Unsteady pressure measurement and numerical simulations in an end-wall region of a linear blade cascade

• Published in: SN applied sciences 2021-08, Vol.3 (8), p.761-12, Article 761
• Main Authors: Flídr, Erik, Straka, Petr, Kladrubský, Milan, Jelínek, Tomáš
• Format: Article
• Language: English
• Subjects: Applied and Technical Physics; Cascade flow; Chemistry/Food Science; Compressibility; Compressibility effects; Earth Sciences; Engineering; Environment; Flow; Fluid flow; Inlet flow; Investigations; Linear blade cascade; Mach number; Materials Science; Mathematical models; Numerical models; Numerical prediction; Numerical simulations; Position measurement; Power spectra; Pressure; Pressure measurement; Pressure transducers; Research Article; Reynolds number; Secondary flow; Shock waves; Simulation; Suction; Surface flow; Unsteady pressure measurement; Viscosity; Visualization; Vortices; Wall flow
• ISSN: 2523-3963; 2523-3971
• DOI: 10.1007/s42452-021-04737-8

This contribution describes experimental and numerical research of an unsteady behaviour of a flow in an end-wall region of a linear nozzle cascade. Effects of compressibility ( M 2 , is ) and inlet flow angle ( α 1 ) were investigated. Reynolds number ( R e 2 , is = 8.5 × 10 5 ) was held constant for all tested cases. Unsteady pressure measurement was performed at the blade mid-span in the identical position s to obtain reference data. Surface flow visualizations were performed as well as the steady pressure measurement to support conclusions obtained from the unsteady measurements. Comparison of the surface Mach number distributions obtained from the experiments and from the numerical simulations are presented. Flow visualizations are then compared with calculated limiting streamlines on the blade suction surface. It was shown, that the flow structures in the end-wall region were not affected by the primary flow at the blade mid-span, even when the shock wave formed. This conclusion was made from the experimental, numerical, steady as well as unsteady points of view. Three significant frequencies in the power spectra suggested that there was a periodical interaction between the vortex structures in the end-wall region. Based on the data analyses, anisotropic turbulence was observed in the cascade. Article Highlights Periodic flow behaviour was found in the near-wall region. Complicated flow structures occur in the position where the shock wave inter- acted with the near-wall flow. In house numerical model can predict the flow properties with accuracy de- scribed in the paper.