University of Stuttgart |
ITSM
|
|
University of Stuttgart |
ITSM
|
Institute of Thermal Turbomachinery
and Machinery Laboratory
Section Numerical Methods for Thermal Turbomachinery
Head: Dr.-Ing. J. F. Mayer
J. E. Anker, K. Findeisen, P. Gerkens, M. Rath, U. Seybold
Visualization (JPEG, 94 kB):
Unsteady pressure distribution in a turbine stage (red: high pressure, blue:
low pressure)
Video animation and
description: Visualization of stator/rotor interaction in a transonic
turbine stage
Excerpt from the presentation
"Simulation of the Unsteady Flow in a Turbine Stage with Outlet Guide Vane
Using a Time-Inclination Method" at the ERCOFTAC Seminar and Workshop on
3D Turbomachinery Flow Prediction V, Courchevel, France, January 6-9, 1997
Title-page of Springer book "High
Performance Computing in Science and Engineering '98" by E. Krause and
W. Jäger (Eds.), ISBN 3-540-65030-X, 1999
Scope of work and equipment
The essential quality features of a turbomachine - efficiency and reliability
- are decisively determined by the blading. The efficiency depends mostly
on the quality of the blades' aerodynamical design. A high reliability can
only be guaranteed if a vibration analysis of the blades has been carried
out. These design aspects can be supported and even determined by numerical
methods. The institute has got an appropriate equipment of workstations for
software development, pre- and post-processing and for the computation of
such problems; problems that require a very large amount of computer time
can be evaluated on the supercomputers of the High Performance Computing Center
Stuttgart.
Computational fluid dynamics
The current research in computational fluid dynamics and its applications focus on turbomachinery internal flows. The finite volume flow solver ITSM3D has been developed to calculate the three-dimensional transonic viscous flow field described by the Navier-Stokes equations. The code is suitable to multi-stage turbomachinery flow applications. Another feature is the modelling and prediction of the leakage flows over the blade tips. A parallel version of the code has been developed so as to allow significant gains in efficiency while increasing the number of grid points for the calculation.
The flow in turbomachines is inherently unsteady due to the relative motion of the stator and the rotor blade rows. However, steady-state simulations of the actually unsteady flow are useful to optimize the geometry of the blades and the flow channel contour. The unsteady phenomena of the flow such as pressure wave motion, vortex shedding or the unsteady loading on the blades can be predicted with the flow solver being switched to its time-accurate mode. In this mode the solver is able to simulate the direct interaction of the flow in multi-blade row environment even if the number of stator blades is different from the number of rotor blades.
The analysis of the complex three-dimensional unsteady flow field inside a turbomachine requires efficient visualization tools. Computer and video animations carried out with software specifically adapted to multi-stage applications have proven very helpful to extract certain flow features and to better understand the flow physics. An example for an animation of the unsteady flow through a turbomachinery stage is offered here by means of an 19 MB MPEG-file.
An additional research topic deals with the behaviour of the flow between
oscillating blades. The objective of this project is to provide a tool for
the prediction of flow effects in blade channels that can arise from the
interaction between shocks and boundary layers. Related to this project is
the investigation of buffeting in turbomachine diffusers with the aims of
improving the efficiency of the machine and reducing the noise emission and
the excitation of last stage blade vibrations.
Structural dynamics
The investigations in structural dynamics deal with:
E-mail: Jürgen F. Mayer