Three-Dimensional Blade Design of Helico-Axial Multiphase Pump Impeller Based on Numerical Solution of Meridian Flow Net and Blade Mean Camber Lines

The three-dimensional blade design method is adopted to design the blades of the impeller of a helico-axial multiphase pump. In this design method, the flow field of the impeller is computed with the hypothesis of multiphase homogeneous flow on the basis that it is the practical flow regime in the multiphase pump. The shape of the blade is obtained from a numerical solution of the meridian flow net the on meridional plane and blade mean camber lines on stream-surfaces of revolution. First, the contour shape and size of the meridian flow channel of the impeller blade is determined by parameterization design. Second, according to the discrete data of the contour shape, the meridian streamlines are determined by iterative computation based on solving the gas-liquid two phase meridional velocity gradient equation and the two phase coupled equations with quasi-orthogonals, and the flow parameters of the meridian flow net are computed simultaneously in order that the characteristics of the meridian fluid flow can be determined. And then the distribution of velocity moments can be obtained further. Third, the blade mean camber line equation is integrated with the point-by-point integral method, and then the blade mean camber line on the stream-surface of revolution which corresponds to every meridian streamline is obtained in order to form the shape of the impeller blade surface. At last, the meridional blade elements, which are the intersecting curves of blade shape surface with several meridional planes at different angles, and the variation of blade thickness, are determined. After that, the solid modeling of the three-dimensional blade of the impeller is formed. In addition, the characteristics of the flow field of the impeller and the performance of the multiphase pump are computed by CFD numerical simulation. The position where air blocking is tends to occur was analyzed on the basis of the result of numerical simulation.