TIME-ACCURATE EULER SIMULATION OF INTERACTION OF NOZZLE WAKE AND SECONDARY FLOW WITH ROTOR BLADE IN AN AXIAL TURBINE STAGE USING NONREFLECTING BOUNDARY-CONDITIONS

Citation
S. Fan et B. Lakshminarayana, TIME-ACCURATE EULER SIMULATION OF INTERACTION OF NOZZLE WAKE AND SECONDARY FLOW WITH ROTOR BLADE IN AN AXIAL TURBINE STAGE USING NONREFLECTING BOUNDARY-CONDITIONS, Journal of turbomachinery, 118(4), 1996, pp. 663-678
Citations number
15
Categorie Soggetti
Engineering, Mechanical
Journal title
ISSN journal
0889504X
Volume
118
Issue
4
Year of publication
1996
Pages
663 - 678
Database
ISI
SICI code
0889-504X(1996)118:4<663:TESOIO>2.0.ZU;2-D
Abstract
The objective of this paper is to investigate the three-dimensional un steady flow interactions in a turbomachine stage. A three-dimensional time-accurate Euler code has been developed using an explicit four-sta ge Runge-Kutta scheme. Three-dimensional unsteady nonreflecting bounda ry conditions are formulated at the inlet and the outlet of the comput ational domain to remove the spurious numerical reflections. The three -dimensional code is first validated for two-dimensional and three-dim ensional cascades with harmonic vortical inlet distortions. The effect iveness of the nonreflecting boundary conditions is demonstrated. The unsteady Euler solver is then used to simulate the propagation of nozz le wake and secondary flow through the rotor and the resulting unstead y pressure field in an axial turbine stage. The three-dimensional and time-dependent propagation of of nozzle wakes in the rotor blade row a nd the effects of nozzle secondary flow on the rotor unsteady surface pressure and passage flow field are studied. It was found that the uns teady flow field in the rotor is highly three dimensional and the nozz le secondary flow has significant contribution to the unsteady pressur e on the blade surfaces. Even though the steady flow at the midspan is nearly two dimensional, the unsteady flow is three dimensional and th e unsteady pressure distribution cannot be predicted by a two-dimensio nal analysis.