ITERATIVE PROCESURE FOR DETERMINIG MERIDIONAL STREAMLINES OF AVERAGED FLOW IN A TURBOMACHINE IMPELLER

Designing a turbomachine impeller is a very demanding procedure, which is largely based on empirical experience. Each turbopump has its own specifics, but for all of them the assumption of axisymmetric fluid flow in their impellers is used. The flow space is divided into a certain number of axisymmetric sections in which the flow calculation is performed. To determine the kinematic characteristics of the fluid flow in the impeller of a turbomachine, the flow can be averaged over a circular coordinate, which results in averaged axisymmetric flow surfaces. According to the averaged fluid flow velocities obtained from numerical simulations of flow in turbomachine impeller, it is possible, using the integral continuity equation, to determine the meridional streamlines of the averaged fluid flow. This paper presents an iterative procedure for determining averaged axisymmetric flow surfaces in the impeller, using the integral continuity equation and the basic differential equation of averaged flow. Solving this task has a theoretical significance, because it does not aim at correcting the average velocities obtained from the results of numerical simulation of flow in the turbomachine impeller. However, determining these surfaces, using some numerical methods, can provide a better insight into how close the assumption of axisymmetric flow in the impeller is to the reality in a specific impeller design.