Analysis and Improvement of Pipeline Resonance in Air-Cooled Chiller
During the whole machine noise testing stage of a fixed frequency air-cooled chiller in a semi anechoic room,low frequency"buzzing sound"appeared on the left side of the unit in refrigeration mode.It was observed that there was a vibration"double shadow"phenomenon in the connecting pipe between the left system storage tank and the shell tube.Three directional vibration acceleration responses of relevant bends were collected,and it was found that the horizontal acceleration response of the pipeline was 67.8m/s2,far exceeding the enterprise standard requirements,firstly,the frequency response and coherence function of the pipeline were identified to obtain multiple reference natural frequencies.It was preliminarily determined that the pipeline had resonance at 58Hz,then,finite element modal analysis was performed on the original pipeline and the pipeline with counterweight blocks to obtain the four modal frequen-cies and vibration modes.The frequency shifting effect of the counterweight blocks was verified,and the influence of the counterweight block position on the modal frequencies of each order was discussed,Finally,the frequency response function of the pipeline system after the application of counterweight blocks was identified.Through experimental meth-ods,it was confirmed that the first-order natural frequency of the pipeline after the addition of counterweight blocks shifted towards low frequencies by 13.5Hz,which was similar to the simulation analysis results.Finally,the vibration acceleration response data of the pipeline under three different counterweight block layout schemes were tested,and the final vibration reduction scheme was compared and confirmed to be executed using one counterweight block on the bending side of Scheme 2.
fixed frequency chiller unitfrequency response functionnatural frequencymodal analysis
万方数据
维普
