Calculation of Pressure Pulsations in the Flow Part of the First Stage of an Axial Turbine in the Rotor-Stator Interaction Zone

S. F. Timushev,A. V. Kondratov,Y. Klochkov

doi:10.1051/e3sconf/202132004011

Abstract

A serious problem in the development of reusable liquid-propellant rocket engines (LRE) is the provision of a high resource and reliability of gas turbines of turbopump, which supply fuel to the combustion chamber. This problem can be solved by reducing the level of pressure pulsations in the interaction zone of the turbine rotor-stator and dynamic loads acting on the working and stator blades. In this regard, a useful tool is the method of numerical simulation of the unsteady turbulent flow of a compressible gas in the turbine flow path with the determination of the amplitude of pressure pulsations in the axial clearance between the stator and rotor blade cascades. The calculation model includes the Navier-Stokes equations and equation of energy. Density, thermal conductivity and diffusion coefficient are linearly dependent on temperature and concentration. Calculations were performed on different meshes, proving the mesh convergence of the method upon reaching the quasi-stationary regime. The calculation results show that the pressure pulsations vary greatly with the axial clearance, and the main frequency of the pressure pulsations in the spectrum is the blade passing frequency. The frequency of dynamic moment acting on the blade also coincides with the indicated frequency.

Highlights

The creation of new reusable transport rocket and space systems makes increased demands on the reliability and service life of the turbopump machines of liquidpropellant rocket engines (LRE)
An increase in the efficiency and power density of LRE turbomachines brings to the fore the problems caused by unsteadiness of the flow: up to 70 % of failures of modern liquidpropellant rocket engines are associated with damage to the structural elements of the fuel feed system due to the high level of vibration of the turbopump units, primarily turbines and centrifugal pumps
In unsteady flow and generation of pressure pulsations and vibration in a turbopump unit, an important role plays the interaction of vortex turbulent flows in the flow path, the presence of two-phase flow zones, resonant amplification of oscillations, and other factors

Summary

Introduction

In these subdomains, the initial computational grid is adapted, the cells of the initial grid are divided into 8 equal cells of the new adaptation level. The cells through which the border passes lose their original parallelepiped shape and turn into freeform polyhedrons This approach makes it possible to perform calculations with a sufficient degree of accuracy, minimizing computational resources and processor time

Equations of hydrodynamics of a compressible medium and boundary conditions

Geometry model

Results

Conclusions