排气噪声预测的改进研究

A Study on the I.C. Engine Exhaust Noise Prediction

作者曾用Benson发展的特征线法模拟内燃机排气系统中的不稳定流动,作为噪声预测的基础,但预测的排气噪声频谱在1kHz以上不能令人满意。针对于此,本文提出了一种改进的特征线算法,旨在改善高频段噪声频谱的预测精度。计算与实测对比表明,其他参数(压力、速度等)与Benson法的结果一致,而噪声预测精度有很大提高,在3kHz以下均能较好地反映实测值。这种算法可作为气流声学分析、排气噪声预测的有效手段。

An improved algorithm based on Benson's fixed grid, fixed time-step characteristic method for engine unsteady flow simulation was proposed to improve the predicted exhaust noise spectrum above 1 kHz which is unsatisfactory by using the original method. The comparisons between measurements and calculations showed that noise prediction accuracy was considerably improved up to 3 kHz, while the calculated pressure, gas velocity and cpu time kept almost the same with those from Benson's method. This new algorithm may be employed in exhaust noise prediction and muffler performance simulation.