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ABSTRACT
In recent decade, industry had started to use intensively 3D
simulation in turbine flow path and its components design. At the
same time, this remains a very labor- and time-consumable process
that sufficiently hampers its usage, whereas unidimensional and
axisymmetric analyses are still widely used in the industry
practice. A comparison of the data obtained from experiments
conducted on a single stage air turbine test model with the results
of 1D and 2D modeling and 3D simulation using a CFD solver
was performed. The results were analyzed to validate a judgement
of the authors that along with 3D CFD methods the low-fidelity
models can be successfully used for turbine flow path optimization
with the help of DoE methods. The forthcomings and advantages
of different models are also discussed.
Key words: Modeling/Experiment Data Comparison, 1D/2D/
3D Analysis, Optimization.
INTRODUCTION
The validation of the computations remains a subject of
meticulous attention in the industry. Some authors introduce
the results of comparison of the turbine rig test data with 2D
computations [1, 2]. An objective of this study was to correlate
the results of 1D, 2D and 3D aerodynamic computations with
the proven test data extracted from experiments on several
designs of a single stage test air turbine.
It was shown that proper unidimensional and axisymmetric
models based on validated empiric methods of loss
computation provide an accuracy of the flow path parameters
estimation sufficient for solving a bulk of practice valuable
optimization problems.
The turbine multidisciplinary optimization problems are the
topic of different authors’ research (see, for example, the list of
references presented in [3]).
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It was proposed to perform optimization on
parameterized geometrical 3D models of blade rows or
stages utilizing the design of numerical experiment
(DoE) technique [4, 6], earlier applied to optimization
on 1D and 2D models. Aside from the problems of
aerodynamic optimization, this permits to solve the
problems of multidisciplinary optimization with regard
to, for instance, strength, vibration and other limitations.
NOMENCLATURE AND GLOSSARY
| (u/C0)opt |
Optimal isentropic velocity ratio; |
| ξ n% |
relative loss in nozzle vane; |
| ξ b % |
relative loss in blade; |
| ξex % |
relative loss with exit velocity; |
| ηi% |
intrinsic efficiency; |
| G |
fluid flow rate; |
| ω |
rotation frequency; |
| δr |
tip clearance; |
| α1 |
nozzle outlet angle; |
| β2 |
blade outlet angle; |
| Co |
isentropic velocity; |
| l |
blade height; |
| D |
diameter; |
| u |
circumferential velocity; |
| NURBS |
non-uniform rational B-spline; |
| Effective (gauging)
vane/blade exit angle |
α (β)eff=arcsin a/t,
where a - throat; t – pitch. |
| Tip clearance |
a clearance between blading shroud
and peripheral seal fins |
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