Optical liquid-crystal-television correlator for particle-image-velocimetry processing

1989 ◽  
Vol 14 (18) ◽  
pp. 978 ◽  
Author(s):  
P. V. Farrell ◽  
D. Goetsch
Keyword(s):  
Particle Image Velocimetry ◽  
Liquid Crystal ◽  
Particle Image ◽  
Image Velocimetry ◽  
Liquid Crystal Television

Aerothermal Investigation of a Single Row Divergent Narrow Impingement Channel by Particle Image Velocimetry and Liquid Crystal Thermography

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Alexandros Terzis ◽  
Christoforos Skourides ◽  
Peter Ott ◽  
Jens von Wolfersdorf ◽  
Bernhard Weigand
Keyword(s):  
Heat Transfer ◽  
Particle Image Velocimetry ◽  
Liquid Crystal ◽  
Flow Field ◽  
Particle Image ◽  
Field Measurements ◽  
Single Row ◽  
Transient Techniques ◽  
Liquid Crystal Thermography ◽  
Image Velocimetry

Integrally cast turbine airfoils with wall-integrated cooling cavities are greatly applicable in modern turbines providing enhanced heat exchange capabilities compared to conventional cooling passages. In such arrangements, narrow impingement channels can be formed where the generated crossflow is an important design parameter for the achievement of the desired cooling efficiency. In this study, a regulation of the generated crossflow for a narrow impingement channel consisting of a single row of five inline jets is obtained by varying the width of the channel in the streamwise direction. A divergent impingement channel is therefore investigated and compared to a uniform channel of the same open area ratio. Flow field and wall heat transfer experiments are carried out at engine representative Reynolds numbers using particle image velocimetry (PIV) and liquid crystal thermography (LCT). The PIV measurements are taken at planes normal to the target wall along the centerline for each individual jet, providing quantitative flow visualization of jet and crossflow interactions. The heat transfer distributions on the target plate of the channels are evaluated with transient techniques and a multilayer of liquid crystals (LCs). Effects of channel divergence are investigated combining both the heat transfer and flow field measurements. The applicability of existing heat transfer correlations for uniform jet arrays to divergent geometries is also discussed.

Aerothermal Investigation of a Two-Pass Rotating Cooling Channel by Means of Particle Image Velocimetry and Liquid Crystal Thermography

2018 ◽  
Author(s):  
Dimitra Tsakmakidou ◽  
Ignacio Mayo ◽  
Tony Arts
Keyword(s):  
Heat Transfer ◽  
Particle Image Velocimetry ◽  
Liquid Crystal ◽  
Particle Image ◽  
Flow Stability ◽  
Secondary Flows ◽  
Mean Flow ◽  
Liquid Crystal Thermography ◽  
Dean Vortices ◽  
Image Velocimetry

Heat transfer and aerodynamic measurements are conducted by means of Liquid Crystal Thermography and Particle Image Velocimetry in a two-pass rotating ribbed channel. The channel presents a square cross section, a sharp U-bend connecting the inlet and outlet passes and square ribs placed on two opposite walls, normal to the mean flow. In the heat transfer experimental campaign, the Reynolds (Re) and rotation (Ro) numbers are respectively ranging between 15,000–55,000 and 0–0.26 to investigate their influence upstream and downstream of the bend region. The aerodynamic measurements are taken in the symmetry plane of the channel at Re = 15,000 and Ro = 0 and 0.26, to complement the heat transfer data in the same regions. The results show how the Coriolis forces affect the flow stability and the secondary flow pattern. In the first pass, the behavior with varying Reynolds and rotation numbers is very similar to the one observed in a similar single-pass channel in terms of flow stability, velocity distribution and heat transfer performance. The measurements indicate an increase of the turbulent kinetic energy and the heat transfer downstream of the bend due to the large separation bubble, the high streamline curvature and the Dean vortices. Both the heat transfer and velocity distributions suggest that the interaction of the Dean vortices and Coriolis-induced secondary flows downstream of the bend is also highly dependent on the rotational regime.

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