| The rotor-stator cavity is a typical transient response component in the air system of aero-engine,and the flow in the rotor-stator cavity is representative and extensive.The accurate prediction of transient flow characteristics is the key to achieving high reliability design of aero-engine.In this paper,the numerical simulation method is used to study the unsteady flow of aero-engine rotor-stator cavity to get the transient response characteristics of the rotor-stator cavity,where the non-steady-state boundary condition is programmed based on user-defined function.In this paper,the response mechanism of transient flow in a rotor-stator cavity was studied firstly,and the influencing factors of transient response characteristics were analyzed from perspective of the hysteresis effect,flow field evolution and physical property parameters,and the parameters such as response time,peak time and overshoot were used to evaluate the transient response characteristics in the rotor-stator cavity.Secondly,the transient flow process of the rotor-stator cavity was studied when the inlet pressure was changed by the jump function,step function and sinusoidal function,and the law of transient response of the rotor-stator cavity under the typical air intake function was obtained.Finally,the transient response characteristics of steam and air in the rotor-stator cavity were compared.The influence of the cooling medium on the transient response characteristics of the rotor-stator cavity was obtained.The results show that the combined effect of volumetric effect and rotational effect in the rotor-stator cavity makes the rate of flow in outlet significantly lag behind that in inlet,and the transient process of the mass flow stored in cavity directly leads to the overshoot of the relative total temperature;the impinging jet and the rotating adherent jet and the vortex on the side of the stator wall constitute the main body of the evolution of disk cavity flow field;the sonic speed and thermal diffusivity are closely related to the transient response characteristics;there are significant differences in the transient response characteristics of the rotor-stator cavity under different intake functions.The transient response of each flow parameter in the cavity under the same intake function has different degrees of hysteresis.The overshoot of the average total temperature of the disk cavity is closely related to the type of the intake function.The overall trend of transient response in the rotor-stator cavity is basically the same for both steam and air under the same dimensionless step coefficient.The transient response characteristics of steam are significantly better than that of air within the scope of this study. |
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