软体外物撞击叶栅时的切割模型

鸟、冰雹、冰块的撞击统称为软体撞击。随空气一起吸入发动机的软体外物首先要受到风扇或压气机叶栅的切割作用,故与叶片发生撞击的是经切割后的软体外物切片。为此,在着手分析撞击过程之前,首先要确定切片的几何形状及质量,即建立软体外物的切割模型。 本文推导了确定最大鸟切片与最大冰球、冰块切片的几何尺寸及质量的表达式。作为算例,针对某型号发动机的有关参数,计算了当受到不同质量的鸟及不同直径的冰球撞击时,最大切片的尺寸与质量。本文的工作为建立软体外物撞击叶栅时的载荷模型提供了前提条件。

Slicing Model for Foreign Soft-Body Objects Impacting on Blade Rows

The impacts caused by birds, hail, and ice slabs are all called the foreign soft-body object impacts. At first the foreign soft-body objects ingested into engines with air are cut into slices by the chopping action of the first-stage ian blades or compressor blades. It is the slice of foreign soft-body object that impacts on a blade. Thus before one proceeds with the analysis of the impact process, it is necessary to determine firs-t the geometry and mass of the slices of bird or ice, formed by rotating fan or compressor blades.In this paper, the expressions which determine the geometry and mass of the greatest slice of birds, ice spheres and ice slabs are derived in detail. As an example, the computations are conducted for some type of engine. The geometry and mass of the greatest slice are obtained for the birds of different sizes, and for the ice spheres of different diameters. The work which is conducted in this paper can provide a prerequisite to establish the load model for foreign soft-body objects impacting on blades.