Acoustic Design And Noise Control Of Ship's Air-conditioning System In Ventilation

The noise of ship's air-conditioning duct is one of the main noise sources in ship cabin.In addition,due to the ship cabin is closed and the various kinds of equipment in ship cabin,the space is small and the noise control is difficult.Therefore,we need to conduct acoustic analysis and research on the air conditioning system of ship.The system of reducing noise in pipeline occupies a very important position in the noise control of the air conditioning system of ship,so it is necessary to evaluate and analyze the acoustic performance of the piping system in ship's air conditioning.Based on the one dimensional plane wave theory,a series transfer matrix of acoustic units which in typical ship's air conditioning have been derived by analytical method.On the basis of the derived transfer matrix,designing a visual simulation program with the GUI in MATLAB,the simulated program called MAP(Muffler Acoustic Prediction).The program put all muffler element which in pipeline in together by transfer matrix method,and then according to the given input frequency to calculate the transmission loss.After the calculation,the obtained data is transmitted through the post-processing to get the curve of transmission loss.Comparing with other mthods of calculation,the program not only can get the transmission loss of the piping system in ship's air conditioning,but also can save the time and the resources of computer.A finite element module in LMS Virtual.Lab is proposed to simulate the transmission loss of a typical ship's air-conditioner ventilation ducting system,which is compared with the one-dimensional plane wave method.The result showed that the two methods of the curve of transmission loss are in good fit within the scope of plane wave,but the noise system when the Marine air-conditioning pipe in wave neglected modes of one dimensional plane wave method is no longer accurate.Measuring the transmission loss of the typical ship's air-conditioning ventilation ducting system,and comparing the result of the measurement with the two methods above.The results of the experiment and the results of the two methods above are in good fit.It is proved that the MAP can be used for fast and accurate prediction of the transmission loss of the sound attenuation system.