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

Date

2001-06-07

Author

Uzol, Oğuz

Metadata

Show full item record

Item Usage Stats

295
views

0
downloads

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

Subject Keywords

Computational fluid dynamics, Flow of fluids, Flow visualization, Heat transfer, Kinetics, Momentum

URI

https://hdl.handle.net/11511/82412
https://www.scopus.com/record/display.uri?eid=2-s2.0-84905726129&origin=resultslist&sort=plf-f&src=s&st1=&st2=&sid=5451c1c01b64693211e1a4729e79ae0a&sot=b&sdt=b&sl=204&s=TITLE-ABS-KEY+%28Elliptical+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%29&relpos=0&citeCnt=15&searchTerm=

Conference Name

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", ASME Turbo Expo 2001: Power for Land, Sea, and Air, 4 - 07 Haziran 2001

Collections

Department of Aerospace Engineering, Conference / Seminar

Suggestions

OpenMETU
Core

Elliptical pin fins as an alternative to circular pin fins for gas turbine blade cooling applications part 1 endwall heat transfer and total pressure loss characteristics Uzol, Oğuz (null; 2001-06-07) Detailed experimental investigation of the wall heat transfer enhancement and total pressure loss characteristics for two alternative elliptical pin fin arrays is conducted and the results are compared to the conventional circular pin fin arrays. Two different elliptical pin fin geometries with different major axis lengths are tested, both having a minor axis length equal to the circular fin diameter and positioned at zero degrees angle of attack to the free stream flow. The major axis lengths for the two e...
Incompressible flow simulations using least squares spectral element method on adaptively refined triangular grids Akdağ, Osman; Sert, Cüneyt; Department of Mechanical Engineering (2012) The main purpose of this study is to develop a flow solver that employs triangular grids to solve two-dimensional, viscous, laminar, steady, incompressible flows. The flow solver is based on Least Squares Spectral Element Method (LSSEM). It has p-type adaptive mesh refinement/coarsening capability and supports p-type nonconforming element interfaces. To validate the developed flow solver several benchmark problems are studied and successful results are obtained. The performances of two different triangular ...
Improving flow structure and natural convection within fin spacings of plate fin heat sinks Özet, Mehmet Erdem; Tarı, İlker; Department of Mechanical Engineering (2015) The main objectives of this thesis are to numerically investigate the previously observed recirculation zones and longitudinal vortices that occur in low fin height plate finned horizontal heat sinks and to improve the flow structures and heat transfer in these zones using various approaches with the help of simulations performed using commercially available CFD software. The approaches used for improvements are replacing the outer most fins with higher ones, introducing gaps on the length of the fins in va...
Numerical Simulation of Reciprocating Flow Forced Convection in Two-Dimensional Channels Sert, Cüneyt (ASME International, 2003-5-20) <jats:p>Numerical simulations of laminar, forced convection heat transfer for reciprocating, two-dimensional channel flows are performed as a function of the penetration length, Womersley (α) and Prandtl (Pr) numbers. The numerical algorithm is based on a spectral element formulation, which enables high-order spatial resolution with exponential decay of discretization errors, and second-order time-accuracy. Uniform heat flux and constant temperature boundary conditions are imposed on certain regions of the ...
Numerical and experimental analysis for comparison of square, cylindrical and plate fin arrays in external flow İnci, Aykut Barış; Bayer, Özgür; Department of Mechanical Engineering (2018) Geometrical optimization of square, cylindrical and plate fins for heat transfer augmentation is numerically performed in the external flow. Heat transfer performance of fins with different profiles are compared with same Reynolds number. The relation between the thermal characteristic of fins and boundary conditions like free-stream velocity and heat input are investigated. Experimental studies are performed using manufacturable fins to validate numerical model. Heat transfer correlations are derived in or...

Citation Formats

O. Uzol, “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,” presented at the 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”, ASME Turbo Expo 2001: Power for Land, Sea, and Air, 4 - 07 Haziran 2001, New Orleans, United States, 2001, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/82412.