VISUALIZATION AND MEASUREMENTS OF TURBULENT FLAME PROPAGATION IN A CONSTANT VOLUME CHAMBER

恒容室中湍流火焰传播的可视化和测量

基本信息

批准号：
08650236
负责人：
OHYAGI Shigeharu
金额：
$ 1.47万
依托单位：
SAITAMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

In the spark-ignition engines, mixtures introduced in the combustion chamber are ignited and a flame propagates to convert the mixtures to a burned gas. For improving the thermal efficiency of the engines, time consumed by this process should be reduced. This research aims at the understanding of the mechanism of turbulent flame propagation in a constant volume chamber. The research consists of two types of experiments, one is for the flame propagation in a swirling flow and the other is for that in a nearly homogeneous isotropic turbulence. In the former experiment, a premixed gas is introduced in the chamber tangentially along its side wall. The strength of this swirling flow decays with time. The mixture is ignited at an appropriate time after the mixture starts to be introduced. When this time is short, so that the strength of the swirl is strong, a burning time is very short while the time is long, the burning time becomes long. It is concluded that the burning time is well correlated to the swirling velocity of the unburned gas flow. On the other hand, in the second experiment, the mixture is introduced radially from eight ports on the side wall. So, thereis no main flow such as a swirl. Turbulence intensity of the mixture was measured by a hot wire anemonater and it decays with a time after the mixture is introduced. Varyng the time of ignition, the burning time was measured for different turbulent intensities. It is elucidated that the burning time is a particuler function of the turbulence inetnsity.

在火花点燃引擎中，燃烧室中引入的混合物被点燃，火焰繁殖以将混合物转化为燃烧的气体。为了提高发动机的热效率，应减少此过程所消耗的时间。这项研究旨在理解恒定体积室内湍流火焰传播的机制。该研究由两种类型的实验组成，一种是用于旋转流中的火焰传播，另一种是在几乎均匀的各向同性湍流中。在以前的实验中，沿其侧壁切向腔室中引入了预混合的气体。这种旋转流的强度随着时间的流逝而衰减。在引入混合物后，在适当的时间点燃混合物。当这段时间很短，以使漩涡的强度很强，时间很长，燃烧时间很短，燃烧时间就会很长。结论是，燃烧时间与未燃烧的气流的旋转速度息息相关。另一方面，在第二个实验中，混合物是从侧壁上的八个端口径向引入的。因此，没有主要流动，例如漩涡。混合物的湍流强度是通过热线的Anemonater测量的，并在引入混合物后的一段时间内腐烂。不同的点火时间，用于不同湍流强度的燃烧时间。阐明燃烧时间是湍流Inetnsity的颗粒功能。