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Manish Mishra - One of the best experts on this subject based on the ideXlab platform.
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detailed heat transfer and fluid Flow Investigation in a rectangular duct with truncated prismatic ribs
Experimental Thermal and Fluid Science, 2018Co-Authors: Naveen Sharma, Andallib Tariq, Manish MishraAbstract:Abstract The paper presents an experimental study of detailed heat transfer and Flow field characteristics in a rectangular duct having different types of truncated prismatic ribs on the bottom surface. The truncated prismatic ribs are manufactured by tapering the square rib from both the sides up to the center to provide rib height at the ends of 0, 2, 4, 6 and 8 mm. Experimental heat transfer results using transient liquid crystal thermography (LCT) are reported along with the mean Flow field results using particle image velocimetry (PIV) at a rib pitch-to-height ratio of 10. The heat transfer effectiveness of proposed rib configurations is evaluated by examining the surface- and spanwise-averaged Nusselt number distribution. The effect of rib configurations on the Flow parameters as well as on the heat transfer augmentation, with an emphasis to overall averaged augmentation Nusselt number, friction factor ratio, and performance index factors, are studied over a wide range of Reynolds number (9400–58,850). Most of the truncated prismatic ribs provide higher augmentation Nusselt number (about 25.15%) and lower pressure penalty (about 54.65%) than those with the square ribs. The truncated prismatic ribs provide better thermohydraulic performance than the square rib, however, these values are about 25–53% higher respectively at the lowest and the highest Reynolds number. Further, the aero-thermal characteristics are studied and documented in order to enhance the understanding and to correlate the Flow dynamic mechanisms with the heat transfer augmentation from the fundamental perspective for all proposed rib configurations at a fixed Reynolds number of 42,500. The combined analysis of aerothermal characteristics puts in evidence the role of fluid dynamic factors i.e. Flow features, mean velocities, and the turbulence intensity in the heat transfer augmentation.
Naveen Sharma - One of the best experts on this subject based on the ideXlab platform.
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detailed heat transfer and fluid Flow Investigation in a rectangular duct with truncated prismatic ribs
Experimental Thermal and Fluid Science, 2018Co-Authors: Naveen Sharma, Andallib Tariq, Manish MishraAbstract:Abstract The paper presents an experimental study of detailed heat transfer and Flow field characteristics in a rectangular duct having different types of truncated prismatic ribs on the bottom surface. The truncated prismatic ribs are manufactured by tapering the square rib from both the sides up to the center to provide rib height at the ends of 0, 2, 4, 6 and 8 mm. Experimental heat transfer results using transient liquid crystal thermography (LCT) are reported along with the mean Flow field results using particle image velocimetry (PIV) at a rib pitch-to-height ratio of 10. The heat transfer effectiveness of proposed rib configurations is evaluated by examining the surface- and spanwise-averaged Nusselt number distribution. The effect of rib configurations on the Flow parameters as well as on the heat transfer augmentation, with an emphasis to overall averaged augmentation Nusselt number, friction factor ratio, and performance index factors, are studied over a wide range of Reynolds number (9400–58,850). Most of the truncated prismatic ribs provide higher augmentation Nusselt number (about 25.15%) and lower pressure penalty (about 54.65%) than those with the square ribs. The truncated prismatic ribs provide better thermohydraulic performance than the square rib, however, these values are about 25–53% higher respectively at the lowest and the highest Reynolds number. Further, the aero-thermal characteristics are studied and documented in order to enhance the understanding and to correlate the Flow dynamic mechanisms with the heat transfer augmentation from the fundamental perspective for all proposed rib configurations at a fixed Reynolds number of 42,500. The combined analysis of aerothermal characteristics puts in evidence the role of fluid dynamic factors i.e. Flow features, mean velocities, and the turbulence intensity in the heat transfer augmentation.
Matthew Yeo - One of the best experts on this subject based on the ideXlab platform.
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Dissecting the phyloepidemiology of Trypanosoma cruzi I (TcI) in Brazil by the use of high resolution genetic markers
2018Co-Authors: Fabiola Roman, Samanta Das Chagas Xavier, Louisa A. Messenger, Márcio G. Pavan, Michael A. Miles, Ana María Jansen, Matthew YeoAbstract:BackgroundTrypanosoma cruzi, the causal agent of Chagas disease, is monophyletic but genetically heterogeneous. It is currently represented by six genetic lineages (Discrete Typing Units, DTUs) designated TcI-TcVI. TcI is the most geographically widespread and genetically heterogeneous lineage, this as is evidenced by a wide range of genetic markers applied to isolates spanning a vast geographic range in Latin America.Methodology/Principal findingsIn total, 78 TcI isolated from hosts and vectors distributed in 5 different biomes of Brazil, were analyzed using 6 nuclear housekeeping genes, 25 microsatellite loci and one mitochondrial marker. Nuclear markers reveal substantial genetic diversity, significant gene Flow between biomes, incongruence in phylogenies, and haplotypic analysis indicative of intra-DTU genetic exchange. Phylogenetic reconstructions based on mitochondrial and nuclear loci were incongruent, and consistent with introgression. Structure analysis of microsatellite data reveals that, amongst biomes, the Amazon is the most genetically diverse and experiences the lowest level of gene Flow. Investigation of population structure based on the host species/genus, indicated that Didelphis marsupialis might play a role as the main disperser of TcI.Conclusions/SignificanceThe present work considers a large TcI sample from different hosts and vectors spanning multiple ecologically diverse biomes in Brazil. Importantly, we combine fast and slow evolving markers to contribute to the epizootiological understanding of TcI in five distinct Brazilian biomes. This constitutes the first instance in which MLST analysis was combined with the use of MLMT and maxicircle markers to evaluate the genetic diversity of TcI isolates in Brazil. Our results demonstrate the existence of substantial genetic diversity and the occurrence of introgression events. We provide evidence of genetic exchange in TcI isolates from Brazil and of the relative isolation of TcI in the Amazon biome. We observe the absence of strict associations with TcI genotypes to geographic areas and/or host species.
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Dissecting the phyloepidemiology of Trypanosoma cruzi I (TcI) in Brazil by the use of high resolution genetic markers.
'Public Library of Science (PLoS)', 2018Co-Authors: Fabiola Roman, Samanta Das Chagas Xavier, Louisa A. Messenger, Márcio G. Pavan, Michael A. Miles, Ana María Jansen, Matthew YeoAbstract:Trypanosoma cruzi, the causal agent of Chagas disease, is monophyletic but genetically heterogeneous. It is currently represented by six genetic lineages (Discrete Typing Units, DTUs) designated TcI-TcVI. TcI is the most geographically widespread and genetically heterogeneous lineage, this as is evidenced by a wide range of genetic markers applied to isolates spanning a vast geographic range in Latin America.In total, 78 TcI isolated from hosts and vectors distributed in 5 different biomes of Brazil, were analyzed using 6 nuclear housekeeping genes, 25 microsatellite loci and one mitochondrial marker. Nuclear markers reveal substantial genetic diversity, significant gene Flow between biomes, incongruence in phylogenies, and haplotypic analysis indicative of intra-DTU genetic exchange. Phylogenetic reconstructions based on mitochondrial and nuclear loci were incongruent, and consistent with introgression. Structure analysis of microsatellite data reveals that, amongst biomes, the Amazon is the most genetically diverse and experiences the lowest level of gene Flow. Investigation of population structure based on the host species/genus, indicated that Didelphis marsupialis might play a role as the main disperser of TcI.The present work considers a large TcI sample from different hosts and vectors spanning multiple ecologically diverse biomes in Brazil. Importantly, we combine fast and slow evolving markers to contribute to the epizootiological understanding of TcI in five distinct Brazilian biomes. This constitutes the first instance in which MLST analysis was combined with the use of MLMT and maxicircle markers to evaluate the genetic diversity of TcI isolates in Brazil. Our results demonstrate the existence of substantial genetic diversity and the occurrence of introgression events. We provide evidence of genetic exchange in TcI isolates from Brazil and of the relative isolation of TcI in the Amazon biome. We observe the absence of strict associations with TcI genotypes to geographic areas and/or host species
J R Buchanan - One of the best experts on this subject based on the ideXlab platform.
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beyond bubbly two phase Flow Investigation using a cfd three field two fluid model
International Journal of Multiphase Flow, 2019Co-Authors: Subash Sharma, Mamoru Ishii, Takashi Hibiki, Joshua P Schlegel, Yang Liu, J R BuchananAbstract:Abstract Modeling and simulation study of industrial scale beyond-bubbly Flows, like cap-bubbly, cap-turbulent and churn-turbulent, using the two-fluid model, has been limited due to the wide range of interfacial length scales involved and lack of physics-based models for bubble hydrodynamics and interaction mechanisms for such Flow conditions. One important feature of beyond bubbly Flow is the existence of a wide range of bubble sizes and shapes and thus different transport characteristics. The accuracy of two-fluid model predictions is strongly dependent on the constitutive relations used for the two-fluid model. The objectives of this proposed work are the following: select a set of physics-based constitutive relations and implement these models into CFX; evaluate these models for a wide range of test conditions in cap-turbulent and churn-turbulent Flows. The interfacial structure is dynamically evaluated using bubble interaction mechanisms (coalescence and break up) from the two-group Interfacial Area Transport Equation implemented as source and sink terms into ANSYS CFX. The assessments for the validity of the models were carried out in comparison to data collected at Purdue University for two-phase Flow in a narrow, rectangular duct. Non-uniform inlet conditions were applied in order to evaluate phase diffusion models in CFX. A new turbulence-induced bubble collision diffusion model for the two-group bubbles system has been implemented in ANSYS CFX. The CFD results predict the measured data to within the expected error, correctly capturing the transverse redistribution of phases due to diffusion for both uniform and non-uniform inlet phase distributions. This illustrates the importance of bubble collision phenomena in correctly predicting phase distributions in a channel.
Christian Oliver Paschereit - One of the best experts on this subject based on the ideXlab platform.
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Aerodynamic Investigation of guide vane configurations downstream a rotating detonation combustor
Journal of Engineering for Gas Turbines and Power, 2020Co-Authors: Majid Asli, Panagiotis Stathopoulos, Christian Oliver PaschereitAbstract:Any outlet restriction downstream of Pressure Gain Combustion (PGC), such as turbine blades, affects its Flow field and may cause additional thermodynamic losses. The unsteadiness in the form of pressure, temperature and velocity vector fluctuations has a negative impact on the operation of conventional turbines. Additionally, experimental measurements and data acquisition present researchers with challenges that have to do mostly with the high temperature exhaust of PGC and the high frequency of its operation. Nevertheless, numerical simulations can provide important insights into PGC exhaust Flow and its interaction with turbine blades. In this paper, a Rotating Detonation Combustor (RDC) and a row of nozzle guide vanes have been modeled based on the data from literature and an available experimental setup. URANS simulations were done for five guide vane configurations with different geometrical parameters to investigate the effect of solidity and blade type representing different outlet restrictions on the RDC exhaust Flow. The results analyzed the connection between total pressure loss and the vanes solidity and thickness to chord ratio. It is observed that more than 57% of the upstream velocity angle fluctuation amplitude was damped by the vanes. Furthermore, the area reduction was found to be the significant driving factor for damping the velocity angle fluctuations, whether in the form of solidity or thickness on chord ratio increment. This RDC exhaust Flow Investigation is an important primary step from a turbomachinery standpoint, which provided details of blade behavior in such an unsteady Flow field.