Author: Nathan J. English
Publisher:
ISBN:
Category : Fluid-structure interaction
Languages : en
Pages : 214
Book Description
"The complex interfacial phenomena involved in two-phase gas-liquid flow have defied mathematical simplification and modeling. However, the systems are used in heat exchangers, condensers, chemical processing plants, and nuclear reactor systems. The present work considera a 1 mm square minichannel and adiabatic flows corresponding to practical PEM fuel cell conditions. Pressure drop data is collected in experimentation covering mass fluxes of 4.0-33.6 kg/m2s, which correspond to superficial gas and liquid velocities of 3.4-10 m/s and 0.001-0.02 m/s respectively. The experiments are repeated with water of reduced surface tension, casued by the addition of surfactant, in order to quantify the surface tension effects and accurate prediction of pressure drop. The addition of surfactant is shown to have no discernable influence on pressure drop. Two models by Chen et al. are found to acceptably predict the experimental data within 20-25%, however a new model is proposed that matches the experimental data with a deviation of less than 5%"--Abstract.
An Experimental Investigation Into the Effect of Surfactants on Air-water Two-phase Flow in Minichannels
Author: Nathan J. English
Publisher:
ISBN:
Category : Fluid-structure interaction
Languages : en
Pages : 214
Book Description
"The complex interfacial phenomena involved in two-phase gas-liquid flow have defied mathematical simplification and modeling. However, the systems are used in heat exchangers, condensers, chemical processing plants, and nuclear reactor systems. The present work considera a 1 mm square minichannel and adiabatic flows corresponding to practical PEM fuel cell conditions. Pressure drop data is collected in experimentation covering mass fluxes of 4.0-33.6 kg/m2s, which correspond to superficial gas and liquid velocities of 3.4-10 m/s and 0.001-0.02 m/s respectively. The experiments are repeated with water of reduced surface tension, casued by the addition of surfactant, in order to quantify the surface tension effects and accurate prediction of pressure drop. The addition of surfactant is shown to have no discernable influence on pressure drop. Two models by Chen et al. are found to acceptably predict the experimental data within 20-25%, however a new model is proposed that matches the experimental data with a deviation of less than 5%"--Abstract.
Publisher:
ISBN:
Category : Fluid-structure interaction
Languages : en
Pages : 214
Book Description
"The complex interfacial phenomena involved in two-phase gas-liquid flow have defied mathematical simplification and modeling. However, the systems are used in heat exchangers, condensers, chemical processing plants, and nuclear reactor systems. The present work considera a 1 mm square minichannel and adiabatic flows corresponding to practical PEM fuel cell conditions. Pressure drop data is collected in experimentation covering mass fluxes of 4.0-33.6 kg/m2s, which correspond to superficial gas and liquid velocities of 3.4-10 m/s and 0.001-0.02 m/s respectively. The experiments are repeated with water of reduced surface tension, casued by the addition of surfactant, in order to quantify the surface tension effects and accurate prediction of pressure drop. The addition of surfactant is shown to have no discernable influence on pressure drop. Two models by Chen et al. are found to acceptably predict the experimental data within 20-25%, however a new model is proposed that matches the experimental data with a deviation of less than 5%"--Abstract.
Encyclopedia Of Two-phase Heat Transfer And Flow Ii: Special Topics And Applications (A 4-volume Set)
Author: John R Thome
Publisher: World Scientific
ISBN: 9814623296
Category : Technology & Engineering
Languages : en
Pages : 1321
Book Description
The aim of the two-set series is to present a very detailed and up-to-date reference for researchers and practicing engineers in the fields of mechanical, refrigeration, chemical, nuclear and electronics engineering on the important topic of two-phase heat transfer and two-phase flow. The scope of the first set of 4 volumes presents the fundamentals of the two-phase flows and heat transfer mechanisms, and describes in detail the most important prediction methods, while the scope of the second set of 4 volumes presents numerous special topics and numerous applications, also including numerical simulation methods.Practicing engineers will find extensive coverage to applications involving: multi-microchannel evaporator cold plates for electronics cooling, boiling on enhanced tubes and tube bundles, flow pattern based methods for predicting boiling and condensation inside horizontal tubes, pressure drop methods for singularies (U-bends and contractions), boiling in multiport tubes, and boiling and condensation in plate heat exchangers. All of these chapters include the latest methods for predicting not only local heat transfer coefficients but also pressure drops.Professors and students will find this 'Encyclopedia of Two-Phase Heat Transfer and Flow' particularly exciting, as it contains authored books and thorough state-of-the-art reviews on many basic and special topics, such as numerical modeling of two-phase heat transfer and adiabatic bubbly and slug flows, the unified annular flow boiling model, flow pattern maps, condensation and boiling theories, new emerging topics, etc.
Publisher: World Scientific
ISBN: 9814623296
Category : Technology & Engineering
Languages : en
Pages : 1321
Book Description
The aim of the two-set series is to present a very detailed and up-to-date reference for researchers and practicing engineers in the fields of mechanical, refrigeration, chemical, nuclear and electronics engineering on the important topic of two-phase heat transfer and two-phase flow. The scope of the first set of 4 volumes presents the fundamentals of the two-phase flows and heat transfer mechanisms, and describes in detail the most important prediction methods, while the scope of the second set of 4 volumes presents numerous special topics and numerous applications, also including numerical simulation methods.Practicing engineers will find extensive coverage to applications involving: multi-microchannel evaporator cold plates for electronics cooling, boiling on enhanced tubes and tube bundles, flow pattern based methods for predicting boiling and condensation inside horizontal tubes, pressure drop methods for singularies (U-bends and contractions), boiling in multiport tubes, and boiling and condensation in plate heat exchangers. All of these chapters include the latest methods for predicting not only local heat transfer coefficients but also pressure drops.Professors and students will find this 'Encyclopedia of Two-Phase Heat Transfer and Flow' particularly exciting, as it contains authored books and thorough state-of-the-art reviews on many basic and special topics, such as numerical modeling of two-phase heat transfer and adiabatic bubbly and slug flows, the unified annular flow boiling model, flow pattern maps, condensation and boiling theories, new emerging topics, etc.
Two-phase Flow Phenomena in Fuel Cell Microchannels
Author: Julie Elizabeth Steinbrenner
Publisher: Stanford University
ISBN:
Category :
Languages : en
Pages : 149
Book Description
Proton exchange membrane (PEM) fuel cells show promise as CO2-free energy-conversion devices. Predictions show that reducing the size of the gas delivery channels could improve the efficiency and power density of PEM fuel cells, however the expected benefits of reduced channel sizes have not been realized due to flooding by water generated at the cathode. Channels with small dimensions exhibit an increased propensity toward flooding as surface tension forces become significant when compared with viscous, inertial, and pressure forces. This study characterizes the distinct two-phase flow profiles that result from the interplay of these forces. We investigate fundamental water-gas interactions in silicon channels of various hydraulic diameters and cross-sectional aspect ratios using a high-contrast fluorescent imaging technique. Then, we develop a test structure to study the evolution of two-phase flow structures in a microchannel geometry designed to mimic conditions in a fuel cell channel -- a 60-cm long channel with distributed water introduction through a porous gas diffusion layer (GDL) on one wall. Finally, we present considerations for the implementation of spinning-disk confocal microscopy to provide three-dimensional (3D) visualization of two-phase flow structures which may provide insight into key flow transitions that were observed during high-speed fluorescent flow visualization. By characterizing and modeling two-phase flow in various microchannel geometries and under a large range of flow conditions, these studies provide insight that enables the improved design of microchannels for two-phase flow in fuel cells and other practical devices.
Publisher: Stanford University
ISBN:
Category :
Languages : en
Pages : 149
Book Description
Proton exchange membrane (PEM) fuel cells show promise as CO2-free energy-conversion devices. Predictions show that reducing the size of the gas delivery channels could improve the efficiency and power density of PEM fuel cells, however the expected benefits of reduced channel sizes have not been realized due to flooding by water generated at the cathode. Channels with small dimensions exhibit an increased propensity toward flooding as surface tension forces become significant when compared with viscous, inertial, and pressure forces. This study characterizes the distinct two-phase flow profiles that result from the interplay of these forces. We investigate fundamental water-gas interactions in silicon channels of various hydraulic diameters and cross-sectional aspect ratios using a high-contrast fluorescent imaging technique. Then, we develop a test structure to study the evolution of two-phase flow structures in a microchannel geometry designed to mimic conditions in a fuel cell channel -- a 60-cm long channel with distributed water introduction through a porous gas diffusion layer (GDL) on one wall. Finally, we present considerations for the implementation of spinning-disk confocal microscopy to provide three-dimensional (3D) visualization of two-phase flow structures which may provide insight into key flow transitions that were observed during high-speed fluorescent flow visualization. By characterizing and modeling two-phase flow in various microchannel geometries and under a large range of flow conditions, these studies provide insight that enables the improved design of microchannels for two-phase flow in fuel cells and other practical devices.
The Canadian Journal of Chemical Engineering
Author:
Publisher:
ISBN:
Category : Chemical engineering
Languages : en
Pages : 540
Book Description
Publisher:
ISBN:
Category : Chemical engineering
Languages : en
Pages : 540
Book Description
An Overview of Heat Transfer Phenomena
Author: Salim Newaz Kazi
Publisher: BoD – Books on Demand
ISBN: 9535108271
Category : Technology & Engineering
Languages : en
Pages : 542
Book Description
In the wake of energy crisis due to rapid growth of industries, urbanization, transportation, and human habit, the efficient transfer of heat could play a vital role in energy saving. Industries, household requirements, offices, transportation are all dependent on heat exchanging equipment. Considering these, the present book has incorporated different sections related to general aspects of heat transfer phenomena, convective heat transfer mode, boiling and condensation, heat transfer to two phase flow and heat transfer augmentation by different means.
Publisher: BoD – Books on Demand
ISBN: 9535108271
Category : Technology & Engineering
Languages : en
Pages : 542
Book Description
In the wake of energy crisis due to rapid growth of industries, urbanization, transportation, and human habit, the efficient transfer of heat could play a vital role in energy saving. Industries, household requirements, offices, transportation are all dependent on heat exchanging equipment. Considering these, the present book has incorporated different sections related to general aspects of heat transfer phenomena, convective heat transfer mode, boiling and condensation, heat transfer to two phase flow and heat transfer augmentation by different means.
Advances in Transport Phenomena
Author: Liqiu Wang
Publisher: Springer Science & Business Media
ISBN: 3642194664
Category : Science
Languages : en
Pages : 336
Book Description
The term transport phenomena is used to describe processes in which mass, momentum, energy and entropy move about in matter. Advances in Transport Phenomena provide state-of-the-art expositions of major advances by theoretical, numerical and experimental studies from a molecular, microscopic, mesoscopic, macroscopic or megascopic point of view across the spectrum of transport phenomena, from scientific enquiries to practical applications. The annual review series intends to fill the information gap between regularly published journals and university-level textbooks by providing in-depth review articles over a broader scope than in journals. The authoritative articles, contributed by internationally-leading scientists and practitioners, establish the state of the art, disseminate the latest research discoveries, serve as a central source of reference for fundamentals and applications of transport phenomena, and provide potential textbooks to senior undergraduate and graduate students. This review book provides state-of-the-art expositions of major advances by theoretical, numerical and experimental studies from a molecular, microscopic, mesoscopic, macroscopic or megascopic point of view across the spectrum of transport phenomena, from scientific enquiries to practical applications. This new volume of the annual review "Advances in Transport Phenomena" series provides in-depth review articles covering the fields of mass transfer, fluid mechanics, heat transfer and thermodynamics. This review book provides state-of-the-art expositions of major advances by theoretical, numerical and experimental studies from a molecular, microscopic, mesoscopic, macroscopic or megascopic point of view across the spectrum of transport phenomena, from scientific enquiries to practical applications. This new volume of the annual review "Advances in Transport Phenomena" series provides in-depth review articles covering the fields of mass transfer, fluid mechanics, heat transfer and thermodynamics.
Publisher: Springer Science & Business Media
ISBN: 3642194664
Category : Science
Languages : en
Pages : 336
Book Description
The term transport phenomena is used to describe processes in which mass, momentum, energy and entropy move about in matter. Advances in Transport Phenomena provide state-of-the-art expositions of major advances by theoretical, numerical and experimental studies from a molecular, microscopic, mesoscopic, macroscopic or megascopic point of view across the spectrum of transport phenomena, from scientific enquiries to practical applications. The annual review series intends to fill the information gap between regularly published journals and university-level textbooks by providing in-depth review articles over a broader scope than in journals. The authoritative articles, contributed by internationally-leading scientists and practitioners, establish the state of the art, disseminate the latest research discoveries, serve as a central source of reference for fundamentals and applications of transport phenomena, and provide potential textbooks to senior undergraduate and graduate students. This review book provides state-of-the-art expositions of major advances by theoretical, numerical and experimental studies from a molecular, microscopic, mesoscopic, macroscopic or megascopic point of view across the spectrum of transport phenomena, from scientific enquiries to practical applications. This new volume of the annual review "Advances in Transport Phenomena" series provides in-depth review articles covering the fields of mass transfer, fluid mechanics, heat transfer and thermodynamics. This review book provides state-of-the-art expositions of major advances by theoretical, numerical and experimental studies from a molecular, microscopic, mesoscopic, macroscopic or megascopic point of view across the spectrum of transport phenomena, from scientific enquiries to practical applications. This new volume of the annual review "Advances in Transport Phenomena" series provides in-depth review articles covering the fields of mass transfer, fluid mechanics, heat transfer and thermodynamics.
Microfluidics and Nanofluidics Handbook
Author: Sushanta K. Mitra
Publisher: CRC Press
ISBN: 1439816778
Category : Science
Languages : en
Pages : 1103
Book Description
This comprehensive handbook presents fundamental aspects, fabrication techniques, introductory materials on microbiology and chemistry, measurement techniques, and applications of microfluidics and nanofluidics. The first volume of the handbook focuses on physics and transport phenomena along with life sciences and related applications. It provides newcomers with the fundamental science background required for the study of microfluidics and nanofluidics. In addition, the advanced techniques and concepts described in the text will benefit experienced researchers and professionals.
Publisher: CRC Press
ISBN: 1439816778
Category : Science
Languages : en
Pages : 1103
Book Description
This comprehensive handbook presents fundamental aspects, fabrication techniques, introductory materials on microbiology and chemistry, measurement techniques, and applications of microfluidics and nanofluidics. The first volume of the handbook focuses on physics and transport phenomena along with life sciences and related applications. It provides newcomers with the fundamental science background required for the study of microfluidics and nanofluidics. In addition, the advanced techniques and concepts described in the text will benefit experienced researchers and professionals.
Microfluidics and Nanofluidics Handbook, 2 Volume Set
Author: Sushanta K. Mitra
Publisher: CRC Press
ISBN: 1466515740
Category : Science
Languages : en
Pages : 1767
Book Description
A comprehensive, two-volume handbook on Microfluidics and Nanofluidics, this text covers fundamental aspects, fabrication techniques, introductory materials on microbiology and chemistry, measurement techniques, and applications with special emphasis on the energy sector. Each chapter begins with introductory coverage to a subject and then narrows in on advanced techniques and concepts, thus making it valuable to students and practitioners. The author pays special attention to applications of microfluidics in the energy sector and provides insight into the world of opportunities nanotechnology has to offer. Figures, tables, and equations to illustrate concepts.
Publisher: CRC Press
ISBN: 1466515740
Category : Science
Languages : en
Pages : 1767
Book Description
A comprehensive, two-volume handbook on Microfluidics and Nanofluidics, this text covers fundamental aspects, fabrication techniques, introductory materials on microbiology and chemistry, measurement techniques, and applications with special emphasis on the energy sector. Each chapter begins with introductory coverage to a subject and then narrows in on advanced techniques and concepts, thus making it valuable to students and practitioners. The author pays special attention to applications of microfluidics in the energy sector and provides insight into the world of opportunities nanotechnology has to offer. Figures, tables, and equations to illustrate concepts.
First International Conference on Microchannels and Minichannels
Author: Satish G. Kandlikar
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 1026
Book Description
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 1026
Book Description
An Experimental Investigation of Effects of Surfactants on Spilling Breakers
Author: Xinan Liu
Publisher:
ISBN:
Category : Surface active agents
Languages : en
Pages : 460
Book Description
Publisher:
ISBN:
Category : Surface active agents
Languages : en
Pages : 460
Book Description