Theoretical And Experimental Investigation Of Jet Noise Of Micropores

Jet noise, widely existing in human life, has become one of the main factors which affect human health and safety of equipments. Based on the thorough learning of aerodynamic noise theory, especially the jet noise generation mechanism, theoretical calculation methods, simulation methods and experimental testing methods, the sound source characteristics of multiple jets noise is investigated by theoretical, simulation and experimental methods in this paper.At first, the flow and noise characteristics of two-dimensional restricted jet in pipe are simulated by the Large-Eddy Simulation method. The results show that the jet noise in pipe has directivity, and the peak frequency is coincident with theoretical calculation results..Then, using the theoretical method, sound pressure level estimating formula of multiple jets noise is obtained, and then it is validated and modified with the experiment results. The study shows that for micro pores with large space between holes, the estimating formula is consistent with the experimental data, also for the micro pores with small space between holes, namely, the overall sound pressure level considering jet noise caused by multiple jets converging, by fitting the experimental data, the formula can be also used to estimate the sound pressure level of jet noise.At last, the paper improves the Temperature and Pressure Reducer design, which is with characteristics of multiple jets noise, simulates the flow field and experimental studies the jet noise characteristics. The research results show that the vibration and sound level are smaller than the prototype. This achieves the aim of decreasing the vibration and noise level, and the results are of reference value for the structure and performance improvements to the Temperature and Pressure Reducer.