Solids flow velocity profiles in mass flow hoppers

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.

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1028: Flow velocity profiles in the descending aorta in hypertensive disease during pregnancy

American Journal of Obstetrics and Gynecology ◽

10.1016/j.ajog.2018.11.1052 ◽

2019 ◽

Vol 220 (1) ◽

pp. S659-S660

Author(s):

Yalda Afshar ◽

Allison Woods ◽

Greggory DeVore ◽

Brian Koos

Keyword(s):

Flow Velocity ◽

Velocity Profiles ◽

Hypertensive Disease ◽

Descending Aorta

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Imaging of subcutaneous blood vessels and flow velocity profiles by optical coherence tomography

Laser Physics ◽

10.1134/s1054660x10070029 ◽

2010 ◽

Vol 20 (4) ◽

pp. 891-899 ◽

Cited By ~ 46

Author(s):

M. Bonesi ◽

S. G. Proskurin ◽

I. V. Meglinski

Keyword(s):

Optical Coherence Tomography ◽

Flow Velocity ◽

Blood Vessels ◽

Velocity Profiles ◽

Optical Coherence

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

Volume 5: Heat Transfer, Parts A and B ◽

10.1115/gt2011-45919 ◽

2011 ◽

Cited By ~ 7

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.

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