电力机车司机室空气传播噪声预测

Prediction Methods of Airborne Sound for Electric Locomotive Cabs

试验分析了电力机车司机室噪声源的噪声特性和司机室各墙体的隔声性能。基于声源声功率的等效原理,将室外声源声功率级等效转换到室内声源声功率级,基于现有隔声设计的基本公式,对电力机车司机室内受声点的噪声进行了预测。结果表明:轮轨噪声、机械间设备噪声和司机室内空调、暖风机噪声是司机室噪声的主要来源;由于机械间内产生了足够的混响声,机械间内受声点声压级的大小与声源到受声点的距离无关;计算结果与测试结果存在一定的误差,但仍在可接受范围之内。预测方法能为电力机车司机室早期的声学设计和改进提供设计依据。

Noise sources characteristics of electric locomotive cabs and sound insulation performance of its all walls were studied experimentally. Based on the sound power level equivalence principle, the sound power level of outdoor noise sources was equivalent to indoor sources. Then, the sound pressure level（SPL） at measuring point in cab was predicted based on the existed empirical formulas for sound insulation designing. Results showed that the wheel/rail noise, equipment room noise, air conditioner and heater blower noise in cab were the main noise sources; Due to noise produced enough reverberation sound in the equipment room, the SPL at measuring point in the equipment room had nothing to do with distance between measuring point and noise sources; There was a certain deviation between the simulated results and measured results, but still in the acceptable range. The analysis method proposed can be utilized to predict SPL of electric locomotive cabs in the early design stage or suggest improvements.