含气率对液力透平影响的非定常分析

发布时间：2018-06-08 21:31

本文选题：含气率 + 液力透平　；参考：《航空动力学报》2017年09期

【摘要】：为了研究含气率对液力透平内部压力的影响,以比转速为84.5的单级单吸离心泵反转作液力透平并对其内部流场进行CFD瞬态数值模拟,获得了气体在液力透平内的分布规律以及气液两相介质下透平内部流场的压力脉动变化规律。结果表明:从蜗壳进口到叶轮出口,含气率逐渐增加,含气率等于0.2时蜗壳出口、叶轮进口气体的尾迹效应明显,分布不够均匀。叶轮出口有气体聚集现象,气体体积分数越高,聚集现象越明显。进口含气率对透平蜗壳、叶轮内各点的相对压力分布影响明显,各点的相对压力随着透平进口含气率增加而降低。含气率小于0.05时其对透平内各监测点的压力脉动主频幅值影响不大,含气率大于0.05后其对液力透平内各监测点的压力脉动主频幅值有影响,含气率越高,压力脉动主频幅值越小。不同含气率下液力透平蜗壳周向、径向以及叶轮内的压力脉动主频均等于叶轮叶片的转动频率。
[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.
【作者单位】：兰州理工大学能源与动力工程学院;
【基金】：国家自然科学基金(51569013,51269011) 甘肃省青年科技基金计划(145RJYA312)
【分类号】：TH311

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