Air Release During Column Separation

1983 ◽  
Vol 105 (1) ◽  
pp. 113-118 ◽  
Author(s):  
Muin Baasiri ◽  
J. Paul Tullis
Keyword(s):  
The Other ◽  
Test Facility ◽  
Empirical Equations ◽  
Column Separation ◽  
Free Air ◽  
Dissolved Air

Air release caused by column separation in a pipeline was investigated in a test facility where column separation could be generated for any desired length of time. The temperature, pressure, amount of dissolved air, and the other variables affecting the process were carefully controlled. Tests were made for cases where there was no initial free air in the system and for cases where there was some initial free air. The parameters influencing air release were identified and empirical equations developed for predicting the amount of air released during each cycle of column separation.

scholarly journals The spectrum of beryllium fluoride

1922 ◽  
Vol 101 (709) ◽  
pp. 187-194 ◽  
Keyword(s):  
Special Reference ◽  
Homologous Series ◽  
Alkaline Earth ◽  
The Other ◽  
Empirical Equations ◽  
Molecular Weights ◽  
Beryllium Fluoride ◽  
Previous Communication

In a previous communication, an account was given of an investigation of the spectra of the fluorides of magnesium, calcium, strontium, and barium, which was undertaken with a view to determine the numerical relations existing between these spectra. It was shown that the homologous series of the different spectra can be connected by empirical equations, involving only the constants of the series equations and the molecular weights or the molecular numbers of the respective compounds. It therefore seemed desirable to extend the investigation in order to ascertain if these relations are maintained in the spectrum of beryllium fluoride. Unlike the other alkaline earth compounds, the spectra of compounds of beryllium have previously received but little attention, and it has even remained doubtful whether the well-known groups of bands between λ4426 and λ5446 belong to the element itself or to the oxide. The present investigation has special reference to the spectrum of beryllium fluoride, which has not previously been recorded.

scholarly journals Effects of Bonding Parameters on Free Air Ball Properties and Bonded Strength of Ag-10Au-3.6Pd Alloy Bonding Wire

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 777 ◽  
Author(s):  
Jun Cao ◽  
Junchao Zhang ◽  
John Persic ◽  
Kexing Song
Keyword(s):  
Quadratic Function ◽  
Golf Ball ◽  
The Other ◽  
Bonding Wire ◽  
Small Ball ◽  
Ball Bond ◽  
Bonding Parameters ◽  
Optimal Geometry ◽  
Other Hand ◽  
Free Air

Free air ball (FAB) and bonded strength were performed on an Ag-10Au-3.6Pd alloy bonding wire (diameter of 0.025 mm) for different electronic flame-off (EFO) currents, times and bonding parameters. The effects of the EFO and bonding parameters on the characteristics of the FAB as well as the bonded strength were investigated using scanning electron microscopy. The results showed that, for a constant EFO time, the FAB of the Ag-10Au-3.6Pd alloy bonding wire transitioned from a pointed defined ball to an oval one, then to a perfectly shaped one, and finally to a golf ball with an increase in the EFO current. On the other hand, when the EFO current was constant and the EFO time was increased, the FAB changed from a small ball to a perfect one, then to a large one, and finally to a golf ball. The FAB exhibited the optimal geometry at an EFO current of 0.030 A and EFO time of 0.8 ms. Further, in the case of the Ag-10Au-3.6Pd alloy bonding wire, for an EFO current of 0.030 A, the FAB diameter exhibited a nonlinear relationship with the EFO time, which could be expressed by a quadratic function. Finally, the bonded strength decreased when the bonding power and force were excessively high, causing the ball bond to overflow. This led to the formation of neck cracks and decrease in the bonded strength. On the other hand, the bonded strength was insufficiently when the bonding power and force were small. The bonded strength was of the desired level when the bonding power and force were 70 mW and 0.60 N (for the ball bonded) and 95 mW and 0.85 N (for the wedge bonded), respectively.

Computational Study of 16 kWth Furnace Cofired Using Pulverized Bituminous Coal and Liquified Petroleum Gas Operated in Un-Staged and Air-Staged Conditions

2020 ◽  
Vol 143 (8) ◽  
Author(s):  
Nitesh Kumar Sahu ◽  
Mayank Kumar ◽  
Anupam Dewan
Keyword(s):  
Particle Size ◽  
Coal Particle ◽  
Bituminous Coal ◽  
Computational Study ◽  
Pearson Correlation ◽  
Turbulence Models ◽  
The Other ◽  
Test Facility ◽  
Measured Temperature ◽  
Inlet Swirl

Abstract This paper presents a computational study on air-fuel combustion of bituminous coal and liquified petroleum gas (LPG) in a 16 kWth test facility with a coflow-swirl burner. The performance of three turbulence models is investigated for the furnace operated under both air-staged and un-staged conditions by comparing their predictions with the reported measurements of temperature and species concentrations. This comparison shows that the shear stress transport (SST) k–ω model and SST k–ω model with low-Re correction predict the profiles of temperature and species concentrations reasonably well, but significantly underpredict the temperature in the furnace core at axial locations away from the burner. On the other hand, the transition SST k–ω model provides better overall congruency with the measured temperature and species concentrations when compared with the other turbulence models used, as indicated by relatively higher values of the Pearson correlation coefficient at locations away from the burner. The present high-fidelity computational model developed is also capable of accurately simulating the effect of coal particle size on the furnace environment, which is verified by the match between the computational predictions and the experimental results for two different sized coal samples. The model is also used to investigate the effect of coal particle size on the internal recirculation zone (IRZ) and the reattachment length (LR) for the same inlet swirl number (SN). A decrease of nearly 50% in the coal sample size results in the increase of LR and IRZ length by 20% and 82.6%, respectively.

Three Component Velocity Field Measurements in the Stagnation Region of a Film Cooled Turbine Vane

2001 ◽  
Author(s):  
Marc D. Polanka ◽  
J. Michael Cutbirth ◽  
David G. Bogard
Keyword(s):  
Field Measurements ◽  
The Other ◽  
Test Facility ◽  
Laser Doppler Velocimeter ◽  
Stagnation Region ◽  
Turbine Engine ◽  
Mainstream Flow ◽  
Turbine Vane ◽  
Component Velocity ◽  
Very High

The showerhead region of a film cooled turbine vane in a gas turbine engine involves a complex interaction between mainstream flow and coolant jets. This flow field was studied using three-component laser Doppler velocimeter measurements in a simulated turbine vane test facility. Measurements were focused around the stagnation row of holes. Low and high mainstream turbulence conditions were used. The spanwise orientation of the coolant jets, typical for showerhead coolant holes, had a dominating effect. Very high levels of turbulence were generated by the mainstream interaction with the coolant jets. Furthermore, this turbulence was highly anisotropic, with the spanwise component of the turbulent fluctuations being twice as large as the other components. Finally, there was an interaction of the high mainstream turbulence with the coolant injection resulting in increased turbulence levels for the spanwise velocity component, but had little effect on the other velocity components.

Reply to Discussion by J. R. Hearst and R. C. Carlson

Geophysics ◽  
1979 ◽  
Vol 44 (8) ◽  
pp. 1464-1464
Author(s):  
J. R. Hearst ◽  
R. C. Carlson
Keyword(s):  
Outer Radius ◽  
The Other ◽  
Gradient Term ◽  
The Earth ◽  
Other Hand ◽  
Free Air ◽  
Inner Radius ◽  
The Mean ◽  
The Difference

Our equations (3) and (4) are correct. They represent the difference between the attraction of the shell viewed from [Formula: see text], the outer radius of the shell, and [Formula: see text], its inner radius. (The attraction of the shell viewed from [Formula: see text] is zero.) On the other hand, equations (5) and (6) of Fahlquist and Carlson represent the difference in attraction of the entire earth from the same viewpoints and thus, as they say, include a free‐air gradient term. However, their equation (5) would be correct only if the mean density of the earth were equal to that of the shell, and the free‐air gradient obtained by their equation (10) is correct only under these circumstances.

Design Considerations for a State of the Art Development Test Cell for Aeroengines

1994 ◽  
Author(s):  
Roger C. Stevens ◽  
David J. Piggott
Keyword(s):  
State Of The Art ◽  
Test Cell ◽  
The Other ◽  
Test Facility ◽  
Cell Design ◽  
Test Bed ◽  
New Developments ◽  
Design Considerations ◽  
Technological Developments ◽  
Reverse Thrust

A number of new considerations are beginning to influence the design of development aeroengine test facilities due to technological, environmental and regulatory developments. Whilst the technological developments are of an evolutionary nature, the other developments, for example, the imposition of mandatory environmental noise constraints and the requirement to perform in-cell reverse thrust testing for early Extended Twin Operations certification, may impose step changes in test facility design. This paper examines the influence of these new developments on test cell design and describes how the new requirements were integrated with the traditional considerations in the design of a new “sea level” Test Bed in Derby, UK.

Temperature Fluctuations Inside the CANDU Reactor Moderator Test Facility (MTF)

2012 ◽  
Author(s):  
Araz Sarchami ◽  
Nasser Ashgriz ◽  
Marc Kwee
Keyword(s):  
High Temperature ◽  
Tube Bundle ◽  
Three Dimensional ◽  
Symmetry Plane ◽  
Temperature Fluctuations ◽  
The Other ◽  
Test Facility ◽  
Temperature Distributions ◽  
Frequency Fluctuations ◽  
Temperature Liquid

Three dimensional numerical simulation is conducted on the CANDU Moderator Test Facility (MTF). Heat generation inside the tank is modeled through surface heating. Transient variations of the temperature and velocity distributions inside the tank are determined. The results show that the flow and temperature distributions inside the moderator tank are three dimensional and no symmetry plane can be identified. A high temperature zone, located on the top left corner of the tank, is identified. The inlet jets are found to flow along the walls of the tank and impinge on each other at the top of the tank. This impingement point is located more towards the right side of the tank. The impingement of these two flow result in a secondary downward moving jet, which penetrates into the tube bundle. This secondary jet divides the tank into two sides. One side contains high temperature liquid and the other side contains low temperature liquid. The temperature contours along the length of the tank have a saddle shape, with high temperatures towards the edges of the saddle. This is due to strong wall jet flows in the middle planes pushing the hotter fluid towards the end walls of the tank. Competition between the upward moving buoyancy driven flows and the downward moving momentum driven flows, results in the formation of circulation zones inside the tank. The numerical results for MTF indicate that the moderator tank operates in the buoyancy driven mode. Any small disturbances in the flow or temperature can make the system unstable and asymmetric. Once the system comes out of symmetry, it cannot go back to symmetry. This results in circulating buoyancy driven flow at one side and a momentum driven flow at the other side of tank. Different types temperature fluctuations are noted inside the tank: (i) large amplitude temperature fluctuations are mainly at the boundaries between the hot and cold; (ii) low amplitude temperature fluctuations are mainly in the core of the tank with more uniform temperature distributions; (iii) high frequency fluctuations are in the regions with high velocities; and (iv) low frequency fluctuations are in the regions with lower fluid velocities.

Three Component Velocity Field Measurements in the Stagnation Region of a Film Cooled Turbine Vane

2002 ◽  
Vol 124 (3) ◽  
pp. 445-452 ◽  
Author(s):  
Marc D. Polanka ◽  
J. Michael Cutbirth ◽  
David G. Bogard
Keyword(s):  
Field Measurements ◽  
The Other ◽  
Test Facility ◽  
Laser Doppler Velocimeter ◽  
Stagnation Region ◽  
Turbine Engine ◽  
Mainstream Flow ◽  
Turbine Vane ◽  
Component Velocity ◽  
Very High

The showerhead region of a film-cooled turbine vane in a gas turbine engine involves a complex interaction between mainstream flow and coolant jets. This flow field was studied using three component laser Doppler velocimeter measurements in a simulated turbine vane test facility. Measurements were focused around the stagnation row of holes. Low and high mainstream turbulence conditions were used. The spanwise orientation of the coolant jets, typical for showerhead coolant holes, had a dominating effect. Very high levels of turbulence were generated by the mainstream interaction with the coolant jets. Furthermore, this turbulence was highly anisotropic, with the spanwise component of the turbulent fluctuations being twice as large as the other components. Finally, there was an interaction of the high mainstream turbulence with the coolant injection resulting in increased turbulence levels for the spanwise velocity component, but had little effect on the other velocity components.

scholarly journals Comparison of Experimental and Theoretical Results for Unsteady Transonic Cascade Flow at Design and Off-Design Conditions

1993 ◽  
Author(s):  
V. Carstens ◽  
A. Bölcs ◽  
H. Körbacher
Keyword(s):  
Transonic Flow ◽  
Incidence Angle ◽  
Design Flow ◽  
The Other ◽  
Test Facility ◽  
Experimental Investigations ◽  
Suction Surface ◽  
Flow Angle ◽  
Flux Vector Splitting ◽  
Theoretical Results

This paper presents experimental and theoretical results for turbine cascades performing harmonic oscillations in transonic flow at design and off-design conditions. The experimental investigations were performed in an annular test facility where unsteady blade pressures were measured in two different test cascades, one operating at the nominal inlet flow angle, the other at an incidence angle exceeding the normal value by more than 20 degrees. The corresponding theoretical results were computed with a 2D Euler code which makes use of flux vector splitting in combination with a time-dependent grid generation. The present data were all obtained for tuned bending modes where the blades performed heaving oscillations with the same frequency and amplitude, but with a constant interblade phase angle. For the cascade operating at design conditions, the steady flow was purely subsonic. The other test cascade was run in transonic flow, and a normal shock appeared on the rear part of the blade’s suction surface. It was found that measured unsteady pressure and damping coefficients are well reproduced by the computed results for the first test cascade. In the case of steady off-design flow (the second test cascade), significant differences between experimental and theoretical results are observed.

scholarly journals Bubbles and microbubbles for hydrodynamic test facilities

2018 ◽  
pp. 43-55
Author(s):  
Yves Lecoffre ◽  
Guillaume Maj ◽  
Vivien Aumelas
Keyword(s):  
Liquid Metals ◽  
Dissolved Gas ◽  
Two Phase ◽  
Void Fractions ◽  
Free Air ◽  
Measuring Techniques ◽  
And Control ◽  
Dissolved O2 ◽  
Optical Velocity ◽  
Dissolved Air

Bubbles are known to have important effects in hydrodynamic facilities such as cavitation tunnels, hydraulic flow loops, pumps, valves and turbines test facilities, towing tanks etc. They are also used to simulate real two-phase flows with various void fractions or bubble size distributions under different pressure and velocity conditions. In order to manage safely these problems or to simulate at best the prototype conditions, an arsenal of theoretical and experimental techniques is necessary, including: – The control of dissolved air, which is under the form of independent molecules moving in the water. – The control of nuclei which are generally microbubbles of some tens of micrometers. – The injection of emulsions. Emulsions are a mixture of water and bubbles of millimetric size. – The separation of free air. Free air concerns bubbles of any size. – The resorption and the control of bubbles growing or shrinking by diffusion of air in water. The production and control of bubbles also implies the use of dedicated measuring techniques. Among these are devices to measure the void fraction and size of bubbles in emulsions as well as dissolved gas: – Local optical and electrical probes [14], – Optical techniques, – Venturi measurements (susceptibility meters). Susceptibility is the pressure at which a nucleus must be submitted to explode and create a vapor bubble. – Optical and polarographic gages for dissolved O2 analysis. Finally, microbubbles can be utilized as non-polluting tracers for optical velocity measurements in water and transparent fluids, such as LDV or PIV. Many of these techniques have been developed by YLEC Consultants. Some of these can be utilized in fluids other than water, such as liquid metals.

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