High Temporal–spatial Distribution of Soot Temperature and Volume Fraction in Single Coal Combustion Flame

Author(s):  
Mengting Si ◽  
Qiang Cheng ◽  
Lin Yuan ◽  
Zixue Luo
Author(s):  
Auclair Gilles ◽  
Benoit Danièle

During these last 10 years, high performance correction procedures have been developed for classical EPMA, and it is nowadays possible to obtain accurate quantitative analysis even for soft X-ray radiations. It is also possible to perform EPMA by adapting this accurate quantitative procedures to unusual applications such as the measurement of the segregation on wide areas in as-cast and sheet steel products.The main objection for analysis of segregation in steel by means of a line-scan mode is that it requires a very heavy sampling plan to make sure that the most significant points are analyzed. Moreover only local chemical information is obtained whereas mechanical properties are also dependant on the volume fraction and the spatial distribution of highly segregated zones. For these reasons we have chosen to systematically acquire X-ray calibrated mappings which give pictures similar to optical micrographs. Although mapping requires lengthy acquisition time there is a corresponding increase in the information given by image anlysis.


2017 ◽  
Vol 140 (2) ◽  
Author(s):  
B. Ravi Kumar ◽  
Vishal Singh ◽  
Tarun Nanda ◽  
Manashi Adhikary ◽  
Nimai Halder ◽  
...  

The authors simulated the industrially used continuous annealing conditions to process dual phase (DP) steels by using a custom designed annealing simulator. Sixty-seven percentage of cold rolled steel sheets was subjected to different processing routes, including the conventional continuous annealing line (CAL), intercritical annealing (ICA), and thermal cycling (TC), to investigate the effect of change in volume fraction, shape, and spatial distribution of martensite on tensile deformation characteristics of DP steels. Annealing parameters were derived using commercial software, including thermo-calc, jmat-pro, and dictra. Through selection of appropriate process parameters, the authors found out possibilities of significantly altering the volume fraction, morphology, and grain size distribution of martensite phase. These constituent variations showed a strong influence on tensile properties of DP steels. It was observed that TC route modified the martensite morphology from the typical lath type to in-grain globular/oblong type and significantly reduced the martensite grain size. This route improved the strength–ductility combination from 590 MPa–33% (obtained through CAL route) to 660 MPa–30%. Finally, the underlying mechanisms of crack initiation/void formation, etc., in different DP microstructures were discussed.


2007 ◽  
Vol 330-332 ◽  
pp. 503-506
Author(s):  
Xiao Wei Fu ◽  
Jie Huang ◽  
E.S. Thian ◽  
Serena Best ◽  
William Bonfield

A Bioglass® reinforced polyethylene (Bioglass®/polyethylene) composite has been prepared, which combines the high bioactivity of Bioglass® and the toughness of polyethylene. The spatial distribution of Bioglass® particles within the composite is important for the performance of composites in-vivo. Recent developments in X-ray microtomography (XμT) have made it possible to visualize internal and microstructural details with different X-ray absorbencies, nondestructively, and to acquire 3D information at high spatial resolution. In this study, the volume fraction and 3D spatial distribution of Bioglass® particles has been acquired quantitatively by XμT. The information obtained provides a foundation for understanding the mechanical and bioactive properties of the Bioglass®/polyethylene composites.


Author(s):  
M. Akif Yalcinkaya ◽  
Gorkem E. Guloglu ◽  
Maya Pishvar ◽  
Mehrad Amirkhosravi ◽  
E. Murat Sozer ◽  
...  

Vacuum-assisted resin transfer molding (VARTM) has several inherent shortcomings such as long mold filling times, low fiber volume fraction, and high void content in fabricated laminates. These problems in VARTM mainly arise from the limited compaction of the laminate and low resin pressure. Pressurized infusion (PI) molding introduced in this paper overcomes these disadvantages by (i) applying high compaction pressure on the laminate by an external pressure chamber placed on the mold and (ii) increasing the resin pressure by pressurizing the inlet resin reservoir. The effectiveness of PI molding was verified by fabricating composite laminates at various levels of chamber and inlet pressures and investigating the effect of these parameters on the fill time, fiber volume fraction, and void content. Furthermore, spatial distribution of voids was characterized by employing a unique method, which uses a flatbed scanner to capture the high-resolution planar scan of the fabricated laminates. The results revealed that PI molding reduced fill time by 45%, increased fiber volume fraction by 16%, reduced void content by 98%, improved short beam shear (SBS) strength by 14%, and yielded uniform spatial distribution of voids compared to those obtained by conventional VARTM.


2001 ◽  
Vol 7 (S2) ◽  
pp. 264-265
Author(s):  
H. A. Calderon ◽  
M. Benyoucef ◽  
N. Clement

The excellent mechanical properties of Ni based superalloys depend upon the presence of γ’ particles (LI2 structure). Their volume fraction, spatial distribution and size determine the mechanical strength of these alloys. Ni alloys for technological applications make use of large volume fractions of precipitates where processes of coarsening and coalescence take place during service leading in some cases to deterioration of properties. Addition of different alloying elements prevents accelerated coalescence by retarding diffusion and thus improving the mechanical properties of such alloys. Coalescence can also take place under the influence of an applied stress leading to the formation of rafts of the y' phase. For example the microstructure changes during creep deformation, depending on the alloy composition, with the corresponding formation of dislocation networks and rafts of different morphologies [1]. The γ-γ’ interfaces are also different depending on the alloy composition and most likely to the local distribution of alloying elements and their strain fields.


2013 ◽  
Vol 52 (33) ◽  
pp. 8040 ◽  
Author(s):  
Haiqing Guo ◽  
Jose A. Castillo ◽  
Peter B. Sunderland

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
D. Liu ◽  
Q. X. Huang ◽  
F. Wang ◽  
Y. Chi ◽  
K. F. Cen ◽  
...  

A nonintrusive measurement technique is presented numerically for simultaneous measurement of three-dimensional (3D) soot temperature and volume fraction fields in the axisymmetric or asymmetric flames with charge-coupled device (CCD) cameras. CCD cameras were introduced to capture the flame images for obtaining the line-of-sight radiation intensities. The distributions of local emission source under two wavelengths can be deduced through solving the reconstruction matrix equation by the least-square QR decomposition method from the knowledge of the line-of-sight radiation intensities of the flames. The two-color distributions of the local emission source were used to retrieve the soot temperature and volume fraction distributions. The effects of the discrete ray number of CCD cameras, the number of CCD cameras, and the system signal-to-noise ratio (SNR) on the measurement were investigated. The results show that for accurate measurement of soot volume fraction field, the CCD cameras number should not be less than four and the system SNR can be as low as 54 dB. The proposed technique can be capable for reconstructing the 3D soot temperature and volume fraction fields in both axisymmetric and asymmetric flames well.


1968 ◽  
Vol 32 (1) ◽  
pp. 203-207 ◽  
Author(s):  
T. N. Smith

The spatial distribution of uniformly sized spheres falling in a viscous liquid is investigated experimentally for a solid volume fraction of 0·025 and a single sphere Reynolds number of 0·6. The observed spatial distribution agrees closely with a random distribution based on allocation of spheres to space cells according to a binomial probability mechanism.


2020 ◽  
Author(s):  
Sidhanth Tyagi ◽  
Cécile Monteux ◽  
Sylvain Deville

The interaction of foreign objects suspended in a liquid melt with an advancing solidification front is of special interest in nature (e.g. frost heave) and engineering sciences (e.g. crystal growth). The front can engulf the object, trapping it into the growing crystal, or the front can repel the object, pushing it ahead of itself. Therefore, the object-front confrontation can have a strong influence on the properties of the solidified material. In particular, the spatial distribution of the objects in the resulting microstructure determines the material's structural and functional properties. The past theoretical models and experimental studies have mostly investigated the interaction of isolated, spherical, and hard objects in pure melts. However, the outcome of object-front interactions in complex (more realistic) systems, where multiple objects and solutes are present, is still poorly understood. Here we show the interaction of multiple oil droplets with an ice-water front in the absence and presence of solute effects using in situ cryo-confocal microscopy. We observe the formation of a compact agglomerated layer resulting in a force equilibrium different from the isolated object approach. We elucidate the role of solute during the evolution of a material microstructure in the presence of foreign objects. We report on how the object size, number of objects, and bulk solute concentration influence the front morphology and the subsequent object spatial distribution. Our results depict how the presence of multiple objects with varying solute concentration can modify the object-front interactions and hence, can lead to the formation of complex microstructures, difficult to predict theoretically. We suggest that the volume fraction of objects suspended in a liquid melt in conjunction with the amount of bulk solute concentration are two important criteria to be incorporated in the development of object-front interaction models. Furthermore, our simplified approach of using oil-in-water emulsions can serve as a good analogue for studying the development of material microstructure in presence of foreign objects. <br>


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