Download or read book An experimental study of pool boiling heat transfer from inclined wires written by Colin Charles Thomas and published by . This book was released on 1960 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Study of Sodium Pool Boiling Heat Transfer written by R. C. Noyes and published by . This book was released on 1962 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bubble Dynamics and Heat Transfer in Pool Boiling on Wires at Different Gravity written by Jian-Fu Zhao and published by . This book was released on 2011 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of experimental studies on bubble dynamical behaviors and heat transfer in pool boiling on thin wires in different gravity conditions have been performed in the past years, including experiments in long-term microgravity aboard the 22nd Chinese recoverable satellite RS-22, in short-term microgravity in the drop tower Beijing, and in normal gravity on the ground. Steady pool boiling of degassed R113 on thin platinum wires has been studied using a temperature-controlled heating method. A voltage-controlled heating method has also been used in normal gravity. A slight enhancement of nucleate boiling heat transfer is observed in microgravity, while dramatic changes of bubble behaviors are very evident. Considering the influence of the Marangoni effects, the different characteristics of bubble behaviors in microgravity have been explained. A new bubble departure model including the influence of the Marangoni effects has also been proposed, which can predict the whole observation both in microgravity and in normal gravity. The value of CHF (critical heat flux) in microgravity is lower than that in normal gravity, but it can be predicted well by the Lienhard-Dhir correlation, although the dimensionless radius, or the square root of the Bond number, in the present case is far beyond its initial application range. A further revisit on the scaling of CHF with heater radius in normal gravity, which is focused on the case of a small Bond number, has also been performed in our laboratory using different kinds of working fluids at different subcooling conditions. Interactions between the influences of the subcooling and heater radius will be important for the case of a small Bond number. In addition to the Bond number, there may exist some other parameters, which may be material-dependent, that play important roles in the CHF phenomenon with a small Bond number.
Download or read book Experimental Study of Pool Boiling Heat Transfer Enhancement Over Microchanneled Surfaces written by Dwight Cooke and published by . This book was released on 2011 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Pool boiling is of interest in heat transfer applications because of its potential for removing large amount of heat resulting from the latent heat of evaporation and little pressure drop penalty for circulating coolant through the system. However, the heat transfer performance of pool boiling systems is still not comparable to the cooling ability provided by enhanced microchannels operating under single-phase conditions. This investigation focuses on the bubble dynamics and heat transfer on plain and structured microchanneled surfaces under various heat fluxes in an effort to understand the underlying heat transfer mechanism through the use of a high speed camera. In a preliminary study, silicon chips have been tested in the nucleate boiling regime, and beneficial microchannel geometries have been identified. It is determined that heat transfer enhancement occurs because of (i) an increase in surface area and (ii) an improvement in the heat transfer mechanism through the channels functioning as liquid conduits for three side heating. The range for channel size in which the greatest enhancement occurs has been identified as being 200 - 400 [micron] width and 300 - 500 [micron] depth. The second study has been investigated with copper chips, with improvements to the test setup for accurate measurement of surface temperature. Ten chips, in addition to a plain chip have been evaluated for heat transfer performance. It has been determined that surfaces with many, small hydraulic diameter channels enhance the heat transfer as well as surfaces with wide and deep channels. The best performing chip had a record heat transfer coefficient of 269 kW/m2K. The large heat fluxes of over 240 W/cm2 were attained without reaching the critical heat flux condition, because of the open channels on the surface acting as conduits for liquid supply to the nucleation sites. The microchannels prevent surface dryout and critical heat flux (CHF), while the channel width controls the size of the departing bubbles."--Abstract.
Download or read book A Study Of Pool Boiling In An Accelerating System written by Herman Merte, Jr. and published by . This book was released on 1959 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Critical Heat Flux for Saturated Pool Boiling from Horizontal and Vertical Wires in Reduced Gravity written by Robert Siegel and published by . This book was released on 1965 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pool Boiling Heat Transfer written by Dong Soo Jung and published by . This book was released on 1984 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book VDI Heat Atlas written by VDI Gesellschaft and published by Springer Science & Business Media. This book was released on 2010-07-21 with total page 1608 pages. Available in PDF, EPUB and Kindle. Book excerpt: For more than 50 years, the Springer VDI Heat Atlas has been an indispensable working means for engineers dealing with questions of heat transfer. Featuring 50% more content, this new edition covers most fields of heat transfer in industrial and engineering applications. It presents the interrelationships between basic scientific methods, experimental techniques, model-based analysis and their transfer to technical applications.
Download or read book Experimental Study of Transient Pool Boiling Heat Transfer Under Exponential Power Excursion on Plate type Heater written by and published by . This book was released on 2015 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conduction and single-phase convective heat transfer are well understood phenomena: analytical models [1] and empirical correlations [2] allow capturing the thermal behavior of plate-type fuels or heaters in contact with a single-phase coolant. On the other hand, transient boiling heat transfer is a scarcely studied and much less understood phenomenon. Although, earlier studies have shown that important features of the boiling curve (i.e. onset of nucleate boiling (ONB), nucleate boiling heat transfer coefficient, and critical heat flux (CHF)) in transient conditions. These parameters significantly differ from those at steady-state. The mechanisms by which these changes occur are not clear. Furthermore, some of the conclusions from different authors are quantitatively or qualitatively in disagreement with each other. This work studied transient pool boiling heat transfer phenomena under exponentially escalating heat fluxes on plate-type heaters, at the time scales of milliseconds typical of Reactivity Initiated Accidents (RIAs) in nuclear reactors. The investigation utilized state-of-the-art diagnostics such as Infrared (IR) thermometry and high-speed video (HSV), to gain insight into the physical phenomena and generate a database that could be used for development and validation of accurate models for transient boiling heat transfer. The tests with exponential power escalation periods ranging from 100 ms to 5 ms and subcoolings of OK (saturation), 25K and 75 K were conducted. The measured pre-ONB heat transfer coefficient agrees well with the theoretical predictions for transient conduction. The ONB and onset of significant void (OSV) temperature and heat flux were found to increase monotonically with decreasing period and increasing subcooling, as expected. The mechanistic ONB model of Hsu was able to predict the measured ONB temperature and heat flux. The transient pool boiling curves were measured up to fully developed nucleate boiling (FDNB). Generally two types of boiling curve were observed: with overshoot (OV) or without overshoot. Data show that, when an OV is present, the OV temperature increases monotonically with decreasing period and increasing subcooling. The present study clears the confusions (eg. the trend of ONB temperature and heat flux versus power period) in previous research, and sheds light to the mechanisms behind transient boiling heat transfer. This can ultimately reduce the uncertainty in both design and safety analyses of the research reactors especially under RIAs.
Download or read book Hydrodynamic Aspects of Boiling Heat Transfer written by N. Zuber and published by . This book was released on 1959 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Heat Transfer written by Ephraim M. Sparrow and published by Academic Press. This book was released on 2021-12-01 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Heat Transfer, Volume 53 in this long-running serial, highlights new advances in the field, with this new volume presenting interesting chapters written by an international board of authors. Provides the authority and expertise of leading contributors from an international board of authors Presents the latest release in the Advances in Heat Transfer series
Download or read book Experimental Investigation of Pool Boiling Heat Transfer Augmentation in R 123 Using the Electrohydrodynamic Technique and Its Long Term Effects written by Alok Kumar and published by . This book was released on 1994 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Master s Theses and Doctoral Dissertations in the Pure and Applied Sciences written by and published by . This book was released on 1970 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Augmentation of Heat Transfer in Pool Boiling from Inclined Surfaces written by B. Khosrowshahi-Miandoab and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Study on Pool Boiling Performance Enhancement and Effect of Aging written by Aniket M. Rishi and published by . This book was released on 2017 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The miniaturization of electronic devices requires advanced thermal management techniques. The two-phase heat transfer process offers more effective and sustainable approach compared to the presently used single-phase cooling techniques. The boiling heat transfer is a two-phase cooling technique, that dissipates a high heat flux while maintaining the low surface temperature thereby, offering an efficient heat transfer mechanism compared to the single-phase process. Furthermore, the surface enhancement techniques such as micro/nano porous coatings help to maintain the low surface temperature thus improving the overall heat transfer performance. Electrodeposition is a simple technique that enhances this performance by creating the porous structure on the surface. This research focuses on developing an enhanced microscale structures on plain copper surfaces to improve the pool boiling performance. Additionally, the longevity (or the long-term stability) and aging of these enhanced structures, and their effects on the pool-boiling performance is also investigated. Initially the pool boiling performance of enhanced surfaces is studied. The enhanced surfaces were prepared using electrodeposition of copper and graphene oxide. Later, the effects of repetitive boiling on the morphology of the surfaces were examined using various characterization techniques such as Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), and Fourier Transform Infrared (FTIR). The chips coated with electrodeposition method rendered a high pool boiling performance for GS-4 (2.5% GO-Cu electrodeposited chip) with CHF of 220 W/cm2 at wall superheat of 14°C, giving ~76% improvement in CHF compared to plain copper chip. While, copper on copper electrodeposited chip, deposited with a different technique, performed better in both CHF and aging. CHF of 192 W/cm2 at wall superheat of 18.8°C was achieved for copper electrodeposited chip, giving ~30% enhancement compared to literature and ~54% enhancement when compared to plain copper chip. Moreover, surface characterization techniques including Scanning Electron Microscope (SEM) with Energy- Dispersive X-Ray Spectroscopy (EDS), Fourier Transform Infrared (FTIR), and X-Ray Diffraction (XRD) were employed to study the morphologies, elemental species, and to confirm the presence of graphene and graphene oxide on the test surfaces."--Abstract.
Download or read book Masters Theses and Doctoral Dissertations in the Pure and Applied Sciences Accepted by Colleges and Universities of the United States written by and published by . This book was released on 1968 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book EHD enhanced Pool Boiling Heat Transfer written by Majid Ali Faani Tabrizi Nezhaad and published by . This book was released on 1997 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:
