Study On Noise And Vibration Reduction Of Providing Water System To High Building

In this thesis, the research on how to lower the vibration and noise of transfusing fluid pipe is based on pipe system of providing water in high building of Tianjin custom.The thesis analyses the signal of vibration and noise of water system in pump room through power frequency spectrum analysis and coherence analysis. Meanwhile uses finite element method (FEM) to investigate the characteristics of pipe system. Finally finding that there are two reasons that cause vibration of pipe and noise. The one is the vibration of pump which transfers to pipe and stimulates the vibration of pipe. The second is the stimulating frequency of pulsating water is coherent with the natural frequency of pipe. So the pipe system sends out noise because of resonance. Especially the frequency 250Hz of pulsating water is in close proximity to natural frequency of pipe, so the 250Hz is a dangerous frequency to the pipe system. There is another reason why the noise is reached to 110dB(A) in pump room that the noise is magnified by the cistern because of the resonance of cistern.The thesis uses isolator to resolve the problem of vibration of pump, and the result is very good.To avoid the resonance of pipe system, the thesis uses the software ANSYS of finite element to analyse the dynamic characteristic of pipe system, and at last finds a pleasing mechanism of pipe.Through redesigning of pipe system to alter its character and using the ways to isolate vibration and reduce vibration, it is yielded very good results of reducing the vibration and noise. In some points the acoustic pressure level drops very much, such as in the standard point of number one pump the acoustic pressure level drops 15dB(A) and in the standard point of cistern also drops 15dB(A), and in the highest point of the acoustic pressure before redesign drops from 105dB(A) to 44dB(A), and in the second floor the acoustic pressure level have reached the requirment.The thesis is focus on preliminary research on the dynamic property of providing water system to high building, and there are some aspects to discuss, such as how the property of fluid to influence the character of pipes and so on. But from the good results of this practicality problem, it can be said that the ways of solving such problems are practical, and it can be used for further research on reducing the vibration and noise of providing water system to high building.