管内脈動による空冷熱交換器の騒音発生に関する研究  [in Japanese] Study on Noise from Air-Cooled Heat Exchanger by Pulsation  [in Japanese]

Noise problems caused by gas pulsations in the tubes of air-cooled heat exchangers have become more serious, since the level of air conditioner fan noise has decreased. In this study, the prediction of noise caused by gas pulsations in an air-cooled heat exchanger was investigated. The predictions of tube vibrations and sound radiation of air-cooled heat exchangers were carried out using Statistical Energy Analysis (SEA). The value of the loss factor of gas pulsations becomes high, when two-phase flows occur in the tubes. Therefore, the values were investigated and used for prediction. For the exiting forces, the forces of pressure at U bends and in straight pipes of heat exchangers were used. The predicted results were in satisfactory agreement with the experimental data.