离心泵用赫姆霍兹水消声器试验研究

为研究离心泵用赫姆霍兹水消声器的性能,基于传递函数法测量了不同连接管长度的赫姆霍兹水消声器声学特性,并与声学仿真计算结果进行对比和试验验证.试验中采用共振腔为单腔半圆柱形的赫姆霍兹水消声器,在消声器的前后分别安装2个水听器和1个压力脉动传感器,水听器用于测量消声器前后的动态声压信号,压力脉动传感器用于测量水消声器前后的静压,然后采用求平均的方法计算水消声器前后平均压力之差,得到水消声器在不同工况下的压力损失.连接管的原始长度为12 cm,然后改变连接管长度,使其安装长度分别为20,30,40和50cm.试验结果表明:赫姆霍兹水消声器的共振频率随连接管长度的增大而降低,传递损失呈现出先增大后减小的趋势,与声学仿真计算结果趋势一致;连接管长度对赫姆霍兹水消声器压力损失的影响不大,但与系统的运行工况有关,随流量的增大而增大.

Experimental study of Helmholtz water-mufflers used in centrifugal pumps

The acoustic characteristics of a Helmholtz water-muffler with different lengths of neck were measured by using the transfer function method to investigate the muffler performance,and then the experimental results were compared with those numerically simulated. In the experiment,a Helmholtz water-muffler with a single resonator of semi-cylinder was used,and two hydrophones and one pressure transducer were installed in the front and back of the muffler. The hydrophones were used to measure dynamic pressure signals,but the transducers were applied to monitor the static pressures at the inlet and outlet of the muffler so as to figure out the differential pressure across it and eventually to obtain the pressure losses across the muffler under different working conditions. The length of the original neck is 12 cm,and this length was altered to 20,30,40 and 50 cm,respectively. It was shown that the resonant frequency decreases with increasing length of neck and the transmission loss ascends initially and then decreases,the measured acoustic characteristics agree well with the theoretical predictions. The length of neck has a modest influence on pressure loss. The pressure loss depends on working condition,and it increases with increasing flow rate.