Study of Critical Heat Flux and Two-Phase Pressure Drop Under Reduced Gravity

Study of Critical Heat Flux and Two-Phase Pressure Drop Under Reduced Gravity PDF Author: National Aeronautics and Space Adm Nasa
Publisher:
ISBN: 9781730990052
Category :
Languages : en
Pages : 96

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Book Description
The design of the two-phase flow systems which are anticipated to be utilized in future spacecraft thermal management systems requires a knowledge of two-phase flow and heat transfer phenomena in reduced gravities. This program was funded by NASA headquarters in response to NRA-91-OSSA-17 and was managed by Lewis Research Center. The main objective of this program was to design and construct a two-phase test loop, and perform a series of normal gravity and aircraft trajectory experiments to study the effect of gravity on the Critical Heat Flux (CHF) and onset of instability. The test loop was packaged on two aircraft racks and was also instrumented to generate data for two-phase pressure drop. The normal gravity tests were performed with vertical up and downflow configurations to bound the effect of gravity on the test parameters. One set of aircraft trajectory tests was performed aboard the NASA DC-9 aircraft. These tests were mainly intended to evaluate the test loop and its operational performance under actual reduced gravity conditions, and to produce preliminary data for the test parameters. The test results were used to demonstrate the applicability of the normal gravity models for prediction of the two-phase friction pressure drop. It was shown that the two-phase friction multipliers for vertical upflow and reduced gravity conditions can be successfully predicted by the appropriate normal gravity models. Limited critical heat flux data showed that the measured CHF under reduced gravities are of the same order of magnitude as the test results with vertical upflow configuration. A simplified correlation was only successful in predicting the measured CHF for low flow rates. Instability tests with vertical upflow showed that flow becomes unstable and critical heat flux occurs at smaller powers when a parallel flow path exists. However, downflow tests and a single reduced gravity instability experiment indicated that the system actually became more stable with a p...

Study of Critical Heat Flux and Two-Phase Pressure Drop Under Reduced Gravity

Study of Critical Heat Flux and Two-Phase Pressure Drop Under Reduced Gravity PDF Author: National Aeronautics and Space Adm Nasa
Publisher:
ISBN: 9781730990052
Category :
Languages : en
Pages : 96

Get Book

Book Description
The design of the two-phase flow systems which are anticipated to be utilized in future spacecraft thermal management systems requires a knowledge of two-phase flow and heat transfer phenomena in reduced gravities. This program was funded by NASA headquarters in response to NRA-91-OSSA-17 and was managed by Lewis Research Center. The main objective of this program was to design and construct a two-phase test loop, and perform a series of normal gravity and aircraft trajectory experiments to study the effect of gravity on the Critical Heat Flux (CHF) and onset of instability. The test loop was packaged on two aircraft racks and was also instrumented to generate data for two-phase pressure drop. The normal gravity tests were performed with vertical up and downflow configurations to bound the effect of gravity on the test parameters. One set of aircraft trajectory tests was performed aboard the NASA DC-9 aircraft. These tests were mainly intended to evaluate the test loop and its operational performance under actual reduced gravity conditions, and to produce preliminary data for the test parameters. The test results were used to demonstrate the applicability of the normal gravity models for prediction of the two-phase friction pressure drop. It was shown that the two-phase friction multipliers for vertical upflow and reduced gravity conditions can be successfully predicted by the appropriate normal gravity models. Limited critical heat flux data showed that the measured CHF under reduced gravities are of the same order of magnitude as the test results with vertical upflow configuration. A simplified correlation was only successful in predicting the measured CHF for low flow rates. Instability tests with vertical upflow showed that flow becomes unstable and critical heat flux occurs at smaller powers when a parallel flow path exists. However, downflow tests and a single reduced gravity instability experiment indicated that the system actually became more stable with a p...

Study of Critical Heat Flux and Two-Phase Pressure Drop Under Reduced Gravity

Study of Critical Heat Flux and Two-Phase Pressure Drop Under Reduced Gravity PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 100

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Book Description


Microgravity Research in Support of Technologies for the Human Exploration and Development of Space and Planetary Bodies

Microgravity Research in Support of Technologies for the Human Exploration and Development of Space and Planetary Bodies PDF Author: National Research Council
Publisher: National Academies Press
ISBN: 0309064910
Category : Science
Languages : en
Pages : 225

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Book Description
The frontier represented by the near solar system confronts humanity with intriguing challenges and opportunities. With the inception of the Human Exploration and Development of Space (HEDS) enterprise in 1995, NASA has acknowledged the opportunities and has accepted the very significant challenges. Microgravity Research in Support of Technologies for the Human Exploration and Development of Space and Planetary Bodies was commissioned by NASA to assist it in coordinating the scientific information relevant to anticipating, identifying, and solving the technical problems that must be addressed throughout the HEDS program over the coming decades. This report assesses scientific and related technological issues facing NASA's Human Exploration and Development of Space endeavor, looking specifically at mission enabling and enhancing technologies which, for development, require an improved understanding of fluid and material behavior in a reduced gravity environment.

Encyclopedia Of Two-phase Heat Transfer And Flow Ii: Special Topics And Applications (A 4-volume Set)

Encyclopedia Of Two-phase Heat Transfer And Flow Ii: Special Topics And Applications (A 4-volume Set) PDF Author: Thome John R
Publisher: World Scientific
ISBN: 9814623296
Category : Technology & Engineering
Languages : en
Pages : 1324

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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.

Second Microgravity Fluid Physics Conference

Second Microgravity Fluid Physics Conference PDF Author:
Publisher:
ISBN:
Category : Fluid dynamics (Space environment)
Languages : en
Pages : 494

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Book Description


Recapturing a Future for Space Exploration

Recapturing a Future for Space Exploration PDF Author: National Research Council
Publisher: National Academies Press
ISBN: 0309163846
Category : Science
Languages : en
Pages : 464

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Book Description
More than four decades have passed since a human first set foot on the Moon. Great strides have been made in our understanding of what is required to support an enduring human presence in space, as evidenced by progressively more advanced orbiting human outposts, culminating in the current International Space Station (ISS). However, of the more than 500 humans who have so far ventured into space, most have gone only as far as near-Earth orbit, and none have traveled beyond the orbit of the Moon. Achieving humans' further progress into the solar system had proved far more difficult than imagined in the heady days of the Apollo missions, but the potential rewards remain substantial. During its more than 50-year history, NASA's success in human space exploration has depended on the agency's ability to effectively address a wide range of biomedical, engineering, physical science, and related obstacles-an achievement made possible by NASA's strong and productive commitments to life and physical sciences research for human space exploration, and by its use of human space exploration infrastructures for scientific discovery. The Committee for the Decadal Survey of Biological and Physical Sciences acknowledges the many achievements of NASA, which are all the more remarkable given budgetary challenges and changing directions within the agency. In the past decade, however, a consequence of those challenges has been a life and physical sciences research program that was dramatically reduced in both scale and scope, with the result that the agency is poorly positioned to take full advantage of the scientific opportunities offered by the now fully equipped and staffed ISS laboratory, or to effectively pursue the scientific research needed to support the development of advanced human exploration capabilities. Although its review has left it deeply concerned about the current state of NASA's life and physical sciences research, the Committee for the Decadal Survey on Biological and Physical Sciences in Space is nevertheless convinced that a focused science and engineering program can achieve successes that will bring the space community, the U.S. public, and policymakers to an understanding that we are ready for the next significant phase of human space exploration. The goal of this report is to lay out steps and develop a forward-looking portfolio of research that will provide the basis for recapturing the excitement and value of human spaceflight-thereby enabling the U.S. space program to deliver on new exploration initiatives that serve the nation, excite the public, and place the United States again at the forefront of space exploration for the global good.

An Index to the Two-phase Gas-liquid Flow Literature

An Index to the Two-phase Gas-liquid Flow Literature PDF Author: S. William Gouse
Publisher: MIT Press (MA)
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 890

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Book Description


Heat Transfer 1994

Heat Transfer 1994 PDF Author: G. F. Hewitt
Publisher: CRC Press
ISBN: 9781560323341
Category : Technology & Engineering
Languages : en
Pages : 660

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Book Description


Nuclear Science Abstracts

Nuclear Science Abstracts PDF Author:
Publisher:
ISBN:
Category : Nuclear energy
Languages : en
Pages : 538

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Book Description


Two-Phase Heat Transfer

Two-Phase Heat Transfer PDF Author: Mirza Mohammed Shah
Publisher: John Wiley & Sons
ISBN: 1119618673
Category : Science
Languages : en
Pages : 388

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Book Description
A guide to two-phase heat transfer theory, practice, and applications Designed primarily as a practical resource for design and development engineers, Two-Phase Heat Transfer contains the theories and methods of two-phase heat transfer that are solution oriented. Written in a clear and concise manner, the book includes information on physical phenomena, experimental data, theoretical solutions, and empirical correlations. A very wide range of real-world applications and formulas/correlations for them are presented. The two-phase heat transfer systems covered in the book include boiling, condensation, gas-liquid mixtures, and gas-solid mixtures. The authora noted expert in this fieldalso reviews the numerous applications of two-phase heat transfer such as heat exchangers in refrigeration and air conditioning, conventional and nuclear power generation, solar power plants, aeronautics, chemical processes, petroleum industry, and more. Special attention is given to heat exchangers using mini-channels which are being increasingly used in a variety of applications. This important book: Offers a practical guide to two-phase heat transfer Includes clear guidance for design professionals by identifying the best available predictive techniques Reviews the extensive literature on heat transfer in two-phase systems Presents information to aid in the design and analysis of heat exchangers. Written for students and research, design, and development engineers, Two-Phase Heat Transfer is a comprehensive volume that covers the theory, methods, and applications of two-phase heat transfer.