Study of transient response characteristics of rotating disc cavity

In order to ensure the engine normal operation in flight envelope, studying the unsteady characteristics 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. Results 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 becomes 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.