共查询到17条相似文献,搜索用时 187 毫秒
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柴油机缸内燃烧温度场分布对柴油机的性能有着重要的影响,因此柴油机缸内燃烧温度场的测量对于分析优化柴油机性能有着重要的作用。本文简单介绍了三基色光学测温原理,通过高速图像摄影仪获得ZS195柴油机缸内燃烧火焰图片,对火焰图片进行处理分析,得到了ZS195柴油机缸内燃烧温度场的分布,为柴油机燃烧过程分析提供了有价值的信息。 相似文献
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柴油机缸内燃烧温度场分布对柴油机的性能有着重要的影响,因此柴油机缸内燃烧温度场的测量对于分析优化柴油机性能有着重要的作用。本文简单介绍了三基色光学测温原理,通过高速图像摄影仪获得ZS195柴油机缸内燃烧火焰图片,对火焰图片进行处理分析,得到了ZS195柴油机缸内燃烧温度场的分布,为柴油机燃烧过程分析提供了有价值的信息。 相似文献
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针对汽油发动机冷起动存在的燃烧不稳定、燃烧效率低的问题,基于单缸可视化发动机在冷起动工况下调节进气涡流,通过分析缸内燃烧火焰特性来探究增强进气涡流对发动机循环波动及输出功率的影响。试验所用发动机为单缸四气门(两进两出)缸内直喷汽油机,其中一个进气道加装有涡流控制阀,通过将一个进气道关闭或者开启来改变缸内涡流的强度。利用高速相机从活塞上的光学通道得到发动机缸内的火焰传播图像,并计算火焰传播面积,提取火焰边界,获取火焰中心速度及火焰扩散速度等信息,同时也利用燃烧分析仪对缸内压力、燃烧放热率等特性进行同步测量和记录,通过多角度的对比和分析揭示缸内燃烧状况与发动机宏观性能的相关联系,有效地发掘了在不同涡流强度下缸内火焰的传播特征。研究结果从缸内燃烧火焰的角度解释了提高涡流比能够很好地提高冷起动的燃烧稳定性,促进发动机缸内燃烧。研究表明,早期火核分布越集中,波动越小,后期循环波动就越小。试验结果还表明,由缸压计算的瞬时放热率与火焰面积存在很好的线性关系。 相似文献
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针对某GDI发动机的喷雾、燃烧过程进行了CFD模拟,并对缸内滚流、涡流形成、壁面油膜生成、以及点火、火焰传播等情况进行了评估,系统地展示了缸内燃烧模拟技术在发动机正向设计中的应用。 相似文献
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均质压燃发动机燃烧与排放的多区模型模拟 总被引:3,自引:0,他引:3
应用一个有质量交换的6区模型模拟正庚烷在HCCI发动机中的燃烧和排放特性.通过把缸内划分为缝隙区、边界层区、外核心区和内核心区,加入Woschni传热模型计入了缸内的温度和浓度的不均匀分布.全部计算基于正庚烷燃烧的包含57种组分290个反应的详细机理,结果表明,该多区模型合理地模拟了HCCI发动机的燃烧过程,并可满意地预测出HC、CO和NO的排放.最后采用此多区模型分别讨论了缝隙容积、边界层厚度和壁面温度对HCCI发动机的燃烧和排放的影响. 相似文献
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柴油机双燃料复合燃烧的最佳运行范围研究 总被引:4,自引:0,他引:4
通过在进气过程中加入容易汽化的燃料与空气形成一定浓度的预混合气进入燃烧室,利用压燃喷入的柴油形成着火源向整个燃烧室传播,以完成燃烧过程的部分预混双燃料燃烧模式可能是减少柴油机碳烟排放的有效措施。而在该燃烧方案中过低的预混浓度可因火焰无法传播到整个燃烧室而增加HC排放,在保持柴油机压缩比的条件下,过高的预混合气浓度可能使燃烧最高温度上升而对NOx排放不利,甚至在柴油喷入前压燃预混合气而发生爆震。燃烧模式的改变对CO排放水平的影响也可能不利;因此,确定双燃料的最佳运行范围是建立双燃料过程控制的基础,介绍了以液化气和柴油形成双燃料系统时的最佳运行范围的初步研究结果。 相似文献
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Understanding the flame structure for different combustion in industries has drawn the increasing attention around the world.Particularly,for increasing the recent interest of using the hydrogen fuelled vehicles in recent world,structural analysis of flame in combustion chamber has attracted the attention of researchers.However,the high flame temperature and strong flame emissions increase the experimental difficulties,especially,in all kinds of intrusive measurement systems for determining the flame structures and flame temperatures.Therefore,a non-intrusive laser interferometer technique based on Shack-Hartmann optical system has been proposed to measure the thermal characteristic of a flame structure.In the present study,a low-stretched diffusion flame of methanol burner has been used.Shack-Hartmann optical system is a type of wave front sensor.It is commonly used in adaptive optical systems.It consists of an array of lenses to focus the image onto a photon sensor (photo-detector) at the focal plane and measures the wave front tilt.The major objective of the present study is to develop a laser interferometer measurement technique for analyzing the flame structure and its temperature propagation by measuring the density gradient of the flame.Optical interferometer technique is a potential candidate for the non-invasive measurement.In the present paper,a novel method for the measurement of density gradient in flame by using Shack-Hartmann optical system is proposed.A collimated laser beam that has been passed through the flame is tilted due to the density gradient inside the flame.A CCD camera (CCD photo sensor) has been used to observe the wave front tilts at the focal plane. 相似文献
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The combustion chamber is an important component for the Stifling engine heated by natural gas. In the paper, we develop a combustion chamber for the Stifling engine which aims to generate 3-5 kWe electric power. The combustion chamber includes three main components: combustion module, heat exchange cavity and thermal head. Its feature is that the structure can divide "combustion" process and "heat transfer" process into two appar- ent individual steps and make them happen one by one. Since natural gas can mix with air fully before burning, the combustion process can be easily completed without the second wind. The flame can avoid contacting the thermal head of Stifling engine, and the temperature fields can be easily controlled. The designed combustion chamber is manufactured and its performance is tested by an experiment which includes two steps. The experi- mental result of the first step proves that the mixture of air and natural gas can be easily ignited and the flame burns stably. In the second step of experiment, the combustion heat flux can reach 20 kW, and the energy utiliza- tion efficiency of thermal head has exceeded 0.5. These test results show that the thermal performance of com- bustion chamber has reached the design goal, The designed combustion chamber can be applied to a real Stifling engine heated by natural gas which is to generate 3-5 kWe electric power. 相似文献
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Visualization of auto-ignition and pressure wave during knocking in a hydrogen spark-ignition engine 总被引:1,自引:0,他引:1
Visualizations of auto-ignition inside the end-gas region due to flame propagation and pressure waves that occur during knocking were carried out in a hydrogen spark-ignition engine using a high-speed camera. Our results demonstrated that auto-ignition in an end-gas region that was compressed by the propagating flame front could be visualized using the high-speed color camera. A large amount of unburned mixture caused by the auto-ignited kernel explosion generated the strong pressure waves. Strong pressure wave oscillations induced by the initial auto-ignition could be visualized using a video camera with a speed of 250 kframes/s. The auto-ignition and pressure waves caused the thermal boundary layer to breakdown near the cylinder wall and piston head, therefore combustion of the lubricant oil grease was visible inside burned gas region. This auto-ignition and pressure waves may result in damage to the cylinder wall and piston head during engine knocking. 相似文献