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含氣率對液力透平影響的非定常分析

發(fā)布時間:2018-06-08 21:31

  本文選題:含氣率 + 液力透平。 參考:《航空動力學報》2017年09期


【摘要】:為了研究含氣率對液力透平內部壓力的影響,以比轉速為84.5的單級單吸離心泵反轉作液力透平并對其內部流場進行CFD瞬態(tài)數(shù)值模擬,獲得了氣體在液力透平內的分布規(guī)律以及氣液兩相介質下透平內部流場的壓力脈動變化規(guī)律。結果表明:從蝸殼進口到葉輪出口,含氣率逐漸增加,含氣率等于0.2時蝸殼出口、葉輪進口氣體的尾跡效應明顯,分布不夠均勻。葉輪出口有氣體聚集現(xiàn)象,氣體體積分數(shù)越高,聚集現(xiàn)象越明顯。進口含氣率對透平蝸殼、葉輪內各點的相對壓力分布影響明顯,各點的相對壓力隨著透平進口含氣率增加而降低。含氣率小于0.05時其對透平內各監(jiān)測點的壓力脈動主頻幅值影響不大,含氣率大于0.05后其對液力透平內各監(jiān)測點的壓力脈動主頻幅值有影響,含氣率越高,壓力脈動主頻幅值越小。不同含氣率下液力透平蝸殼周向、徑向以及葉輪內的壓力脈動主頻均等于葉輪葉片的轉動頻率。
[Abstract]:In order to study the effect of gas content on the internal pressure of hydraulic turbine, a single stage suction centrifugal pump with a specific speed of 84.5 was used to reverse the hydraulic turbine and the CFD transient numerical simulation of its internal flow field was carried out. The distribution of gas in hydraulic turbine and the variation of pressure fluctuation in turbine flow field in gas-liquid two-phase medium are obtained. The results show that from the inlet of the volute to the outlet of the impeller, the gas content increases gradually, and the gas content is equal to 0.2 at the outlet of the volute. The wake effect of the inlet gas of the impeller is obvious and the distribution is not uniform. The higher the volume fraction of gas, the more obvious the phenomenon of gas accumulation at the outlet of impeller. The relative pressure distribution of each point in the turbine volute and impeller is obviously affected by the inlet gas content, and the relative pressure at each point decreases with the increase of the inlet gas content of the turbine. When the gas content is less than 0.05, it has little effect on the main frequency amplitude of pressure pulsation in each monitoring point in turbine. When the gas content is greater than 0.05, it has an effect on the main frequency amplitude of pressure pulsation in each monitoring point of hydraulic turbine. The higher the gas content is, the higher the gas content is. The smaller the main frequency amplitude of pressure pulsation is. The main frequency of pressure pulsation is equal to the rotating frequency of the impeller blade in the circumferential direction, radial direction and impeller pressure pulsation frequency of the volute with different gas content.
【作者單位】: 蘭州理工大學能源與動力工程學院;
【基金】:國家自然科學基金(51569013,51269011) 甘肅省青年科技基金計劃(145RJYA312)
【分類號】:TH311

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