Endoscopic 2D particle image velocimetry (PIV) flow field measurements in IC engines

2002 ◽  
Vol 33 (6) ◽  
pp. 794-800 ◽  
Author(s):  
U. Dierksheide ◽  
P. Meyer ◽  
T. Hovestadt ◽  
W. Hentschel
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Particle Image ◽  
Field Measurements ◽  
Image Velocimetry ◽  
Ic Engines

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.

Electroosmotic Flow Field Measurements With Particle Image Velocimetry

2000 ◽  
Author(s):  
Shankar Devasenathipathy ◽  
Joshua I. Molho ◽  
James C. Mikkelsen ◽  
Juan G. Santiago ◽  
Kohsei Takehara
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Electric Field ◽  
Particle Tracking ◽  
Electroosmotic Flow ◽  
Particle Image ◽  
Field Measurements ◽  
Local Electric Field ◽  
Seed Particles ◽  
Image Velocimetry

Abstract A micron-resolution particle image velocimetry (PIV) system has been developed to spatially and temporally resolve electroosmotic flow fields within microfluidic bioanalytical devices. A second diagnostic technique, particle tracking velocimetry (PTV) has been used to determine the distribution of electrophoretic mobilities of seed particles and thereby make the PIV measurements quantitative. This second particle tracking technique has been used to determine probability distribution functions of the seed particles. Results from simulations of electric fields yield local electric field strengths in the geometries of interest. The measured mean mobility of the seed particles (obtained from PTV measurements) is then multiplied by the local electric field vector to obtain the electrophoretic velocity. The variance on the particle mobility measurement influences the errors introduced in the electroosmotic flow measurements. After total particle velocities are measured within a microfluidic system of interest, the seed particle electrophoretic velocities are subtracted from the PIV total velocity data to obtain electroosmotic flow field velocities. Ensemble-averaged velocity field measurements for electroosmotic flow at the intersection of a cross-channel are presented.

Flow Field Measurements in Gain Zone of XeF(C-A) Gas Laser Based on Particle Image Velocimetry

2019 ◽  
Vol 46 (2) ◽  
pp. 0204007
Author(s):  
栾昆鹏 Luan Kunpeng ◽  
叶景峰 Ye Jingfeng ◽  
王晟 Wang Sheng ◽  
沈炎龙 Shen Yanlong ◽  
赵柳 Zhao Liu ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Particle Image ◽  
Field Measurements ◽  
Gas Laser ◽  
Image Velocimetry

scholarly journals Feasibility of Optical Flow Field Measurements of the Coolant in a Grinding Machine

2021 ◽  
Vol 11 (24) ◽  
pp. 11615
Author(s):  
Björn Espenhahn ◽  
Lukas Schumski ◽  
Christoph Vanselow ◽  
Dirk Stöbener ◽  
Daniel Meyer ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Fluid Flow ◽  
Flow Field ◽  
Optical Flow ◽  
Particle Image ◽  
Field Measurements ◽  
Optical Flow Field ◽  
Metalworking Fluid ◽  
Image Velocimetry ◽  
Grinding Machine

For industrial grinding processes, the workpiece cooling by metalworking fluids, which strongly influences the workpiece surface layer quality, is not yet fully understood. This leads to high efforts for the empirical determination of suitable cooling parameters, increasing the part manufacturing costs. To close the knowledge gap, a measurement method for the metalworking fluid flow field near the grinding wheel is desired. However, the varying curved surfaces of the liquid phase result in unpredictable light deflections and reflections, which impede optical flow measurements. In order to investigate the yet unknown optical measurement capabilities achievable under these conditions, shadowgraphy in combination with a pattern correlation technique and particle image velocimetry (PIV) are applied in a grinding machine. The results show that particle image velocimetry enables flow field measurements inside the laminar metalworking fluid jet, whereby the shadowgraph imaging velocimetry complements these measurements since it is in particular suitable for regions with spray-like flow regimes. As a conclusion, optical flow field measurements of the metalworking fluid flow in a running grinding machine are shown to be feasible.

Elliptical Pin Fins as an Alternative to Circular Pin Fins for Gas Turbine Blade Cooling Applications: Part 2 — Wake Flow Field Measurements and Visualization Using Particle Image Velocimetry

2001 ◽  
Author(s):  
Oğuz Uzol ◽  
Cengiz Camci
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Particle Image ◽  
Field Measurements ◽  
Wake Flow ◽  
Wake Region ◽  
Pin Fin ◽  
Image Velocimetry ◽  
Pin Fins ◽  
Pin Fin Arrays

Extensive wake flow field measurements and visualizations are conducted using particle image velocimetry (PIV) inside the wakes of the elliptical and circular pin fin arrays in order to better understand the flow physics and the loss mechanisms of these devices. The true-mean velocity field inside the wake two diameters downstream of the pin fin arrays is obtained by collecting and ensemble averaging a large number of PIV samples in the midplane of the test section. Additional experiments are also conducted inside the very near wake of the pin fins in order to visualize instantaneous flow field features. The results of the study reveal that the circular pin fin array creates a large low momentum wake region when compared to the elliptical pin fin arrays. It is observed from the flow visualization inside the wake that this kind of a very large momentum deficit is created due to the early separation of the flow from the circular fins in the second row. In the case of elliptical fins, however, the flow stays attached to the fin surface and the separation occurs very close to the downstream stagnation point on the surface which in turn results in a very small low momentum wake region behind the elliptical pin fin arrays. The mean turbulent kinetic energy levels from the PIV measurements show very high turbulence levels in the wake of the circular fin arrays compared to the elliptical fins. However, the smaller momentum deficit inside the elliptical pin fin wakes results in higher local Reynolds numbers inside the wake when compared to the circular pin fin wakes. This in turn helps to keep the endwall heat transfer enhancement levels close to the circular fin arrays although the turbulence levels are much lower in this region.

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