2-D MASS-FLOW VELOCITY FIELDS

2020 ◽  
pp. 65-71
Keyword(s):  
Flow Velocity ◽  
Mass Flow ◽  
Velocity Fields

Development of a Surface Flow Sensor for Measuring Turbulent Drag Force

2019 ◽  
Author(s):  
Il Doh ◽  
Il-Bum Kwon ◽  
Jiho Chang ◽  
Sejong Chun
Keyword(s):  
Wind Tunnel ◽  
Flow Velocity ◽  
Drag Force ◽  
Mass Flow ◽  
Surface Flow ◽  
Flow Sensor ◽  
Constant Current ◽  
Thermal Mass ◽  
Turbulent Drag ◽  
Mass Flow Sensor

Abstract A surface flow sensor is needed if turbulent drag force is to be measured over a vehicle, such as a car, a ship, and an airplane. In case of automobile industry, there are no automobile manufacturers which measure surface flow velocity over a car for wind tunnel testing. Instead, they rely on particle image velocimetry (PIV), pressure sensitive paint (PSP), laser Doppler anemometry (LDA), pitot tubes, and tufts to get information regarding the turbulent drag force. Surface flow sensors have not devised yet. This study aims at developing a surface flow sensor for measuring turbulent drag force over a rigid body in a wind tunnel. Two sensing schemes were designed for the fiber-optic distributed sensor and the thermal mass flow sensor. These concepts are introduced in this paper. As the first attempt, a thermal mass flow sensor has been fabricated. It was flush-mounted on the surface of a test section in the wind tunnel to measure the surface flow velocity. The thermal mass flow sensor was operated by either constant current or constant resistance modes. Resistance ratio was changed as the electric current was increased by the constant current mode, while power ratio was saturated as the resistance was increased by the constant resistance mode. Either the resistance ratio or the power ratio was changed with the flow velocity measured by a Pitot tube, located at the center of test section.

Characterizing the Effect of Radial Vane Height on Flame Migration in an Ultra Compact Combustor

2011 ◽  
Author(s):  
Kenneth D. LeBay ◽  
Marc D. Polanka ◽  
Richard D. Branam
Keyword(s):  
Flow Velocity ◽  
Mass Flow ◽  
Temperature Profiles ◽  
Core Mass ◽  
Freestream Velocity ◽  
Flow Rates ◽  
Core Flow ◽  
Injection Angle ◽  
The Core ◽  
Mass Flow Rates

The Ultra Compact Combustor (UCC) has shown viable merit for significantly improving gas turbine combustor performance. UCC models for small engines can provide centrifugal loading up to 4,000 gs. However, as the scale of the combustor increases, the g-load will necessarily decrease and the radial vane height will increase. Thus, the importance of understanding flame migration over increasing radial vane heights is pivotal to the applicability of this design to larger engine diameters. The Air Force Institute of Technology’s Combustion Optimization and Analysis Laser laboratory studied this effect with a sectional UCC model using three different vane heights. By varying the mass flow rates of the circumferential UCC section, the g-loading was varied from 500–2,000 gs. Two-line Planar Laser Induced Fluorescence at 10Hz was used for 2D temperature profiles. High-speed video at 2kHz was also used for qualitative flame migration characterization. Several cases were studied varying the radial vane height, the circumferential g-load, and the UCC/core mass flow ratio but specifically focusing on the interaction between matching the core mass flow and the core freestream velocity among the different vane heights. Finally, the decreased core flow velocity for the same mass flow weakened the shear layer between the main and cavity flows and this allowed deeper flame migration into the core flow from the UCC. Control of the overall flame migration is the key to produce desirable combustor exit temperature profiles. Increased spans lead to higher velocity gradients and increased flame injection angles at the same mass flow rates. However, at the same core flow velocities and UCC to core flow velocity ratios the flame injection angle was relatively independent of the radial vane height and almost entirely dependent on the core flow velocity alone.

Solids flow velocity profiles in mass flow hoppers

1987 ◽  
Vol 42 (4) ◽  
pp. 737-744 ◽  
Author(s):  
H.G. Polderman ◽  
J. Boom ◽  
E. De Hilster ◽  
A.M. Scott
Keyword(s):  
Flow Velocity ◽  
Mass Flow ◽  
Velocity Profiles

scholarly journals Numerical Study on Non-Uniform Temperature Distribution and Thermal Performance of Plate Heat Exchanger

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8280
Author(s):  
Jeonggyun Ham ◽  
Gonghee Lee ◽  
Dong-wook Oh ◽  
Honghyun Cho
Keyword(s):  
Heat Exchanger ◽  
Temperature Distribution ◽  
Flow Velocity ◽  
Mass Flow ◽  
Flow Rate ◽  
Temperature Difference ◽  
Plate Heat Exchanger ◽  
Outlet Temperature ◽  
Uniform Temperature ◽  
Plate Heat

In this study, computational fluid dynamics (CFD) analysis was performed to investigate the cause of the thermal stratification in the channel and the temperature non-uniformity of the plate heat exchanger. The flow velocity maldistribution of the channel and the merging parts caused temperature non-uniformity in the channel width direction. The non-uniformity of flow velocity and temperature in the channel is shown in Section 1 > Section 3 > Section 2 from the heat exchanger. The non-uniform temperature distribution in the channel caused channel stratification and non-uniform outlet temperature. Stratification occurred at the channel near the merging due to the flow rate non-uniformity in the channel. In particular, as the mass flow rate increased from 0.03 to 0.12 kg/s and the effectiveness increased from 0.436 to 0.615, the cold-side stratified volume decreased from 4.06 to 3.7 cm3, and the temperature difference between the stratified area and the outlet decreased from 1.21 K to 0.61 K. The increase in mass flow and the decrease in temperature difference between the cold and hot sides alleviated the non-uniformity of the outlet temperature due to the increase in effectiveness. Besides, as the inlet temperature difference between the cold and the hot side increases, the temperature non-uniformity at the outlet port is poor due to the increase in the stratified region at the channel, and the distance to obtain a uniform temperature in the outlet pipe increases as the temperature at the hot side increases.

scholarly journals Measurements of Mass Flow in the Transition Region and Inner Corona

1980 ◽  
Vol 91 ◽  
pp. 375-378
Author(s):  
Gary J. Rottman
Keyword(s):  
Transition Region ◽  
Mass Flow ◽  
Spectral Resolution ◽  
Solar Disk ◽  
Velocity Fields ◽  
Emission Lines ◽  
High Spectral Resolution ◽  
Sounding Rocket ◽  
Line Profiles ◽  
Euv Emission

A recent sounding rocket experiment has provided high spectral resolution line profiles across the solar disk. The objective of this experiment is to provide information on the systematic velocity fields at the base of the corona by observing the displacement, width and shape of EUV emission lines.

scholarly journals Experimental setup to study two phase flows for environmental applications

2019 ◽  
Vol 85 ◽  
pp. 07010
Author(s):  
Irina Murgan ◽  
Florentina Bunea ◽  
Adrian Nedelcu ◽  
Gabriel Dan Ciocan
Keyword(s):  
Flow Velocity ◽  
Good Accuracy ◽  
Velocity Fields ◽  
Experimental Setup ◽  
Two Phase ◽  
Environmental Application ◽  
Water Flow Velocity ◽  
Flow Velocity Field ◽  
Flow Parameters ◽  
Mean Fields

The air water mix is a major concern for the environmental application. This paper proposes an experimental method to accede simultaneously at the water flow velocity field and at the void fraction. Instantaneous and mean fields, as well as the evolution with the flow parameters variation are obtained in cavitation or aerated flows. This method allows a good accuracy for the flow velocity fields (2%) and void (vapours or air) contours (4%).

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