Research On Jet Noise Reduction

Jet noise is very common, and it is the most important source of environmental pollution. With the development of modern industry, aero dynamical noise is usually higher than the mechanical noise with wide range and heavy damage. Most exhausting equipment in industry such as high-pressure nozzle used in processing the steel slag will produce the strong noise of 120dB or above. This will seriously pollute the working environment of workshop and make negative effect on the health and work efficiency of workers. Therefore, to research the mechanism and character of the jet noise and to grasp the discipline is very meaningful to inhibit the interference and hazard of the noise.Combined with the project of noise reduction in Masteel, this thesis is base on the theoretical analysis and the former experience. Besides that, the thesis is focused on the research of technology in inhibiting the jet noise and improvement of the nozzle, by the means of computation simulation and experimental analysis.This thesis is composed of 4 main parts:Firstly, predicting the jet noise by concluding the character, mechanism and a series of experienced formula.Secondly, analyzing the turbulent noise caused by the flow turbulence from the turbulent sonic radiation theory; calculating the best model of jet flow by comparing different turbulent models by the means hydrodynamics.Thirdly, establishing the computation model of jet noise based on the jet flow analysis and hydrodynamics; improving the nozzle by changing the parameters of nozzle which results in the change of pressure and velocity flow; verifying the result by experiment.At last, elaborating the application of the new nozzle in industry; identifying the source of noise and making out the project; comparing the improved nozzle with the old nozzle to testify the function in noise reduction.