D005 Effect of Mist Flow Pattern in Determining the Nozzle Distance in MQL using Particle Image Velocimetry

2013 ◽  
Vol 2013.7 (0) ◽  
pp. 469-473
Author(s):  
Hemarani DORAIRAJU ◽  
Zazuli MOHID ◽  
Erween Abd RAHIM
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Pattern ◽  
Particle Image ◽  
Image Velocimetry ◽  
Mist Flow

scholarly journals Determination of Mist Flow Characteristic for MQL Technique Using Particle Image Velocimetry (PIV) and Computer Fluid Dynamics (CFD)

2015 ◽  
Vol 773-774 ◽  
pp. 403-407 ◽  
Author(s):  
E.A. Rahim ◽  
Hemarani Dorairaju ◽  
Norzilawati Asmuin ◽  
M.H.A.R. Mantari
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Pattern ◽  
Particle Image ◽  
Fluid Dynamic ◽  
Cutting Temperature ◽  
Machining Process ◽  
Cutting Fluid ◽  
Minimum Quantity ◽  
Image Velocimetry ◽  
Mist Flow

In recent years, minimum quantity lubrication (MQL) machining is regarded as a promising method for reducing machining cost and cutting fluid, while improving cutting performance. However the effectiveness and the working principle of MQL are still questionable with very few explanations provided. The aim of this study is to determine the optimum distance between the nozzle and tool tip and appropriate flow pattern of the mist flow for minimum quantity lubricant using Particle Image Velocimetry (PIV) and Computer Fluid Dynamic (CFD) for optimizing the spraying conditions thus reducing the lubricant consumption. The spray from the nozzle with outlet diameter of 2.5mm is analysed using Particle Image Velocimetry (PIV) to measure the mist flow velocity and identify the flow pattern. The input pressure of 0.2, 0.3 and 0.4MPa will be discharged throughout the experiment. Higher pressure produce more mass flow rate which helps in reducing the cutting force and cutting temperature efficiently and prolong tool life. Thus the appropriate distance can reduce lubricant consumption and increase the cooling and lubricating ability with best nozzle position. The applied distance increases the efficiencies of MQL applied during machining process.

Flow Pattern Evolution With Time Mixing of Non-Newtonian Fluid in a Stirred Tank Using Particle Image Velocimetry

Volume 1 ◽  
2004 ◽  
Author(s):  
E. Fransolet ◽  
P. Marchot ◽  
D. Toye ◽  
M. Crine
Keyword(s):  
Aqueous Solution ◽  
Particle Image Velocimetry ◽  
Flow Pattern ◽  
Newtonian Fluid ◽  
Particle Image ◽  
Mixing Time ◽  
Time Dependent ◽  
Stirred Tank ◽  
Image Velocimetry ◽  
Evolution With Time

This paper presents an experimental analysis of the evolution with time of the flow pattern in a stirred tank equipped with a rotor-stator mixer, when mixing a time dependent non-Newtonian fluid. Particle image velocimetry (PIV) is used to determine 2D velocity maps. Polyacrylamide (PAAm) aqueous solution is used as model of time dependent shear thinning fluids. Creep compliance and recovery tests are performed to follow the evolution of the fluid rheology, from a viscoelastic behaviour to a purely viscous one. This indicates mixing has almost completely destroyed the initial network structure of the non-Newtonian fluid. The evolution of the flow pattern with the mixing time is compared with the flow patterns obtained in presence of Newtonian fluids as water and glycerol aqueous solution.

PIV Analysis of the Flow Pattern Around an Ablation Catheter to Observe the Flow Effect on the Electrode

2013 ◽  
Author(s):  
Kaihong Yu ◽  
Tetsui Yamashita ◽  
Shigeaki Shingyochi ◽  
Kazuo Matsumoto ◽  
Makoto Ohta
Keyword(s):  
Blood Flow ◽  
Particle Image Velocimetry ◽  
Catheter Ablation ◽  
Flow Pattern ◽  
Open Channel ◽  
Particle Image ◽  
Circulation System ◽  
Convection Flow ◽  
Image Velocimetry ◽  
Catheter Tip

Radiofrequency (RF) catheter ablation is a highly effective treatment for many cardiac arrhythmias, especially for tachyarrhythmia. RF energy is introduced through the catheter onto the endocardial surface to destroy the abnormal heart tissue causing the heart rhythm disorder. Many parameters relate to myocardial temperature, such as RF power, tissue contact, and blood flow. Blood flow is an important factor that has a cooling effect on myocardium and affects the final lesion size. Many previous studies have shown that under temperature control, lesion sizes are larger and tissue temperatures rise faster with a high flow rate. If the flow causes a decrease in the temperature of the catheter tip, the generator will increase the power output to maintain the tip at a constant temperature. However, few studies of RF catheter ablation have investigated how ablation affects blood flow. Observation of the flow pattern around the catheter can help to determine the mechanism of the flow effects on the temperature of the catheter tip. The purpose of this study is to observe the flow pattern during ablation using an in-vitro circulation system developed for Particle Image Velocimetry (PIV). We developed an open-channel circulation system to simulate blood flow. The mold for the open-channel was built with acrylic boards for transparency. The working fluid was 0.9% saline, which was used at room temperature (20°C). Instead of animal myocardium, we used a poly (vinyl alcohol) hydrogel (PVA-H), which has mechanical characteristics that approximate those of biological soft tissue, and contact with the PVA-H surface by the catheter is similar to that with myocardium. A 7 Fr catheter with a 4-mm ablation electrode tip was set perpendicular to the PVA-H surface, and the contact weight between the electrode of the catheter and the PVA-H surface was 2.2 gf. To measure the temperature profile in the PVA-H, a K-type thermocouple with the diameter of 0.5 mm was placed at the depth of 2 mm from the surface. The thermocouple tip was always placed on the catheter axis. The flow pattern at the location where the catheter was held was observed by a high speed camera, and the resulting images were analyzed by particle image velocimetry (PIV). The results showed that in the absence of applied flow, convection flow from the electrode is observed in the areas around the catheter. However, under a 1.6 L/min flow rate, convection flow disappears. In conclusion, blood flow could decrease the catheter tip temperature, and the influence of ablation in the flow around the catheter disappeared.

PIV Measured Hemodynamic Study With Several Stents in a Cerebral Aneurysm Model for New Stent Design

2011 ◽  
Author(s):  
Chang-Ho Yu ◽  
Shuya Shida ◽  
Kaoru Matsumoto ◽  
Makoto Ohta
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Pattern ◽  
Cerebral Aneurysm ◽  
Particle Image ◽  
Stent Design ◽  
Coagulation Mechanism ◽  
Image Velocimetry ◽  
Hemodynamic Study ◽  
Aneurysm Model

The rupture of an aneurysm can lead to a subarachnoid hemorrhage, which can be a fatal illness in a large percentage of cases. In treating aneurysm intravascular stenting is thought as a better option compared with clipping treatment. The treatment of cerebral aneurysm with a porous stent also has recently proposed as a minimally invasive way to prevent rupture and favor coagulation mechanism inside aneurysm. The analysis of a flow pattern with and without stent in cerebral aneurysm model was performed with Particle Image Velocimetry (PIV). Three types of stents were used in the present investigation and the porosity of stent 1, 2 and 3 is 80%, 74% and 64%, respectively. Reduced velocity, smaller average vorticity magnitude and different flow patterns inside aneurysm are observed when the three different proposed stents are used. The stent 3 (Porosity = 64%) decrease the magnitude of the velocity by 98% and change the flow pattern in the aneurysm. Our results show that not only the role of the porosity but also the stent shape affect the flow and help us understand the characteristic of stent designs.

Flow Field Measurements Near a Moving Meniscus of a Capillary Flow With Micro Particle Image Velocimetry (µPIV)

2008 ◽  
Author(s):  
Ralph Nasarek ◽  
Steve Wereley ◽  
Peter Stephan
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Flow Pattern ◽  
Contact Line ◽  
Particle Image ◽  
Field Measurements ◽  
Phase Contact ◽  
Micro Particle Image Velocimetry ◽  
Image Velocimetry ◽  
Three Phase

Due to the relevance of capillary flows for industrial applications, the dynamics of menisci have been extensively investigated. Contrary to the meniscus velocity, the flow pattern near the meniscus is rather unexplored. The main focus of this study is the visualization of the flow field near the fast moving meniscus with micro particle image velocimetry (μPIV). Therefore an invasive flow of ethanol in a vertical cylindrical glass tube is investigated. The entrance of the tube is located inside a reservoir with a rising liquid surface. Especially near the tube entrance the flow is high dynamical (ca. 120 mm/s) which necessitates high temporal resolution measurement techniques. Flow field measurements at several positions in flow direction have been conducted to compare the meniscus shape and the flow fields near the three phase contact line. The flow pattern near the meniscus is extremely complex. While the typical Hagen-Poiseuille profile with no radial velocity component is to be found far from the meniscus, the flow near the meniscus cannot be a convex velocity profile. As a matter of fact the meniscus movement is characterized by adsorption of the liquid near the wall and liquid transport from the middle of the flow to the three phase contact line. This special flow pattern has been examined. Furthermore it was found that the shape of the meniscus varies over the whole invasion of the tube. The curvature of the meniscus and therefore the contact angle between solid and liquid are getting smaller over the infiltration length which has influence on the capillary force. Measurements near the entrance of the tube show an acceleration of the liquid column until it reaches a certain speed and after that a deceleration. To determine the velocity of the raising meniscus, global measurements of the whole tube have been performed.

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