多管式貫流ボイラで生じた空力学的自励音に関する研究 : 発生メカニズムおよび発生周波数の究明(流体工学,流体機械)

概要

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A pure tone noise generated from a multitube once-through boiler (test product) at non-combustion testing was investigated in order to clarify the generation mechanism and the oscillating frequency. The acoustic analysis of a boiler, the water tank test and the two-dimensional CFD analysis for an in-line tube array model were conducted. As a result, it was found that the vortex in wake of the tube shed periodically with the same frequency as the acoustic natural frequency of the boiler, namely the aerodynamic self-sustained tone was generated. Moreover, a wind tunnel test of the in-line tube array model with the various diameters and intervals of tubes was conducted. As a result, it was found that the values of Strouhal number St based on the length of separation shear layer were about 0.3〜0.6, and the phenomena of periodic vortex shedding on a boiler were similar to those on a bellows flow and a cavity flow. This paper presents some useful experimental data for low noise design of a boiler.
社団法人日本機械学会の論文
2003-03-25