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The noise generated in the rotary compressor can be classified by pressure pulsation of the refrigerant and structural vibration. This paper deals with the noise generated by pressure pulsation of refrigerant in a rotary compressor. During the operation of the compressor, the refrigerant and the internal structure of the compressor have strong interaction with each other. At this time, the oil around the reed valve causes the compressor to overpressure the refrigerant, which is the main cause of noise generation. Therefore, the interaction between the refrigerant and the valve during the compressor operation is analyzed using the FSI technique. The pressure pulsation of the refrigerant and the behavior of the valve were analyzed. Also, the noise characteristics were confirmed through the spectrum analysis of the generated noise.

During a lift-off of a launch vehicle, a large amount of acoustic wave is generated by jet plumes. Acoustic waves lead to pressure fluctuations on the surface of the vehicle in the form of acoustic loads and these are transmitted to the internal payload. In order to evaluate the effects of acoustic loads, we developed the integrated simulation model. The model is mainly divided into two parts, prediction and reduction parts. First, the external acoustic loads are predicted empirically based on the Distributing Source Method-II (DSM-II) of NASA SP-8072. We developed the improved method able to consider the additional effects of surrounding structures. We perform a next prediction process for the internal acoustic environment by using Statistical Energy Analysis (SEA). For the Korean Sounding Rocket-III (KSR-III), we predict the internal acoustic environment and evaluate the stability of the payload in the fairing. After the prediction process, we perform the noise reduction simulation. With an active noise control (ANC) simulation, we could confirm the possibility and reliability of the noise reduction system.

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