Численная модель проточной части ЦНД мощной паровой турбины с учетом протечек

Abstract

Рассмотрены результаты расчетно-конструкторских разработок и численных исследований проточной части цилиндра низкого давления (ЦНД) турбины К-1250-6,9/25 с учетом отборов пара, протечек через диафрагменные, надбандажные уплотнения и разгрузочные отверстия в дисках, и отсоса влагоемкого пара из межвенцового зазора последних ступеней. Представлены некоторые методические аспекты и результаты совершенствования исследованных объектов с помощью численного эксперимента.

The results of computational and engineering developments and numerical studies of low pressure cylinder of five stages are represented, taking into account the steam extraction, leakages under the diaphragms, shroud seals and discharge openings in the disks of the turbine K-1250-6.9/25. All the computations were done by MTFS®oftware, ensured the integration of Reynolds-Favre averaged Navier-Stokes equations, were based on the model of one speed wet steam flow without droplets and super cooling were not taken into account. The sectorial approach was applied to description of the interaction of the inlet pipe, the group stages and exhaust hood. The stages were considered in steady state formulation. The initial data and boundary conditions were taken basing on thermal design of "TURBOATOM". The calculated domains were approximated by unstructured hexahedral meshes. The rigid walls were supposed adiabatic under condition of adhesion. The turbulent phenomena were described basing on the SST model of F.Menter. Some methodological aspects and the directions for improving of studied facilities by numerical experiment by MTFS® code are discussed. The initial version of low pressure cylinder of slow-motion steam turbine К-1250-6.9/25 is considered. The variants of Inlet are considered taking in view the parameters: height and form of flow divider, throat size etc. It is shown, that blade №4 needs to be improved because of aerodynamically imperfect profile in wire zone. Also blades № 4, 5 flow around under attacks angle. So these stages need to be adjusted.