A Swirl Cooling Flow Experimental Investigation on a Circular Chamber Using Three-Dimensional Stereo-Particle Imaging Velocimetry

2019 ◽  
Vol 142 (4) ◽  
Author(s):  
Daisy Galeana ◽  
Asfaw Beyene
Keyword(s):  
Experimental Investigation ◽  
Axial Velocity ◽  
Three Dimensional ◽  
Swirl Flow ◽  
Internal Cooling ◽  
Swirl Number ◽  
Cooling Flow ◽  
Downstream Distance ◽  
Flow Phenomena ◽  
Particle Imaging

Abstract An experimental investigation is presented using three-dimensional (3-D) stereo-particle image velocimetry (stereo-PIV) of a swirl flow that models a gas turbine blade internal cooling configuration. The study is intended to provide an evaluation of the developments of the swirl cooling flow methodology utilizing the 3-D stereo-PIV. The objective is to determine the critical swirl number that has the potential to deliver the maximum axial velocity results. The swirl cooling flow methodology comprises cooling air channeling through the blade’s internal passages lowering the temperature; therefore, the experimental circular chamber is made of acrylic allowing detailed measurements and includes seven discrete tangential jets designed to create the swirl flow. An oil particle seeder (LAVision) is used to provide the particles for velocity measurements while the clear acrylic chamber allows visualization of the flow phenomena. The post-processed data are completed using davis, velocity calculations are conducted in matlab, and techplot is used for data visualization. The focus of this investigation is on the continuous swirl flow that must be sustained via continuous injection of tangential flow at three different Reynolds number, 7000, 14,000, and 21,000, where the swirl flow is generated with seven inlets. Important variations in the swirl number are present near the air inlets and decreases with downstream distance as predicted, since the second half of the chamber has no more inlets. The axial velocity reaches the maximum downstream in the second half of the chamber. The circumferential velocity decreases the downstream distance and reaches the highest toward the center of the chamber.

Experimental Study of Swirl Cooling Flow on a Circular Chamber Using 3-D Stereo-PIV

2018 ◽  
Author(s):  
Daisy Galeana ◽  
Asfaw Beyene
Keyword(s):  
Experimental Study ◽  
Turbine Blades ◽  
Swirl Flow ◽  
Internal Cooling ◽  
Swirl Number ◽  
Maximum Heat ◽  
Cooling Flow ◽  
Maximum Heat Transfer ◽  
Flow Phenomena ◽  
Cooling Air

Experimental study of a swirl flow using 3-D Stereo-PIV (Particle Image Velocimetry) that models a gas turbine blade internal cooling configuration is presented. The work is intended to provide an understanding of the advancements of swirl cooling flow methodology utilizing 3-D Stereo-PIV. The study aims at determining the critical swirl number that has the potential to deliver the maximum heat transfer results. In the swirl cooling flow methodology, cooling air is routed to the turbine blades where it passes through the blade’s internal passages lowering the temperature. An experimental setup with seven discrete tangential jets at three different Reynolds numbers is designed to allow detail measurements of the flow. To provide the particles for velocity measurements an oil particle seeder (LAVision) is used. The circular chamber is made of clear acrylic to allow visualization of the flow phenomena. Data is post-processed in DaVis, velocity calculations are conducted in MATLAB, and TechPlot is used for data visualization. This investigation focuses on the continuous swirl flow that must be maintained via continuous injection of tangential flow, where swirl flow is generated with seven inlets and decays with downstream distance. It was also determined that the critical swirl number, Sn, depends greatly on the location and size of the tangential slots.

Merging flows in an arterial confluence: the vertebro-basilar junction

1995 ◽  
Vol 304 ◽  
pp. 119-141 ◽  
Author(s):  
J. Ravensbergen ◽  
J. K. B. Krijger ◽  
B. Hillen ◽  
H. W. Hoogstraten
Keyword(s):  
Velocity Profile ◽  
Flow Pattern ◽  
Basilar Artery ◽  
Axial Velocity ◽  
Average Length ◽  
Rectangular Cross Section ◽  
Three Dimensional ◽  
Axial Velocity Profile ◽  
Flow Phenomena ◽  
Junction Geometry

The basilar artery is one of the three vessels providing the blood supply to the human brain. It arises from the confluence of the two vertebral arteries. In fact, it is the only artery of this size in the human body arising from a confluence instead of a bifurcation. Earlier work, concerning flow computations in simplified models of the basilar artery, has demonstrated that a junction causes distinctive flow phenomena. This paper presents three-dimensional finite-element computations of steady viscous flow in a rigid symmetrical junction geometry representing the anatomical situation in a more realistic way. The geometry consists of two round tubes merging into a single round outlet tube. The Reynolds number for the basilar artery ranges from 200 to 600, and both symmetrical and asymmetrical inflow from the two inlet tubes has been considered.Just downstream of the confluence a ‘double hump’ axial velocity profile is found. In the transition zone the flow pattern appears to have a complicated structure. In the symmetrical case the axial velocity profile shows a sharp central ridge, whereas in the asymmetrical case the highest ‘hump’ crosses the centreline of the tube. The flow has a highly three-dimensional character with secondary velocities easily exceeding 25% of the mean axial flow velocity. The secondary flow pattern consists of four vortices. Under all simulated flow conditions, the inlet length turns out to be much larger than the average length of the human basilar artery.To validate the computational model, a comparison is made between numerical and experimental results for a junction geometry consisting of tubes with a rectangular cross-section. The experiments have been performed in a Perspex model with laser Doppler velocimetry and dye injection techniques. Good agreement between experimental and computational results is found. Moreover, all essential flow phenomena turn out to be quite similar to those obtained for the circular tube geometry.

scholarly journals Development of a Thermal and Structural Analysis Procedure for Cooled Radial Turbines

1988 ◽  
Author(s):  
Ganesh N. Kumar ◽  
Russell G. Deanna
Keyword(s):  
Heat Transfer ◽  
Boundary Conditions ◽  
Three Dimensional ◽  
Internal Flow ◽  
Stream Velocity ◽  
Internal Cooling ◽  
Nasa Lewis Research ◽  
Transfer Coefficients ◽  
Cooling Flow ◽  
Radial Turbine

A procedure for computing the rotor temperature and stress distributions in a cooled radial turbine is considered. Existing codes for modeling the external mainstream flow and the internal cooling flow are used to compute boundary conditions for the heat transfer and stress analyses. An inviscid, quasi three-dimensional code computes the external free stream velocity. The external velocity is then used in a boundary layer analysis to compute the external heat transfer coefficients. Coolant temperatures are computed by a viscous one-dimensional internal flow code for the momentum and energy equation. These boundary conditions are input to a three-dimensional heat conduction code for calculation of rotor temperatures. The rotor stress distribution may be determined for the given thermal, pressure and centrifugal loading. The procedure is applied to a cooled radial turbine which will be tested at the NASA Lewis Research Center. Representative results from this case are included.

Flow Dynamics of Unconfined Swirling Flames Under Fuel-Lean Conditions

2006 ◽  
Author(s):  
S. S. Archer ◽  
A. K. Gupta ◽  
K. Kitagawa
Keyword(s):  
Direct Injection ◽  
Air Flow ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Swirl Flow ◽  
Flow Dynamics ◽  
Swirl Number ◽  
Burner Exit ◽  
Swirl Vane

This study provides the role of co- and counter swirl distribution in a experimental double concentric swirl burner that simulates the that simulates one swirl cup of a practical gas turbine combustor. Results of the effect of radial distribution of swirl in a burner under unconfined non-burning and combustion conditions are presented on the flow dynamics of a fuel-lean direct injection (LDI) configuration using propane as the fuel. Three-dimensional (3-D) flowfield data has been obtained immediately downstream of the burner exit to determine the detailed flow dynamics associated with the flow. The fuel was injected radially into the surrounding swirl flow. Flow characteristics, both without and with combustion, have been obtained for the co- and counter-swirl distributions to the combustion air flow under unconfined conditions. Flat vane swirlers have been used to induce swirl to the air flow. Both combustion and swirl distribution significantly influences the resulting flowfield. The resulting swirl number of the flow was calculated using the 3-D velocity data. Results show that swirl distribution in the burner and combustion provides significant effect on the characteristics of the internal and external recirculation zones. The heat release from combustion enhances the inner recirculation zone by increasing its width and length. Combustion causes significant increase to the velocity and vorticity magnitudes in the flow, and promotes flowfield symmetry. Combustion also affects the swirl number of the flow. The swirl number calculated from the geometrical relationships, derived from the swirl vane angle and swirler dimensions, is much different than that determined from the 3-D velocity field data. The entrained mass flow rate is larger for the co-swirl distribution case and this entrainment is further enhanced with combustion. The results provide the role of radial swirl distribution on the mean and turbulence characteristics of flows for the two different shear flow conditions between the inner and outer annulus of the burner.

Fundamental Issues and Recent Advancements in Analysis of Aircraft Brake Natural Convective Cooling

1998 ◽  
Vol 120 (4) ◽  
pp. 840-857 ◽  
Author(s):  
M. P. Dyko ◽  
K. Vafai
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Flow Field ◽  
Three Dimensional ◽  
Convective Cooling ◽  
Cooling Flow ◽  
Physical Mechanisms ◽  
Braking System ◽  
Flow And Heat Transfer ◽  
Convection Cooling

A heightened awareness of the importance of natural convective cooling as a driving factor in design and thermal management of aircraft braking systems has emerged in recent years. As a result, increased attention is being devoted to understanding the buoyancy-driven flow and heat transfer occurring within the complex air passageways formed by the wheel and brake components, including the interaction of the internal and external flow fields. Through application of contemporary computational methods in conjunction with thorough experimentation, robust numerical simulations of these three-dimensional processes have been developed and validated. This has provided insight into the fundamental physical mechanisms underlying the flow and yielded the tools necessary for efficient optimization of the cooling process to improve overall thermal performance. In the present work, a brief overview of aircraft brake thermal considerations and formulation of the convection cooling problem are provided. This is followed by a review of studies of natural convection within closed and open-ended annuli and the closely related investigation of inboard and outboard subdomains of the braking system. Relevant studies of natural convection in open rectangular cavities are also discussed. Both experimental and numerical results obtained to date are addressed, with emphasis given to the characteristics of the flow field and the effects of changes in geometric parameters on flow and heat transfer. Findings of a concurrent numerical and experimental investigation of natural convection within the wheel and brake assembly are presented. These results provide, for the first time, a description of the three-dimensional aircraft braking system cooling flow field.

Experimental Investigation of Vortex Generator Effect on Two- and Three-Dimensional NASA Common Research Models

2015 ◽  
Author(s):  
Shunsuke Koike ◽  
Kazuyuki Nakakita ◽  
Tsutomu Nakajima ◽  
Seigo Koga ◽  
Mamoru Sato ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Three Dimensional ◽  
Vortex Generator
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