Developing X-Ray Particle Tracking Velocimetry for Applications in Fluidized Beds

2008 ◽  
Author(s):  
Joshua B. Drake ◽  
Nathan P. Franka ◽  
Theodore J. Heindel
Keyword(s):  
Fluidized Bed ◽  
Particle Tracking ◽  
Particle Tracking Velocimetry ◽  
Fluidized Beds ◽  
Tracer Particle ◽  
Scale Up ◽  
Solid Particles ◽  
X Rays ◽  
X Ray ◽  
High Heat Transfer

Fluidized beds utilize a gas stream to fluidize solid particles and are used in the process industries because they provide a low pressure drop, uniform temperature distribution, and high heat transfer rates. Knowledge of fluidized bed hydrodynamics is necessary in the design and scale up of such devices. However, fluidized bed hydrodynamics are difficult to visualize and quantify because the systems are opaque and intrusive probes do not provide satisfactory measurements. This paper describes the development of X-ray particle tracking velocimetry (XPTV) to study fluidized bed hydrodynamics. XPTV utilizes X-rays to track specially designed tracer particles in a fluidized bed to noninvasively determine particle velocities. Stereoscopic X-ray imaging is used to locate the 3D position of the tracer particle as a function of time within a fluidized bed, from which particle velocity can be determined. An example of particle tracking will be shown and the automation of this process will be described.

X-Ray Particle Tracking Velocimetry in Fluidized Beds

2009 ◽  
Author(s):  
Joshua B. Drake ◽  
Lie Tang ◽  
Theodore J. Heindel
Keyword(s):  
Particle Tracking ◽  
Particle Tracking Velocimetry ◽  
Fluidized Beds ◽  
Tracer Particle ◽  
High Heat ◽  
Inert Material ◽  
X Ray ◽  
Bubbling Bed ◽  
High Heat Transfer ◽  
Biomass Particles

Fluidized beds are commonly found in the chemical and energy processing industries because of their low pressure drop, uniform temperature distribution, and high heat transfer rates. For example, in biomass gasification, biomass particles are injected into a heated bubbling bed of inert material (typically refractory sand) that volatilizes to form a flammable gas. However, the movement of the biomass particle through the bubbling bed is difficult to quantify because the systems are opaque. This paper describes X-ray particle tracking velocimetry (XPTV) applied to fluidized beds, where X-ray flow visualization is used to track the location of a single fabricated tracer particle as a function of time in a fluidized bed to study the bed/particle hydrodynamics. Using stereoscopic X-ray imaging, the 3D position of the tracer particle as a function of time is determined, from which tracer particle velocity can be calculated. Details and challenges of the XPTV process are also summarized.

Scale Effects on Fluidized Bed Hydrodynamics

2005 ◽  
Vol 3 (1) ◽  
Author(s):  
Rachid Mabrouk ◽  
Ramin Radmanesh ◽  
Jamal Chaouki ◽  
Christophe Guy
Keyword(s):  
Fluidized Bed ◽  
Particle Tracking ◽  
Fluidized Beds ◽  
Fiber Optic ◽  
Scale Effects ◽  
Scale Up ◽  
Radial Profile ◽  
Radioactive Particle Tracking ◽  
Industrial History ◽  
Radioactive Particle

Industrial history is full of events related to scale-up challenges. Failure at the scale-up stage is no longer surprising. Engineers and scientists have been trying to gather all the key parameters for decades, but, unfortunately, there are still no exact and well-established rules ensuring an accurate transition from one scale to another. Even the minimum lab-scale fluidized bed is still undefined.In this work, the effect of bed diameter on gas-solid behavior is investigated in three fluidized beds, 152mm, 78mm, and 50mm in diameter, in which the conventional scale-up rules are respected. The experiments were carried out using sand and alumina particles.The results were obtained and confirmed using fiber optic techniques and radioactive particle tracking, respectively. The results show that radial solid hold-up behavior on a small bed diameter scale is completely different from that on the intermediate bed diameter scale. The radial profile of solid hold-up on a small and very small bed diameter indicates an increase from a low value near the wall to a high value at the center at different heights from the distributor. By contrast, the opposite profile is observed on the intermediate bed diameter, similar to what is usually reported in the literature.

scholarly journals Developing Tracer Particles for X-Ray Particle Tracking Velocimetry

2011 ◽  
Author(s):  
Joshua B. Drake ◽  
Andrea L. Kenney ◽  
Timothy B. Morgan ◽  
Theodore J. Heindel
Keyword(s):  
Fluid Flow ◽  
Flow Visualization ◽  
Particle Tracking ◽  
Particle Tracking Velocimetry ◽  
Flow Characteristics ◽  
Effective Density ◽  
X Rays ◽  
Visualization Technique ◽  
X Ray ◽  
Tracer Particles

X-ray imaging, as a noninvasive flow visualization technique, has been shown to be a useful method for observing and characterizing multiphase flows. One type of X-ray flow visualization technique, called X-ray Particle Tracking Velocimetry (XPTV), tracks an X-ray attenuating particle in an opaque fluid flow. A significant challenge with XPTV is identifying tracer particles with the desired fluid flow characteristics (e.g., small and neutrally buoyant) but yet differentially attenuate X-rays, which is based primarily on density differences. This paper describes the manufacturing of XPTV tracer particles that satisfy specific particle characteristics including high X-ray attenuation, uniform shape, specified effective density, and desired diameter. An example use of these particles as an intruder particle in a fluidized bed (to simulate biomass injection) is then demonstrated using X-ray stereographic imaging to determine intruder particle position as a function of time in a three-dimensional opaque system.

Dual-Energy X-Ray Tomographic Measurement of Local Phase Fractions in 3-Phase Bubble Columns

2006 ◽  
Author(s):  
Martin Behling ◽  
Dieter Mewes
Keyword(s):  
Measurement Technique ◽  
Bubble Column ◽  
Dual Energy ◽  
Solid Particles ◽  
Bubble Columns ◽  
X Rays ◽  
Local Phase ◽  
X Ray ◽  
Measurement Plane ◽  
Tomographic Measurement

For measuring local phase fractions in 2- and 3-phase bubble columns, an X-ray tomographic measurement system is applied. This measurement technique, also referred to as Computer Tomography or CT, is based on the attenuation of X-rays along their path through the bubble column. An X-ray source and an X-ray detector are mounted on opposite sides of the bubble column. The bubble column is irradiated by an X-ray fan beam perpendicular to the bubble column axis. The X-ray intensity measured by each detector pixel is an integral measure for the penetrated material along the path of the X-rays. By rotating the X-ray source and X-ray detector around the bubble column axis, multiple projection measurements of the measurement plane are collected. In a second step, the phase distribution in the measurement plane (the so-called CT-slice) is calculated from the projection measurements by applying mathematical reconstruction algorithms. The reconstructed phase fractions are time-averaged over the measurement interval of 200 seconds for the measurements presented in this work. In order to distinguish all 3 phases, a special dual-energy technique is used. In this technique, 2 separate CT measurements are conducted successively, applying 2 different X-ray wavelengths. By combining the information gained from these 2 measurements, all 3 phase fractions are determined for every image pixel. The local phase fractions of all 3 phases are measured simultaneously for the whole cross-section. The measurement technique is fully non-intrusive. It is not restricted to limited ranges of phase fractions, solid loadings or flow rates of any of the phases. A 244 mm diameter, 7 m high bubble column is examined. It can be operated either with only 2 phases (liquid and gas) or with additional solid particles. Measurements are conducted with air as gas, water as liquid and PVC particles as solid phase. In this paper, the measurement principle of the tomographic technique and the dual-energy algorithm are explained. The experimental setup is described and the results of the measurements are presented.

Particle Tracking Velocimetry (PTV) Measurement of Abrasive Microparticle Impact Speed and Angle in Both Air-Sand and Slurry Erosion Testers

2016 ◽  
Author(s):  
Amir Mansouri ◽  
Hadi Arabnejad Khanouki ◽  
Siamack A. Shirazi ◽  
Brenton S. McLaury
Keyword(s):  
Solid Particle ◽  
Particle Tracking ◽  
Particle Tracking Velocimetry ◽  
Erosion Rate ◽  
Solid Particles ◽  
Particle Impact ◽  
Solid Particle Erosion ◽  
Impact Speed ◽  
Sand Flow ◽  
Sand Particles

Solid particle laden flows are very common in many industries including oil and gas and mining. Repetitive impacts of the solid particles entrained in fluid flow can cause erosion damage in industrial equipment. Among the numerous factors which are known to affect the solid particle erosion rate, the particle impact speed and angle are the most important. It is widely accepted that the erosion rate of material is dependent on the particle speed by a power law Vn, where typically n = 2–3. Therefore, accurate measurements of abrasive particle impact speed and angle are very important in solid particle erosion modeling. In this study, utilizing a Particle Image Velocimetry (PIV) system, particle impact conditions were measured in a direct impinging jet geometry. The measurements were conducted with two different test rigs, for both air-sand and liquid-sand flows. In air-sand testing, two types of solid particles, glass beads and sharp sand particles, were used. The measurements in air-sand tests were carried out using particles with various sizes (75, 150, and 500 μm). Also, submerged testing measurements were performed with 300 μm sand particles. In the test conditions, the Stokes number was relatively high (St = 3000 for air/sand flow, St = 27 for water/sand flow), and abrasive particles were not closely following the fluid streamlines. Therefore, a Particle Tracking Velocimetry (PTV) technique was employed to measure the particle impact speed and its angle with the target surface very near the impact. Furthermore, Computational Fluid Dynamics (CFD) simulations were performed, and the CFD results were compared with the experimental data. It was found that the CFD results are in very good agreement with experimental data.

A cone-beam compensated back-projection algorithm for X-ray particle tracking velocimetry

2014 ◽  
Vol 39 ◽  
pp. 64-75 ◽  
Author(s):  
Todd A. Kingston ◽  
Timothy B. Morgan ◽  
Taylor A. Geick ◽  
Teshia R. Robinson ◽  
Theodore J. Heindel
Keyword(s):  
Particle Tracking ◽  
Particle Tracking Velocimetry ◽  
Projection Algorithm ◽  
Cone Beam ◽  
Back Projection ◽  
X Ray

scholarly journals Measurements of the Flow in the Vicinity of an Additively Manufactured Turbine Leading-Edge Using X-Ray Particle Tracking Velocimetry

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Alex Ruiz ◽  
Kamel Fezzaa ◽  
Jayanta Kapat ◽  
Samik Bhattacharya
Keyword(s):  
Velocity Field ◽  
Turbine Blade ◽  
Particle Tracking ◽  
High Speed ◽  
Particle Tracking Velocimetry ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Leading Edge ◽  
Inlet Channel ◽  
X Ray

Abstract X-ray particle tracking velocimetry (PTV) is performed, for the first time, to measure the velocity field inside a leading-edge of a turbine blade made by laser-additive-manufacturing (LAM) process. The traditional showerhead holes were replaced by a porous matrix in the leading-edge. The flow through such a leading-edge piece cannot be faithfully recreated by traditional prototype testing methods due to the surface roughness and imperfections caused by LAM process. Hence, direct measurement is the only option. However, it is difficult to measure flow inside such pieces with traditional velocimetry measurements due to the existence of metallic walls. Moreover, small internal size and high flow speeds call for a measurement technique with high spatial and temporal resolutions. To address these issues, we performed time-resolved X-ray PTV using the Advanced Photon Source (APS) synchrotron facility at the Argonne National Laboratory (ANL). A hydraulic system was constructed to run water, mixed with seeding particles, through the leading-edge piece. A high-speed camera captured the images of the seeding particles, which were later processed to create particle tracks. The time-averaged velocity field showed distinct pairs of vortices located in front of the porous outlet inside the leading-edge piece. The inlet channel showed reversed flow due to partial obstruction by the porous inlet of the test piece. Such knowledge of the flow field inside a leading-edge of a turbine blade will help us to design better cooling paths leading to higher cooling efficiency and increased life-span of a turbine blade.

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