Investigation of Transient Two-phase Flow During Refrigeration and Air Conditioning System Startup PDF Download

Author: Michael J. Hedrick
Publisher:
ISBN:
Category :
Languages : en
Pages : 256

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Author: Kunal Dutta-Roy
Publisher:
ISBN:
Category : Transients (Dynamics)
Languages : en
Pages : 75

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Author: Somchai Baotong
Publisher:
ISBN:
Category : Fourier transformations
Languages : en
Pages : 178

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The main objective of this research is to analyze and simulate the startup transient in two-phase natural circulation loop. Two rectangular loops have been designed and constructed to simulate a two-phase flow under two different configurations. Fast Fourier Transform (FFT) is used to analyze the oscillation of unstable temperature and differential pressure. A computer program, TEXAS, has been modified to simulate the two-phase flow in the rectangular natural circulation loop and compared with the experimental data. The same water temperature difference across the heater was measured both when the cooling system was turned on and turned off. The temperature oscillation was observed in both loops under unstable boiling condition. The temperature oscillation was due to two factors. The first factor was the presence of the horizontal tube. The second was the flow instabilities, known as geysering and flashing-induced density wave oscillation, which occurred when water flowed from small channel to large channel in the heated section. The frequency of the temperature oscillation at the condenser outlet increased when the heat flux increased. The results from the computer simulation agreed with the experimental results. However, the simulation had some limitation, and still required further modification.

Author: John R Thome
Publisher: World Scientific
ISBN: 9814623296
Category : Technology & Engineering
Languages : en
Pages : 1321

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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.

Author: N. Zuber
Publisher:
ISBN:
Category : Heat
Languages : en
Pages :

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Author: Ronald P. Porter
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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In this paper, implications of the quasi-steady approach to numerical solutions of two-phase flow problems are addressed by the application of basic principles. First, a simple criterion to determine the limitations of the quasi-steady approach is discussed. This criterion is used to determine the minimum time-step size required during the quasi-steady solution. Using this same concept, a method for making truly transient problems artifically quasi-steady is developed. Finally, these concepts are applied to a simple interfacial heat-transfer problem. The numerical instability that results from the quasi-steady approach during the explicit solution of this problem is investigated.

Author: Sadik Kakaç
Publisher: Springer
ISBN: 9789400968509
Category : Science
Languages : en
Pages : 457

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Book Description
Over the past two decades, two-phase flow and heat transfer problems associated with two-phase phenomena have been a challenge to many investigators. Two-phase flow applications are found in a wide range of engineering systems, such as nuclear and conventional power plants, evaporators of refrigeration systems and a wide vari ety of evaporative and condensive heat exchangers in the chemical industry. This publication is based on the invited lectures presented at the NATO Advanced Research Workshop on the Advances in Two-Phase Flow and Heat Transfer. The Horkshop was attended by more than 50 leading scientists and practicing engineers who work actively on two-phase flow and heat transfer research and applications in dif ferent sectors (academia, government, industry) of member countries of NATO. Some scientific leaders and experts on the subject matter from the non-NATO countries were also invited. They convened to discuss the state-of-the-art in two-phase flow and heat transfer and formulated recommendations for future research directions. To achieve these goals, invited key papers and a limited number of contributions were presented and discussed. The specific aspects of the subject were treated in depth in the panel sessions, and the unresolved problems identified. Suitable as a practical reference, these volumes incorporate a systematic approach to two-phase flow analysis.

Author: G F Hundy
Publisher: Butterworth-Heinemann
ISBN: 0081006667
Category : Science
Languages : en
Pages : 512

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Book Description
Refrigeration, Air Conditioning and Heat Pumps, Fifth Edition, provides a comprehensive introduction to the principles and practice of refrigeration. Clear and comprehensive, it is suitable for both trainee and professional HVAC engineers, with a straightforward approach that also helps inexperienced readers gain a comprehensive introduction to the fundamentals of the technology. With its concise style and broad scope, the book covers most of the equipment and applications professionals will encounter. The simplicity of the descriptions helps users understand, specify, commission, use, and maintain these systems. It is a must-have text for anyone who needs thorough, foundational information on refrigeration and air conditioning, but without textbook pedagogy. It includes detailed technicalities or product-specific information. New material to this edition includes the latest developments in refrigerants and lubricants, together with updated information on compressors, heat exchangers, liquid chillers, electronic expansion valves, controls, and cold storage. In addition, efficiency, environmental impact, split systems, retail refrigeration (supermarket systems and cold rooms), industrial systems, fans, air infiltration, and noise are also included. Full theoretical and practical treatment of current issues and trends in refrigeration and air conditioning technology Meets the needs of industry practitioners and system designers who need a rigorous, but accessible reference to the latest developments in refrigeration and AC that is supported by coverage at a level not found in typical course textbooks New edition features updated content on refrigerants, microchannel technology, noise, condensers, data centers, and electronic control

Author: Milton Spinoza Plesset
Publisher:
ISBN:
Category :
Languages : en
Pages : 736

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