Comparison of Visualized Turbine Endwall Secondary Flows and Measured Heat Transfer Patterns

Abstract

Various flow visualization techniques were used to define the secondary flows near the endwall in a large scale turbine vane cascade. The cascade was scaled up from one used to generate endwall heat transfer data under a joint NASA-USAF contract. A comparison of the visualized flow patterns and the measured Stanton number distributions was made for cases where the inlet Reynolds number and exit Mach number were matched. Flows were visualized by using neutrally buoyant helium-filled soap bubbles, by using smoke from oil soaked cigars, and by a new technique using permanent marker pen ink dots and synthetic wintergreen oil. For the first time, details of the horseshoe vortex and secondary flows can be directly compared with heat transfer distributions. Near the cascade entrance, there is an obvious correlation between the two sets of data, but well into the passage the effect of secondary flow is not as obvious.

Effect of Simulated Combustor Temperature Nonuniformity on HP Vane and End Wall Heat Transfer: An Experimental and Computational Investigation

“…The work by Harvey and Jones [5]. Gaugler and Rus-.sell [8], and Spencer et al [9] is an example of such analysis. Other work done in this area includes the work by Harvey et al [10], Kang and Thole [II], and Kang et al [12] on the effects of the secondary flows on end wall heat transfer characteristics; the work by Friedrich et al [13] and Knost and Thole [14,15] on the effectiveness of end wall cooling; the work by Harvey et al [16].…”

Influence of different film cooling arrangements on endwall cooling

“…The vortices originate from the leading edge horseshoe vortex migrate and develop through the entire passage [4]. The early researches on endwall mainly focused on the flow field structures, aerodynamic and heat transfer characteristics when it was unnecessary to cool the endwall [5][6][7]. Afterwards discrete film holes were applied to the endwall cooling.…”

Film cooling effectiveness distribution of cylindrical hole injections at different locations on a vane endwall

“…The vortices originate from the leading edge horseshoe vortex migrate and develop through the entire passage [4]. The early researches on endwall mainly focused on the flow field structures, aerodynamic and heat transfer characteristics when it was unnecessary to cool the endwall [5][6][7].…”