Numerical investigations on the effect of total pressure and nozzle divergent length on the flow character and particle impact velocity in cold spraying

2013 ◽  
Vol 232 ◽  
pp. 290-297 ◽  
Author(s):  
Shuo Yin ◽  
Meng Zhang ◽  
Zhiwei Guo ◽  
Hanlin Liao ◽  
Xiaofang Wang
Keyword(s):  
Impact Velocity ◽  
Total Pressure ◽  
Cold Spraying ◽  
Particle Impact ◽  
Numerical Investigations ◽  
Particle Impact Velocity

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.

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.

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.

Numerical Investigation of Effect of Inlet Distortion on Compressor Flow Field and Stability

2017 ◽  
Author(s):  
HaoGuang Zhang ◽  
Kang An ◽  
Feng Tan ◽  
YanHui Wu ◽  
WuLi Chu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Total Pressure ◽  
Tip Clearance ◽  
Numerical Work ◽  
Stall Margin ◽  
Numerical Investigations ◽  
Inlet Distortion ◽  
Compressor Rotor ◽  
The Stability

The compressor aerodynamic design is conducted under the condition of clean inlet in general, but a compressor often operates under the condition of inlet distortion in the practical application. It has been proven by a lot of experimental and numerical investigations that inlet distortion can decrease the performance and stability of compressors. The circumferential or radial distorted inlet in mostly numerical investigations is made by changing the total pressure and total temperature in the inlet ring surface of the compressors. In most of inlet distortion experiments, distorted inlets are usually created by using wire net, flashboards, barriers or the generator of rotating distortion. The fashion of generating distorted inlet for experiment is different from that for numerical simulation. Consequently, the flow mechanism of affecting the flow field and stability of a compressor with distorted inlet for experiment is partly different than that for numerical simulation. In the numerical work reported here, the inlet distortion is generated by setting some barriers in the inlet ring surface of an axial subsonic compressor rotor. Two kinds of distorted inlet are investigated to exploring the effect of distorted range on the flow field and stability of the compressor with ten-passage unsteady numerical method. The numerical results show that the inlet distortions not only degrade the total pressure and efficiency of the compressor rotor, but also decrease the stability of the rotor. The larger the range of distorted inlet is, the stronger the adverse effect is. The comprehensive stall margin for the inlet distortion of 24 degrees and 48 degrees of ten-passages is reduced about 3.35% and 5.88% respectively. The detailed analysis of the flow field in the compressor indicates that the blockage resulted from tip clearance leakage vortex (TLV) and the flow separation near the suction surfaces of some blades tip for distorted inlet is more serious than that resulted from TLV for clean inlet. Moreover, the larger the range of distorted inlet is, the larger the range of the blockage is. The analysis of unsteady flow shows that during this process, which is that one rotor blade passes through the region affected by the distorted inlet, the range of the blockage in the rotor passage increases first, then reduces, and increases last.

Length Reduction of a Compressor Multi-Spool Transition Annular S-Duct

2020 ◽  
Author(s):  
M. Agrawal ◽  
D. Sinha ◽  
S. P. Das ◽  
N. Vidhyashankar ◽  
R. Abbas
Keyword(s):  
High Pressure ◽  
Flow Separation ◽  
Total Pressure ◽  
Loss Coefficient ◽  
Turbofan Engine ◽  
Numerical Investigations ◽  
Pressure Loss Coefficient ◽  
Total Pressure Loss Coefficient ◽  
Length Reduction ◽  
Pressure Compressor

Abstract Increasing interest in improving the efficiency of the turbo-fan engine results in a large low pressure compressor and small high pressure core. The consequence of the increment in radial offset is that the importance of the transition duct is growing. Shortening this transition duct length can effectively reduce the weight of the engine. However, it conflicts with the need to avoid flow separation within the duct. Further, radial struts are also present in duct passage for support. In present work, numerical investigations were performed on an annular S-duct with bypass suitable for connecting the compressor spools of a small turbofan engine. The length of S-duct was reduced by 6%, 12%, and 18% from the original S-duct length. The wall contour was selected based on the optimum value of the total pressure loss coefficient for the particular length. It was found that the loss coefficient is a weak function of duct length as long as the flow is attached. Further, the effect of the radial strut on the selected contour for two different lengths was studied. The increase in loss for 100% and 88% length in the presence of all struts was 17% and 27%.

NUMERICAL INVESTIGATIONS ON EFFECTS OF IMPACT VELOCITY AND SPRAY ANGLE OF PARTICLE ON ITS DEFORMATION BEHAVIOR IN COLD SPRAYING

2006 ◽  
Vol 13 (05) ◽  
pp. 613-620 ◽  
Author(s):  
XINPING ZHANG ◽  
XUEZHENG WANG ◽  
YUXUAN LI ◽  
GUANG CHEN
Keyword(s):  
Impact Velocity ◽  
Deformation Behavior ◽  
Cold Spraying ◽  
Spray Angle ◽  
High Particle ◽  
Localized Heating ◽  
Major Factors ◽  
The Impact ◽  
Contact Pressures ◽  
Spraying Process

The cold spraying process is analyzed by numerical modeling of the impact between a single spherical particle and a substrate; the effects of impact velocity and spray angle of a particle on the particle and substrate deformation behavior were investigated. It was found that much localized stress, localized strain, and localized heating are present near the particle/substrate interface. When impact velocity exceeds a critical velocity, a jet-type flow of material at the interface was formed. High particle/substrate contact pressures and better developed interfacial jets appear to be the major factors controlling the strength of interfacial bonding. As the particle impact velocity or spray angle increases, the length of interfacial jets increases and it may strengthen the bonding of the particle and the substrate.

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