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Research for Improving the Accuracy in Numerical Simulations of Gas Flow Behaviors in Internal Combustion Engines

提高内燃机气体流动行为数值模拟精度的研究

基本信息

批准号：
02650155
负责人：
SHIMAMOTO Yuzuru
金额：
$ 1.22万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02650155/
关键词：
Internal combustion engine One-dimensional gas flow analysis with high accuracy Intake and exhaust systems Three-dimensional gas flow analysis Preduction of intake and exhaust noises Prediction of engine performance turbulent diffusion phenome

项目摘要

It is important to reduce the numerical error, that is false diffusion error in order to improve the calculation accuracy of the phenomena of unsteady gas flows in internal combustion engines. The results obtained through the investigation of various methods are as follows :1. In one-dimensional calculation a new scheme of the characteristic method was proposed to eliminate the numerical diffusion. This scheme, in which two kinds of meshes are prepared corresponding to the trajectories of preassure waves and gas particle movement, respectively, provides good agreements between calculated and experimental results, and much less numerical diffusion has been achieved in comparison with the conventional scheme. Consequently, this scheme is seemed to be well suited for the analysis of gas flows in intake and exhaust systems.2. With the purpose to predict quantitatively the noise level and the pressure loss of silencers in intake and exhaust systems, the gas flow with pressure and temperature fluctuations has been calculated by using the CIP method. The comparison between calculated results and the experimental ones shows that both the pressure wave propagations and the gas particle movements can be predicted with high accuracy. The two- and three-dimensional calculations of the gas flow in expansion chamber type silencers have been carried out under actual engine conditions.3. Through the investigation to analyze accurately the turbulence and concentration diffusion in three-dimensional gas flow fields, it has ben shown that the newly developed GTT method with the k-epsilon turbulence model can predict the turbulent flow fields in engine cylinders properly, and that the CIP method enables the accurate analysis of concentration because its false diffusion is very small. Then the process of the stratification of mixture concentration distribution in the cylinder of an engine with two intake valves has been analyzed.

为了提高内燃机内气体非定常流动现象的计算精度，减小数值误差即伪扩散误差是非常重要的。通过各种方法的研究，得到以下结果：1.在一维计算中，提出了一种新的特征线法格式，以消除数值扩散。该格式分别对应于压力波和气体粒子运动的轨迹，计算结果与实验结果吻合较好，且数值扩散比传统格式少得多。因此，该方案似乎非常适合于分析进气和排气系统中的气体流动。为了定量预测进排气系统消声器的噪声级和压力损失，采用CIP方法计算了压力和温度波动时的气流。计算结果与实验结果的比较表明，该方法可以很好地预测压力波的传播和气体颗粒的运动。对实际发动机工况下膨胀室式消声器内的气体流动进行了二维和三维计算.通过对三维气体流场中湍流和浓度扩散的精确分析研究，表明采用k-ε湍流模型的GTT方法能较好地预测发动机缸内湍流流场，而CIP方法由于其伪扩散很小，使浓度的精确分析成为可能。分析了双进气门发动机缸内混合气浓度分布分层的过程。