جریان تراکم پذیر بر روی یک توربین آبشاری - Compressible Flow over a Turbine Cascade

Introduction

The purpose of this tutorial is to provide guidelines and recommendations for solving a real world CFD problem which includes

 Building the geometry and generating a mesh in GAMBIT
 Setting up the CFD model in FLUENT
Solving the problem and comparing the results with the experimental data

The problem is to predict the performance of a highly-loaded linear transonic turbine guide vane cascade. The experimental measurements were performed at the Von Karman Institute for Fluid Dynamics

Problem Description

The schematic of the problem is shown in Figure. The linear cascade consists of 5 blades. The central blade is instrumented for data measurements and is also the focus of this numerical simulation. The incident flow angle to the cascade is 0 degree. Isentropic Mach number at the outlet is 0.84, and outlet Reynolds number is 1e6. The boundary conditions of total pressure, total temperature, turbulence intensity are

143500 Pa	Total Pressure-absolute
300 K	Total Temperature
5 %	Turbulence Intensity
12 mm	Turbulence Length Scale

Static pressure at the outlet is 90405 Pa. Periodicity of the flow through the cascade allows
the use of periodic boundary condition along the top and the bottom sides of the domain surrounding the central blade

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دانلود فایل های اموزشی

 

Availability	File
	Tutorial - pdf
	Mesh
	Case and Data

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ماشین های دوار- Solving Transonic Flow over a Turbine Blade with Turbo-Specific NRBCs

Introduction
The standard pressure boundary conditions for compressible flow fix specific flow variables at the boundary (e.g., static pressure at an outlet boundary). a

As a result, pressure waves incident on the boundary will reflect in an unphysical manner, leading to local errors. The effect are more pronounced for internal flow problems where boundaries are usually close to geometry inside the domain, such as compressor or turbine blade rows

The turbo-specific non-reflecting boundary conditions (NRBCs) permit waves to pass through the boundaries without spurious reflections. The method used in FLUENT is based on the Fourier transformation of solution variables at the non-reflecting boundary

This tutorial demonstrates how to do the following
Set up and solve the turbine blade flow eld using the standard pressure outlet boundary treatment -
Activate the turbo-specic NRBCs and solve the problem again -
Compare the results for the standard and non-reflecting pressure boundaries -

ادامه نوشته