基于声学的迟滞效应计算内燃机的热声耦合性质

Analyzing Thermal Acoustic Coupling in an IC Engine Based on the Hysteresis Effect of Acoustic Wave Propagation

将燃烧理论和声学理论结合,在KIVA软件流场算法的基础上,把燃烧室空间网格内的发生化学反应的单元作为产生燃烧噪声的声源,这些声源在燃烧过程中产生声波.根据声波传播的影响范围将声源周围区域划分为声内单元和声外单元,单元的压力依据其所处区域的不同来计算.计算的结果可以体现燃烧室空间内某个位置的压力震荡过程以及分析造成该位置压力震荡的主要声源的特性.通过对比试验数据与模拟计算结果,对内燃机燃烧过程进行研究时应考虑声波在缸内传播时的声学迟滞效应.

By combination of combustion theories, acoustic theories and KIVA algorithm on the basis of the flow field, grid cells in the combustion chamber involving chemical reactions are served as acoustic sources that generate the combustion noise. These sources will produce the acoustic waves during the com- bustion. Areas around sources were divided into cells inside the acoustic wave and the others outside the acoustic wave according to the range of acoustic wave propagation. Thus, the pressure in combustion chamber can be calculated. The process of pressure oscillations in some positions can be captured. The characteristics of main acoustic sources leading to pressure oscillations were analyzed. Comparison on calculation and experiment shows that the hysteresis effect of acoustic wave propagation needs to be con- sidered in the study of combustion process of IC engines.