Download or read book An Experimental Study of Heat Transfer from Co rotating Disks Simulating Computer Hard Disk Drive Systems written by Evren Deniz Erturan and published by . This book was released on 2001 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Convective Heat and Mass Transfer in Rotating Disk Systems written by Igor V. Shevchuk and published by Springer Science & Business Media. This book was released on 2009-12-01 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is devoted to investigation of a series of problems of convective heat and mass transfer in rotating-disk systems. Such systems are widespread in scienti?c and engineering applications. As examples from the practical area, one can mention gas turbine and computer engineering, disk brakes of automobiles, rotating-disk air cleaners, systems of microclimate, extractors, dispensers of liquids, evaporators, c- cular saws, medical equipment, food process engineering, etc. Among the scienti?c applications, it is necessary to point out rotating-disk electrodes used for experim- tal determination of the diffusion coef?cient in electrolytes. The system consisting of a ?xed disk and a rotating cone that touches the disk by its vertex is widely used for measurement of the viscosity coef?cient of liquids. For time being, large volume of experimental and computational data on par- eters of ?uid ?ow, heat and mass transfer in different types of rotating-disk systems have been accumulated, and different theoretical approaches to their simulation have been developed. This obviously causes a need of systematization and generalization of these data in a book form.
Download or read book Convective Heat Transfer From Rotating Disks Subjected To Streams Of Air written by Stefan aus der Wiesche and published by Springer. This book was released on 2015-07-15 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Brief describes systematically results of research studies on a series of convective heat transfer phenomena from rotating disks in air crossflow. Phenomena described in this volume were investigated experimentally using an electrically heated disk placed in the test section of a wind tunnel. The authors describe findings in which transitions between different heat transfer regimes can occur in dependency on the involved Reynolds numbers and the angle of incidence, and that these transitions could be related to phenomenological Landau and Landau-de Gennes models. The concise volume closes a substantial gap in the scientific literature with respect to flow and heat transfer in rotating disk systems and provides a comprehensive presentation of new and recent results not previously published in book form.
Download or read book The experimental study of the heat transfer from a rotating disk written by N. Hattori and published by . This book was released on 1967 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A NUMERICAL AND EXPERIMENTAL STUDY ON THE FLOW AND HEAT TRANSFER CHARACTERISTICS IN CO ROTATING DISK SYSTEMS written by Yoon Sub Sim and published by . This book was released on 1983 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: Average Nusselt numbers were measured experimentally in the Reynolds number range of 500 to 4000 with disk rotation speeds from zero to 3600 RPM.
Download or read book Flow and Heat Transfer in Rotating disc Systems written by J. M. Owen and published by . This book was released on 1989 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is devoted to the flow and heat transfer between co-rotating discs, and unifies the subject by means of physical insight and mathematical models, validated using experimental data. Many phenomena, unique to rotating flows, are explained, and empirical correlations and theoretical methods, suitable for design purposes, are presented. Data is provided within the book for validating CFD codes which are being increasingly used to compute the flow in rotating-disc systems. Since the publication of Volume 1 in 1989, there has been an increasing interest in rotating disc systems, mainly from research workers and engine designers concerned with understanding and computing the complex flow and heat transfer that occur inside the internal cooling-systems of gas-turbine engines. This book should be of interest to them as it may assist them in making more efficient use of cooling air systems, resulting in both economic and environmental benefits.
Download or read book A Study of the Head Disk Interface in Heat Assisted Magnetic Recording Energy and Mass Transfer in Nanoscale written by Haoyu Wu and published by . This book was released on 2018 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: The hard disk drive (HDD) is still the dominant technology in digital data storage due to its cost efficiency and long term reliability compared with other forms of data storage devices. The HDDs are widely used in personal computing, gaming devices, cloud services, data centers, surveillance, etc. Because the superparamagnetic limit of perpendicular magnetic recording (PMR) has been reached at the data density of about 1 Tb/in^2 , heat assisted magnetic recording (HAMR) is being pursued and is expected to help increase the areal density to over 10 Tb/in^2 in HDDs in order to fulfill the future worldwide data storage demands. In HAMR, the magnetic media is heated locally (~50nm x 50nm) and momentarily (~10ns) to its Curie temperature (~750K) by a laser beam. The laser beam is generated by a laser diode (LD) and focused by a near field transducer (NFT). But the energy and mass transfer at high temperature from the laser heating can cause potential reliability issues. The design temperature of the NFT is much lower than the media’s Curie temperature. However, the distance between the NFT and the media is less than 10nm. As a result, the heat can flow back from the media to the NFT, which is called the back-heating effect. This can cause undesired additional temperature increase on the NFT, shortening its lifetime. Additionally, depletion, evaporation and degradation can happen on the lubricant and the carbon overcoat (COC) layer of the media. The material can transfer from the media to the head at high temperature and cause solid contamination on the head, adversely affecting its reliability. Since the laser heating in HAMR happens at nanoscale spatially and temporally, it is difficult to measure experimentally. In this dissertation, a comprehensive experimental stage, called the Computer Mechanics Laboratory (CML)-HAMR stage, was built to study different aspects of HAMR systems, including the heat and mass transfer in the head-disk interface during laser heating. The CML-HAMR stage includes an optical module, a spinstand module and a signal generation/acquisition module. And it can emulate the HAMR scenario. The head’s temperature was measured during the laser heating using the stage and heads with an embedded contact sensor (ECS). It was estimated, based on a linear extrapolation, that the ECS temperature rise is 139K, 132K, 127K and 122K when the disk is heated to the Curie temperature (~750K) and the head-disk clearance is 0nm, 1nm, 2nm and 3nm, respectively. The heating effect of the ECS was also studied and a related heat transfer experiment was performed. The normalized ECS self heating temperature rise, an indicator of the heat transfer in the head-disk interface (HDI), was measured. It was concluded that the heat transfer coefficient across the HDI strongly depends on the width of the gap size, especially when the gap size is smaller than 1nm. The head disk interaction during the laser heating was studied using a waveguide head, i.e., a HAMR head without the NFT. It showed that the laser heating can cause head surface protrusion. This lowers the fly-height (FH) and results in early touchdown (TD). It was shown that the ratio of touchdown power (TDP) change to the laser current is 0.3mW/mA. The dynamics of the head also changes during the laser heating. It was found that the magnitude of the 1st-pitch-mode vibration on the head increases over time both in short term and long term. The accumulation of material transferred to the head was also investigated. It was found that the solid contamination caused by the laser heating forms in the center of the waveguide. The round-shaped contamination formed on the head surface after laser heating. Finally the disk lubricant reflow after laser heating was studied. In the experiment, a beam of free space laser shines on the rotating disk at different laser powers, disk rotating speeds and repetitions. Then the disk was examined by an optical surface analyzer (OSA). It was found that 80% of the displaced lubricant recovers within 20 minutes. A simulation was also performed. The experiments and the simulation are in good agreement.
Download or read book Study of Dynamics and Nanoscale Heat Transfer of Head Disk Interface in Hard Disk Drives written by Yuan Ma and published by . This book was released on 2018 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since its introduction in 1956, hard disk drives have become one of the dominant products in the industry of data storage. The capacity of the hard disk drives must keep evolving to store the exploding data generated in the era of big data. This demand pushes the development of technologies including heat assisted magnetic recording (HAMR), microwave assisted magnetic recording (MAMR) and bit-patterned media (BPM) to increase the areal density beyond 1Tb/in2. In the development of these technologies, it is essential to have a clear understanding of the dynamics and nanoscale heat transfer behavior across the head-disk interface. In this dissertation, dynamics and nano-scale heat transfer in the head disk interface are discussed. Experimental study of nano-scale heat transfer is conducted with the specifically designed static touchdown experiment. Simulation strategy that incorporates the wave-based phonon conduction theory was also developed. In the flying condition, correlation between the temperature and head disk spacing was found at both passive flying stage and modulation stage. When the flying height increases due to either disk surface microwaviness or contact induced modulation, head temperature will increase, with a slight time delay, indicating the existence of a cooling effect as the head approaches the disk. The static touchdown experiment, which decouples the complicated air bearing from the nano-scale interface was further designed and performed. The heat transfer behavior across a closing nano-scale gap between head and disk was observed and measured. Experimental and simulation results showed general agreement with the theoretical predictions of the wave based theory for radiation and phonon conduction. The effect of different factors including humidity, air pressure, lubricant layer and disk substrate in the static touchdown experiment were also studied separately. Furthermore, the dynamics of HAMR condition was studied with waveguide heads. The laser induced protrusion was found to be around 1~2 nm in height. The findings of this dissertation could be applied to future HAMR head/media design, and the static touchdown experiment could be potentially improved to be a new approach to measure material conduction coefficient and emissivity with high special resolution.
Download or read book Flow and Heat Transfer in Rotating disc Systems Rotating cavities written by J. M. Owen and published by Research Studies PressLtd. This book was released on 1989 with total page 295 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is devoted to the flow and heat transfer between co-rotating discs, and unifies the subject by means of physical insight and mathematical models, validated using experimental data. Many phenomena, unique to rotating flows, are explained, and empirical correlations and theoretical methods, suitable for design purposes, are presented. Data is provided within the book for validating CFD codes which are being increasingly used to compute the flow in rotating-disc systems. Since the publication of Volume 1 in 1989, there has been an increasing interest in rotating disc systems, mainly from research workers and engine designers concerned with understanding and computing the complex flow and heat transfer that occur inside the internal cooling-systems of gas-turbine engines. This book should be of interest to them as it may assist them in making more efficient use of cooling air systems, resulting in both economic and environmental benefits.
Download or read book Flow and Heat Transfer in Rotating Disc Systems written by Owen and published by Research Studies Press. This book was released on 1995-11-01 with total page 622 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume one of this set discusses fluid mechanics and heat transfer in rotating-disc systems, and simplifies and extends existing information to provide a basic understanding of the subject. Physical insight, mathematical models and experimental data are used to explain the flow structure and provide theoretical methods and correlations which will be of use to research workers and designers.
Download or read book Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Studies of Convective Heat Transfer on Rotating Disks and Mainstream Entrainment Into Disk Cavities written by Yong Weon Kim and published by . This book was released on 1992 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Heat Transfer in Rotating Disc Systems written by and published by . This book was released on 1973 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the ASME Heat Transfer Division written by and published by . This book was released on 2002 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flow and Heat Transfer in Rotating disc Systems written by John Michael Owen and published by . This book was released on 1989 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discussing fluid mechanics and heat transfer in rotating-disc systems, this text simplifies and extends existing information to provide a basic understanding of the subject. Physical insight, mathematical models and experimental data are used to explain the flow structure and provide theoretical methods and correlations which will be of use to research workers and designers.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 880 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Compounding in Co Rotating Twin Screw Extruders written by Yeh Wang and published by iSmithers Rapra Publishing. This book was released on 2000 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the geometric structure of modular extruders, development of the various units of an extruder and their functions, the flow mechanisms and models of their behaviour and experimental studies of extruder performance and applications. An additional indexed section containing several hundred abstracts from the Rapra Polymer Library database gives useful references for further reading.
