Download or read book Effect of Gravity and Liquid Subcooling on Bubble Dynamics written by Satjeet Singh and published by . This book was released on 1999 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Fluid Properties and Gravity Level on Boiling in the Discrete Bubble Region written by Thomas H. Cochran and published by . This book was released on 1967 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Subcooling and Gravity Level on Boiling in the Discrete Bubble Region written by Thomas H. Cochran and published by . This book was released on 1966 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interacting Effects of Inertia and Gravity on Bubble Dynamics written by Yohann Lilian Rousselet and published by . This book was released on 2014 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: Knowledge of the physical mechanisms governing bubble dynamics and two-phase heat transfer is critical in order to accurately predict and scale the performance of two-phase systems, most importantly in low-g environments. To better understand flow boiling, especially under microgravity conditions, the dynamics of single and multiple bubbles under different levels of bulk liquid velocity, surface orientation, contact angle, and substrate materials are studied in this work. Microfabricated cavities at the center of a flat heating surface are used to generate bubbles. Silicon and aluminum are used as substrate materials, with contact angles of 56° and 19°, respectively, with water as test liquid. The investigated bulk liquid velocities ranged from 0 m/s to 0.25 m/s, while surface orientation varies from horizontal to vertical, through 30°, 45° and 60°, and cavity spacing from 0.4 mm to 1.2 mm, in upflow conditions. Bulk liquid temperature was set close to saturation temperature, with bulk liquid subcooling less than 1° C, and wall superheat was maintained between 5.0° C and 6.0 °C. Based on the experimental data, a simple force balance model was developed, and is used to develop a model to predict bubble lift off. These forces are the lift force (F_b), the buoyancy force (F_b), the surface tension force (F_s), the contact pressure force (F_cp), and the inertia of both the vapor and the liquid displaced by the growing bubble. It is showed that at the instant when bubble lift off is initiated, the sum of forces acting on the bubble is equal to zero (and then becomes positive in the direction normal to the heater). This force balance is used to develop an expression for bubble lift off diameter. It also is found that for single and merged bubbles, when lift off occurs, buoyancy and lift forces are the only forces acting on the bubble, regardless of orientation, contact angle and flow velocity, and that for all cases, the ratio (F_b + F1) / A1 is constant and equal to 2.25 N/m2, where A1 is the bubble surface area at lift off.
Download or read book Experimental Investigation of Nucleate Boiling Bubble Dynamics in Normal and Zero Gravities written by Thomas H. Cochran and published by . This book was released on 1968 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics of Fluids in Microgravity written by Rodolfo Monti and published by CRC Press. This book was released on 2002-01-10 with total page 630 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a microgravity experiment, the conditions prevalent in fluid phases can be substantially different from those on the ground and can be exploited to improve different processes. Fluid physics research in microgravity is important for the advancement of all microgravity scients: life, material, and engineering. Space flight provides a unique laboratory that allows scientists to improve their understanding of the behaviour of fluids in low gravity, allowing the investigation of phenomena and processes normally masked by the effects of gravity and thus difficult to study on Earth. Physics of Fluids in Microgravity provides a clear view of recent research and progress in the different fields of fluid research in space. The topics presented include bubles and drops dynamics, Maragoni flows, diffustion and thermodiffusion, solidfication,a nd crystal growth. The results obtained so far are, in some cases, to be confirmed by extensive research activities on the International Space station, where basic and applied microgravity experimentation will take place in the years to come.
Download or read book NASA Technical Note written by and published by . This book was released on 1968 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Velocity and Gravity on Bubble Dynamics written by Sandipan Maity and published by . This book was released on 2000 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Simulations of Bubble Dynamics and Heat Transfer in Pool Building written by Eduardo Aktinol and published by . This book was released on 2014 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the complex nature of the subprocesses involved in nucleate boiling, it has not been possible to develop comprehensive models or correlations despite decades of accumulated data and analysis. Complications such as the presence of dissolved gas in the liquid further confound attempts at modeling nucleate boiling. Moreover, existing empirical correlations may not be suitable for new applications, especially with regards to varying gravity level. More recently, numerical simulations of the boiling process have proven to be capable of reliably predicting bubble dynamics and associated heat transfer by showing excellent agreement with experimental data. However, most simulations decouple the solid substrate by assuming constant wall temperature. In the present study complete numerical simulations of the boiling process are performed--including conjugate transient conduction in the solid substrate and the effects of dissolved gas in the liquid at different levels of gravity. Finite difference schemes are used to discretize the governing equations in the liquid, vapor, and solid phases. The interface between liquid and vapor phases is tracked by a level set method. An iterative procedure is used at the interface between the solid and fluid phases. Near the three-phase contact line, temperatures in the solid are observed to fluctuate significantly over short periods. The results show good agreement with the data available in the literature. The results also show that waiting and growth periods can be related directly to wall superheat. The functional relationship between waiting period and wall superheat is found to agree well with empirical correlations reported in the literature. For the case of a single bubble in subcooled nucleate boiling, the presence of dissolved gas in the liquid is found to cause noncondensables to accumulate at the top of the bubble where most condensation occurs. This results in reduced local saturation temperature and condensation rates. The numerical predictions show reasonable agreement with the results from experiments performed at microgravity. For nucleate boiling at microgravity the simulations predict a drastic change in vapor removal pattern when compared to Earth normal gravity. The predictions match well with experimental results. However, simulated heat transfer rates were significantly under-predicted.
Download or read book Microscale Heat Transfer Fundamentals and Applications written by S. Kakaç and published by Springer Science & Business Media. This book was released on 2006-05-20 with total page 517 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains an archival record of the NATO Advanced Institute on Microscale Heat Transfer – Fundamental and Applications in Biological and Microelectromechanical Systems held in Çesme – Izmir, Turkey, July 18–30, 2004. The ASIs are intended to be high-level teaching activity in scientific and technical areas of current concern. In this volume, the reader may find interesting chapters and various Microscale Heat Transfer Fundamental and Applications. The growing use of electronics, in both military and civilian applications has led to the widespread recognition for need of thermal packaging and management. The use of higher densities and frequencies in microelectronic circuits for computers are increasing day by day. They require effective cooling due to heat generated that is to be dissipated from a relatively low surface area. Hence, the development of efficient cooling techniques for integrated circuit chips is one of the important contemporary applications of Microscale Heat Transfer which has received much attention for cooling of high power electronics and applications in biomechanical and aerospace industries. Microelectromechanical systems are subject of increasing active research in a widening field of discipline. These topics and others are the main themeof this Institute.
Download or read book Advances in Heat Transfer written by James P. Hartnett and published by Academic Press. This book was released on 2001-04-24 with total page 335 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heat transfer is the exchange of heat energy between a system and its surrounding environment, which results from a temperature difference and takes place by means of a process of thermal conduction, mechanical convection, or electromagnetic radiation. Advances in Heat Transfer is designed to fill the information gap between regularly scheduled journals and university-level textbooks by providing in-depth review articles over a broader scope than is allowable in either journals or texts.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1965 with total page 1652 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bubble Growth Dynamics in Nucleate Pool Boiling with Liquid Subcooling Effects written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fundamentals of Convective Heat Transfer written by Gautam Biswas and published by CRC Press. This book was released on 2019-07-15 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermal convection is often encountered by scientists and engineers while designing or analyzing flows involving exchange of energy. Fundamentals of Convective Heat Transfer is a unified text that captures the physical insight into convective heat transfer and thorough, analytical, and numerical treatments. It also focuses on the latest developments in the theory of convective energy and mass transport. Aimed at graduates, senior undergraduates, and engineers involved in research and development activities, the book provides new material on boiling, including nuances of physical processes. In all the derivations, step-by-step and systematic approaches have been followed.
Download or read book NASA Reference Publication written by and published by . This book was released on 1977 with total page 984 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analytical and Experimental Study of Pool Heating of Liquid Hydrogen Over a Range of Accelerations written by Robert W. Graham and published by . This book was released on 1965 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Low Gravity Fluid Dynamics and Transport Phenomena written by Robert L. Sani and published by AIAA. This book was released on 1990 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt:
