叶轮机中振动叶片非定常气动力的研究

Study on the Unsteady Aerodynamic Forces and Moments Actingon Vibrating Blades of Turbomachinery

采用“单一叶片振动方法”代替传统的“全部叶片振动方法”，用线性化的方法推导出计算振动叶片非定常气动力（引起叶片弯曲振动）及力矩（引起叶片扭转振动）方程。通过输入叶型及气流参数，它可以方便有效地估计出作用在振动叶片上的非定常气动力和力矩，以及振动叶片不稳定工况发生的条件和范围。并在氟里昂超音速风洞上进行了实验测量，结果表明，理论计算结果与实验测试结果符合较好。

There exist many investigations concerning aeroelasticity of vibrating cascade blades, but present situation is not yet at the stage of sufficiet elucidation on this complicated problem both in theory and experiment. In this paper the assumption 'one blade oscillation method', replacing the conventional ' all blades osciliation method', makes theoretical analysis very easy. It means that only the unsteady forces induced on the vibrating blade and other neighbouring blades at rest are measured and calculated. Consider a cascade of flat plates operating at zero incidence so that the unsteady effects are small perturbation of a uniform flow and the calculation equations can be deduced by linearized way. By inputting some blade structure and flow parameters, it can evaluate the unsteady aerodynamic forces and moments acting on the vibrating blades effectively, and conditions and regions of vibrating blade unsteady phenomena occurence are decided fast and easily. Some experiments have been made at the supersonic Freon gas wind tunnel. The data measured from experiments are in good agreement with the ones of theoretical calculations.