scholarly journals Transition Effect on the Flow Dynamics in a Compressor Blade Passage

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Ryszard Szwaba ◽  
Piotr Kaczynski ◽  
Janusz Telega
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Flow Control ◽  
Flow Dynamics ◽  
Boundary Layer Transition ◽  
The Other ◽  
Control Methods ◽  
Layer Transition ◽  
Blade Passage ◽  
Transition Control

An experimental investigation was carried out to study the effect of the boundary layer transition on the flow dynamics in the blade passage of a compressor cascade. A model of a turbine compressor passage was designed and assembled in a transonic wind tunnel for this purpose. Two different flow control methods were used in the experiment to induce the transition upstream of the shock wave, one concerning the microstep application and the other using distributed roughness strips. Two locations of spanwise microsteps for the transition trigger were chosen, one at the leading edge and the other closer to the shock wave position. The distributed roughness in the form of standard sandpaper strips with different heights was applied in three various locations on the blade upstream of the shock. The main objective of investigations is to present the influence of the laminar and turbulent shock wave-boundary layer interaction on the flow dynamics in a compressor fan passage, and the specific objective is to show how the parameters of particular transition control methods affect the flow dynamics in the investigated channel. The major challenge for this research was to minimize the disturbance caused by the microstep or roughness to the laminar boundary layer, while still ensuring a successful transition. Very interesting results were obtained in the flow control application for the boundary layer transition control, demonstrating a positive effect on the flow unsteadiness in changing the nature of the interaction.

Transition effect on aerodynamic performance of compressor profile

2020 ◽  
Vol 92 (4) ◽  
pp. 611-620
Author(s):  
Ryszard Szwaba ◽  
Piotr Kaczyński ◽  
Piotr Doerffer
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Aerodynamic Performance ◽  
Negative Influence ◽  
Good Choice ◽  
Boundary Layer Transition ◽  
Roughness Height ◽  
Compressor Cascade ◽  
Layer Transition ◽  
Content Type

Purpose The purpose of this paper is to study experimentally the effect of transition and also the roughness height on the flow structure of the shock wave boundary layer interaction in the blades passage of a compressor cascade. Design/methodology/approach A model of a turbine compressor passage was designed and assembled in a transonic wind tunnel. In the experiment, the distributed roughness with different heights and locations was used to induce transition upstream of the shock wave. Findings Recommendation regarding the roughness parameters for the application depends on what is more important as goal, whether the reduction of losses or unsteadiness. In case if more important are the losses reduction, a good choice for the roughness location seems to be the one close to the shock wave position. Research limitations/implications The knowledge gained by this paper will enable the implementation of an effective laminar flow technology for engines in which the interaction of a laminar boundary layer with a shock wave takes place in the propulsion system and causes severe problems. Originality/value The paper focuses on the influence of the boundary layer transition induced by different roughness values and locations on aerodynamic performance of a compressor cascade. Very valuable results were obtained in the roughness application for the boundary layer transition control, demonstrating a positive effect in changing the nature of the interaction and also some negative influence in case of oversized roughness height, which cannot be found in the existing literature.

scholarly journals Plasma-Actuated Flow Control of Hypersonic Crossflow-Induced Boundary-Layer Transition

AIAA Journal ◽  
2020 ◽  
Vol 58 (5) ◽  
pp. 2093-2108
Author(s):  
Harrison B. Yates ◽  
Eric H. Matlis ◽  
Thomas J. Juliano ◽  
Matthew W. Tufts
Keyword(s):  
Boundary Layer ◽  
Flow Control ◽  
Boundary Layer Transition ◽  
Layer Transition

Separated Flow Transition on an LP Turbine Blade With Pulsed Flow Control

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Jeffrey P. Bons ◽  
Daniel Reimann ◽  
Matthew Bloxham
Keyword(s):  
Boundary Layer ◽  
Flow Control ◽  
Turbine Blade ◽  
Separation Bubble ◽  
Operating Conditions ◽  
Boundary Layer Transition ◽  
Single Element ◽  
Layer Transition ◽  
Flow Measurements ◽  
Pulsed Flow

Flow measurements were made on a highly loaded low pressure turbine blade in a low-speed linear cascade facility. The blade has a design Zweifel coefficient of 1.34 with a peak pressure coefficient near 47% axial chord (midloaded). Flow and surface pressure data were taken for Rec=20,000 with 3% inlet freestream turbulence. For these operating conditions, a large separation bubble forms over the downstream portion of the blade suction surface, extending from 59% to 86% axial chord. Single-element hot-film measurements were acquired to clearly identify the role of boundary layer transition in this separated region. Higher-order turbulence statistics were used to identify transition and separation zones. Similar measurements were also made in the presence of unsteady forcing using pulsed vortex generator jets just upstream of the separation bubble (50% cx). Measurements provide a comprehensive picture of the interaction of boundary layer transition and separation in this unsteady environment. Similarities between pulsed flow control and unsteady wake motion are highlighted.

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