2つの並列管群ダクトを有するガス加熱器の異音に関する研究 : 第2報,孔あきバッフル板の音響減衰特性とその効果(流体工学,流体機械)

概要

論文の詳細を見る
This paper describes a High SPL sound generated from banks of gas heater tubes in two ducts with an internal flow which are located parallel to each other and used in a boiler. The tube banks have two tubes each, with diameters of 6mm and 3mm. They are used in this experiment. The sound pressure, the flow velocity and the acoustic damping of the ducts are measured in order to clarify the cause of the High SPL sound and the suppression effect of various perforated baffle plates. First, the acoustic damping abilities of various perforated baffle plates and the damping treatments using the damping material are measured by the speaker test. Second, the relation between the acoustic damping abilities of the perforated baffle plates (ζ_h) and the damping treatment (ζ_m) are studied. As a result, I discovered the perforated baffle plates have a damping effect and the damping ability increases with the perforated ratio being smaller. Also the relaion of the ζ_h and ζ_m as the criterion of the High SPL sound occurrence can be obtained. The criterion can be used in case of P/D<2.0, where P is the tube pitch and D is the tube diameter. And it was found that the suppression effect of the baffle plate on the SPL is not only the destruction of the mode as is often said, but the suppression of the vortex shedding due to the change of the local mode.
一般社団法人日本機械学会の論文
2004-01-25