Turbulent flume velocities were derived as the product of the inlet velocity and the sine of the angle between the flow direction and the mean surface of the flame.

The results fully supported the wrinkled laminar flame concept of turbulent flame propagation. Turbulent flame speed was found to increase with increases in laminar flame speed, turbulent velocity and flow velocity. Under turbulent flow conditions the flame surface was characterized by a cellular structure, the average cell size diminishing with increase in approach stream velocity and turbulence. However, the main effect of turbulence was in lacerating and disrupting the flame and thereby increasing its surface area.

The results of previous investigations were confirmed in regard to the relatively slight dependence of flame spreading rate on inlet velocity, especially at high velocities. However, flame spreading rate was found to vary appreciably with turbulence and also with fuel-air ratio, a result which was consistent with the wrinkled laminar flame model, but which contradicted previous findings on enclosed flames.     

火焰筒扩张角与旋流匹配对燃烧特性的影响

为研究旋流器流量分配对干式低排放(Dry Low Emission,DLE)燃烧室燃烧特性的影响规律,针对单头部中心分级旋流燃烧室,以天然气作为燃料,在保持旋流数不变的前提下开展两级旋流器不同空气分配比例下的试验测试和数值模拟,获得不同结构参数条件下燃烧室的综合燃烧性能以及污染物排放等变化规律。研究表明：随主燃级/预燃级旋流器流量比增大,燃烧室中心回流区变小、回流区长度变短;预燃级局部当量比的增大造成燃烧室出口CO排放增加,主燃区燃烧加剧,热力型NOx排放也增加;同时,燃烧室中心高温区域向燃烧室出口方向扩张,出口温度分布均匀性变差。     

2100型柴油机燃烧系统的改进和性能试验

介绍了紊流型燃烧系统利用进气道产生的涡流和燃烧室结构产生的强挤流和微紊流的混合效应，促进油气的充分混合，提高燃烧速度。在延迟喷油定时的条件下，可降低噪声和ＭＯｘ的排放，改善烟度，从而兼顾了小型车用柴油机的经济性、动力性和排放性能，通过在２１００型柴油机上的试验研究证实了其应用效果。     

Theoretical analysis of aqueous residues incineration with oxygen enriched flames

The use of oxygen to euich the oxidizer can be an attractive alternate to increase incineration rates of a combustion chamber originally designed to operate with air. For a certain fuel flow rate, if some incineration parameters are held constant (as combustion chamber temperature, turbulence level, and residence time), an increase of incineration rates becomes possible with injection of oxygen. This work presents a theoretical evaluation of combustion air enrichment in a combustion chamber designed to incinerate aqueous residues using methane as fuel and air as oxidizer. Detailed chemistry was employed to predict pollutants formation. The overall process was investigated using the PSR routine from the CHEMKIN library.