旋转盘腔瞬态响应特性的研究

Study of Transient Response Characteristics of Rotating Disc Cavity

为保证发动机在飞行包线内正常运转,需研究旋转盘腔的瞬态响应特性。采用1-D模型方法和计算流体力学(CFD方法对旋转盘腔进口压力突升的情况进行非稳态数值计算,所得结果与文献中的结果进行对比,提出1-D模型方法的一些缺点,并证明了CFD计算的正确性。然后用CFD方法并通过用户自定义函数(UDF编程研究了进口压力渐增、正弦变化以及盘腔尺寸对旋转盘腔流动瞬态响应特性的影响。结果表明:1-D模型的计算结果不能显示出CFD模型计算结果的一个高阶震荡;进口压力以不同方式变化,瞬态响应存在不同程度的滞后;进口压力突增和进口压力渐增响应的特征时间比进口压力正弦变化的特征时间分别增加56.0%和106.4%盘腔宽径比由0.2变化到0.39时,腔内均压变高,出口质量流量变低,特征响应时间缩短至40%当宽径比由0.2变化到0.58时,特征响应时间缩短至25%。

In order to ensure the engine normal operation in flight envelope,studying the unsteady charac-teristics of transient response of rotating disk cavity is required. 1-D model method and the CFD method were used to simulate the unsteady characteristics of a rotating disk cavity when the inlet pressure increased suddenly and the results were compared with the result in a reference. The shortcomings of the existing 1-D model were put forward and the accuracy of CFD method was proved. Then the CFD method was used to simulate the flow characteristics of the cavity through User-Defined Function(UDF)with inlet pressure changing differently. Re-sults show that there is a notable higher-order oscillation in the CFD results that is not represented by the current 1-D system dynamics. The responses have different levels of lag with different change styles of inlet pressure. The response time of inlet pressure changes suddenly and of the pressure increased linearly increased by 56%and 106.4%, respectively, to the response time of inlet pressure with sine change. The average pressure be-comes higher and the mass flow rate becomes lower when the width-radius of the cavity changes from 0.2 to 0.39 and from 0.2 to 0.58,and characteristic time of pressure response shrink to 40%and 25%,respectively.