scholarly journals The Effect Of Tangential Velocity Component In Abrasive Jet Micro-Machining Of Borosilicate Glass

2021 ◽  
Author(s):  
Md. A. Hasem
Keyword(s):  
Borosilicate Glass ◽  
Velocity Component ◽  
Tangential Velocity ◽  
Micro Machining ◽  
Target Holder ◽  
Air Blast ◽  
Tangential Velocity Component ◽  
Erosion Testing ◽  
Oxide Particles ◽  
Velocity Effect

Generally two types of erosion testers are used in solid particle erosion testing: air blast erosion testers and mechanically powered erosion testers. In the first portion of this thesis, the feasibility of implementing a mechanically powered erosion tester for abrasive jet micro-machining applications using very small particles was studied. It was found that, due to the ultrahigh vacuum requirement, such a device would not be practical. Therefore, in the second part of the thesis, the designed rotary mechanism was utilized as a rotary disc target holder apparatus and blasted with a typical air blast system. The apparatus could add or deduct a tangential velocity component into the system, allowing for detailed studies of the effect that the tangential velocity component has on the erosion of borosilicate glass using 25-150 μm aluminum oxide particles. Although the tangential velocity effect has been ignored for brittle materials by most researchers, the present results show that it can have an important role in erosion rate.Generally two types of erosion testers are used in solid particle erosion testing: air blast erosion testers and mechanically powered erosion testers. In the first portion of this thesis, the feasibility of implementing a mechanically powered erosion tester for abrasive jet micro-machining applications using very small particles was studied. It was found that, due to the ultrahigh vacuum requirement, such a device would not be practical. Therefore, in the second part of the thesis, the designed rotary mechanism was utilized as a rotary disc target holder apparatus and blasted with a typical air blast system. The apparatus could add or deduct a tangential velocity component into the system, allowing for detailed studies of the effect that the tangential velocity component has on the erosion of borosilicate glass using 25-150 μm aluminum oxide particles. Although the tangential velocity effect has been ignored for brittle materials by most researchers, the present results show that it can have an important role in erosion rate.

scholarly journals The Effect Of Tangential Velocity Component In Abrasive Jet Micro-Machining Of Borosilicate Glass

2021 ◽  
Author(s):  
Md. A. Hasem
Keyword(s):  
Borosilicate Glass ◽  
Velocity Component ◽  
Tangential Velocity ◽  
Micro Machining ◽  
Target Holder ◽  
Air Blast ◽  
Tangential Velocity Component ◽  
Erosion Testing ◽  
Oxide Particles ◽  
Velocity Effect

Generally two types of erosion testers are used in solid particle erosion testing: air blast erosion testers and mechanically powered erosion testers. In the first portion of this thesis, the feasibility of implementing a mechanically powered erosion tester for abrasive jet micro-machining applications using very small particles was studied. It was found that, due to the ultrahigh vacuum requirement, such a device would not be practical. Therefore, in the second part of the thesis, the designed rotary mechanism was utilized as a rotary disc target holder apparatus and blasted with a typical air blast system. The apparatus could add or deduct a tangential velocity component into the system, allowing for detailed studies of the effect that the tangential velocity component has on the erosion of borosilicate glass using 25-150 μm aluminum oxide particles. Although the tangential velocity effect has been ignored for brittle materials by most researchers, the present results show that it can have an important role in erosion rate.Generally two types of erosion testers are used in solid particle erosion testing: air blast erosion testers and mechanically powered erosion testers. In the first portion of this thesis, the feasibility of implementing a mechanically powered erosion tester for abrasive jet micro-machining applications using very small particles was studied. It was found that, due to the ultrahigh vacuum requirement, such a device would not be practical. Therefore, in the second part of the thesis, the designed rotary mechanism was utilized as a rotary disc target holder apparatus and blasted with a typical air blast system. The apparatus could add or deduct a tangential velocity component into the system, allowing for detailed studies of the effect that the tangential velocity component has on the erosion of borosilicate glass using 25-150 μm aluminum oxide particles. Although the tangential velocity effect has been ignored for brittle materials by most researchers, the present results show that it can have an important role in erosion rate.

Turbulence measurements with inclined hot-wires Part 2. Hot-wire response equations

1967 ◽  
Vol 28 (1) ◽  
pp. 177-182 ◽  
Author(s):  
F. H. Champagne ◽  
C. A. Sleicher
Keyword(s):  
Velocity Component ◽  
Wire Array ◽  
Tangential Velocity ◽  
Constant Current ◽  
Hot Wire ◽  
Tangential Velocity Component ◽  
Low Intensity ◽  
Hot Wires ◽  
Current Operation ◽  
Cosine Law

Hot-wire response equations to include the effects of the tangential velocity component as well as the non-linearities caused by high intensity turbulence are derived for linearized constant temperature operation. For low intensity turbulence similar equations are derived for constant current operation. The equations are applied to an X-wire array to determine the errors in selected turbulence quantities which arise from the assumption of cosine law cooling. The error depends upon the quantity measured, the method of operation, and [lscr ]/d. For [lscr ]/d = 200 the error ranges from 0 to 17%.

New Design Method for Spiral Casings Considering the Properties of the Impeller and Spiral Casing at Design and Off-Design Conditions and Numerical Verification With CFD

2018 ◽  
Author(s):  
Philipp Epple ◽  
Manuel Fritsche ◽  
Michael Steppert ◽  
Michael Steber
Keyword(s):  
Design Process ◽  
Flow Rate ◽  
Velocity Component ◽  
Tangential Velocity ◽  
Sectional Area ◽  
Cross Sectional ◽  
Flow Rates ◽  
Tangential Velocity Component ◽  
Design Point ◽  
Spiral Casing

Radial fans for industrial applications are very commonly operated with a spiral casing, also called volute. The function of the volute is to collect the air from the impellers outlet and to transport it to the fans outlet. In the volute the tangential velocity component of the impeller is transformed in a straight velocity component at the volute’s outlet. In the volute the static pressure is increased according to the cross sectional area of the volute. When the flow exits the impeller the flow rate is given basically by the radial velocity component times the outlet area of the impeller. In the volute, however, the flow rate is basically given by the tangential velocity component at the impeller exit and in the volute considering the conservation of angular momentum. Hence, there is only one operating point, i.e. the design point of the volute, where the flow rate in the impeller matches the flow rate in the volute. In the literature the design of the volute is performed at the design point only and the cross sectional area of the volute is usually computed distributing the flow rate linearly from the tongue to the exit of the volute. In this work an extended theoretical approach was developed considering the design point flow rate and off design flow rates. At the design point, the properties of the specific impeller, i.e. it’s radial and its tangential velocity components at the impeller’s exit are considered to design the volute. Furthermore, also the off-design characteristics of the impeller, i.e. its radial and tangential velocity components are considered in the design process of the volute. The flow rates in the impeller and in the volute match only at the design point, at off-design points the flow rates in the impeller and in the volute are different. This has an important impact on the design process of impeller – volute units. Each volute has also to be matched to the specific impeller. In the numerical part a usual volute was designed considering the properties of a particular impeller. The performance of the volute and of complete fan was investigated with the commercial Navier–Stokes Solver ANSYS CFX. A detailed analysis of the results and the flow conditions in volute as well as in the impeller-volute unit and a comparison with the results predicted by the new volute theory is given.

A Study on Unstable S-Shape Characteristic Curves of Pump Turbines at No-Flow

1987 ◽  
Vol 109 (1) ◽  
pp. 77-82 ◽  
Author(s):  
Y. Senoo ◽  
M. Yamaguchi
Keyword(s):  
Velocity Component ◽  
Tangential Velocity ◽  
Pressure Rise ◽  
Tangential Velocity Component ◽  
Shape Characteristic ◽  
Small Model ◽  
The Difference ◽  
Shape Characteristics ◽  
Turbine Mode ◽  
The Relationship

A small model of a Francis-type pump turbine was tested without the rotating shroud and the radial distribution of pressure in the rotor was measured using pressure taps on the stationary shroud. The mean tangential velocity component in the rotor was measured with a laser velocimeter, and the flow pattern was visualized using a camera which rotated with the rotor. Comparing data at the no-flow condition in the turbine mode with those in the pump mode, the effect of semi-open spaces at the inlet and at the exit of blade rows on the difference of pressure rise between the two modes was recognized, and the flow patterns and the distributions of tangential velocity component in these zones were utilized to understand the phenomena. Furthermore, some discussion is included on the relationship between the design head coefficient in the turbine mode and the S-shape characteristics.

Wechselwirkung kondensierter Molekularstrahlen mit festen Oberflächen

1968 ◽  
Vol 23 (2) ◽  
pp. 274-279 ◽  
Author(s):  
E. W. Becker ◽  
R. Klingelhöfer ◽  
H. Mayer
Keyword(s):  
Steel Surface ◽  
Tangential Velocity ◽  
Incident Beam ◽  
Stainless Steel Surface ◽  
Angle Of Incidence ◽  
Mean Velocity ◽  
Tangential Velocity Component ◽  
Polished Stainless Steel ◽  
The Mean ◽  
Angle Of Reflection

The reflection of a beam of nitrogen clusters from a polished stainless steel surface is investigated. The scattered flux shows a strong maximum at an angle of reflection almost 90°, independent of angle of incidence. The mean velocity of the reflected beam is about equal to the tangential velocity component of the incident beam. Measurements with increased background pressure demonstrate that the reflected beam still consists essentially of clusters.

Performance of a Trapped Vortex Spray Combustor

2001 ◽  
Author(s):  
Paulo C. Mancilla ◽  
Pitchaiah Chakka ◽  
Sumanta Acharya
Keyword(s):  
Reasonable Agreement ◽  
Tangential Velocity ◽  
Flow Distribution ◽  
Spray Combustion ◽  
Combustion Chemistry ◽  
Tangential Velocity Component ◽  
Wide Range ◽  
Liquid Spray ◽  
Inside Face ◽  
Trapped Vortex

The performance of a liquid-fueled trapped vortex (TV) combustor is analyzed both experimentally and computationally. The TV cavity, formed between a forebody and an afterbody, is placed coaxially inside a combustor shell. Fuel and primary air are injected from the inside face of the afterbody. The flame holding capability of this trapped vortex configuration is evaluated for different primary equivalence ratios. Very low overall lean-blow-out (LBO) equivalence ratios are obtained for the TV combustor over a wide range of annular and primary airflow rates. It is found that by injecting the primary air with a tangential velocity component the circumferential mixing is improved without disrupting the vortex trapped in the cavity. The performance of the TV combustor is also evaluated through emissions measurements at the exit of the combustor and temperature distribution inside the cavity. Numerical simulations are performed for the TV configuration with a k-ε turbulence model coupled with a PDF combustion chemistry model for simulating liquid spray combustion. The predicted results are in reasonable agreement with the measurements and provide an assessment of the flow distribution in the cavity region.

scholarly journals The Influence of Hydrodynamic Changes in a System with a Pitched Blade Turbine on Mixing Power

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 68
Author(s):  
Jacek Stelmach ◽  
Czesław Kuncewicz ◽  
Szymon Szufa ◽  
Tomas Jirout ◽  
Frantisek Rieger
Keyword(s):  
Velocity Component ◽  
Tangential Velocity ◽  
Critical Value ◽  
Rotational Frequency ◽  
Water Levels ◽  
Liquid Stream ◽  
Piv Method ◽  
Pitched Blade Turbine ◽  
Turbine Impeller

This paper presents an analysis of hydrodynamics in a tank with a 45° and 60° pitched blade turbine impeller operating while emptying the mixer and with an axial agitator working during axial pumping-down of water at different water levels above the impeller. Measurements made with the PIV method confirmed the change in direction of pumping liquid after the level dropped below the critical value, with an almost unchanged liquid stream flowing through the mixer. It was found that an increase in the value of the tangential velocity in the area of the impeller took place and the quantity of this increase depended on the angle of the blade pitch and the rotational frequency of the impeller. Change in this velocity component increased the mixing power.

Effect of Process Parameters on Heat Affected Zone in Micro Machining of Borosilicate Glass Using μ-ECDM Process

2014 ◽  
Vol 592-594 ◽  
pp. 224-228 ◽  
Author(s):  
Lijo Paul ◽  
S. Hiremath Somashekhar
Keyword(s):  
Process Parameters ◽  
Borosilicate Glass ◽  
Heat Affected Zone ◽  
Micro Machining ◽  
Mems Devices ◽  
Process Variables ◽  
Grey Relation Analysis ◽  
Micro Electro Mechanical Systems ◽  
Immense Potential ◽  
Grey Relation

Application of borosilicate glass in Micro Electro Mechanical Systems (MEMS) devices are increasing due to many of its intrigue properties. Micro machining of glass for such applications needs hybrid technology so as to produce precise products. Electro Chemical Discharge Machining (ECDM) has proved immense potential in micro machining of glass. Present paper focuses on the effect of various process parameters of μ-ECDM on Heat Affected Zone (HAZ) while machining borosilicate glass. Grey Relation Analysis (GRA) is used to optimize the process variables. The optimized process variables are confirmed with experimental results.

scholarly journals COMPUTATIONAL STUDY OF CYCLONE FLOW FLUID DYNAMICS USING A DIFFERENT INLET SECTION ANGLE

2005 ◽  
Vol 4 (1) ◽  
Author(s):  
S. Bernardo ◽  
A. P. Peres ◽  
M. Mori
Keyword(s):  
Fluid Dynamics ◽  
Numerical Experiments ◽  
Computational Study ◽  
Tangential Velocity ◽  
Reynolds Stress Model ◽  
Inlet Section ◽  
Tangential Velocity Component ◽  
Computational Code ◽  
Tangential Inlet ◽  
Equipment Performance

The conventional design of the cyclone model has been used without significant modifications for about a century. Recently, some studies were carried out to improve equipment performance by evaluating the geometric influence of the tangential inlet section and scroll inlet duct design. In this work, the influence of cyclone inlet section geometry was studied using an angle of 45 degrees in relation to the cyclone body. The study was conducted for the gas and gas-particle phases, based on an experimental study available in the literature, where a conventional inlet section was used. Numerical experiments were carried out with the CFX computational code. The fluid dynamics profiles and tangential velocity component were evaluated for three inlet velocities (2.75, 7.75 and 15.2 m/s) using the Reynolds Stress model. The results showed that this proposal is useful for improving the cyclone performance.

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