基于管网外声场的区间隧道串联通风机调节反演

Inversion of adjustment of series tunnel fans based on an external sound field of a pipe network

明确串联风机调节依据,可有效提高通风排烟系统的通风效率。围绕该问题,依托缩尺寸过海地铁区间隧道通风试验平台,以串联通风机组为试验对象,确定了串联风机组的9种工况,测定了声压级、电功消耗和风量。通过噪声源频谱分析而发现,100~300 Hz的宽频噪声对通风机组噪声贡献大,近风井端风机和远风井端通风机对各阶谐波影响不同;基频出现叠加现象,并且该基频主要受近风井端通风机的影响。最终,基于噪声场反演,提出减噪降耗的调节方法,即近风井端通风机转速不低于远风井端通风机转速。

Aimed at the problem of series fans on the tunnel pipe network,it is a key that sound fields adjacent to the network of the system should be clarified.This clarification provides the adjustment method for those serial fans,to improve the ventilation efficiency of the ventilation and smoke exhaust system.In the ventilation experiment system,which was downscaled to a submarine long-distance and large-section interval tunnel,the two axial fans were arranged in series of this system,and the serial fans were used as experimental objects.Experiments included 9 conditions.These conditions were divided into three groups,as follows:single fan operation,double fan operation at the same speeds,and double fan operation at different speeds.In experimental conditions,sound pressure level,power,and air volume were measured.Furthermore,the relationship between the 3 variables was discussed respectively.The obtained data show that the simultaneous operation of series fans greatly increases the noise;for example,the operation of two fans increased by 10 dB(A)and 9.4 dB(A),respectively,when the rotational speed of 1200 r/min and 1500 r/min,compared with a single fan.Based on spectrum analysis,it can be found that the sound intensity of broadband between 100-300 Hz should change obviously,compared with the working conditions;especially,this broadband sound contributes greatly to the noise of the series fans.The series fans were divided into a fan near an air shaft and one far from this,and it is notable that each harmonic is differently affected by those 2 fans.When series fans operate at the same speed,the two fundamental frequencies appear in superposition at low rotational speed and are separated at a high one.On the premise of an air volume,the adjustment method,which has noise reduction and consumption reduction,the rotational speed fan near an air shaft should not be lower than that far from one.