Download or read book Heat Transfer Under Impinging Jets at Very Close Jet to target Spacings written by Christopher J. Danek and published by . This book was released on 1995 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Heat Transfer from Swirling Impinging Jets written by M. Mahmood and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is concerned with the determination of thelocal and average mass/heat transfer--from swirling jetsimpinging orthogonally onto flat surfaces. ApplicatioCn>of swirl alters the flow field of the jet considerablyand eventually the maximum velocity in the jet is displacedfrom the axis resulting in a typical double-peak profile. Further increase of swirl, can even result in arecirculation in the inner core of the flow. The turbulencecharacteristics of the jet are also affected. itis expected that these changes will, in addition, modifythe heat transfer behaviour. Consequently, a study of both single free jets and asquare array (of 3x 3) of jets was undertaken. Therange of swirls examined in this study was from zerothrough to weak and then medium swirl, i. e. the swirlnumber S was varied from 0 to 0.48. The other parametersvaried in the experiments were the nozzle-to-targetspacing z/D from 2 to 12, the nozzle pitches x/D (forarrays of jets) which were 3.2,4.8 and 6.4, and the jGtReynolds number. In the single frce jet tests, two flowrates corresponding to ReD-":2 32pOOO and 60,000 were studiedwhilst, for the multiple jets, the measurementswere confined. to the lower of these Reynolds numbers.(ReD is based on the mean exit velocity in the non-swirlingcase and the diameter of the nozzle.)Limited velocity and turbulence measurements were alsoundertaken on the single jet to characterise the flowand also to compare the behaviour of the present jetswith those in previous studies. The flows were similarto those observed previously for swirling jets so thatthe heat transfer results should be generally applicable. A thin-film naphthalene sublimation technique was usedto measure mass transfers over the target surface. Theheat transfer coefficients were then derived using theChilton-Colburn analogy. A rig was developed to spraya uniform coating of naphthalene on the target surface. This thin-film technique was found to provide repeatableresults and the validity of the experiments was further assessed by comparing the results with previouslypublished data for the no swirl case. These were inreasonable agreement. For the single free jets, the application of swirl wasfound to continuously reduce the heat transfers. Theheat transfers, however, became more uniform. An empiricalcorrelation has also been suggested for the averageNusselt number associated with these single swirling jets and is valid for S= 0.12-to 0.48. In some circumstancesin the multiple jet tests (e. g. at close nozzle-to-target spacings) the average heat transfers increasedto a maximum of IS =0.24 (approximately). Further increasesin the degree of swirl brought about a subsequentreduction in average heat transfer coefficients untileventually the performance of the swirling jets was poorerthan that of the non-swirling flows. This discrepancyin behaviour can be explained in terms of changes in thelocal heat transfer distributions.

Download or read book A Study of the Heat Transfer Resulting from a Heated Jet Impinging Upon a Cylinder written by Kevin William Whitaker and published by . This book was released on 1986 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Flow and Heat Transfers Associated with Impinging Jets in Crossflows written by and published by . This book was released on 1911 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis reports the results of an experimental study into the flow and heat transfers associated with both inclined and orthogonally impinging axisymmetric air jets. The majority of previously reported studies have been mainly confined to orthogonally impinging jets in stagnant surroundings. In this investigation, free jets as well as the effects of crossflows are considered. This investigation is Primarily concerned with local heat transfer variations. The experimental tests were. conducted with a single 12.7 mm diameter jet impinging on a flat surface, and heat transfers were evaluated using a heat-mass transfer analogy (t e Chilton-Colburn analogy). The sublimation of naphthalene was employed as the mass transfer technique. The flowfield associated with impinging jets has a significant influence on their heat transfer characteristics., In view of the present limited level of understanding of this 'complex' flowfield, extensive flow visualisation techniques were employed in this present investigation. Those were primarily intended to aid interpretation of the experimental heat transfer results, and also to provide further physical understanding of the flowfields resulting from the interactions between impinging jets and crossflowing streams. The flow and heat transfer tests conducted in the programme of work reported in this thesis covered typical ranges of flow parameters of interest in many practical applications of jet impingement systems. Jet inclinations of 45°, 600, and 90°, nozzle to target spacings of 2,11, and 8 nozzle diameters were studied. The Reynolds nuinbers were 30,200,32,700 and 55,100 and mass velocity ratios In the range 4.0 to 3.8 were studied. The effects of these parameters on the flow and heal transfers associated with impinging jets are reported. Comparisons were drawn between the heat transfer results and those of previously reported studies where appropriate.

Download or read book Impingement Jet Cooling in Gas Turbines written by R.S. Amano and published by WIT Press. This book was released on 2014-05-28 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the requirement for enhanced cooling technologies on modern gas turbine engines, advanced research and development has had to take place in field of thermal engineering. Among the gas turbine cooling technologies, impingement jet cooling is one of the most effective in terms of cooling effectiveness, manufacturability and cost. The chapters contained in this book describe research on state-of-the-art and advanced cooling technologies that have been developed, or that are being researched, with a variety of approaches from theoretical, experimental, and CFD studies. The authors of the chapters have been selected from some of the most active researchers and scientists on the subject. This is the first to book published on the topics of gas turbines and heat transfer to focus on impingement cooling alone.

Download or read book Heat Transfer from Swirling Impinging Jets written by and published by . This book was released on 1904 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is concerned with the determination of the local and average mass/heat transfer--from swirling jets impinging orthogonally onto flat surfaces. ApplicatioCn> of swirl alters the flow field of the' jet considerably and eventually the maximum velocity in the jet is displaced from the axis resulting in a typical 'double-peak' profile. Further increase of swirl, can even result in a recirculation in the inner core of the flow. The turbulence characteristics of the jet are also affected. it is expected that these changes will, in addition, modify the heat transfer behaviour. Consequently, a study of both single free jets and a square array (of 3x 3) of jets was undertaken. The range of swirls examined in this study was from zero through to weak and then medium swirl, i. e. the swirl number S was varied from 0 to 0.48. The other parameters varied in the experiments were the nozzle-to-target spacing z/D from 2 to 12, the nozzle pitches x/D (for arrays of jets) which were 3.2,4.8 and 6.4, and the jGt Reynolds number. In the single frce jet tests, two flow rates corresponding to ReD-":2 32pOOO and 60,000 were studied whilst, for the 'multiple' jets, the measurements were confined. to the lower of these Reynolds numbers. (ReD is based on the mean exit velocity in the non-swirling case and the diameter of the nozzle.) Limited velocity and turbulence measurements were also undertaken on the single jet to characterise the flow and also to compare the behaviour of the present jets with those in previous studies. The flows were similar to those observed previously for swirling jets so that the heat transfer results should be generally applicable. A 'thin-film' naphthalene sublimation technique was used to measure mass transfers over the target surface. The heat transfer coefficients were then derived using the Chilton-Colburn analogy. A rig was developed to spray a uniform coating of naphthalene on the target surface. This 'thin-film' technique was found to provide re.

Download or read book Analysis of Impingement Heat Transfer for Two Parallel Liquid metal Slot Jets written by Robert Siegel and published by . This book was released on 1974 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analytical method is developed for determining heat transfer by impinging liquid-metal slot jets. The method involves mapping the jet flow region, which is bounded by free streamlines, into a potential plane where it becomes a uniform flow in a channel of constant width. The energy equation is transformed into potential plane coordinates and is solved in the channel flow region. Conformal mapping is then used to transform the solution back into the physical plane and obtain the desired heat-transfer characteristics. The analysis given here determines the heat-transfer characteristics for two parallel liquid-metal slot jets impinging normally against a uniformly heated flat plate. The liquid-metal assumptions are made that the jets are inviscid and that molecular conduction is dominating heat diffusion. Wall temperature distributions along the heated plate are obtained as a function of spacing between the jets and the jet Peclet number.

Download or read book Heat Transfer Characteristics Within an Array of Impinging Jets Effects of Crossflow Temperature Relative to Jet Temperature written by L. W. Florschuetz and published by . This book was released on 1985 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spanwise average heat fluxes, resolved in the streamwise direction to one stream-wise hole spacing were measured for two-dimensional arrays of circular air jets impinging on a heat transfer surface parallel to the jet orifice plate. The jet flow, after impingement, was constrained to exit in a single direction along the channel formed by the jet orifice plate and heat transfer surface. The crossflow originated from the jets following impingement and an initial crossflow was present that approached the array through an upstream extension of the channel. The regional average heat fluxes are considered as a function of parameters associated with corresponding individual spanwise rows within the array. A linear superposition model was employed to formulate appropriate governing parameters for the individual row domain. The effects of flow history upstream of an individual row domain are also considered. The results are formulated in terms of individual spanwise row parameters. A corresponding set of streamwise resolved heat transfer characteristics formulated in terms of flow and geometric parameters characterizing the overall arrays is described.

Download or read book Thermal Engineering in Power Systems written by Ryoichi Amano and published by WIT Press. This book was released on 2008 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research and development in thermal engineering for power systems are of significant importance to many scientists who are engaged in research and design work in power-related industries and laboratories. This book focuses on variety of research areas including Components of Compressor and Turbines that are used for both electric power systems and aero engines, Fuel Cells, Energy Conversion, and Energy Reuse and Recycling Systems. To be competitive in today's market, power systems need to reduce the operating costs, increase capacity factors and deal with many other tough issues. Heat Transfer and fluid flow issues are of great significance and it is likely that a state-of-the-art edited book with reference to power systems will make a contribution for design and R&D engineers and the development towards sustainable energy systems.

Download or read book Thermal Measurements in Electronics Cooling written by Kaveh Azar and published by CRC Press. This book was released on 2020-08-26 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: Filled with careful explanations, step-by-step instructions, and useful examples, this handbook focuses on real-world considerations and applications of thermal measurement methods in electronics cooling. Fifteen experts in thermal engineering combine their expertise to create a complete guide to this complex topic. This practical reference covers all aspects of thermal characterization in electronics cooling and thermal management. The first part of the book introduces the concept of electronics cooling and its associated thermal phenomenon and explains why experimental investigation is required. Subsequent chapters explain methods of measuring different parameters and introduce relevant examples. Sources for locating needed equipment, tables, checklists, and to-do lists are included. Sample calculations and methodologies for error analysis ensure that you can put this valuable information to use in your work.

Download or read book Heat Transfer from Normally Impinging Two dimensional Air Jets written by Donald Gene Arganbright and published by . This book was released on 1971 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of the Heat Transfer of Two Parallel Jets Impinging Normal to a Flat Surface written by Nicholas Rudenko and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The recent development of fifth generation fighter aircraft has been designed to takeoff in short distances, accelerate to supersonic flight, and land vertically. For short takeoff and vertical landing operations, STOVL, aircraft use thrust vectoring to direct high-speed, high temperature jet exhaust from the primary nozzle towards the ground. This redirection of flow provides approximately half of the thrust required for lift. The remaining thrust is generated by a lift fan which produces a sonic jet plume. The complex nature of the flow-field generated by these aircraft severely impacts the surrounding operational environment. The need to understand the high temperature, high velocity flow-field associated with these aircraft in close proximity to the ground is extremely important. These flow conditions give rise to hazardous conditions for personnel and equipment in the nearby proximity of the landing aircraft.To understand the effects of high temperature impinging flows and the subsequent heat transfer into the impingement plane, the existing High Speed Aeroacoustics Laboratory was redesigned to achieve high temperatures flows while in impinging configurations. High temperature flows are achieved through the use of two electric heaters in a parallel configuration. The parallel heater configuration allows the jet exhaust on an impinging jet model to reach a total temperature ratio of 2.0 with a jet Mach number of 1.34. More importantly, the use of electric heaters and PID controllers produces stable flow conditions within 4 K of the desired jet temperature.Once facility development was completed, a series of experiments were conducted to determine the flow-field characteristics of a heated, supersonic rear jet impinging on a ground plane. A dual impinging jet model (using a cold, sonic front jet) was also studied. This model is representative of a generic military-style STOVL aircraft in a hover configuration. The operational conditions were limited to jet stand-off distances between 4 and 15 nozzle diameters, and jet Mach numbers between 1.16 and 1.56. The total temperature of the jet was also varied between 1.2 and 2.0.Schlieren flow visualization was used to qualify the average flow-field behavior exhibited in both single and dual jet configurations. Single jet configurations showed a strong relationship between jet stand-off distances and thickness of the thermal outwash. For dual jet configurations, the interaction between the two jets, and the subsequent mixing, can be seen. The location of this mixing region is strongly dependent on the Mach number of the rear jet.Steady-state and transient surface temperature measurements were also a focus in this study. Steady-state measurements were compared to adiabatic wall temperatures calculated from CFD. For the limited CFD cases, experimental results compared well with the calculations, with less than 10% difference at all locations. For single impinging jets, the normalized temperature distribution in the impingement region is heavily dependent upon the jet separation distance. For large separation distances, increases in the total temperature ratio can reduce the peak normalized temperature at the stagnation point by as much as 10%. For dual impinging jet operations, the region between the two jets experience an increase in normalized temperature when compared to the single jet operations. A slight increase in the stagnation temperature is also seen.Transient thermal distributions obtained for a rear jet Mach number of 1.16 at a total temperature of 1.5 and a jet separation distance of 6 nozzle diameters are compared to a transient conduction computation model. The experimental model compared poorly to the experimental model for all time increments. However the differences can be attributed to boundary condition assumptions, and accuracy can be improved with model refinement.

Download or read book Encyclopedia Of Two phase Heat Transfer And Flow Iii Macro And Micro Flow Boiling And Numerical Modeling Fundamentals A 4 volume Set written by John R Thome and published by World Scientific. This book was released on 2018-03-13 with total page 1460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Set III of this encyclopedia is a new addition to the previous Sets I and II. It contains 26 invited chapters from international specialists on the topics of numerical modeling of two-phase flows and evaporation, fundamentals of evaporation and condensation in microchannels and macrochannels, development and testing of micro two-phase cooling systems for electronics, and various special topics (surface wetting effects, microfin tubes, two-phase flow vibration across tube bundles). The chapters are written both by renowned university researchers and by well-known engineers from leading corporate research laboratories. Numerous 'must read' chapters cover the fundamentals of research and engineering practice on boiling, condensation and two-phase flows, two-phase heat transfer equipment, electronics cooling systems, case studies and so forth. Set III constitutes a 'must have' reference together with Sets I and II for thermal engineering researchers and practitioners.

Download or read book Gas Turbine Heat Transfer and Cooling Technology Second Edition written by Je-Chin Han and published by CRC Press. This book was released on 2012-11-27 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive reference for engineers and researchers, Gas Turbine Heat Transfer and Cooling Technology, Second Edition has been completely revised and updated to reflect advances in the field made during the past ten years. The second edition retains the format that made the first edition so popular and adds new information mainly based on selected published papers in the open literature. See What’s New in the Second Edition: State-of-the-art cooling technologies such as advanced turbine blade film cooling and internal cooling Modern experimental methods for gas turbine heat transfer and cooling research Advanced computational models for gas turbine heat transfer and cooling performance predictions Suggestions for future research in this critical technology The book discusses the need for turbine cooling, gas turbine heat-transfer problems, and cooling methodology and covers turbine rotor and stator heat-transfer issues, including endwall and blade tip regions under engine conditions, as well as under simulated engine conditions. It then examines turbine rotor and stator blade film cooling and discusses the unsteady high free-stream turbulence effect on simulated cascade airfoils. From here, the book explores impingement cooling, rib-turbulent cooling, pin-fin cooling, and compound and new cooling techniques. It also highlights the effect of rotation on rotor coolant passage heat transfer. Coverage of experimental methods includes heat-transfer and mass-transfer techniques, liquid crystal thermography, optical techniques, as well as flow and thermal measurement techniques. The book concludes with discussions of governing equations and turbulence models and their applications for predicting turbine blade heat transfer and film cooling, and turbine blade internal cooling.

Download or read book Handbook of Industrial Drying Second Edition Revised and Expanded written by A. S. Mujumdar and published by CRC Press. This book was released on 1995-02-22 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamental aspects, drying in various industrial sectors: drying of solids, experimental techniques, basic process calculations, transportproperties in the drying solids, rotary drying, horizontal vacuum rotary dryers, fluidized bed drying drum dryers, industrial spray drying, freeze drying, microwave and dielectric drying, solar drying, spouted bed drying, impingement drying, flash drying, conveyor dryers, impinging stream dryers, infrared drying, drying of foodstuffs, agricultural products, fruits and vegetables, evaporation and spray drying in the dairy industry.

Download or read book Advances in Gas Turbine Technology written by Ernesto Benini and published by BoD – Books on Demand. This book was released on 2011-11-04 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gas turbine engines will still represent a key technology in the next 20-year energy scenarios, either in stand-alone applications or in combination with other power generation equipment. This book intends in fact to provide an updated picture as well as a perspective vision of some of the major improvements that characterize the gas turbine technology in different applications, from marine and aircraft propulsion to industrial and stationary power generation. Therefore, the target audience for it involves design, analyst, materials and maintenance engineers. Also manufacturers, researchers and scientists will benefit from the timely and accurate information provided in this volume. The book is organized into five main sections including 21 chapters overall: (I) Aero and Marine Gas Turbines, (II) Gas Turbine Systems, (III) Heat Transfer, (IV) Combustion and (V) Materials and Fabrication.

Download or read book High Performance Computing in Science and Engineering 09 written by Wolfgang E. Nagel and published by Springer Science & Business Media. This book was released on 2010-04-28 with total page 541 pages. Available in PDF, EPUB and Kindle. Book excerpt: At the end of the year 2008, we have seen a strategic step towards a funct- ning HPC infrastructure on Tier-0 level in Germany. Based on an agreement (Verwaltungsabkommen") between the Federal Ministry of Education and " Research (BMBF) and the state ministries for research of Baden-Wurttem- · berg, Bayern, and Nordrhein-Westfalen, a budget of overall 400 Million Euro had been allocated - equally shared between federal and state authorities in a?ve year time frame - to establish the next generation of HPC systems at the Gauss Centre for Supercomputing (GCS) - consisting of the three nat- nal supercomputing centres HLRS (Stuttgart), NIC/JSC (Julich), and LRZ · (Munich). As part of that strategic initiative, in May 2009 already NIC/JSC has installed the?rst phase of the GCS HPC Tier-0 resources, an IBM Blue Gene/P with roughly 300. 000 Cores, this time in Julic · h, With that, the GCS provides the most powerfulhigh-performance computing infrastructure in - rope already today. HLRS and its partners in the GCS have agreed on a common strategy for the installation of the next generation of leading edge HPC systems. Over the next few years, HLRS and LRZ as the other two GCS centers will upgrade their systems accordingly. The plan is to have a Tier-0 HPC system within GCS operating at any time in this?ve year period. Asanintermediatestep, HLRShasreplacedmostoftheirNECSX-8nodes by the NEC SX-9/12M192, a system with roughly 20 TFLOPs peak