Measurement of Particulate Flow in Discrete Structure Particle Heating Receivers

2015 ◽  
Author(s):  
A. W. Khayyat ◽  
R. C. Knott ◽  
C. L. Nguyen ◽  
M. C. Golob ◽  
S. I. Abdel-Khalik ◽  
...  
Keyword(s):  
Collection Efficiency ◽  
Vertical Plane ◽  
Perforated Plate ◽  
The Body ◽  
Wire Mesh ◽  
Discrete Structure ◽  
Mesh Material ◽  
Error Propagation Analysis ◽  
Particle Heating ◽  
Wire Meshes

Conventional central receiver power tower plants typically use steam or molten salts as the heat collection medium. Recently, attention has returned to using solid particulates in a particle-heating receiver (PHR). In this project we are interested in discrete structure PHR that includes structures, such as an array of wire mesh protrusions in our current design, to increase the residence time of particles falling through the receiver. The meshes should be sized to accommodate the falling particles without exposing too much mesh to concentrated radiation, which might degrade collection efficiency and expose the mesh material to high temperature thermal degradation. The experiment described in this paper was implemented to measure the appropriate exposed length of such discrete porous structures for a PHR. Particulates are introduced to the model PHR from a perforated plate distributor. As detailed in the body of the paper, a laser and photosensor (responding in units of lux) are used at positions 546 mm and then 1111 mm downstream from the perforated plate to measure the transparency of the flow in a vertical plane across the receiver. The laser light forms a vertical sheet, and its intensity is measured by the photosensor on the opposite side of the receiver. By comparing the lux data with and without particles flowing, the transparency of the particulate curtain can be determined. Different mesh counts have been tested and compared, and plotted for comparison. This research is useful for designers to use when planning a PHR and will inform the proper length of wire meshes to use. This paper reports the results obtained so far including a standard error propagation analysis.

Preliminary Design of an All-Ceramic Discrete-Structure Particle Heating Receiver

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
George Peters ◽  
Matthew Golob ◽  
Clayton Nguyen ◽  
Sheldon Jeter ◽  
Syed Danish ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Mass Flux ◽  
Metal Wire ◽  
Particle Flow ◽  
Discrete Structure ◽  
Ceramic Tiles ◽  
Particle Mixing ◽  
Particle Heating ◽  
Wire Meshes ◽  
The Impact

Abstract Discrete structure particle heating receivers (DS-PHR), as used in concentrated solar power (CSP) systems, employ suitable discrete porous structures to intermittently halt the falling particles to control the speed and increase the residence time of falling particulates, thereby increasing the temperature rise of particulates exiting the DS-PHR. Previous designs of DS-PHRs have considered both porous foam structures, which have mass flux limits, and metal wire meshes, which are effective but have temperature and other functional limitations. This paper recounts recent studies at Georgia Tech and King Saud University that have investigated the use of ceramic tiles made porous by discrete slot-shaped passages in place of previous metal wire meshes. Currently, for experimental use, the slot-like passages are cut into the tiles by water jet, but operational units are expected to be formed into shape and fired by more economical conventional ceramic techniques. Benefits of ceramic and other refractory materials include higher temperature and heat flux limits at a reasonable cost. The tiles are expected to be installed in chevron configuration, which have been shown by experience to be especially effective, and these so-called ceramic chevrons have been shown to deliver adequate mass flux densities while still removing most of the kinetic energy from the particles. In addition, the thickness of the tile allows the incorporation of angled slots capable of redirecting the particle flow, adding a method to control particle mixing by purposefully directing the particulate streams. These enhanced slots are typically arranged with adequate spacing to allow for increased penetration of concentrated light into the depth of the falling bed of particles and may be angled to redirect hot particles toward the back plane of the DS-PHR. Both of these features should help minimize depthwise temperature variation. The testing reported here will focus on the degree of velocity and flow control that can be achieved by proper design of these ceramic chevrons as well as demonstrate the effectiveness of different designs on light penetration. Prior to this research, the effectiveness of ceramic obstructions might have been properly doubted because of the very high coefficient of restitution (COR) for the impact of ceramic particles on ceramic solids. In reality, it will be shown that a layer of particulates will form on a chevron, which effectively dissipates the kinetic energy of the impacting particles. Overall, this paper will report improvements in DS-PHR designs that can withstand high temperatures and fluxes, achieve additional control of particle flow, enhance particle mixing, and allow deeper penetration of light into the depth of the falling bed.

ANALYSIS OF THE CREW PART OF THE LOCOMOTIVE TEM23 AND PROPOSALS FOR ELIMINATION OF DISADVANTAGES

2020 ◽  
Author(s):  
Dmitriy Antipin ◽  
Vladimir Vorobev ◽  
Denis Bondarenko ◽  
Gennadiy Petrov
Keyword(s):  
Vertical Plane ◽  
The Body ◽  
Diesel Locomotive ◽  
Design Features ◽  
Bogie Frame ◽  
Spring Suspension ◽  
In Series

The analysis of the design features of the bogie of the TEM23 shunting diesel locomotive is carried out. In the process of analysis, the directions of its improvement are determined. It is proposed to rotate the bogie frame in the vertical plane by reducing the body supports to two and using a pivot with low lowering, equip the bogies with pneumatic spring suspension in the form of two corrugations installed in series with shortened suspension springs. The proposed options for improving the undercarriage of a diesel locomotive will increase the competitiveness of products and reduce costs

scholarly journals Discrete element analysis of the punching behaviour of a secured drapery system: from laboratory characterization to idealized in situ conditions

2021 ◽  
Author(s):  
Antonio Pol ◽  
Fabio Gabrieli ◽  
Lorenzo Brezzi
Keyword(s):  
Mechanical Response ◽  
Steel Wire ◽  
Discrete Element ◽  
Wire Mesh ◽  
Steel Plates ◽  
Loading Conditions ◽  
Element Analysis ◽  
In Situ Conditions ◽  
Wire Meshes

AbstractIn this work, the mechanical response of a steel wire mesh panel against a punching load is studied starting from laboratory test conditions and extending the results to field applications. Wire meshes anchored with bolts and steel plates are extensively used in rockfall protection and slope stabilization. Their performances are evaluated through laboratory tests, but the mechanical constraints, the geometry and the loading conditions may strongly differ from the in situ conditions leading to incorrect estimations of the strength of the mesh. In this work, the discrete element method is used to simulate a wire mesh. After validation of the numerical mesh model against experimental data, the punching behaviour of an anchored mesh panel is investigated in order to obtain a more realistic characterization of the mesh mechanical response in field conditions. The dimension of the punching element, its position, the anchor plate size and the anchor spacing are varied, providing analytical relationships able to predict the panel response in different loading conditions. Furthermore, the mesh panel aspect ratio is analysed showing the existence of an optimal value. The results of this study can provide useful information to practitioners for designing secured drapery systems, as well as for the assessment of their safety conditions.

High Speed Flow through Perforated Plates

1960 ◽  
Vol 64 (590) ◽  
pp. 103-105
Author(s):  
P. G. Morgan
Keyword(s):  
Pressure Drop ◽  
High Speed ◽  
Perforated Plate ◽  
Wire Mesh ◽  
Flow Conditions ◽  
High Speed Flow ◽  
Perforated Plates ◽  
Speed Flow ◽  
Flow Through ◽  
Points Of View

The flow through porous screens has been widely studied from both the theoretical and experimental points of view. The most widely used types of screen are the wire mesh and the perforated plate, and the majority of the literature has been concerned with the former. Several attempts have been made to correlate the parameters governing the flow through such screens, i.e. the pressure drop, the flow conditions and the geometry of the mesh.

The vestibuloocular reflex of the adult flatfish. I. Oculomotor organization

1985 ◽  
Vol 54 (4) ◽  
pp. 887-899 ◽  
Author(s):  
W. Graf ◽  
R. Baker
Keyword(s):  
Eye Movements ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Vertical Plane ◽  
Extraocular Muscles ◽  
The Body ◽  
Medial Rectus ◽  
Inferior Rectus ◽  
Abducens Nucleus ◽  
Eye Muscles

The flatfish species constitute a natural paradigm for investigating adaptive changes in the vertebrate central nervous system. During metamorphosis all species of flatfish experience a 90 degree change in orientation between their vestibular and extraocular coordinate axes. As a result, the optic axes of both eyes maintain their orientation with respect to earth horizontal, but the horizontal semicircular canals become oriented vertically. Since the flatfish propels its body with the same swimming movements when referenced to the body as a normal fish, the horizontal canals are exposed to identical accelerations, but in the flatfish these accelerations occur in a vertical plane. The appropriate compensatory eye movements are simultaneous rotations of both eyes forward or backward (i.e., parallel), in contrast to the symmetric eye movements in upright fish (i.e., one eye moves forward, the other backward). Therefore, changes in the extraocular muscle arrangement and/or the neuronal connectivity are required. This study describes the peripheral and central oculomotor organization in the adult winter flounder, Pseudopleuronectes americanus. At the level of the peripheral oculomotor apparatus, the sizes of the horizontal extraocular muscles (lateral and medial rectus) were considerably smaller than those of the vertical eye muscles, as quantified by fiber counts and area measurements of cross sections of individual muscles. However, the spatial orientations and the kinematic characteristics of all six extraocular muscles were not different from those described in comparable lateral-eyed animals. There were no detectable asymmetries between the left and the right eye. Central oculomotor organization was investigated by extracellular horseradish peroxidase injections into individual eye muscles. Commonly described distributions of extraocular motor neurons in the oculomotor, trochlear, and abducens nuclei were found. These motor neuron pools consisted of two contralateral (superior rectus and superior oblique) and four ipsilateral populations (inferior oblique, inferior rectus, medial rectus, and lateral rectus). The labeled cells formed distinct motor neuron populations, which overlapped little. As expected, the numbers of labeled motoneurons differed in horizontal and vertical eye movers. The numerical difference was especially prominent in comparing the abducens nucleus with one of the vertical recti subdivisions. Nevertheless, there was bilateral symmetry between the motoneurons projecting to the left and right eyes.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Comparison of Cranial and External Morphology of Tree Squirrels (Funiscurus leucogenys) in Selected Locations of Rainforest in Nigeria

2020 ◽  
pp. 1-12
Author(s):  
A. O. Bamidele ◽  
A. I. Akinpelu
Keyword(s):  
External Genitalia ◽  
The Body ◽  
Wire Mesh ◽  
Cranial Morphology ◽  
Generic Level ◽  
History Museum ◽  
Cranial Measurements ◽  
In Captivity ◽  
Tree Squirrels ◽  
Body Parameters

This study looked at the differences in cranial morphology of tree squirrel species (F. leucogenys) from four different locations in Rainforest part of Nigeria. The squirrels were captured through the use of locally fabricated live traps made of wire-mesh and steel. Trapped specimens were immediately transferred to the laboratory in captivity cages, where they were euthanized in a bell-jar containing chloroform-soaked cotton wool. Specimens were then preliminarily identified to the generic level, using an identification key. The skull of 131 tree squirrels were prepared using Long Island Natural History Museum guide and the sex of the specimens was determined by visual inspection of the external genitalia. The skull and other body parameters were measured using digital venier caliper. The results showed that the body parameters (HBL, TL, TBL, EL, HFL and BW) measured were slightly different from one location to another. Also, the cranial measure showed some similarities among some locations (Ile-Ife, Emure-Ekiti and Ado-Ekiti), while measurement on squirrels from Sekona was different from other three locations. In conclusion, the cranial measurements of the tree squirrels shows there was no new species of F. leucogeny from the sampled locations.

A Study of the Transient Pitching Oscillations of a Ship

1959 ◽  
Vol 3 (01) ◽  
pp. 22-30
Author(s):  
Paul Golovato
Keyword(s):  
Vertical Plane ◽  
The Body ◽  
Plane Symmetry ◽  
Moment Equations ◽  
Longitudinal Modes ◽  
Second Order Differential Equations ◽  
Stability Derivatives ◽  
Submerged Body ◽  
Constant Coefficients ◽  
Instantaneous Values

The motions of a deeply submerged body with vertical-plane symmetry, e.g., a submarine, are commonly treated in a manner completely analogous to that used for aircraft motions. The body is assumed to have its lateral and longitudinal modes uncoupled. The small motions are described by a set of force-and-moment equations which are linear, second-order differential equations with constant coefficients. These proportionality constants ("stability derivatives") relate the forces and moments to the instantaneous values of the position, velocity, and acceleration of the body. They are generally experimentally determined in the wind or water tunnel, and the controlled or uncontrolled motions of the craft are predicted based thereon.

Interdisciplinary approach to the treatment of rare visual illusions in a veteran

2021 ◽  
Vol 14 (1) ◽  
pp. e238362
Author(s):  
Michelle Zeller ◽  
Wilhelmina Stamps
Keyword(s):  
Vertical Plane ◽  
Interdisciplinary Approach ◽  
Interdisciplinary Team ◽  
Visual Illusions ◽  
The Body ◽  
Hip Surgery ◽  
Coronal Plane ◽  
Team Approach ◽  
Physical Medicine ◽  
Rare Form

Upside-down reversal of vision (UDRV) is a rare form of metamorphopsia, or visual illusions that can distort the size, shape or inclination of objects. This phenomenon is paroxysmal and transient in nature, with patients reporting a sudden inversion of vision in the coronal plane, which typically remains for seconds or minutes, though occasionally persists for hours or days, before returning to normal. Distorted egocentric orientation (ie, the patient perceives the body to be tilted away from the vertical plane) is even more rare as a co-occurring phenomenon. To the best of our knowledge, this is the first reported case of a veteran who presented with UDRV and distorted egocentric orientation during hospitalisation on an inpatient physical medicine and rehabilitation setting following an elective hip surgery. This case serves not only to document the presence of rare visual illusions, but also illustrates the importance and value of an interdisciplinary team approach.

Many-legged maneuverability: dynamics of turning in hexapods

1999 ◽  
Vol 202 (12) ◽  
pp. 1603-1623 ◽  
Author(s):  
D.L. Jindrich ◽  
R.J. Full
Keyword(s):  
Horizontal Plane ◽  
Center Of Mass ◽  
Vertical Plane ◽  
Force Production ◽  
The Body ◽  
Mean Velocity ◽  
Blaberus Discoidalis ◽  
Body Design ◽  
Reaction Forces ◽  
Straight Ahead

Remarkable similarities in the vertical plane of forward motion exist among diverse legged runners. The effect of differences in posture may be reflected instead in maneuverability occurring in the horizontal plane. The maneuver we selected was turning during rapid running by the cockroach Blaberus discoidalis, a sprawled-postured arthropod. Executing a turn successfully involves at least two requirements. The animal's mean heading (the direction of the mean velocity vector of the center of mass) must be deflected, and the animal's body must rotate to keep the body axis aligned with the heading. We used two-dimensional kinematics to estimate net forces and rotational torques, and a photoelastic technique to estimate single-leg ground-reaction forces during turning. Stride frequencies and duty factors did not differ among legs during turning. The inside legs ended their steps closer to the body than during straight-ahead running, suggesting that they contributed to turning the body. However, the inside legs did not contribute forces or torques to turning the body, but actively pushed against the turn. Legs farther from the center of rotation on the outside of the turn contributed the majority of force and torque impulse which caused the body to turn. The dynamics of turning could not be predicted from kinematic measurements alone. To interpret the single-leg forces observed during turning, we have developed a general model that relates leg force production and leg position to turning performance. The model predicts that all legs could turn the body. Front legs can contribute most effectively to turning by producing forces nearly perpendicular to the heading, whereas middle and hind legs must produce additional force parallel to the heading. The force production necessary to turn required only minor alterations in the force hexapods generate during dynamically stable, straight-ahead locomotion. A consideration of maneuverability in the horizontal plane revealed that a sprawled-postured, hexapodal body design may provide exceptional performance with simplified control.

Behavior of Self Compacted Concrete Ferrocement Beams

2021 ◽  
pp. 1-14
Author(s):  
Abeer M. Erfan ◽  
Tamer H. K. Elafandy ◽  
Mahmoud M. Mahran ◽  
Mohamed Said
Keyword(s):  
Energy Absorption ◽  
Low Cost ◽  
Steel Wire ◽  
Construction Material ◽  
Point Load ◽  
Wire Mesh ◽  
Experimental Program ◽  
Cracking Behavior ◽  
Group B ◽  
Wire Meshes

Many researchers have been conducted on the ferrocement as a low cost construction material and a flexible structural system. This experimental investigation on the behavior of ferrocement beams after exposed to different type of ferrocement and different of ferrocement layer are presented in this paper. The experimental program consisted of seven simply supported beams tested up to failure under four-point load. The dimensions of 150mm×250mm×2000mm. Each beam was reinforced using steel 2 f 12 in top and 2 f10 in bottom and the stirrups was 10 f 10/m. In addition to six of them contains ferrocement different steel wire meshes and different of ferrocement layer. The test specimens are divided in three groups and the results of each one compared with the control specimen. The first group (A) which used the welded wire mesh. The second group (B) which used the expanded wire mesh. But the third group (C) which reinforced using woven wire mesh. The mid span deflection, cracks, reinforcement and concrete strains of the tested beams were recorded and compared. The performance of the test beams in terms of ultimate flexure load cracking behavior and energy absorption were investigated. The experimental results emphasized that high ultimate loads, better crack resistance control, high ductility, and good energy absorption properties could be achieved by using the proposed ferrocement beams. The cracks propagation decreased and its number and width decreased by using woven, expanded and welded wire mesh especially in specimens with two layers of wire mesh. Theoretical calculation was carried out to compare the oplained results with the theoretical ones, which show good agreement.

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