| At present,the seawater pipeline silencer plays a positive role in the process of control and management to the noise produced by the seawater pipeline flow.Researches on the silencer are mainly concentrated in the performance simulation and experiment verification.In the aspect of experimental test,however,the measurement results changes larger because of the influence of measurement method,instrument,external environment and other factors,which made the measurement results lack of credibility.How to improve the measurement precision of the silencer’s acoustic performance becomes an urgent problem to solve.In this paper,the test methods and uncertainty theory are studied respectively and combined,which provide a theory basis to find the factors affecting measurement precision.First of all,based on the evaluation index,the test methods of every index are studied;at the same time,the measurement uncertainty methods are studied,such as Bessel method,Maximum range method,Residual method,Grey evaluation method,Maximum information entropy method(ME)and so on.By compare the evaluation results of each method,the select principle of uncertainty evaluation method was proposed.Then,DN100 silencer’s acoustic performance test was carried out on the static test bench,analyzing the effect of sensor,charge amplifier,change of acoustic velocity and pipe-wall vibration on the measurement uncertainty.Finally,a circle pipe test bench was built,the silencer’s dynamic performance was tested at different flow rates by using different sensors and measurement methods.The measurement results and its uncertainty assessment were cross-compared.The results demonstrates that adding grit can reduce the pipe-wall vibration and to some extent the uncertainty of measurement results has decreased;The uncertainty of measurement results produced by circle pipeline is larger than the static pipeline;there is no much more difference between the uncertainty of measurement results collected by pulsating pressure sensor and hydrophone at high flow;In the whole the uncertainty measured by small chamber method is slightly less than the uncertainty measured by direct measurement. |
