Open AccessSimulation and Experimental Investigation of the Stay Vane Channel Flow in a Reversible Pump Turbine at Off-Design Conditions
Author(s) -
Sandro Erne,
Gernot Edinger,
Anton Maly,
Christian Bauer
Publication year - 2017
Publication title -
periodica polytechnica. mechanical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.259
H-Index - 16
eISSN - 1587-379X
pISSN - 0324-6051
DOI - 10.3311/ppme.9345
Subject(s) - shroud , stall (fluid mechanics) , mechanics , turbine , transient (computer programming) , flow (mathematics) , computational fluid dynamics , engineering , simulation , materials science , physics , mechanical engineering , computer science , operating system
This work presents the assessment of the mean flow field and low frequency disturbances in the stay vane channel of a model pump turbine using transient numerical simulations and LDV-based measurements. The focus is laid on transient CFD simulations of characteristic flow states in the stay vane channel when operating at off-design conditions in pump mode. Experimental and numerical investigations obtained a shifting velocity distribution between the shroud and hub of the distributor when continuously increasing the discharge in the part-load range. Simulations captured the occurrence of this changing flow state in the stay vane channel reasonably well. A further increase of the discharge showed a uniformly redistributed mean flow of both hub and shroud side. Monitoring points and integral quantities from measurements and transient simulations were used to interpret the development of transient flow patterns in the stay vane channel at the operating point of strongest asymmetrical flow. During simulation and measurement, a dominant rotating stall inception was observed near the design flow of the pump turbine. At this point where the stall becomes severe, a high level of correlation between the signals of the upper and lower stalled flow in the stay vane channel was calculated. Further simulations for different guide vane positions predicted a strong influence of the guide vane position on the structure of rotating stall.