本研究主要以主動控制之方法以定量及定性之實驗法探討壓電晶片振動對低速管流中懸浮粒子於壁面沉積的影響，實驗之控制參數?出口風速、晶片輸入電壓、振動頻率及晶片裝置位置等。實驗中，基於出口高度(H=30mm)?特徵長度之雷諾數?111與133，研究過程藉量測植入與流失的粒子重量差作沉積之定量分析。結果顯示在較高出口風速及較低振動頻率時對沉積有較大的減少量，此點由沉積於壁面粒子波紋之定性分析中可相互得到應證。以一字型熱線測速儀?主要設備的量測中發現在晶片後方之流場有較大的流向速度擾動強度，頻譜分析則顯示激擾頻率的改變對晶片下游之流場較晶片間之流場有較顯著之影響，過近的晶片距離會交互作用使得沉積增加。
The main objective of this study was to investigate the particle deposition in a low-speed tunnel flow excited by piezoelectric plates experimentally. The controlling parameters were flow speed, excitation frequency, input voltage and the setting position of plates. The Reynolds numbers base on the exit height H=30mm were 111 and 133 corresponding to two flow speeds. The quantitative analysis was done by measuring the difference of weights between seeded and outflow particles. The results revealed that the decrement of deposition was due to higher flow speed and lower oscillating frequency. Similar results were also been obtained by comparing the peak-to-peak distance and the amplitude of the wavy shaped distributions of sediments on the wall. Stronger fluctuations were observed downstream of the plates measured using hot-wire anemometry. The spectra distribution also revealed that the variation of the excitation frequency affected the downstream flow field more than between each other. In addition, the deposition was increased by the strong interaction of the plates while they were closely placed.
Relation:
Journal of Aeronautics,Astronautics and Aviation, Series B 43(1), pp.11-17
