Particle Velocity Measurements to Improve Erosion Prediction

Volume 3 ◽  
2004 ◽  
Author(s):  
Matthew J. Sampson ◽  
Siamack A. Shirazi ◽  
Brenton S. McLaury
Keyword(s):  
Impact Velocity ◽  
Particle Velocity ◽  
Particle Interaction ◽  
Particle Impact ◽  
Average Particle ◽  
Rotating Disks ◽  
Erosion Testing ◽  
Erosion Prediction ◽  
Particle Velocities ◽  
Particle Impact Velocity

Previous work on Computational Fluid Dynamics (CFD) based erosion modeling indicated a strong influence of particle impact velocity on erosion. Equations to predict erosion are based on particle impacting velocity, material properties and particle characteristics such as particle shape and size. Previous studies did not measure particle velocity directly but used rotating disks or simplified computer models to determine the particle velocity. In the present work, a series of experiments have been conducted to measure the velocity of small particles (sand and aluminum) as they approach a target. A laser Doppler velocimetry system was used to measure particle velocities in a jet of air as the jet impinges a target. The angle between the target and the incoming jet is varied. Particle concentration is also controlled, allowing the effects of particle to particle interaction on average particle impact velocity to be observed. These findings are expected to improve the results of erosion testing and provide new data for improving erosion models.

Effect of Particle Impact Velocity on Cone Crack Shape in Ceramic Material

2005 ◽  
Vol 297-300 ◽  
pp. 1321-1326 ◽  
Author(s):  
Sang Yeob Oh ◽  
Hyung Seop Shin
Keyword(s):  
Impact Velocity ◽  
Computational Simulation ◽  
Back Surface ◽  
Particle Impact ◽  
Cone Crack ◽  
Crack Shape ◽  
The Impact ◽  
Particle Impact Velocity ◽  
Sic Particle ◽  
Ring Cracks

The damage behaviors induced in a SiC by a spherical particle impact having a different material and size were investigated. Especially, the influence of the impact velocity of a particle on the cone crack shape developed was mainly discussed. The damage induced by a particle impact was different depending on the material and the size of a particle. The ring cracks on the surface of the specimen were multiplied by increasing the impact velocity of a particle. The steel particle impact produced the larger ring cracks than that of the SiC particle. In the case of the high velocity impact of the SiC particle, the radial cracks were generated due to the inelastic deformation at the impact site. In the case of the larger particle impact, the morphology of the damages developed were similar to the case of the smaller particle one, but a percussion cone was formed from the back surface of the specimen when the impact velocity exceeded a critical value. The zenithal angle of the cone cracks developed into the SiC decreased monotonically as the particle impact velocity increased. The size and material of a particle influenced more or less on the extent of the cone crack shape. An empirical equation was obtained as a function of impact velocity of the particle, based on the quasi-static zenithal angle of the cone crack. This equation will be helpful to the computational simulation of the residual strength in ceramic components damaged by the particle impact.

Particle Velocities in the Rotating Impeller of a Slurry Pump

2007 ◽  
Author(s):  
M. Mehta ◽  
J. R. Kadambi ◽  
S. Sastry ◽  
J. M. Sankovic ◽  
M. P. Wernet ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Particle Velocity ◽  
Suction Side ◽  
Solid Particles ◽  
Working Fluid ◽  
Average Particle ◽  
Pump Speed ◽  
Velocity Magnitude ◽  
Refractive Index Matching ◽  
Particle Velocities

The velocities of the slurry particles in the impeller of a centrifugal slurry pump were obtained utilizing Particle image velocimetry (PIV) technique in conjunction with refractive index matching. Tests were performed in an optically clear centrifugal slurry pump at speeds of 725 rpm and 1000 rpm using a slurry made up of sodium iodide solution as a working fluid and glass beads (500μm mean diameter) as solid particles at volumetric concentrations of 1%, 2%, and 3%. In the intra blade region of the impeller, the highest particle velocities were obtained in the suction side of the blade and in the blade trailing edge region as the blade sweeps through and velocity magnitude increases with the increase in the pump speed. But this magnitude was less than that of circumferential velocity of the blade tip. The average particle velocities were obtained and it was found that the average particle velocity decreases with increase in concentration. The fluctuating component of particle velocity, which is related to the fluctuation kinetic energy were obtained. With the increase in the particle volumetric concentration, fluctuation kinetic energy decreases and the maximum fluctuation kinetic energy typically occurs on the suction side of the blade. The slurry particles are pushed on the pressure side of the blade and slide on it which can result in frictional wear. These results are discussed in this paper.

Experimental Investigation of the Location of Maximum Erosive Wear Damage in Elbows

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Quamrul H. Mazumder ◽  
Siamack A. Shirazi ◽  
Brenton McLaury
Keyword(s):  
Experimental Investigation ◽  
Mass Loss ◽  
Solid Particle ◽  
Impact Velocity ◽  
Single Phase ◽  
Erosive Wear ◽  
Particle Impact ◽  
Erosion Behavior ◽  
Wear Damage ◽  
Particle Impact Velocity

Erosive wear damage of elbows due to solid particle impact has been recognized as a significant problem in several fluid handling industries. Solid particle erosion is a complex phenomenon due to different parameters causing material removal from the metal surface. The particle density, size, shape, velocity, concentration, impact angle, and impacting surface material properties are some of the major parameters. Among the various factors, the particle impact velocity has the greatest influence in erosion. The particle impact velocity and impact angles depend on the fluid velocity and fluid properties. The particle to particle, particle to fluid, and particle to wall interactions increase the complexity of the erosive wear behavior. In multiphase flow, the presence of different fluids and their corresponding spatial distribution of the phases, adds another dimension to the problem. Most of the previous investigations were focused on determination of erosion in terms of mass loss of the eroding surfaces without identifying the specific location of the maximum erosive wear. During this investigation, magnitude of erosion at different location of an elbow specimen was measured to determine the location of maximum erosion. Experimental investigation of erosion in single-phase and multiphase flows was conducted at different fluid velocities. Both mass loss and thickness loss measurements were taken to characterize erosion behavior and erosion patterns in an elbow. Experimental results showed different erosion behavior and location of maximum erosion damage in single-phase and multiphase flows. The locations of maximum wear due to erosion were also different for horizontal flow compared to vertical flow.

Irregular Wave and Current Loads on a Fish Farm System

2018 ◽  
Author(s):  
Arnt G. Fredriksen ◽  
Basile Bonnemaire ◽  
Øyvind Nilsen ◽  
Leiv Aspelund ◽  
Andreas Ommundsen
Keyword(s):  
Particle Velocity ◽  
Fish Farm ◽  
Fluid Particle ◽  
Irregular Waves ◽  
Engineering Practice ◽  
Irregular Wave ◽  
Environmental Force ◽  
The Mean ◽  
Particle Velocities ◽  
Farm System

Accurate calculation of the design mooring loads on an aquaculture fish farm mooring system is often a difficult task. The fish farm system has a large horizontal extension with variable environmental conditions across the entire structure. In addition, the drag loads on the fish nets are thought to be the governing environmental force. This means that the mean position of the fish farm is a function of the mean of the fluid particle velocity squared, where the fluid particle velocity must be taken as the sum of current and wave induced fluid particle velocities. Additional offsets will be slowly varying, where the response time will depend on the total mooring stiffness. The magnitudes depend on the height and length on wave groups in the irregular sea state. The paper presents simulations of the response of such a system to a set of combined irregular waves and current conditions. The response evolution in time is discussed as well as parameters affecting the maximum responses in the systems (displacements and loads). Finally, the resulting loads on the fish farm in irregular waves are compared to loads obtained in equivalent regular waves, as this is an often used engineering practice when analyzing the response and mooring loads of a fish farm.

Factorial Analysis on the 2-D Transient Solid Velocity in Fluidized Bed Combustor

2003 ◽  
Author(s):  
Seong W. Lee ◽  
Yun Liu
Keyword(s):  
Fluidized Bed ◽  
Particle Velocity ◽  
Design Method ◽  
Factorial Analysis ◽  
Cold Model ◽  
Experimental Conditions ◽  
Image Velocimetry ◽  
Transient Velocity ◽  
Particle Velocities ◽  
Fluidized Bed Combustor

The transient solid velocity analysis in fluidized bed combustor (FBC) freeboard has been critical in the past two decades (Haidin et al 1998). The FBC cold model (6-in ID) was designed and fabricated. The solid transient velocity in FBC freeboard was measured and analyzed with the assistance of the advanced instrumentation. The laser-based Particle Image Velocimetry (PIV) was applied to the FBC cold model to visualize the transient solid velocity. A series of transient particle velocity profiles were generated for factorial analysis. In each profile, the particle velocity vectors for 100 position points were in the format of Vx and Vy. Analysis of Variance (ANOVA) was used to determine the significant factors that affect the transient particle velocities, time, and position coordinates. Then, the 1010factorial design method was used to develop a specific empirical model of transient particle velocity in FBC freeboard which was in the shape of Vx = f1(t, x, y), and Vy = f2(t, x, y). This unique factorial analysis method was proved to be very effective and practical to evaluate the experimental conditions and analyze the experimental results in FBC systems.

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