Author
Sreenivas Jayanti
Other affiliations: Ohio State University, Imperial College London, Indian Institutes of Technology
Bio: Sreenivas Jayanti is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Pressure drop & Combustion. The author has an hindex of 37, co-authored 142 publications receiving 3884 citations. Previous affiliations of Sreenivas Jayanti include Ohio State University & Imperial College London.
Topics: Pressure drop, Combustion, Two-phase flow, Coal, Flow battery
Papers published on a yearly basis
Papers
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TL;DR: In this article, computational fluid dynamics (CFD) simulations have been used to study the convective-diffusive heat transfer to the drop for various combinations of Re and Pr. The heat transfer within the drop is found to comprise of three regimes, two diffusion controlled heat transfer regimes (initial and final) connected by an intermediate convection-controlled heat transfer regime.
Abstract: Motion of drops and bubbles plays a critical role in the efficiency of industrial operations such as extraction. As the drop moves in the continuous phase, the tangential shear stress induced by the continuous fluid at the drop interface results in internal circulation, which may enhance transport of components and energy between the dispersed phase (drop) phase and the continuous phase. In the present study, computational fluid dynamics (CFD) simulations have been used to study this aspect in detail. Coupled calculations for the two phases have been carried out for fluid flow over a spherical, non-deformable drop of a given diameter. The predicted internal circulation is validated by comparing with analytical results for very low Reynolds numbers and experimental data at higher Re. The calculation framework is then used to study the convective-diffusive heat transfer to the drop for various combinations of Re and Pr. The heat transfer within the drop is found to comprise of three regimes, two diffusion controlled heat transfer regimes (initial and final) connected by an intermediate convection controlled heat transfer regime. The heat transfer enhancement by convection has been deduced and is found to depend both on Re and Pr. A dimensionless correlation has been developed to predict the convective heat transfer enhancement.
10 citations
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TL;DR: In this paper, the response of turbulent flow to abrupt changes in pipe wall roughness is studied and it is shown that a circumferential flow will not develop near the wall in a pipe with a short patch of circumferentially varying roughness.
10 citations
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TL;DR: In this paper, a single-phase flow in curved ducts is numerically simulated by imposing a spatially varying centrifugal force on a fluid flowing in a straight tube, and a set of partial differential equations is solved using the HARWELL-FLOW3D computer program.
Abstract: SUMMARY The advent of standard algorithms for the numerical solution of partial differential equations has given researchers a new tool for fluid flow calculations. In this paper, single-phase flow in curved ducts is numerically simulated by imposing a spatially varying centrifugal force on a fluid flowing in a straight tube. The resulting set of partial differential equations is solved using the HARWELL-FLOW3D computer program. Comparison with other numerical and experimental results shows that this simplified formulation gives accurate results. The model neglects certain geometric terms of the order d/D, the duct-to-coil diameter ratio. The effect of these terms is investigated by considering the flow in a 90" bend for large d/D. It is shown that while there may be significant error in the prediction of the local variables for large d/D, the circumference-averaged quantities are well predicted.
10 citations
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TL;DR: In this article, a detailed thermodynamic analysis of a sodium-air system has been carried out for equivalence ratios in the range of 0.1-1.9 and for flame temperatures ranging from 1100 to 1950 K.
9 citations
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TL;DR: A computational method for achieving desired flow distribution in a flow manifold using optimally positioned guide plates using a well-established algorithm coupled to a computational fluid dynamics (CFD)-based flow solver is described.
9 citations
Cited by
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TL;DR: Oxy-coal combustion has generated significant interest since it was proposed as a carbon capture technology for newly built and retrofitted coal-fired power plants, and numerical models for sub-processes are also used to examine the differences between combustion in an oxidizing stream diluted by nitrogen and carbon dioxide as mentioned in this paper.
866 citations
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TL;DR: The role of ammonia in future energy infrastructure is discussed in this article, where the authors focus on the catalytic decomposition of ammonia as a key step and highlight other aspects such as catalytic removal of ammonia from gasification product gas or direct ammonia fuel cells.
Abstract: The possible role of ammonia in a future energy infrastructure is discussed. The review is focused on the catalytic decomposition of ammonia as a key step. Other aspects, such as the catalytic removal of ammonia from gasification product gas or direct ammonia fuel cells, are highlighted as well. The more general question of the integration of ammonia in an infrastructure is also covered.
495 citations
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TL;DR: In this paper, the challenges and the developments of direct ethanol fuel cells at present are addressed and the applications of DEFC are presented, as well as the challenges that need to be addressed.
461 citations
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TL;DR: In this paper, a literature review on heat transfer and flow characteristics of single-phase and two-phase flow in curved tubes is presented, where three main categories of curved tubes; helically coiled tubes, spirally coiling tubes, and other coiled tube, are described.
Abstract: The performance of heat exchangers can be improved to perform a certain heat-transfer duty by heat transfer enhancement techniques. In general, these techniques can be divided into two groups: active and passive techniques. The active techniques require external forces, e.g. electric field, acoustic or surface vibration, etc. The passive techniques require fluid additives or special surface geometries. Curved tubes have been used as one of the passive heat transfer enhancement techniques and are the most widely used tubes in several heat transfer applications. This article provides a literature review on heat transfer and flow characteristics of single-phase and two-phase flow in curved tubes. Three main categories of curved tubes; helically coiled tubes, spirally coiled tubes, and other coiled tubes, are described. A review of published relevant correlations of single-phase heat transfer coefficients and single-phase, two-phase friction factors are presented.
441 citations
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TL;DR: In this article, the authors provided information encompassing the recent discovery of the High Temperature Proton Exchange Membrane Fuel Cell (HT-PEMFC) focusing on systems requirement.
419 citations