Analysis Of Turbo Rotor Dynamic Properties With Fluid-structure Interactions For A Liquid-propellant Rocket Engine

Turbine blade is an important part of rotor systems in the turbo-pump of a liquid-propellant rocket engine. The fluid-structure interaction between turbine blade and fluid has a great impact on the performance of the turbo-pump. The numerical analysis for the flow of fluid between two adjacent blades is helpful to understand the fluid-structure interactions between the blades and the fluid. The conclusions can provide theoretical references for the dynamic designs and improvements.In the present paper, the fluid-structure interactions between the blades and fluid are investigated. The steady state properties of the flow between two adjacent blades are analyzed by the physical modeling, theoretical analyses and numerical calculations. The numerical integrations based on the complete Navier-Stokes equations are too complex and time consuming due to the complexity of the flow between the blades. The NURBS method is adapted to construct the physical model of the turbine blades. The corresponding governing equations for the fluid flow between the two adjacent blades are developed based on the Bulk-Flow model and according to Hirs turbulent flow theory and Blasius friction coefficient equations. The nondimensional zeroth perturbation equations are obtained by the dimensionless analysis for the steady state properties of flow. Three discretized governing equations are developed with the staggered grid and the finite deference method. A computer code for solving the governing equations is written by using the SIMPLE algorithm. The steady state pressure and velocity distributions of the fluid are obtained with the code. It is shown that at the root of the blades, the pressure reaches the maximum value but the circumferential and path velocities the minimum value; at the tip of the blades, the pressure gets its minimum value but the circumferential and path velocities the maximum value; the pressure reduces gradually along the path downward and the radius outward; the circumferential velocity increases gradually along the radius outward and the path velocity reduces gradually along the path downward but increases along the radius outward. These conclusions are of theoretical significance for guiding the dynamic designs of the turbine blades of the liquid-propellant rocket engines.In order to verify the results, comparisons are done between the results from the present paper and those from the commercial software FLUENT and the experiments. It is shown that the method used in the present paper, which is based on the Bulk-Flow model, can simplify the governing equations of flow when solving the flow problems in very small gaps and reduce the computational work without compromising the preciseness of the results. But considerable discrepancies between the results from the present paper and those form experiments occur when solving the flow problems in larger gaps.