【摘要】：淹沒條件下自振射流的頻率特性決定著射流的打擊效果,而獲取射流的壓力脈動信號對研究自振射流頻率特性至關(guān)重要。射流的壓力信號通常借助于沖蝕試驗(yàn)和標(biāo)靶打擊試驗(yàn)來間接獲得,這里采用噴嘴腔內(nèi)壓力信號提取方法對自振射流頻率特性進(jìn)行試驗(yàn)研究。通過比對分析證明,直接采集腔內(nèi)壓力信號可以有效獲取自振射流的頻譜特征。與標(biāo)靶打擊試驗(yàn)相比,該方法受隨機(jī)擾動少,頻譜清晰,更有利于自振射流特征頻率的提取。在此基礎(chǔ)上,通過頻譜分析得到自振射流的共振頻率,并研究來流參數(shù)對自振射流頻率特性的影響。試驗(yàn)結(jié)果顯示,自振射流的共振頻率并非是對來流擾動頻率的直接放大,且受來流擾動的影響很小。來流速度對自振射流共振頻率的影響較大,隨著來流速度的增加,自振射流的共振頻率及其對應(yīng)的幅值均顯著增加。這表明適當(dāng)加大來流速度可以有效地改善自振射流的振蕩特性。
[Abstract]:The frequency characteristic of the self-oscillating jet in the submerged condition determines the striking effect of the jet, and the pressure pulse signal of the obtained jet is of great importance to the frequency characteristic of the natural gas jet. The pressure signal of the jet is obtained indirectly by means of the erosion test and the target striking test, and the frequency characteristics of the self-vibration jet are studied by using the pressure signal extraction method in the nozzle cavity. By comparison with the analysis, the frequency spectrum of the self-vibration jet can be obtained by directly collecting the pressure signal in the cavity. Compared with the target-striking test, the method has less random disturbance and clear spectrum, and is more beneficial to the extraction of the characteristic frequency of the natural-vibration jet. On this basis, the resonance frequency of the natural-vibration jet is obtained by the spectrum analysis, and the influence of the flow parameters on the frequency characteristics of the natural-vibration jet is studied. The experimental results show that the resonant frequency of the free-vibration jet is not the direct amplification of the flow disturbance frequency, and the influence of the current disturbance is very small. The influence of the flow velocity on the resonant frequency of the self-vibration jet is large, and with the increase of the flow velocity, the resonant frequency of the self-vibration jet and its corresponding amplitude are obviously increased. This indicates that the oscillation characteristics of the self-oscillating jet can be effectively improved by increasing the flow velocity.
【作者單位】： 北京科技大學(xué)機(jī)械工程學(xué)院;
【基金】：國家自然科學(xué)基金資助項(xiàng)目(51274021)
【分類號】：O358

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本文編號：2503961