摘要
为进一步改善低比转速叶轮性能,针对低比转速叶轮广泛使用的圆柱形叶片的叶片包角都是由叶片型线的进、出口边条件确定的常数,以极坐标系下的插值方法为基础,导出了一种新的圆柱形叶片投影曲线的插值方程,这一平面曲线的主要特点是其包角可作为设计常量由设计人员根据需要事先给定.给出了基于艾尔米特插值方法的曲线方程的推导过程和结果,即在根据给定叶片包角后,在边界条件支持下,通过计算获得了艾尔米特插值函数的相关四项表达式.同时分析了曲线的部分几何特征,通过微分证明了这一曲线在进、出口半径处,叶片安放角等于给定值,且曲线包角等于给定值.这一新颖的圆柱形叶片将有利于改善圆柱形叶片的水力性能和水力效率.
Blade wrapping angle is an important geometric parameter pertinent to blade passage divergence and flow separation inside centrifugal impellers, Cylindrical blades are extensively used in low specific speed impellers. Currently several types of cylindrical blades exist, but their wrapping angles are all determined by boundary conditions at blade entrance and exit, and can＇t be specified and adjusted by designers, which has been a significant problem in improving cylindrical blade performance. Based on interpolation method in a polar coordinate system, an interpolating function of the projected curve of a new type of cylindrical blades is formulated. The most notable feature of the new curve is that its wrapping angle can be specified by impeller designer. The process and results in deriving the interpolating function of the new curve are presented; four term expressions contained in the equation are obtained. Meanwhile, some geometric properties are analyzed, which proved the blade angles at exit and entrance of the curve equal to the angles required. This kind of cylindrical blade will be beneficial to improving hydraulic performance and efficiency of low specific speed impellers.
出处
《排灌机械》
2008年第5期46-49,共4页
Drainage and Irrigation Machinery
基金
四川省重点学科项目(SZD6412)
关键词
离心泵
叶轮
可控包角
圆柱形叶片
设计
centrifugal pump
impeller
controlled wrapping angle
cylindrical blade
design
