ボイラ管群で発生する自励音対策ための穴あき板の利用に関する数値的研究

抄録

In the heat exchanger and the boiler, the tube bank is set in a duct, water passes through the inside of the tube, and gas flows the outside of the tube. Due to the external flow around tube banks, the resonance called the self-sustained tone occurs at a certain velocity. In general, baffle plates are used to suppress the self-sustained tone. However, it is difficult to use them effectively, because appropriate insertion positions have not been established. On the other hand, to suppress the self-sustained tones, a method using perforated plates has been proposed. In this method, perforated plates were installed on both sides of the duct to suppress the self-sustained tones. The perforated plate has an acoustic damping and a resonance mode of the duct transverse direction to the flow is suppressed by its damping effect, when the self-sustained tone occurs. The purpose of this study is to verify the effect of the perforated plates on the self-sustained tone numerically. CFD and acoustic simulations were carried out to examine the suppression effect of the perforated plates installed, and compared with the measurement data. The results show that the suppression effect appeared in all aperture ratio φ => 0.01 (1%) of the perforated plate and that the measurement and simulation data are in reasonable agreement in terms of prediction of effects of perforated plates on the self-sustained tones.