Three-Dimensional Velocity and Droplet Size Measurements of Spray Flow (Keynote Paper)

Author(s):  
Yoshio Zama ◽  
Masaaki Kawahashi ◽  
Hiroyuki Hirahara

The present investigation describes an application of a novel technique of simultaneous measurement of droplet size and three-dimensional components of velocity in a high density spray with swirl. The spray has a complicated and three-dimensional structure caused by mixing with surrounding airflow entrained by high speed fuel jet issuing from a nozzle. The breakup process of fuel film to fine-droplet-cloud, the droplet size dispersion and the velocity distribution of droplets are important factors in practical application of fuel spray for combustors. The conventional technique can be applied to local measurement of droplet speed and size. Recent methods, based on optical and image processing techniques, provide measurement of the velocity and droplet size distribution in observation area or volume. Maeda et al. proposed an excellent measurement technique of the size and the velocity distribution of droplet in spray based on interferometric laser imaging in which the fringe pattern is generated at the out of focus plane by interference between 0th order and 1st order refractions of droplet illuminated by high power laser light sheet. And also, in this technique, the separation of overlapping droplets image has been successfully done by optical method. As a practical application, the size and velocity distributions of droplets in a high density spray without swirl have been measured by this technique. In general, the droplet motion in a spray field is highly three-dimensional. Especially, a spray generated by a swirl nozzle shows complicated droplet motion in the three-dimensional field. In order to analyze the configuration of a complicated spray field, three-dimensional velocity measurement of droplets must be required. In the present paper, a combined measurement technique of the size and three velocity components of droplets in three-dimensional spray field based on doublet imaging technique of droplets and stereoscopic PIV method has been developed. And its feasibility and applicability was confirmed by practical application to measurements of spray fields induced by a swirl jet nozzle using in gas turbine.

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1127
Author(s):  
Junpeng Wang ◽  
Cuicui Xu ◽  
Gang Zhou ◽  
Yansong Zhang

In order to understand the characteristics of the spray field of a dust suppression nozzle and provide a reference for dust nozzle selection according to dust characteristics, a three-dimensional phase Doppler particle analyzer (PDPA) spray measurement system is used to analyze the droplet size and velocity characteristics in a spray field, particularly the joint particle size–velocity distribution. According to the results, after the ejection of the jet from the nozzle, the droplets initially maintained some velocity; however, the distribution of particles with different sizes was not uniform. As the spray distance increased, the droplet velocity decreased significantly, and the particle size distribution changed very little. As the distance increased further, the large droplets separated into smaller droplets, and their velocity decreased rapidly. The distributions of the particle size and velocity of the droplets then became stable. Based on the particle size-velocity distribution characteristics, the spray structure of pressure-swirl nozzles can be divided into five regions, i.e., the mixing, expansion, stabilization, decay, and rarefied regions. The expansion, stabilization, and decay regions are the effective dust fall areas. In addition, the droplet size in the stabilization region is the most uniform, indicating that this region is the best dust fall region. The conclusions can provide abundant calibration data for spray dust fall nozzles.


Author(s):  
Ceheng Duan ◽  
Yan Meng ◽  
Yujue Wang ◽  
Zhaokun Zhang ◽  
Yunchen Ge ◽  
...  

Prussian blue and its analogues are considered to be cathode materials for practical application in sodium-ion batteries due to their open three-dimensional structure and low cost. However, PBAs synthesized by...


2020 ◽  
pp. 001872672093331
Author(s):  
Andrew K Schnackenberg ◽  
Edward Tomlinson ◽  
Corinne Coen

In this article, we advance research on transparency by developing and validating a measure based on recent theoretical insights about its dimensionality. We find that transparency—defined as the perceived quality of information—is a three-dimensional construct consisting of perceived information disclosure, clarity, and accuracy. Evidence shows items associated with these dimensions can be aggregated into a single transparency construct. We also find that transparency (as an aggregate construct) is distinct from neighboring constructs such as informational justice and capable of predicting perceptions of the source’s trustworthiness (ability, benevolence, and integrity). Finally, we find evidence of measurement invariance between two commonly used referents of analysis, yielding confidence in the application of the proposed measure across research settings. We discuss implications of the new measure for research on transparency, the extension of the new measure to related research traditions, and the practical application of the new measure for managers interested in constructing and appraising transparent messages.


2017 ◽  
Vol 263 ◽  
pp. 160-164
Author(s):  
Maxim Arsentev ◽  
Marina Kalinina ◽  
Petr Tikhonov ◽  
Anastasia Shmigel ◽  
Nadezhda Kovalko ◽  
...  

The reversibility of phase transformations in Li2MnSiO4 and related materials during charge/discharge of the material is an important factor to enable the practical application of the cathode materials. However, the stability of this material is still unattainable. Here we report the computational identification of a new form of Li2MnSiO4 as a stable candidate with acceptable characteristics. The stability could arise due to the presence of the three-dimensional structure of the inorganic framework. The presence of a structure with a compact unit cell forms the basis for high capacity. Surprisingly it was found to have a stable analogue occurring in nature – Na2CaSiO4 with the same structure. Using this information the possible routes of obtaining such material are presented. The prediction of such material has been not found in the literature previously. Of course the problems such as phase transformations upon delithiation may exist, and to check the data the experimental and computer studies needed.


2018 ◽  
Vol 193 ◽  
pp. 02024 ◽  
Author(s):  
Andrey Zuikov ◽  
Genrikh Orekhov ◽  
Tatiana Suehtina

The article is devoted to the theoretical study of laminar flows with the coaxial layers rotating in opposite directions moving along the pipe. These flows have a wide practical application potential in technologies of mixing multiphase and heterogeneous media in microbiology, chemistry, ecology, heat engineering, power engineering, civil engineering and engine and rocket science. Such flows have a complicated three-dimensional structure. The theoretical model of the test flow is based on the Navier – Stokes's equations and Fourier – Bessel's method of expansion of differential equations. The article presents the formulas and graphs showing the radial-axial distributions of tangential, axial and radial flow velocities, stream functions and viscous vortex components. The authors made the theoretical analysis of the kinematic structure of such flows.


Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.


Author(s):  
Robert Glaeser ◽  
Thomas Bauer ◽  
David Grano

In transmission electron microscopy, the 3-dimensional structure of an object is usually obtained in one of two ways. For objects which can be included in one specimen, as for example with elements included in freeze- dried whole mounts and examined with a high voltage microscope, stereo pairs can be obtained which exhibit the 3-D structure of the element. For objects which can not be included in one specimen, the 3-D shape is obtained by reconstruction from serial sections. However, without stereo imagery, only detail which remains constant within the thickness of the section can be used in the reconstruction; consequently, the choice is between a low resolution reconstruction using a few thick sections and a better resolution reconstruction using many thin sections, generally a tedious chore. This paper describes an approach to 3-D reconstruction which uses stereo images of serial thick sections to reconstruct an object including detail which changes within the depth of an individual thick section.


Author(s):  
T.D. Pollard ◽  
P. Maupin

In this paper we review some of the contributions that electron microscopy has made to the analysis of actin and myosin from nonmuscle cells. We place particular emphasis upon the limitations of the ultrastructural techniques used to study these cytoplasmic contractile proteins, because it is not widely recognized how difficult it is to preserve these elements of the cytoplasmic matrix for electron microscopy. The structure of actin filaments is well preserved for electron microscope observation by negative staining with uranyl acetate (Figure 1). In fact, to a resolution of about 3nm the three-dimensional structure of actin filaments determined by computer image processing of electron micrographs of negatively stained specimens (Moore et al., 1970) is indistinguishable from the structure revealed by X-ray diffraction of living muscle.


Author(s):  
J.L. Williams ◽  
K. Heathcote ◽  
E.J. Greer

High Voltage Electron Microscope already offers exciting experimental possibilities to Biologists and Materials Scientists because the increased specimen thickness allows direct observation of three dimensional structure and dynamic experiments on effectively bulk specimens. This microscope is designed to give maximum accessibility and space in the specimen region for the special stages which are required. At the same time it provides an ease of operation similar to a conventional instrument.


Author(s):  
G. E. Tyson ◽  
M. J. Song

Natural populations of the brine shrimp, Artemia, may possess spirochete- infected animals in low numbers. The ultrastructure of Artemia's spirochete has been described by conventional transmission electron microscopy. In infected shrimp, spirochetal cells were abundant in the blood and also occurred intra- and extracellularly in the three organs examined, i.e. the maxillary gland (segmental excretory organ), the integument, and certain muscles The efferent-tubule region of the maxillary gland possessed a distinctive lesion comprised of a group of spirochetes, together with numerous small vesicles, situated in a cave-like indentation of the base of the tubule epithelium. in some instances the basal lamina at a lesion site was clearly discontinuous. High-voltage electron microscopy has now been used to study lesions of the efferent tubule, with the aim of understanding better their three-dimensional structure.Tissue from one maxillary gland of an infected, adult, female brine shrimp was used for HVEM study.


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