Cool colored coating and phase change materials as complementary cooling strategies for building cooling load reduction in tropics

International Nuclear Information System (INIS)

Lei, Jiawei; Kumarasamy, Karthikeyan; Zingre, Kishor T.; Yang, Jinglei; Wan, Man Pun; Yang, En-Hua

2017-01-01

Highlights: • Cool colored coating and PCM are two complementary passive cooling strategies. • A PCM cool colored coating system is developed. • The coating reduces cooling energy by 8.5% and is effective yearly in tropical Singapore. - Abstract: Cool colored coating and phase change materials (PCM) are two passive cooling strategies often used separately in many studies and applications. This paper investigated the integration of cool colored coating and PCM for building cooling through experimental and numerical studies. Results showed that cool colored coating and PCM are two complementary passive cooling strategies that could be used concurrently in tropical climate where cool colored coating in the form of paint serves as the “first protection” to reflect solar radiation and a thin layer of PCM forms the “second protection” to absorb the conductive heat that cannot be handled by cool paint. Unlike other climate zones where PCM is only seasonally effective and cool paint is only beneficial during summer, the application of the proposed PCM cool colored coating in building envelope could be effective throughout the entire year with a monthly cooling energy saving ranging from 5 to 12% due to the uniform climatic condition all year round in tropical Singapore.

Experiments with a laser cooled cloud of atoms

International Nuclear Information System (INIS)

Natarajan, Vasant; Banerjee, Ayan; Rapol, Umakant

1999-01-01

We discuss two experiments that can be performed using a cloud of laser-cooled and trapped atoms, namely Bose-Einstein condensation (BEC) and search for a permanent Electric Dipole Moment (EDM). BEC can be observed in Rb atoms in a magnetic trap by using forced evaporative cooling to continuously lower the temperature below the condensation limit. The cloud is cooled by preferentially ejecting the hottest atoms from a magnetic trap. The magnetic trap is loaded with laser-cooled atoms from a magneto-optic trap. The EDM experiment can be performed with a laser-cooled cloud of Yb atoms. The atoms are spin polarized and the precession of the spin is measured in the presence of a strong electric field applied perpendicular to the spin direction. The use of laser-cooled atoms should greatly enhance the sensitivity of the experiment. (author)

Cooling compact stars and phase transitions in dense QCD

Energy Technology Data Exchange (ETDEWEB)

Sedrakian, Armen [J.W. Goethe University, Institute for Theoretical Physics, Frankfurt am Main (Germany)

2016-03-15

We report new simulations of cooling of compact stars containing quark cores and updated fits to the Cas A fast cooling data. Our model is built on the assumption that the transient behaviour of the star in Cas A is due to a phase transition within the dense QCD matter in the core of the star. Specifically, the fast cooling is attributed to an enhancement in the neutrino emission triggered by a transition from a fully gapped, two-flavor, red-green color-superconducting quark condensate to a superconducting crystalline or an alternative gapless, color-superconducting phase. The blue-colored condensate is modeled as a Bardeen-Cooper-Schrieffer (BCS)-type color superconductor with spin-one pairing order parameter. We study the sensitivity of the fits to the phase transition temperature, the pairing gap of blue quarks and the timescale characterizing the phase transition (the latter modelled in terms of a width parameter). Relative variations in these parameter around their best-fit values larger than 10{sup -3} spoil the fit to the data. We confirm the previous finding that the cooling curves show significant variations as a function of compact star mass, which allows one to account for dispersion in the data on the surface temperatures of thermally emitting neutron stars. (orig.)

Operation of a forced two phase cooling system on a large superconducting magnet

International Nuclear Information System (INIS)

Green, M.A.; Burns, W.A.; Eberhard, P.H.; Gibson, G.H.; Pripstein, M.; Ross, R.R.; Smits, R.G.; Taylor, J.D.; Van Slyke, H.

1980-05-01

This paper describes the operation of a forced two phase cooling system on a two meter diameter superconducting solenoid. The magnet is a thin high current density superconducting solenoid which is cooled by forced two phase helium in tubes around the coil. The magnet, which is 2.18 meters in diameter and 3.4 meters long, has a cold mass of 1700 kg. The two phase cooling system contains less than 300 liters of liquid helium, most of which is contained in a control dewar. This paper describes the operating characteristics of the LBL two phase forced cooling system during cooldown and warm up. The paper presents experimental data on operations of the magnet using either a helium pump or the refrigerator compressor to circulate two phase helium through the superconducting coil cooling tubes

Python bindings for C++ using PyROOT/cppyy: the experience from PyCool in COOL

CERN Multimedia

CERN. Geneva

2016-01-01

The COOL software is used by the ATLAS and LHCb experiments to handle the time variation and versioning of their conditions data, using a variety of different relational database technologies. While the COOL core libraries are written in C++ and are integrated in the experiment C++ frameworks, a package offering Python bindings of the COOL C++ APIs, PyCool, is also provided and has been an essential component of the ATLAS conditions data management toolkit for over 10 years. Almost since the beginning, the implementation of PyCool has been based on ROOT to generate Python bindings for C++, initially using Reflex and PyROOT in ROOT5 and more recently using clang and cppyy in ROOT6. This presentation will describe the PyCool experience with using ROOT to generate Python bindings for C++, throughout the many evolutions of the underlying technology.

Application of two-phase flow for cooling of hybrid microchannel PV cells: A comparative study

International Nuclear Information System (INIS)

Valeh-e-Sheyda, Peyvand; Rahimi, Masoud; Karimi, Ebrahim; Asadi, Masomeh

2013-01-01

Highlights: ► Showing cooling potential of gas–liquid two-phase flow in microchannels for PV cell. ► Introducing the concept of using slug flow in microchannels for cooling of PV cells. ► In single-phase flow, increasing the liquid flow rate enhances the PV power. ► Showing that in two-phase flow the output power related the fluid flow regime. ► By coupling PV and microchannel an increase up to 38% in output power was observed. - Abstract: This paper reports the experimental data from performance of two-phase flows in a small hybrid microchannel solar cell. Using air and water as two-phase fluid, the experiments were conducted at indoor condition in an array of rectangular microchannels with a hydraulic diameter of 0.667 mm. The gas superficial velocity ranges were between 0 and 3.27 m s −1 while liquid flow rate was 0.04 m s −1 . The performance analysis of the PV cell at slug and transitional slug/annular flow regimes are the focus of this study. The influence of two-phase working fluid on PV cell cooling was compared with single-phase. In addition, the great potential of slug flow for heat removal enhancement in PV/T panel was investigated. The obtained data showed the proposed hybrid system could substantially increases the output power of PV solar cells

Carbon-based nanostructured surfaces for enhanced phase-change cooling

Science.gov (United States)

Selvaraj Kousalya, Arun

. Nanostructured samples having a thicker copper coating provided a considerable increase in dryout heat flux while maintaining lower surface superheat temperatures compared to a bare sintered powder sample; this enhancement is attributed primarily to the improved surface wettability. Dynamic contact angle measurements are conducted to quantitatively compare the surface wetting trends for varying copper coating thicknesses and confirm the increase in hydrophilicity with increasing coating thickness. The second and relatively new carbon nanostructured coating, carbon nanotubes decorated with graphitic nanopetals, are used as a template to manufacture boiling surfaces with heterogeneous wettability. Heat transfer surfaces with parallel alternating superhydrophobic and superhydrophilic stripes are fabricated by a combination of oxygen plasma treatment, Teflon coating and shadow masking. Such composite wetting surfaces exhibit enhanced flow-boiling performance compared to homogeneous wetting surfaces. Flow visualization studies elucidate the physical differences in nucleate boiling mechanisms between the different heterogeneous wetting surfaces. The third and the final carbon nanomaterial, graphene, is examined as an oxidation barrier coating for liquid and liquid-vapor phase-change cooling systems. Forced convection heat transfer experiments on bare and graphene-coated copper surfaces reveal nearly identical liquid-phase and two-phase thermal performance for the two surfaces. Surface analysis after thermal testing indicates significant oxide formation on the entire surface of the bare copper substrate; however, oxidation is observed only along the grain boundaries of the graphene-coated substrate. Results suggest that few-layer graphene can act as a protective layer even under vigorous flow boiling conditions, indicating a broad application space of few-layer graphene as an ultra-thin oxidation barrier coating.

Longitudinal electron cooling experiments at HIRFL-CSRe

International Nuclear Information System (INIS)

Mao, L.J.; Zhao, H.; Yang, X.D.; Li, J.; Yang, J.C.; Yuan, Y.J.; Parkhomchuk, V.V.; Reva, V.B.; Ma, X.M.; Yan, T.L.; Tang, M.T.; Xia, J.W.

2016-01-01

At the heavy ion storage ring HIRFL-CSRe an electron cooler is operated to improve the beam conditions for experiments. The properties of cooled beams have been studied. The longitudinal beam dynamics during the cooling process was measured by a resonant Schottky detector. The dependencies of the parameters electron beam density and profile on cooling times were investigated. The friction force was measured directly with the aid of the high voltage system of the cooler and with the application of the beam bunching system as well. An experiment with bunched cold beam showed a dependence of the bunch length on the beam density.

Longitudinal electron cooling experiments at HIRFL-CSRe

Energy Technology Data Exchange (ETDEWEB)

Mao, L.J., E-mail: maolijun@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhao, H. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Yang, X.D.; Li, J.; Yang, J.C.; Yuan, Y.J. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Parkhomchuk, V.V.; Reva, V.B. [Budker Institute of Nuclear Physics, Novosibirsk 630090 (Russian Federation); Ma, X.M.; Yan, T.L. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Tang, M.T. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xia, J.W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2016-02-01

At the heavy ion storage ring HIRFL-CSRe an electron cooler is operated to improve the beam conditions for experiments. The properties of cooled beams have been studied. The longitudinal beam dynamics during the cooling process was measured by a resonant Schottky detector. The dependencies of the parameters electron beam density and profile on cooling times were investigated. The friction force was measured directly with the aid of the high voltage system of the cooler and with the application of the beam bunching system as well. An experiment with bunched cold beam showed a dependence of the bunch length on the beam density.

HANARO cooling features: design and experience

International Nuclear Information System (INIS)

Park, Cheol; Chae, Hee-Taek; Han, Gee-Yang; Jun, Byung-Jin; Ahn, Guk-Hoon

1999-01-01

In order to achieve the safe core cooling during normal operation and upset conditions, HANARO adopted an upward forced convection cooling system with dual containment arrangements instead of the forced downward flow system popularly used in the majority of forced convection cooling research reactors. This kind of upward flow system was selected by comparing the relative merits of upward and downward flow systems from various points of view such as safety, performance, maintenance. However, several operational matters which were not regarded as serious at design come out during operation. In this paper are presented the design and operational experiences on the unique cooling features of HANARO. (author)

Phases Evolution of an ASTM 335 steel under continuous cooling P91

International Nuclear Information System (INIS)

Carrizo, D.A; Danon, C.A; Ramos, C.P

2012-01-01

This paper studies the influence of the cooling rate on phase transformations and the resulting microstructure in continuous cooling cycles for an ASTM A335 P91 steel, under fixed austenization conditions. The CCT (Continuous Cooling Transformation) diagram of this material is reported in the literature, so the main phase fields are known. The final structure of the samples depends on the austenitic grain size and the cooling rate. The studied samples were austenized at 1050 o C for 30 minutes and then cooled at different rates between 50 o C/h and 300 o C/h. The identification and characterization of the phases was carried out by using Scanning Electron Microscopy, X-ray Diffraction and Moessbauer Spectroscopy. From the results so obtained, additions to the CCT diagram of the material are proposed, providing new information to it

Development of a single-phase thermosiphon for cold collection and storage of radiative cooling

Energy Technology Data Exchange (ETDEWEB)

Zhao, Dongliang; Martini, Christine Elizabeth; Jiang, Siyu; Ma, Yaoguang; Zhai, Yao; Tan, Gang; Yin, Xiaobo; Yang, Ronggui

2017-11-01

A single-phase thermosiphon is developed for cold collection and storage of radiative cooling. Compared to the conventional nocturnal radiative cooling systems that use an electric pump to drive the heat transfer fluid, the proposed single-phase thermosiphon uses the buoyancy force to drive heat transfer fluid. This solution does not require electricity, therefore improving the net gain of the radiative cooling system. A single-phase thermosiphon was built, which consists of a flat panel, a cold collection tank, a water return tube, and a water distribution tank. Considering that outdoor radiative cooling flux is constantly changing (i.e. uncontrollable), an indoor testing facility was developed to provide a controllable cooling flux (comparable to a radiative cooling flux of 100 W/m2) for the evaluation of thermosiphon performance. The testing apparatus is a chilled aluminum flat plate that has a controlled air gap separation relative to the flat panel surface of the thermosiphon to emulate radiative cooling. With an average of 105 W/m2 cooling flux, the 18 liters of water in the thermosiphon was cooled to an average temperature of 12.5 degrees C from an initial temperature of 22.2 degrees C in 2 h, with a cold collection efficiency of 96.8%. The results obtained have demonstrated the feasibility of using a single-phase thermosiphon for cold collection and storage of radiative cooling. Additionally, the effects of the thermosiphon operation conditions, such as tilt angle of the flat panel, initial water temperature, and cooling energy flux, on the performance have been experimentally investigated. Modular design of the single-phase thermosiphon gives flexibility for its scalability. A radiative cooling system with multiple thermosiphon modules is expected to play an important role in cooling buildings and power plant condensers.

The Muon Ionization Cooling Experiment User Software

Science.gov (United States)

Dobbs, A.; Rajaram, D.; MICE Collaboration

2017-10-01

The Muon Ionization Cooling Experiment (MICE) is a proof-of-principle experiment designed to demonstrate muon ionization cooling for the first time. MICE is currently on Step IV of its data taking programme, where transverse emittance reduction will be demonstrated. The MICE Analysis User Software (MAUS) is the reconstruction, simulation and analysis framework for the MICE experiment. MAUS is used for both offline data analysis and fast online data reconstruction and visualization to serve MICE data taking. This paper provides an introduction to MAUS, describing the central Python and C++ based framework, the data structure and and the code management and testing procedures.

The nature and dynamic of phase transitions during cooling - warming of garlic cell sap

Directory of Open Access Journals (Sweden)

А. Т. Ходько

2015-04-01

Full Text Available To identify the type of phase transition during cooling-warming in the garlic cell sap by cryomicroscopy of samples in transmitted light phenomenon of critical opalescence was recorded. Critical state is peculiar only for phase transitions between the isotropic mediums. This fact gives grounds to include phase transition in the investigated system to liquid-liquid type, which proceeds according to spinodal mechanism and nucleus growth mechanism. During rapid cooling cracking of the samples due to high internal stresses (in contrast to the slow cooling was observed. After the phase transition during cooling rouglydispersed system – highly concentrated emulsion-gel was formed. Signs of crystallization in the system under the studied conditions were not found.

Simulation of Two-Phase Natural Circulation Loop for Core Cather Cooling Using Air Water

International Nuclear Information System (INIS)

Revankar, S. T.; Huang, S. F.; Song, K. W.; Rhee, B. W.; Park, R. J.; Song, J. H.

2012-01-01

A closed loop natural circulation system employs thermally induced density gradients in single phase or two-phase liquid form to induce circulation of the working fluid thereby obviating the need for any mechanical moving parts such as pumps and pump controls. This increases the reliability and safety of the cooling system and reduces installation, operation and maintenance costs. That is the reason natural circulation cooling has been considered in advanced reactor core cooling and in engineered safety systems. Natural circulation cooling has been proposed to remove reactor decay heat by external vessel cooling for in-vessel core retention during sever accident scenario. Recently in APR1400 reactor core catcher design natural circulation cooling is proposed to stabilize and cool the corium ejected from the reactor vessel following core melt and breach of reactor vessel. The natural circulation flow is similar to external vessel cooling where water flows through an inclined narrow gap below hot surface and is heated to produce boiling. The two-phase natural circulation enables cooling of the corium pool collected on core catcher. Due to importance of this problem this paper focuses simulation of the two-phase natural circulation through inclined gap using air-water system. Scaling criteria for air-water loop are derived that enable simulation of the flow regimes and natural circulation flow rates in such systems using air-water system

Electron cooling experiments at the ESR

International Nuclear Information System (INIS)

Steck, M.; Beller, P.; Beckert, K.; Franzke, B.; Nolden, F.

2004-01-01

The properties of electron cooled beams of highly charged ions have been studied at the ESR. New experiments using a beam scraper to determine the transverse beam size provide the beam parameters in the intrabeam scattering dominated intensity regime, but also at very low intensity when the ion beam enters into an ultra-cold state. Extremely low values of longitudinal and transverse beam temperature on the order of meV were achieved for less than 1000 stored ions. An experiment with bunched ultra-cold beam showed a limit of the line density which agrees with the one observed for coasting beams. Cooling of decelerated ions at a minimum energy of 3 MeV/u has been demonstrated recently

Use of fluorocarbons in the cooling of LHC experiments

CERN Document Server

Pimenta dos Santos, M

2003-01-01

Perfluorochemicals sold by 3M under the trade name 3M Fluorinert Electronic Liquids have been used for many years as heat transfer media in a variety of industries. The suitability of these liquids for the cooling of LHC experiment originates from their high dielectric strength as well as from their chemical stability under ionizing radiation. The Fluorinerts are clear, colorless, non-flammable with low toxicity and low corrosiveness. Additionally, they offer low global waming potential – GWP – and zero ozone-depletion potential – ODP. Some examples of fluorinert application in the cooling of LHC experiments will be presented : (a) the ATLAS Inner detector C3F8 evaporative cooling system (b) the ATLAS TRF C6F14 monophase cooling system and (c) the ALICE SPD “active heat pipe” C4F10 evaporative cooling system. A brief comparison of evaporative and monophase cooling systems will be outlined.

Converging coolness and investigating its relation to user experience

DEFF Research Database (Denmark)

Raptis, Dimitrios; Bruun, Anders; Kjeldskov, Jesper

2017-01-01

Recently a number of studies appeared that operationalised coolness and explored its relation to digital products. Literature suggests that perceived coolness is another factor of user experience, and this adds to an existing explosion of dimensions related to aesthetics, hedonic quality, pragmatic...... quality, attractiveness, etc. A critical challenge highlighted in prior research is to study the relationships among those factors and so far, no studies have empirically examined the relationship between coolness and other established user experience factors. In this paper, we address this challenge...... cool and UX factors converge into 5 for the case of mobile devices. Our findings are important for researchers, as we demonstrate through a validated model that coolness is part of UX research, as well as for practitioners, by developing a questionnaire that can reliably measure both perceived inner...

Phase transformations at continuous cooling in VT6ch and VT23 alloys

International Nuclear Information System (INIS)

Lyasotskaya, V.S.; Lyasotskij, I.V.; Meshcheryakov, V.N.; Ravdonikas, N.Yu.; Nadtochij, S.I.; Faustov, N.N.

1986-01-01

Phase transformations at continuous cooling at β-region temperatures in VT6ch and VT23 alloys are studied. Nonequilibrium phases: α', α'', (ω), βsub(e), αsub(e), are shown to be formed in these alloys depending on cooling composition and rate. It is established that at cooling at temperatures below Ar 3 in alloys studied high-temperature α-phase is formed, and at temperatures below 650 deg C - more dispersed low-temperature α-phase precipitating from β-solution volumes mostly enriched by alloying elements according to the intermediate mechanism. Diagrams of anisothermal β-phase decomposition for VT6ch and VT23 alloys are plotted in coincidence with the results of thermal, thermodifferential, metallographic and X-ray diffraction analyses; lines of martensite transformation, lines of high- and low-temperature α-phase formation are pointed on the diagrams. Besides, for VT23 alloy a line for (ω)-phase formation is pointed

Liouville's theorem and phase-space cooling

International Nuclear Information System (INIS)

Mills, R.L.; Sessler, A.M.

1993-01-01

A discussion is presented of Liouville's theorem and its consequences for conservative dynamical systems. A formal proof of Liouville's theorem is given. The Boltzmann equation is derived, and the collisionless Boltzmann equation is shown to be rigorously true for a continuous medium. The Fokker-Planck equation is derived. Discussion is given as to when the various equations are applicable and, in particular, under what circumstances phase space cooling may occur

Dry cooling tower operating experience in the LOFT reactor

International Nuclear Information System (INIS)

Hunter, J.A.

1980-01-01

A dry cooling tower has been uniquely utilized to dissipate heat generated in a small experimental pressurized water nuclear reactor. Operational experience revealed that dry cooling towers can be intermittently operated with minimal wind susceptibility and water hammer occurrences by cooling potential steam sources after a reactor scram, by isolating idle tubes from the external atmosphere, and by operating at relatively high pressures. Operating experience has also revealed that tube freezing can be minimized by incorporating the proper heating and heat loss prevention features

γ-U phase in U-Pt system retained to low temperatures by means of rapid cooling

Energy Technology Data Exchange (ETDEWEB)

Kim-Ngan, N.-T.H., E-mail: tarnawsk@up.krakow.pl [Institute of Physics, Pedagogical University, Podchorazych 2, 30 084 Kraków (Poland); Paukov, M. [Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 12116 Prague (Czech Republic); Tarasenko, R. [Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 12116 Prague (Czech Republic); Institute of Physics, Faculty of Science, P.J. Šafárik University, Park Angelinum 9, 04154 Košice (Slovakia); Tkáč, V.; Minarik, P.; Drozdenko, D.; Havela, L. [Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 12116 Prague (Czech Republic)

2016-10-15

Splat-cooling technique with a cooling rate better than 10{sup 6} K/s helps to increase the Pt solubility in the (cubic) γ-U phase and retain such γ-U phase in U-15 at.% Pt splat down to low temperatures. The splat-cooled U-Pt alloys are very stable in exposing to air. The γ-U phase (U-15 at.% Pt splat) is characterized by a negative temperature coefficient of the resistivity (dρ/dT < 0). The splats become superconducting below 1.1 K. - Highlights: • γ-U phase stabilization in U-15 at.% Pt splat-cooled alloys. • Splat-cooling helps to increase the Pt solubility in cubic γ-U phase. • All U-Pt alloys (0–15 at.% Pt) become superconducting below 1.1 K.

Pressure Effects on Solid State Phase Transformation of Aluminium Bronze in Cooling Process

International Nuclear Information System (INIS)

Hai-Yan, Wang; Jian-Hua, Liu; Gui-Rong, Peng; Yan, Chen; Yu-Wen, Liu; Fei, Li; Wen-Kui, Wang

2009-01-01

Effects of high pressure (6 GPa) on the solid state phase transformation kinetic parameters of aluminum bronze during the cooling process are investigated, based on the measurement and calculation of its solid state phase transformation temperature, duration and activation energy and the observation of its microstructures. The results show that high pressure treatment can reduce the solid phase transformation temperature and activation energy in the cooling process and can shorten the phase transformation duration, which is favorable when forming fine-grained aluminum bronze

Analysis of SONACO axial cooling experiments

International Nuclear Information System (INIS)

Sigg, B.; Dury, T.V.; Hudina, M.

1994-01-01

The SONACO test rig contained a sodium-cooled, electrically heated 37-pin bundle. On this rig, a series of forced, mixed and natural convection experiments have been performed with the aim of contributing to the understanding of thermal-hydraulic phenomena and providing data for code validation for a subassembly at decay heat power level with low flow or stagnant coolant. The test section and especially the heater pins were equipped with an extensive number of chromel-alumel thermocouples. In addition, special permanent-magnet probes were used for measuring local velocities. In this paper we give a survey of results from axial cooling experiments, where heat was removed by natural convection to a cooling coil situated in the coolant channel (plenum) above the bundle. The experimental conditions led to turbulent convection with a slowly varying, large scale flow pattern. It is shown that a power tilt in the bundle reduces these fluctuations but does not eliminate them. For the uniformly heated bundle, aglebraic expressions for the average turbulent heat flux as well as for temperature and velocity fluctuations are derived from a second-moments model and compared with experimental data. Furthermore, heat transfer in the plenum and the consequences of the SONACO experiments for the coolability of reactor fuel elements under loss-of-flow conditions are discussed. ((orig.))

Optimum gain and phase for stochastic cooling systems

International Nuclear Information System (INIS)

Meer, S. van der.

1984-01-01

A detailed analysis of optimum gain and phase adjustment in stochastic cooling systems reveals that the result is strongly influenced by the beam feedback effect and that for optimum performance the system phase should change appreciably across each Schottky band. It is shown that the performance is not greatly diminished if a constant phase is adopted instead. On the other hand, the effect of mixing between pick-up and kicker (which produces a phase change similar to the optimum one) is shown to be less perturbing than is usually assumed, provided that the absolute value of the gain is not too far from the optimum value. (orig.)

Effect of Continuous Cooling on Secondary Phase Precipitation in the Super Duplex Stainless Steel ZERON-100

Science.gov (United States)

Calliari, Irene; Bassani, Paola; Brunelli, Katya; Breda, Marco; Ramous, Emilio

2013-12-01

The precipitation of secondary phases in super duplex stainless steels (SDSS) is a subject of great relevance owing to their dangerous effects on both mechanical and corrosion-resistance properties. This paper examines the effect of continuous cooling after solution annealing treatment on secondary phase precipitation in the ZERON-100 SDSS. It considers the influence of cooling rate on volume fraction, morphology and chemical composition. It has been found that the formation of sigma and chi phases can be avoided only at cooling rates higher than 0.7 °C/s. In addition, at the lowest cooling rate the sigma phase amount approaches the equilibrium value, but the chi phase amount remains significantly low.

A portable solar-powered air-cooling system based on phase-change materials for a vehicle cabin

International Nuclear Information System (INIS)

Qi, Lingfei; Pan, Hongye; Zhu, Xin; Zhang, Xingtian; Salman, Waleed; Zhang, Zutao; Li, Li; Zhu, Miankuan; Yuan, Yanping; Xiang, Bo

2017-01-01

Graphical abstract: This paper proposed a portable solar-powered air cooling system for a vehicle cabin based on Phase-change Materials. The cooling system contains three main parts: a solar-energy collection module, an energy-storage module and a phase-change cooling module. The operating principle can be described as follows. For energy input, the solar-energy-collection module harvests solar energy and converts it to electricity. The power-storage module stores the electrical energy in the supercapacitor to power the electrical equipment, mainly the air pump (AP) and water pump (WP) of the phase-change cooling module. Finally, the phase-change cooling module provides cold air for the vehicle cabin to create a comfortable vehicle interior in a hot summer. The proposed system is demonstrated through thermal simulations, which show the long-duration cooling effect of the system. Temperature drops of were obtained in field tests, predicting that the proposed cooling system is beneficial and practical for cooling vehicle cabins. - Highlights: • A novel portable air cooling system based on PCMs is presented. • Solar energy was adopted to power the proposed air cooling system. • This proposed system is used for cooling vehicle cabins exposed to the sun. • Experimental results show that the proposed system has a good cooling effect. - Abstract: In summer, the temperature is very high inside vehicles parked under the hot sun. This causes consuming more fossil energy to power the air conditioner and generation of harmful gases. There is currently no effective method to address this problem in an energy-saving and environmentally friendly manner. In this paper, a novel solar-powered air-cooling system for vehicle cabins is proposed based on Phase-change Materials (PCMs); the system prevents the temperature inside a vehicle cabin from rising too high when the vehicle is parked outdoor exposure to the sun. The proposed system consists of three main parts: a solar

Superconducting solenoids for an international muon cooling experiment

International Nuclear Information System (INIS)

Green, M.A.; Rey, J.M.

2002-01-01

The international muon ionization cooling experiment MICE will consist of two focusing cooling cells and a pair of uniform field solenoids used for particle identification and emittance measurements. The 2.75-meter long cooling cells have a pair of field flip coils and a coupling coil. The 0.52-meter diameter field flip coils surround an absorber that removes transverse and longitudinal momentum from the muons to be cooled. The beam in the absorber is at a minimum beta point so that scattering of the muons is minimized. The 1.7-meter diameter coupling coils are outside of conventional 201.25 MHz RF cavities that accelerate the muons putting longitudinal momentum into the muons without putting back the transverse momentum into the beam. A third set of flip coils helps the muon beam transition from and to the experimental solenoids. The 0.6-meter diameter experimental solenoids have a uniform field region (good to about 1 part in 1000) that is 1.3-meters long. The MICE experiment magnets must operate as a single unit so that the field profile will produce the maximum muon cooling

Two-phase flow experiments in emergency core cooling feed through the hot leg for developing numerical models

International Nuclear Information System (INIS)

Staebler, T.; Meyer, L.; Schulenberg, T.; Laurien, E.

2006-01-01

When a leakage, a 'loss-of-coolant accident', occurs in a light water reactor, the emergency cooling system is able to supply large amounts of coolant to ensure residual heat removal. This supply can be routed through a special emergency cooling pipe, the 'scoop', into the horizontal section of the main coolant pipe, the 'hot leg'. At the same time, hot steam from the superheated, partly voided core flows against the coolant. This gives rise to a two-phase flow in the opposite direction. A factor of primary interest in this situation is whether the coolant supplied by the emergency cooling system will reach the reactor core. The research project is being conducted in order to compute the rate of water supply by numerical methods. The WENKA test facility has been designed and built at the Karlsruhe Research Center to verify numerical calculations. It can be used to study the fluid dynamics phenomena expected to arise in emergency coolant feeding into the hot leg; the necessary local data can be determined experimentally. An extensive database for validating the numerical calculations is then available to complete the experimental work. (orig.)

ANL stochastic-cooling experiments using the FNAL 200-MeV cooling ring

International Nuclear Information System (INIS)

Hogrefe, R.L.; Kellogg, K.D.; Konecny, R.S.; Kramer, S.L.; Simpson, J.D.; Suddeth, D.E.; Hardek, T.W.

1981-01-01

Studies of stochastic momentum cooling are being conducted on the FNAL 200-MeV Storage Ring. The specific goal of the activity is to establish confidence in the theory and simulation methods used to describe the cooling process, and to develop techniques and devices suitable for use in the antiproton-accumulation scheme now planned for construction at FNAL. A summary of the activity, including hardware design, results of experiments, comparison with theory, and implications for the antiproton accumulator are presented

Phasing of Debuncher Stochastic Cooling Transverse Systems

International Nuclear Information System (INIS)

Pasquinelli, Ralph

2000-01-01

With the higher frequency of the cooling systems in the Debuncher, a modified method of making transfer functions has been developed for transverse systems. (Measuring of the momentum systems is unchanged.) Speed in making the measurements is critical, as the beam tends to decelerate due to vacuum lifetime. In the 4-8 GHz band, the harmonics in the Debuncher are 6,700 to 13,400 times the revolution frequency. Every Hertz change in revolution frequency is multiplied by this harmonic number and becomes a frequency measurement error, which is an appreciable percent of the momentum width of the beam. It was originally thought that a momentum cooling system would be phased first so that the beam could be kept from drifting in revolution frequency. As it turned out, the momentum cooling was so effective (even with the gain turned down) that the momentum width normalized to fo became less than one Hertz on the Schottky pickup. A beam this narrow requires very precise measurement of tune and revolution frequency. It was difficult to get repeatable results. For initial measuring of the transverse arrays, relative phase and delay is all that is required, so the measurement settings outlined below will suffice. Once all input and output arrays are phased, a more precise measurement of all pickups to all kickers can be done with more points and both upper and lower side bands, as in figure 1. Settings on the network analyzer were adjusted for maximum measurement speed. Data is not analyzed until a complete set of measurements is taken. Start and stop frequencies should be chosen to be just slightly wider than the band being measured. For transverse systems, select betatron USB for the measurement type. This will make the measurement two times faster. Select 101 for the number of points, sweep time of 5 seconds, IF bandwidth 30 Hz, averages = 1. It is important during the phasing to continually measure the revolution frequency and beam width of the beam for transverse systems

Next-Generation Factory-Produced Cool Asphalt Shingles: Phase 1 Final Report

Energy Technology Data Exchange (ETDEWEB)

Levinson, Ronnen M.; Chen, Sharon S.; Ban-Weiss, George A.; Gilbert, Haley E.; Berdahl, Paul H.; Rosado, Pablo J.; Destaillats, Hugo; Sleiman, Mohamad; Kirchstetter, Thomas W.

2016-11-01

As the least expensive category of high-slope roofing in the U.S., shingles are found on the roofs of about 80% of U.S. homes, and constitute about 80% (by product area) of this market. Shingles are also among the least reflective high-slope roofing products, with few cool options on the market. The widespread use of cool roofs in the two warmest U.S. climate zones could reduce annual residential cooling energy use in these zones by over 7%. This project targets the development of high-performance cool shingles with initial solar reflectance at least 0.40 and a cost premium not exceeding US$0.50/ft². Phase 1 of the current study explored three approaches to increasing shingle reflectance. Method A replaces dark bare granules by white bare granules to enhance the near-infrared reflectance attained with cool pigments. Method B applies a white basecoat and a cool-color topcoat to a shingle surfaced with dark bare granules. Method C applies a visually clear, NIR-reflecting surface treatment to a conventionally colored shingle. Method A was the most successful, but our investigation of Method B identified roller coating as a promising top-coating technique, and our study of Method C developed a novel approach based on a nanowire mesh. Method A yielded red, green, brown, and black faux shingles with solar reflectance up to 0.39 with volumetric coloration. Since the base material is white, these reflectances can readily be increased by using less pigment. The expected cost premium for Method A shingles is less than our target limit of $0.50/ft², and would represent less than a 10% increase in the installed cost of a shingle roof. Using inexpensive but cool (spectrally selective) iron oxide pigments to volumetrically color white limestone synthesized from sequestered carbon and seawater appears to offer high albedo at low cost. In Phase 2, we plan to refine the cool shingle prototypes, manufacture cool granules, and manufacture and market high-performance cool shingles.

Laser cooled ion beams and strongly coupled plasmas for precision experiments

International Nuclear Information System (INIS)

Bussmann, Michael

2008-01-01

This cumulative thesis summarizes experimental and theoretical results on cooling of ion beams using single-frequency, single-mode tabletop laser systems. It consists of two parts. One deals with experiments on laser-cooling of ion beams at relativistic energies, the other with simulations of stopping and sympathetic cooling of ions for precision in-trap experiments. In the first part, experimental results are presented on laser-cooling of relativistic C 3+ ion beams at a beam energy of 122 MeV/u, performed at the Experimental Storage Ring (ESR) at GSI. The main results presented in this thesis include the first attainment of longitudinally space-charge dominated relativistic ion beams using pure laser-cooling. The second part lists theoretical results on stopping and sympathetic cooling of ions in a laser-cooled one-component plasma of singly charged 24 Mg ions, which are confined in a three-dimensional harmonic trap potential. (orig.)

A water-cooling solution for PC-racks of the LHC experiments

CERN Document Server

Vannerem, P

2004-01-01

With ever increasing power consumption and heat dissipation of todays CPUs, cooling of rack-mounted PCs is an issue for the future online farms of the LHC experiments. In order to investigate the viability of a water-cooling solution, a prototype PC-farm rack has been equipped with a commercially available retrofitted heat exchanger. The project has been carried out as a collaboration of the four LHC experiments and the PH-ESS group . This note reports on the results of a series of cooling and power measurements of the prototype rack with configurations of 30 to 48 PCs. The cooling performance of the rack-cooler is found to be adequate; it extracts the heat dissipated by the CPUs efficiently into the cooling water. Hence, the closed PC rack transfers almost no heat into the room. The measurements and the failure tests show that the rack-cooler concept is a viable solution for the future PC farms of the LHC experiments.

Preliminary Study of Applying Phase Change Materials (PCM) for Containment Passive Cooling

International Nuclear Information System (INIS)

Ko, A Reum; Lee, Jeong Ik; Yoon, Ho Joon

2016-01-01

Most of Pressurized Water Reactor (PWR) containments use fan cooler systems and containment spray systems. However, the importance of passive safety system has increased after the Fukushima accident. As the main passive safety system, Passive Containment Cooling System (PCCS), which utilizes natural phenomena to remove the heat released from the reactor, is suggested in the advanced pressurized water reactor (APWR). To increase the efficiency of passive cooling, additional passive containment cooling method using Phase Change Material (PCM) is suggested in this paper. For containment using PCMs, there are many advantages. Phase Change Material (PCM) is proposed as an additional passive containment cooling method to increase the efficiency of passive cooling in this paper. To apply proper PCMs to containment, commercially available PCMs were screened while reviewing thermophysical properties data and suggested selection criteria. A sensitivity study was also carried out to identify the effect of potential installation location of PCM using the CAP code. The pressure of containment in most cases showed slightly higher than that of the initial case. For the temperature of steam and water and humidity, similar results with the initial case were showed in most cases

Preliminary Study of Applying Phase Change Materials (PCM) for Containment Passive Cooling

Energy Technology Data Exchange (ETDEWEB)

Ko, A Reum; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of); Yoon, Ho Joon [KUSTAR, Abu Dhabi (United Arab Emirates)

2016-05-15

Most of Pressurized Water Reactor (PWR) containments use fan cooler systems and containment spray systems. However, the importance of passive safety system has increased after the Fukushima accident. As the main passive safety system, Passive Containment Cooling System (PCCS), which utilizes natural phenomena to remove the heat released from the reactor, is suggested in the advanced pressurized water reactor (APWR). To increase the efficiency of passive cooling, additional passive containment cooling method using Phase Change Material (PCM) is suggested in this paper. For containment using PCMs, there are many advantages. Phase Change Material (PCM) is proposed as an additional passive containment cooling method to increase the efficiency of passive cooling in this paper. To apply proper PCMs to containment, commercially available PCMs were screened while reviewing thermophysical properties data and suggested selection criteria. A sensitivity study was also carried out to identify the effect of potential installation location of PCM using the CAP code. The pressure of containment in most cases showed slightly higher than that of the initial case. For the temperature of steam and water and humidity, similar results with the initial case were showed in most cases.

Laser cooled ion beams and strongly coupled plasmas for precision experiments

Energy Technology Data Exchange (ETDEWEB)

Bussmann, Michael

2008-03-17

This cumulative thesis summarizes experimental and theoretical results on cooling of ion beams using single-frequency, single-mode tabletop laser systems. It consists of two parts. One deals with experiments on laser-cooling of ion beams at relativistic energies, the other with simulations of stopping and sympathetic cooling of ions for precision in-trap experiments. In the first part, experimental results are presented on laser-cooling of relativistic C{sup 3+} ion beams at a beam energy of 122 MeV/u, performed at the Experimental Storage Ring (ESR) at GSI. The main results presented in this thesis include the first attainment of longitudinally space-charge dominated relativistic ion beams using pure laser-cooling. The second part lists theoretical results on stopping and sympathetic cooling of ions in a laser-cooled one-component plasma of singly charged {sup 24}Mg ions, which are confined in a three-dimensional harmonic trap potential. (orig.)

Detailed evaluation of two phase natural circulation flow in the cooling channel of the ex-vessel core catcher for EU-APR1400

Energy Technology Data Exchange (ETDEWEB)

Park, Rae-Joon, E-mail: rjpark@kaeri.re.kr; Ha, Kwang-Soon; Rhee, Bo-Wook; Kim, Hwan Yeol

2016-03-15

Highlights: • Ex-vessel core catcher of PECS is installed in EU-APR1400. • CE-PECS has been conducted to test a cooling capability of the PECS. • Two phase flow in CE-PECS and PECS was analyzed using RELAP5/MOD3. • RELAP5 results are very similar to the CE-PECS data. • The super-step design is suitable for steam injection into the downcomer in PECS. - Abstract: The ex-vessel core catcher of the PECS (Passive Ex-vessel corium retaining and Cooling System) is installed to retain and cool down the corium in the reactor cavity of the EU (European Union)-APR (Advanced Power Reactor) 1400. A verification experiment on the cooling capability of the PECS has been conducted in the CE (Cooling Experiment)-PECS. Simulations of a two-phase natural circulation flow using the RELAP5/MOD3 computer code in the CE-PECS and PECS have been conducted to predict the two-phase flow characteristics, to determine the natural circulation mass flow rate in the cooling channel, and to evaluate the scaling in the experimental design of the CE-PECS. Particularly from a comparative study of the prototype PECS and the scaled test facility of the CE-PECS, the orifice loss coefficient in the CE-PECS was found to be 6 to maintain the coolant circulation mass flux, which is approximately 273.1 kg/m{sup 2} s. The RELAP5 results on the coolant circulation mass flow rate are very similar to the CE-PECS experimental results. An increase in the coolant injection temperature and the heat flux lead to an increase in the coolant circulation mass flow rate. In the base case simulation, a lot of vapor was injected into the downcomer, which leads to an instability of the two-phase natural circulation flow. A super-step design at a downcomer inlet is suitable to prevent vapor injection into the downcomer piping.

Detailed evaluation of two phase natural circulation flow in the cooling channel of the ex-vessel core catcher for EU-APR1400

International Nuclear Information System (INIS)

Park, Rae-Joon; Ha, Kwang-Soon; Rhee, Bo-Wook; Kim, Hwan Yeol

2016-01-01

Highlights: • Ex-vessel core catcher of PECS is installed in EU-APR1400. • CE-PECS has been conducted to test a cooling capability of the PECS. • Two phase flow in CE-PECS and PECS was analyzed using RELAP5/MOD3. • RELAP5 results are very similar to the CE-PECS data. • The super-step design is suitable for steam injection into the downcomer in PECS. - Abstract: The ex-vessel core catcher of the PECS (Passive Ex-vessel corium retaining and Cooling System) is installed to retain and cool down the corium in the reactor cavity of the EU (European Union)-APR (Advanced Power Reactor) 1400. A verification experiment on the cooling capability of the PECS has been conducted in the CE (Cooling Experiment)-PECS. Simulations of a two-phase natural circulation flow using the RELAP5/MOD3 computer code in the CE-PECS and PECS have been conducted to predict the two-phase flow characteristics, to determine the natural circulation mass flow rate in the cooling channel, and to evaluate the scaling in the experimental design of the CE-PECS. Particularly from a comparative study of the prototype PECS and the scaled test facility of the CE-PECS, the orifice loss coefficient in the CE-PECS was found to be 6 to maintain the coolant circulation mass flux, which is approximately 273.1 kg/m"2 s. The RELAP5 results on the coolant circulation mass flow rate are very similar to the CE-PECS experimental results. An increase in the coolant injection temperature and the heat flux lead to an increase in the coolant circulation mass flow rate. In the base case simulation, a lot of vapor was injected into the downcomer, which leads to an instability of the two-phase natural circulation flow. A super-step design at a downcomer inlet is suitable to prevent vapor injection into the downcomer piping.

Single phase and two phase erosion corrosion in broilers of gas-cooled reactors

International Nuclear Information System (INIS)

Harrison, G.S.; Fountain, M.J.

1988-01-01

Erosion-corrosion is a phenomenon causing metal wastage in a variety of locations in water and water-steam circuits throughout the power generation industry. Erosion-corrosion can occur in a number of regions of the once-through boiler designs used in the later Magnox and AGR type of gas cooled nuclear reactor. This paper will consider two cases of erosion-corrosion damage (single and two phase) in once through boilers of gas cooled reactors and will describe the solutions that have been developed. The single phase problem is associated with erosion-corrosion damage of mild steel downstream of a boiler inlet flow control orifice. With metal loss rates of up to 1 mm/year at 150 deg. C and pH in the range 9.0-9.4 it was found that 5 μg/kg oxygen was sufficient to reduce erosion-corrosion rates to less than 0.02 mm/year. A combined oxygen-ammonia-hydrazine feedwater regime was developed and validated to eliminate oxygen carryover and hence give protection from stress corrosion in the austenitic section of the AGR once through boiler whilst still providing erosion-corrosion control. Two phase erosion-corrosion tube failures have occurred in the evaporator of the mild steel once through boilers of the later Magnox reactors operating at pressures in the range 35-40 bar. Rig studies have shown that amines dosed in the feedwater can provide a significant reduction in metal loss rates and a tube lifetime assessment technique has been developed to predict potential tube failure profiles in a fully operational boiler. The solutions identified for both problems have been successfully implemented and the experience obtained following implementation including any problems or other benefits arising from the introduction of the new regimes will be presented. Methods for monitoring and evaluating the efficiency of the solutions have been developed and the results from these exercises will also be discussed. Consideration will also be given to the similarities in the metal loss

Single phase and two phase erosion corrosion in broilers of gas-cooled reactors

Energy Technology Data Exchange (ETDEWEB)

Harrison, G S; Fountain, M J [Operational Engineering Division (Northern Area), Central Electricity Generating Board, Manchester (United Kingdom)

1988-07-01

Erosion-corrosion is a phenomenon causing metal wastage in a variety of locations in water and water-steam circuits throughout the power generation industry. Erosion-corrosion can occur in a number of regions of the once-through boiler designs used in the later Magnox and AGR type of gas cooled nuclear reactor. This paper will consider two cases of erosion-corrosion damage (single and two phase) in once through boilers of gas cooled reactors and will describe the solutions that have been developed. The single phase problem is associated with erosion-corrosion damage of mild steel downstream of a boiler inlet flow control orifice. With metal loss rates of up to 1 mm/year at 150 deg. C and pH in the range 9.0-9.4 it was found that 5 {mu}g/kg oxygen was sufficient to reduce erosion-corrosion rates to less than 0.02 mm/year. A combined oxygen-ammonia-hydrazine feedwater regime was developed and validated to eliminate oxygen carryover and hence give protection from stress corrosion in the austenitic section of the AGR once through boiler whilst still providing erosion-corrosion control. Two phase erosion-corrosion tube failures have occurred in the evaporator of the mild steel once through boilers of the later Magnox reactors operating at pressures in the range 35-40 bar. Rig studies have shown that amines dosed in the feedwater can provide a significant reduction in metal loss rates and a tube lifetime assessment technique has been developed to predict potential tube failure profiles in a fully operational boiler. The solutions identified for both problems have been successfully implemented and the experience obtained following implementation including any problems or other benefits arising from the introduction of the new regimes will be presented. Methods for monitoring and evaluating the efficiency of the solutions have been developed and the results from these exercises will also be discussed. Consideration will also be given to the similarities in the metal loss

Gas-cooled reactors

International Nuclear Information System (INIS)

Schulten, R.; Trauger, D.B.

1976-01-01

Experience to date with operation of high-temperature gas-cooled reactors has been quite favorable. Despite problems in completion of construction and startup, three high-temperature gas-cooled reactor (HTGR) units have operated well. The Windscale Advanced Gas-Cooled Reactor (AGR) in the United Kingdom has had an excellent operating history, and initial operation of commercial AGRs shows them to be satisfactory. The latter reactors provide direct experience in scale-up from the Windscale experiment to fullscale commercial units. The Colorado Fort St. Vrain 330-MWe prototype helium-cooled HTGR is now in the approach-to-power phase while the 300-MWe Pebble Bed THTR prototype in the Federal Republic of Germany is scheduled for completion of construction by late 1978. THTR will be the first nuclear power plant which uses a dry cooling tower. Fuel reprocessing and refabrication have been developed in the laboratory and are now entering a pilot-plant scale development. Several commercial HTGR power station orders were placed in the U.S. prior to 1975 with similar plans for stations in the FRG. However, the combined effects of inflation, reduced electric power demand, regulatory uncertainties, and pricing problems led to cancellation of the 12 reactors which were in various stages of planning, design, and licensing

Feasibility Study on Two-phase Thermosiphon for External Vessel Cooling Application of SFR

Energy Technology Data Exchange (ETDEWEB)

Choi, Jae Young; Song, Sub Lee; Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2014-05-15

This study shows that ex-vessel cooling by two-phase thermosiphon is feasible for large size of SFR. The result presents that further studies to increase heat transfer on condenser-air and gap is necessary and the experiment should be conducted for the validation. Also, the heat loss through evaporator during normal operation, corrosion, consideration of organic fluid to exclude the poison of mercury should be studied. As the necessity of sodium fast reactor in order to reduce spent fuel, the development of designing sodium fast reactor becomes an issue. Even though there is PDRC and RVACS for the decay heat removal (DHR) system, each system has disadvantage of sodium fire and low performance, respectively. Therefore, to increase the safety of SFR, the new passive safety system design is needed without sodium fire and high performance, which can applied for large SFR. The DHR system using two-phase thermosiphon for external vessel cooling application is suggested in this paper. The proposed design have advantage that there is no structure in reactor vessel, which means no system modification and no sodium fire with perfect isolation. Also, it provide the method to mitigate sodium fire in case of sodium leakage from reactor vessel.

Development of a prototype thermoelectric space cooling system using phase change material to improve the performance

Science.gov (United States)

Zhao, Dongliang

The thermoelectric cooling system has advantages over conventional vapor compression cooling devices, including compact in size, light in weight, high reliability, no mechanical moving parts, no refrigerant, being powered by direct current, and easily switching between cooling and heating modes. However, it has been long suffering from its relatively high cost and low energy efficiency, which has restricted its usage to niche applications, such as space missions, portable cooling devices, scientific and medical equipment, where coefficient of performance (COP) is not as important as reliability, energy availability, and quiet operation environment. Enhancement of thermoelectric cooling system performance generally relies on two methods: improving thermoelectric material efficiency and through thermoelectric cooling system thermal design. This research has been focused on the latter one. A prototype thermoelectric cooling system integrated with phase change material (PCM) thermal energy storage unit for space cooling has been developed. The PCM thermal storage unit used for cold storage at night, functions as the thermoelectric cooling system's heat sink during daytime's cooling period and provides relatively lower hot side temperature for the thermoelectric cooling system. The experimental test of the prototype system in a reduced-scale chamber has realized an average cooling COP of 0.87, with the maximum value of 1.22. Another comparison test for efficacy of PCM thermal storage unit shows that 35.3% electrical energy has been saved from using PCM for the thermoelectric cooling system. In general, PCM faces difficulty of poor thermal conductivity at both solid and liquid phases. This system implemented a finned inner tube to increase heat transfer during PCM charging (melting) process that directly impacts thermoelectric system's performance. A simulation tool for the entire system has been developed including mathematical models for a single thermoelectric module

Mixed convection in a two-phase flow cooling loop

International Nuclear Information System (INIS)

Janssens-Maenhout, G.; Daubner, M.; Knebel, J.U.

2002-03-01

This report summarizes the numerical simulations using the CFD code CFX4.1 which has additional models for subcooled flow boiling phenomena and the interfacial forces. The improved CFX4.1 code can be applied to the design of boiling induced mixed convection cooling loops in a defined parameter range. The experimental part describes the geysering experiments and the instability effects on the two-phase natural circulation flow. An experimentally validated flow pattern map in the Phase Change Number - Subcooling Number (N PCh - N Sub ) diagram defines the operational range in which flow instabilities such as geysering can be expected. One important perspective of this combined experimental/numerical work, which is in the field of two-phase flow, is its application to the development of accelerator driven systems (ADS). The main objective on an ADS is its potential to transmute minor actinides and long-lived fission products, thus participating in closing the fuel cycle. The development of an ADS is an important issue within the Euratom Fifth FP on Partitioning and Transmutation. One concept of an ADS, which is investigated in more detail within the ''preliminary design study of an experimental ADS'' Project (PDS-XADS) of the Euratom Fifth FP, is the XADS lead-bismuth cooled Experimental ADS of ANSALDO. An essential feature of this concept is the natural circulation of the primary coolant within the reactor pool. The natural circulation, which is driven by the density differences between the blanket and the heat exchanger, is enhanced by the injection of the nitrogen cover gas through spargers located in a riser part just above the blanket. This so-called gas-lift pump system has not been investigated in more detail nor has this gas-lift pump system been numerically/experimentally confirmed. The knowledge gained within the SUCO Programe, i.e. the modelling of the interfacial forces, the experimental work on flow instabilities and the modelling of the interfacial area

Mixed convection in a two-phase flow cooling loop

Energy Technology Data Exchange (ETDEWEB)

Janssens-Maenhout, G.; Daubner, M.; Knebel, J.U.

2002-03-01

This report summarizes the numerical simulations using the CFD code CFX4.1 which has additional models for subcooled flow boiling phenomena and the interfacial forces. The improved CFX4.1 code can be applied to the design of boiling induced mixed convection cooling loops in a defined parameter range. The experimental part describes the geysering experiments and the instability effects on the two-phase natural circulation flow. An experimentally validated flow pattern map in the Phase Change Number - Subcooling Number (N{sub PCh} - N{sub Sub}) diagram defines the operational range in which flow instabilities such as geysering can be expected. One important perspective of this combined experimental/numerical work, which is in the field of two-phase flow, is its application to the development of accelerator driven systems (ADS). The main objective on an ADS is its potential to transmute minor actinides and long-lived fission products, thus participating in closing the fuel cycle. The development of an ADS is an important issue within the Euratom Fifth FP on Partitioning and Transmutation. One concept of an ADS, which is investigated in more detail within the ''preliminary design study of an experimental ADS'' Project (PDS-XADS) of the Euratom Fifth FP, is the XADS lead-bismuth cooled Experimental ADS of ANSALDO. An essential feature of this concept is the natural circulation of the primary coolant within the reactor pool. The natural circulation, which is driven by the density differences between the blanket and the heat exchanger, is enhanced by the injection of the nitrogen cover gas through spargers located in a riser part just above the blanket. This so-called gas-lift pump system has not been investigated in more detail nor has this gas-lift pump system been numerically/experimentally confirmed. The knowledge gained within the SUCO Programe, i.e. the modelling of the interfacial forces, the experimental work on flow instabilities and the

Heat transfer characteristics of coconut oil as phase change material to room cooling application

Science.gov (United States)

Irsyad, M.; Harmen

2017-03-01

Thermal comfort in a room is one of human needs in the workplace and dwellings, so that the use of air conditioning system in tropical countries is inevitable. This equipment has an impact on the increase of energy consumption. One method of minimizing the energy use is by using the phase change material (PCM) as thermal energy storage. This material utilizes the temperature difference between day and night for the storage and release of thermal energy. PCM development on application as a material for air cooling inlet, partitioning and interior needs to be supported by the study of heat transfer characteristics when PCM absorbs heat from ambient temperature. This study was conducted to determine the heat transfer characteristics on coconut oil as a phase change material. There are three models of experiments performed in this research. Firstly, an experiment was conducted to analyze the time that was needed by material to phase change by varying the temperature. The second experiment analyzed the heat transfer characteristics of air to PCM naturally convection. The third experiment analyzed the forced convection heat transfer on the surface of the PCM container by varying the air velocity. The data of experimental showed that, increasing ambient air temperature resulted in shorter time for phase change. At temperatures of 30°C, the time for phase change of PCM with the thickness of 8 cm was 1700 min, and it was stable at temperatures of 27°C. Increasing air temperature accelerated the phase change in the material. While for the forced convection heat transfer, PCM could reduce the air temperature in the range of 30 to 35°C at about 1 to 2°C, with a velocity of 1-3 m/s.

Stochastic cooling

International Nuclear Information System (INIS)

Bisognano, J.; Leemann, C.

1982-03-01

Stochastic cooling is the damping of betatron oscillations and momentum spread of a particle beam by a feedback system. In its simplest form, a pickup electrode detects the transverse positions or momenta of particles in a storage ring, and the signal produced is amplified and applied downstream to a kicker. The time delay of the cable and electronics is designed to match the transit time of particles along the arc of the storage ring between the pickup and kicker so that an individual particle receives the amplified version of the signal it produced at the pick-up. If there were only a single particle in the ring, it is obvious that betatron oscillations and momentum offset could be damped. However, in addition to its own signal, a particle receives signals from other beam particles. In the limit of an infinite number of particles, no damping could be achieved; we have Liouville's theorem with constant density of the phase space fluid. For a finite, albeit large number of particles, there remains a residue of the single particle damping which is of practical use in accumulating low phase space density beams of particles such as antiprotons. It was the realization of this fact that led to the invention of stochastic cooling by S. van der Meer in 1968. Since its conception, stochastic cooling has been the subject of much theoretical and experimental work. The earliest experiments were performed at the ISR in 1974, with the subsequent ICE studies firmly establishing the stochastic cooling technique. This work directly led to the design and construction of the Antiproton Accumulator at CERN and the beginnings of p anti p colliding beam physics at the SPS. Experiments in stochastic cooling have been performed at Fermilab in collaboration with LBL, and a design is currently under development for a anti p accumulator for the Tevatron

Modeling and Control of a Single-Phase Marine Cooling System

DEFF Research Database (Denmark)

Hansen, Michael; Stoustrup, Jakob; Bendtsen, Jan Dimon

2013-01-01

This paper presents two model-based control design approaches for a single-phase marine cooling system. Models are derived from first principles and aim at describing significant system dynamics including nonlinearities and transport delays, while keeping the model complexity low. The two...

The MICE Muon Beam on ISIS and the beam-line instrumentation of the Muon Ionization Cooling Experiment

CERN Document Server

Bogomilov, M.; Kolev, D.; Russinov, I.; Tsenov, R.; Vankova-Kirilova, G.; Wang, L.; Xu, F.Y.; Zheng, S.X.; Bertoni, R.; Bonesini, M.; Ferri, F.; Lucchini, G.; Mazza, R.; Paleari, F.; Strati, F.; Palladino, V.; Cecchet, G.; de Bari, A.; Capponi, M.; Cirillo, A.; Iaciofano, A.; Manfredini, A.; Parisi, M.; Orestano, D.; Pastore, F.; Tonazzo, A.; Tortora, L.; Mori, Y.; Kuno, Y.; Sakamoto, H.; Sato, A.; Yano, T.; Yoshida, M.; Ishimoto, S.; Suzuki, S.; Yoshimura, K.; Filthaut, F.; Garoby, R.; Gilardoni, S.; Gruber, P.; Hanke, K.; Haseroth, H.; Janot, P.; Lombardi, A.; Ramberger, S.; Vretenar, M.; Bene, P.; Blondel, A.; Cadoux, F.; Graulich, J.S.; Grichine, V.; Gschwendtner, E.; Masciocchi, F.; Sandstrom, R.; Verguilov, V.; Wisting, H.; Petitjean, C.; Seviour, R.; Alexander, J.; Charnley, G.; Collomb, N.; Griffiths, S.; Martlew, B.; Moss, A.; Mullacrane, I.; Oates, A.; Owens, P.; White, C.; York, S.; Adams, D.; Apsimon, R.; Barclay, P.; Baynham, D.E.; Bradshaw, T.W.; Courthold, M.; Drumm, P.; Edgecock, R.; Hayler, T.; Hills, M.; Ivaniouchenkov, Y.; Jones, A.; Lintern, A.; MacWaters, C.; Nelson, C.; Nichols, A.; Preece, R.; Ricciardi, S.; Rochford, J.H.; Rogers, C.; Spensley, W.; Tarrant, J.; Tilley, K.; Watson, S.; Wilson, A.; Forrest, D.; Soler, F.J.P.; Walaron, K.; Cooke, P.; Gamet, R.; Alekou, A.; Apollonio, M.; Barber, G.; Clark, D.; Clark, I.; Dobbs, A.; Dornan, P.; Fish, A.; Hare, R.; Greenwood, S.; Jamdagni, A.; Kasey, V.; Khaleeq, M.; Leaver, J.; Long, K.; McKigney, E.; Matsushita, T.; Pasternak, J.; Sashalmi, T.; Savidge, T.; Takahashi, M.; Blackmore, V.; Carlisle, T.; Cobb, J.H.; Lau, W.; Rayner, M.; Tunnell, C.D.; Witte, H.; Yang, S.; Booth, C.N.; Hodgson, P.; Howlett, L.; Nicholson, R.; Overton, E.; Robinson, M.; Smith, P.; Adey, D.; Back, J.; Boyd, S.; Harrison, P.; Ellis, M.; Kyberd, P.; Littlefield, M.; Nebrensky, J.J.; Bross, A.D.; Geer, S.; Neuffer, D.; Moretti, A.; Popovic, M.; Cummings, M.A.C.; Roberts, T.J.; DeMello, A.; Green, M.A.; Li, D.; Virostek, S.; Zisman, M.S.; Freemire, B.; Hanlet, P.; Huang, D.; Kafka, G.; Kaplan, D.M.; Snopok, P.; Torun, Y.; Blot, S.; Kim, Y.K.; Bravar, U.; Onel, Y.; Cline, D.; Fukui, Y.; Lee, K.; Yang, X.; Rimmer, R.A.; Cremaldi, L.M.; Gregoire, G.; Hart, T.L.; Sanders, D.A.; Summers, D.J.; Coney, L.; Fletcher, R.; Hanson, G.G.; Heidt, C.; Gallardo, J.; Kahn, S.; Kirk, H.; Palmer, R.B.

2012-01-01

The international Muon Ionization Cooling Experiment (MICE), which is under construction at the Rutherford Appleton Laboratory (RAL), will demonstrate the principle of ionization cooling as a technique for the reduction of the phase-space volume occupied by a muon beam. Ionization cooling channels are required for the Neutrino Factory and the Muon Collider. MICE will evaluate in detail the performance of a single lattice cell of the Feasibility Study 2 cooling channel. The MICE Muon Beam has been constructed at the ISIS synchrotron at RAL, and in MICE Step I, it has been characterized using the MICE beam-instrumentation system. In this paper, the MICE Muon Beam and beam-line instrumentation are described. The muon rate is presented as a function of the beam loss generated by the MICE target dipping into the ISIS proton beam. For a 1 V signal from the ISIS beam-loss monitors downstream of our target we obtain a 30 KHz muon rate, with a neglible pion contamination in the beam.

The MICE Muon Beam on ISIS and the beam-line instrumentation of the Muon Ionization Cooling Experiment

Energy Technology Data Exchange (ETDEWEB)

Bogomilov, M. [University of Sofia (Bulgaria); et al.

2012-05-01

The international Muon Ionization Cooling Experiment (MICE), which is under construction at the Rutherford Appleton Laboratory (RAL), will demonstrate the principle of ionization cooling as a technique for the reduction of the phase-space volume occupied by a muon beam. Ionization cooling channels are required for the Neutrino Factory and the Muon Collider. MICE will evaluate in detail the performance of a single lattice cell of the Feasibility Study 2 cooling channel. The MICE Muon Beam has been constructed at the ISIS synchrotron at RAL, and in MICE Step I, it has been characterized using the MICE beam-instrumentation system. In this paper, the MICE Muon Beam and beam-line instrumentation are described. The muon rate is presented as a function of the beam loss generated by the MICE target dipping into the ISIS proton beam. For a 1 V signal from the ISIS beam-loss monitors downstream of our target we obtain a 30 KHz instantaneous muon rate, with a neglible pion contamination in the beam.

Numerical investigation on critical heat flux and coolant volume required for transpiration cooling with phase change

International Nuclear Information System (INIS)

He, Fei; Wang, Jianhua

2014-01-01

Highlights: • Five states during the transpiration cooling are discussed. • A suit of applicable program is developed. • The variations of the thickness of two-phase region and the pressure are analyzed. • The relationship between heat flux and coolant mass flow rate is presented. • An approach is given to define the desired case of transpiration cooling. - Abstract: The mechanism of transpiration cooling with liquid phase change is numerically investigated to protect the thermal structure exposed to extremely high heat flux. According to the results of theoretical analysis, there is a lower critical and an upper critical external heat flux corresponding a certain coolant mass flow rate, between the two critical values, the phase change of liquid coolant occurs within porous structure. A strongly applicable self-edit program is developed to solve the states of fluid flow and heat transfer probably occurring during the phase change procedure. The distributions of temperature and saturation in these states are presented. The variations of the thickness of two-phase region and the pressure including capillary are analyzed, and capillary pressure is found to be the main factor causing pressure change. From the relationships between the external heat flux and coolant mass flow rate obtained at different cooling cases, an approach is given to estimate the maximal heat flux afforded and the minimal coolant consumption required by the desired case of transpiration cooling. Thus the pressure and coolant consumption required in a certain thermal circumstance can be determined, which are important in the practical application of transpiration cooling

COOL, LCG Conditions Database for the LHC Experiments Development and Deployment Status

CERN Document Server

Valassi, A; Clemencic, M; Pucciani, G; Schmidt, S A; Wache, M; CERN. Geneva. IT Department, DM

2009-01-01

The COOL project provides common software components and tools for the handling of the conditions data of the LHC experiments. It is part of the LCG Persistency Framework (PF), a broader project set up within the context of the LCG Application Area (AA) to devise common persistency solutions for the LHC experiments. COOL software development is the result of the collaboration between the CERN IT Department and ATLAS and LHCb, the two experiments that have chosen it as the basis of their conditions database infrastructure. COOL supports conditions data persistency using several relational technologies (Oracle, MySQL, SQLite and FroNTier), based on the CORAL Common Relational Abstraction Layer. For both experiments, Oracle is the backend used for the deployment of COOL database services at Tier0 and Tier1 sites of the LHC Computing Grid. While the development of new software functionalities is being frozen as LHC operations are ramping up, the main focus for the project in 2008 has shifted to performance optimi...

Status of the international Muon ionization cooling experiment

International Nuclear Information System (INIS)

Palladino, V.; Bonesini, M.

2009-01-01

Muon ionization cooling provides the only practical solution to prepare high brilliance beams necessary for a neutrino factory or muon colliders. The muon ionization cooling experiment (MICE) is under development at the Rutherford Appleton Laboratory (UK). It comprises a dedicated beam line to generate a range of input emittance and momentum, with time-of-flight and Cherenkov detectors to ensure a pure muon beam. A first measurement of emittance is performed in the upstream magnetic spectrometer with a scintillating fiber tracker. A cooling cell will then follow, alternating energy loss in liquid hydrogen and RF acceleration. A second spectrometer identical to the first one and a particle identification system provide a measurement of the outgoing emittance. By July 2009 it is expected that the beam and first set of detectors will have been commissioned and a first measurement of input beam emittance may be reported. Along with the steps in the measurement of emittance reduction (cooling) that will follow later and in 2010. (authors)

Performance comparison between ethanol phase-change immersion and active water cooling for solar cells in high concentrating photovoltaic system

International Nuclear Information System (INIS)

Wang, Yiping; Wen, Chen; Huang, Qunwu; Kang, Xue; Chen, Miao; Wang, Huilin

2017-01-01

Highlights: • Thermal performances of ethanol phase-change immersion and active water cooling are compared. • Effects of operation parameters on ethanol phase-change immersion are studied. • Optimum filling ratio is 30% for ethanol phase-change immersion cooling system. • Exergy efficiency of ethanol phase-change immersion method increases by 57%. - Abstract: This paper presents an optimized ethanol phase-change immersion cooling method to obtain lower temperature of dense-array solar cells in high concentrating photovoltaic system. The thermal performances of this system were compared with a conventional active water cooling system with minichannels from the perspectives of start-up characteristic, temperature uniformity, thermal resistance and heat transfer coefficient. This paper also explored the influences of liquid filling ratio, absolute pressure and water flow rate on thermal performances. Dense-array LEDs were used to simulate heat power of solar cells worked under high concentration ratios. It can be observed that the optimal filling ratio was 30% in which the thermal resistance was 0.479 °C/W and the heat transfer coefficient was 9726.21 W/(m 2 ·°C). To quantify the quality of energy output of two cooling systems, exergy analysis are conducted and maximum exergy efficiencies were 17.70% and 11.27%, respectively. The experimental results represent an improvement towards thermal performances of ethanol phase-change immersion cooling system due to the reduction in contact thermal resistance. This study improves the operation control and applications for ethanol phase-change immersion cooling technology.

Assessment of the MARS Code Using the Two-Phase Natural Circulation Experiments at a Core Catcher Test Facility

Directory of Open Access Journals (Sweden)

Dong Hun Lee

2017-01-01

Full Text Available A core catcher has been developed to maintain the integrity of nuclear reactor containment from molten corium during a severe accident. It uses a two-phase natural circulation for cooling molten corium. Flow in a typical core catcher is unique because (i it has an inclined cooling channel with downwards-facing heating surface, of which flow processes are not fully exploited, (ii it is usually exposed to a low-pressure condition, where phase change causes dramatic changes in the flow, and (iii the effects of a multidimensional flow are very large in the upper part of the core catcher. These features make computational analysis more difficult. In this study, the MARS code is assessed using the two-phase natural circulation experiments that had been conducted at the CE-PECS facility to verify the cooling performance of a core catcher. The code is a system-scale thermal-hydraulic (TH code and has a multidimensional TH component. The facility was modeled by using both one- and three-dimensional components. Six experiments at the facility were selected to investigate the parametric effects of heat flux, pressure, and form loss. The results show that MARS can predict the two-phase flow at the facility reasonably well. However, some limitations are obviously revealed.

A phase quantification method based on EBSD data for a continuously cooled microalloyed steel

Energy Technology Data Exchange (ETDEWEB)

Zhao, H.; Wynne, B.P.; Palmiere, E.J., E-mail: e.j.palmiere@sheffield.ac.uk

2017-01-15

Mechanical properties of steels depend on the phase constitutions of the final microstructures which can be related to the processing parameters. Therefore, accurate quantification of different phases is necessary to investigate the relationships between processing parameters, final microstructures and mechanical properties. Point counting on micrographs observed by optical or scanning electron microscopy is widely used as a phase quantification method, and different phases are discriminated according to their morphological characteristics. However, it is difficult to differentiate some of the phase constituents with similar morphology. Differently, for EBSD based phase quantification methods, besides morphological characteristics, other parameters derived from the orientation information can also be used for discrimination. In this research, a phase quantification method based on EBSD data in the unit of grains was proposed to identify and quantify the complex phase constitutions of a microalloyed steel subjected to accelerated coolings. Characteristics of polygonal ferrite/quasi-polygonal ferrite, acicular ferrite and bainitic ferrite on grain averaged misorientation angles, aspect ratios, high angle grain boundary fractions and grain sizes were analysed and used to develop the identification criteria for each phase. Comparing the results obtained by this EBSD based method and point counting, it was found that this EBSD based method can provide accurate and reliable phase quantification results for microstructures with relatively slow cooling rates. - Highlights: •A phase quantification method based on EBSD data in the unit of grains was proposed. •The critical grain area above which GAM angles are valid parameters was obtained. •Grain size and grain boundary misorientation were used to identify acicular ferrite. •High cooling rates deteriorate the accuracy of this EBSD based method.

Experimental study of in-and-ex-vessel melt cooling during a severe accident

Energy Technology Data Exchange (ETDEWEB)

Kim, Sang Baik; Yoo, K J; Park, C K; Seok, S D; Park, R J; Yi, S J; Kang, K H; Ham, Y S; Cho, Y R; Kim, J H; Jeong, J H; Shin, K Y; Cho, J S; Kim, D H

1997-07-01

After code damage during a severe accident in a nuclear reactor, the degraded core has to be cooled down and the decay heat should be removed in order to cease the accident progression and maintain a stable state. The cooling of core melt is divided into in-vessel and ex-vessel cooling depending on the location of molten core which is dependent on the timing of vessel failure. Since the cooling mechanism varies with the conditions of molten core and surroundings and related phenomena, it contains many phenomenological uncertainties so far. In this study, an experimental study for verification of in-vessel corium cooling and several separate effect experiments for ex-vessel cooling are carried out to verify in- and ex-vessel cooling phenomena and finally to develop the accident management strategy and improve engineered reactor design for the severe accidents. SONATA-IV (Simulation of Naturally Arrested Thermal Attack in Vessel) program is set up for in-vessel cooling and a progression of the verification experiment has been done, and an integral verification experiment of the containment integrity for ex-vessel cooling is planned to be carried out based on the separate effect experiments performed in the first phase. First phase study of SONATA-IV is proof of principle experiment and it is composed of LALA (Lower-plenum Arrested Vessel Attack) experiment to find the gap between melt and the lower plenum during melt relocation and to certify melt quenching and CHFG (Critical Heat Flux in Gap) experiment to certify heat transfer mechanism in an artificial gap. As separate effect experiments for ex-vessel cooling, high pressure melt ejection experiment related to the initial condition for debris layer formation in the reactor cavity, crust formation and heat transfer experiment in the molten pool and molten core concrete interaction experiment are performed. (author). 150 refs., 24 tabs., 127 figs.

Dynamics of RF captured cooled proton beams

International Nuclear Information System (INIS)

Kells, W.; Mills, F.

1983-01-01

In the course of electron cooling experiments at the Electron Cooling Ring (ECR) at Fermilab, several peculiar features of the longitudinal phase space of cold protons (200 MeV) captured in RF buckets were observed. Here we present the experimental facts, present a simple theory, and summarize computer simulation results which support the theory and facts

Experimental and numerical simulation of passive decay heat removal by sump cooling after cool melt down

International Nuclear Information System (INIS)

Knebel, J.U.; Kuhn, D.; Mueller, U.

1997-01-01

This article presents the basic physical phenomena and scaling criteria of passive decay heat removal from a large coolant pool by single-phase and two-phase natural circulation. The physical significance of the dimensionless similarity groups derived is evaluated. The above results are applied to the SUCO program that is performed at the Forschungszentrum Karlsruhe. The SUCO program is a three-step series of scaled model experiments investigating the possibility of a sump cooling concept for future light water reactors. The sump cooling concept is based on passive safety features within the containment. The work is supported by the German utilities and the Siemens AG. The article gives results of temperature and velocity measurements in the 1:20 linearly scaled SUCOS-2D test facility. The experiments are backed up by numerical calculations using the commercial software package Fluent. Finally, using the similarity analysis from above, the experimental results of the model geometry are scaled-up to the conditions in the prototype, allowing a first statement with regard to the feasibility of the sump cooling concept. 11 refs., 9 figs., 3 tabs

Experiments on aerosol-induced cooling in the nocturnal boundary layer

Science.gov (United States)

Sreenivas, K.; Singh, D. K.; Vk, P.; Mukund, V.; Subramanian, G.

2012-12-01

In the nocturnal boundary layer (NBL), under calm & clear-sky conditions, radiation is the principal mode of heat transfer & it determines the temperature distribution close to the ground. Radiative processes thus influence the surface energy budget, & play a decisive role in many micro-meteorological processes including the formation of radiation-fog & inversion layer. Here, we report hyper-cooling of air layers close to the ground that has a radiative origin. Resulting vertical temperature distribution has an anomalous profile with an elevated minimum few decimetres above the ground (known as Lifted Temperature Minimum; LTM). Even though the first observation of this type of profile dates back to 1930s, its origin has not been explained till recently. We report field experiments to elucidate effects of emissivity and other physical properties of the ground on the LTM profile. Field observations clearly indicate that LTM-profiles are observed as a rule in the lowest meter of the NBL. We also demonstrate that the air-layer near the ground, rather than the ground itself, leads the post sunset cooling. This fact changes the very nature of the sensible heat-flux boundary condition. A laboratory experimental setup has been developed that can reproduce LTM. Lab-experiments demonstrate that the high cooling rates observed in the field experiments arise from the presence of aerosols & the intensity of cooling is proportional to aerosol concentration (Fig-1). We have also captured penetrative convection cells in the field experiments (Fig-2). Results presented here thus help in parameterizing transport processes in the NBL.

Experimental facility with two-phase flow and with high concentration of non-condensable gases for research and development of emergency cooling system of advanced nuclear reactors

International Nuclear Information System (INIS)

Macedo, Luiz Alberto; Baptista Filho, Benedito Dias

2006-01-01

The development of emergency cooling passive systems of advanced nuclear reactors requires the research of some relative processes to natural circulation, in two-phase flow conditions involving condensation processes in the presence of non-condensable gases. This work describes the main characteristics of the experimental facility called Bancada de Circulacao Natural (BCN), designed for natural circulation experiments in a system with a hot source, electric heater, a cold source, heat exchanger, operating with two-phase flow and with high concentration of noncondensable gas, air. The operational tests, the data acquisition system and the first experimental results in natural circulation are presented. The experiments are transitory in natural circulation considering power steps. The distribution of temperatures and the behavior of the flow and of the pressure are analyzed. The experimental facility, the instrumentation and the data acquisition system demonstrated to be adapted for the purposes of research of emergency cooling passive systems, operating with two-phase flow and with high concentration of noncondensable gases. (author)

Solar heating and cooling of mobile homes, Phase II. Final report

Energy Technology Data Exchange (ETDEWEB)

Jacobsen, A.A.

1976-12-01

The specific objectives of the Phase II program were: (1) through system testing, confirm the feasibility of a solar heated and cooled mobile home; (2) update system performance analysis and provide solar heating and cooling computer model verification; (3) evaluate the performance of both an absorption and a Rankine air conditioning system; (4) perform a consumer demand analysis through field survey to ascertain the acceptance of solar energy into the mobile home market; and (5) while at field locations to conduct the consumer demand analysis, gather test data from various U.S. climatic zones. Results are presented and discussed. (WHK)

Safety Research Experiment Facility Project. Conceptual design report. Volume VII. Reactor cooling

International Nuclear Information System (INIS)

1975-12-01

The Reactor Cooling System (RCS) will provide the required cooling during test operations of the Safety Research Experiment Facility (SAREF) reactor. The RCS transfers the reactor energy generated in the core to a closed-loop water storage system located completely inside the reactor containment building. After the reactor core has cooled to a safe level, the stored heat is rejected through intermediate heat exchangers to a common forced-draft evaporative cooling tower. The RCS is comprised of three independent cooling loops of which any two can remove sufficient heat from the core to prevent structural damage to the system components

Melt cooling by bottom flooding: The experiment CometPC-H3. Ex-vessel core melt stabilization research

International Nuclear Information System (INIS)

Alsmeyer, H.; Cron, T.; Merkel, G.; Schmidt-Stiefel, S.; Tromm, W.; Wenz, T.

2003-03-01

The CometPC-H3 experiment was performed to investigate melt cooling by water addition to the bottom of the melt. The experiment was performed with a melt mass of 800 kg, 50% metal and 50% oxide, and 300 kW typical decay heat were simulated in the melt. As this was the first experiment after repair of the induction coil, attention was given to avoid overload of the induction coil and to keep the inductor voltage below critical values. Therefore, the height of the sacrificial concrete layer was reduced to 5 cm only, and the height of the porous concrete layers was also minimized to have a small distance and good coupling between heated melt and induction coil. After quite homogeneous erosion of the upper sacrificial concrete layer, passive bottom flooding started from the porous concrete after 220 s with 1.3 liter water/s. The melt was safely stopped, arrested and cooled. The porous, water filled concrete was only slightly attacked by the hot melt in the upper 25 mm of one sector of the coolant device. The peak cooling rate in the early contact phase of coolant water and melt was 4 MW/m 2 , and exceeded the decay heat by one order of magnitude. The cooling rate remarkably dropped, when the melt was covered by the penetrating water and a surface crust was formed. Volcanic eruptions from the melt during the solidification process were observed from 360 - 510 s and created a volcanic dome some 25 cm high, but had only minor effect on the generation of a porous structure, as the expelled melt solidified mostly with low porosity. Unfortunately, decay heat simulation in the melt was interrupted at 720 s by an incorrect safety signal, which excluded further investigation of the long term cooling processes. At that time, the melt was massively flooded by a layer of water, about 80 cm thick, and coolant water inflow was still 1 l/s. The melt had reached a stable situation: Downward erosion was stopped by the cooling process from the water filled, porous concrete layer. Top

On analog simulation of ionization cooling of muons

International Nuclear Information System (INIS)

Xie, Ming

2001-01-01

Analog simulation, proposed here as an alternative approach for the study of ionization cooling of muons, is a scaled cooling experiment, using protons instead of muons as simulation particles. It is intended to be an effective and flexible, quick and inexpensive experiment for the understanding and validation of unprecedentedly complicated cooling physics, for the demonstration and optimization of various elaborated techniques for beam manipulation in 6D phase space. It can be done and perhaps should be done before the costly and time-consuming development of extremely challenging, muon-specific cooling technology. In a nutshell, the idea here is to build a toy machine in a playground of ideas, before staking the Imperial Guard of Napoleon into the bloody battlefield of Waterloo

Experimental Studies of NGNP Reactor Cavity Cooling System With Water

Energy Technology Data Exchange (ETDEWEB)

Corradini, Michael; Anderson, Mark; Hassan, Yassin; Tokuhiro, Akira

2013-01-16

This project will investigate the flow behavior that can occur in the reactor cavity cooling system (RCCS) with water coolant under the passive cooling-mode of operation. The team will conduct separate-effects tests and develop associated scaling analyses, and provide system-level phenomenological and computational models that describe key flow phenomena during RCCS operation, from forced to natural circulation, single-phase flow and two-phase flow and flashing. The project consists of the following tasks: Task 1. Conduct separate-effects, single-phase flow experiments and develop scaling analyses for comparison to system-level computational modeling for the RCCS standpipe design. A transition from forced to natural convection cooling occurs in the standpipe under accident conditions. These tests will measure global flow behavior and local flow velocities, as well as develop instrumentation for use in larger scale tests, thereby providing proper flow distribution among standpipes for decay heat removal. Task 2. Conduct separate-effects experiments for the RCCS standpipe design as two-phase flashing occurs and flow develops. As natural circulation cooling continues without an ultimate heat sink, water within the system will heat to temperatures approaching saturation , at which point two-phase flashing and flow will begin. The focus is to develop a phenomenological model from these tests that will describe the flashing and flow stability phenomena. In addition, one could determine the efficiency of phase separation in the RCCS storage tank as the two-phase flashing phenomena ensues and the storage tank vents the steam produced. Task 3. Develop a system-level computational model that will describe the overall RCCS behavior as it transitions from forced flow to natural circulation and eventual two-phase flow in the passive cooling-mode of operation. This modeling can then be used to test the phenomenological models developed as a function of scale.

Water Cooling for the Frontend Electronics and a modular Phase Separator for the COMPASS Silicon Detectors and Alignment for the 2012 Primakoff Run

CERN Document Server

Holzgartner, Bernd

The COMPASS experiment at CERN uses sili- con microstrip detectors for beam definition and vertex reconstruction. Since 2009, the detectors are operated at cryogenic temperatures to min- imize radiation damage. This thesis describes the development of a new, modular phase sep- arator for the liquid nitrogen cooling system of the detector modules as well as the construction and the commissioning of a water cooling sys- tem for the frontend electronics of these detec- tors. In addition, results of the alignment stud- ies for the 2012 Primakoff run are presented.

Boiling induced mixed convection in cooling loops

International Nuclear Information System (INIS)

Knebel, J.U.; Janssens-Maenhout, G.; Mueller, U.

2000-01-01

This article describes the SUCO program performed at the Forschungszentrum Karlsruhe. The SUCO program is a three-step series of scaled model experiments investigating the possibility of a sump cooling concept for future light water reactors. In case of a core melt accident, the sump cooling concept realises a decay heat removal system that is based on passive safety features within the containment. The article gives, first, results of the experiments in the 1:20 linearly scaled SUCOS-2D test facility. The experimental results are scaled-up to the conditions in the prototype, allowing a statement with regard to the feasibility of the sump cooling concept. Second, the real height SUCOT test facility with a volume and power scale of 1:356 that is aimed at investigating the mixed single-phase and two-phase natural circulation flow in the reactor sump, together with first measurement results, are discussed. Finally, a numerical approach to model the subcooled nucleate boiling phenomena in the test facility SUCOT is presented. Physical models describing interfacial mass, momentum and-heat transfer are developed and implemented in the commercial software package CFX4.1. The models are validated for an isothermal air-water bubbly flow experiment and a subcooled boiling experiment in vertical annular water flow. (author)

Night time cooling by ventilation or night sky radiation combined with in-room radiant cooling panels including phase change materials

DEFF Research Database (Denmark)

Bourdakis, Eleftherios; Olesen, Bjarne W.; Grossule, Fabio

Night sky radiative cooling technology using PhotoVoltaic/Thermal panels (PVT) and night time ventilation have been studied both by means of simulations and experiments to evaluate their potential and to validate the created simulation model used to describe it. An experimental setup has been...... depending on the sky clearness. This cooling power was enough to remove the stored heat and regenerate the ceiling panels. The validation simulation model results related to PCM were close to the corresponding results extracted from the experiment, while the results related to the production of cold water...... through the night sky radiative cooling differed significantly. The possibility of night time ventilation was studied through simulations for three different latitudes. It was concluded that for Danish climatic conditions night time ventilation would also be able to regenerate the panels while its...

Activation calculations for dismantling - The feedback of a 7 years experience in activation calculations for graphite gas cooled reactors in France

International Nuclear Information System (INIS)

Eid, M.; Nimal, J.C.; Gerat, L.M.

1994-01-01

This is a revision of the past seven years experience in activation calculations for dismantling. It aims at evaluating the experience and at making better understanding to help in decision making during the following phases. Five gas cooled reactors are shutdown and are waiting for the EDF (Electricite De France) dismantling decision. The sixth (BUGEY1) will be shutdown by 1994 and will be waiting a dismantling decision as well. (authors). 3 figs., 3 tabs

Towards a Symmetric Momentum Distribution in the Muon Ionisation Cooling Experiment

CERN Document Server

Hansen, O M; Efthymiopoulos, I

2013-01-01

TheMuon Ionisation Cooling Experiment (MICE) is under development at Rutherford Appleton Labratory (UK). It is a proof-of-principle experiment for ionisation cooling, which is a prerequisite for a future Neutrino Factory (NF) or a Muon Collider. The muon beam will have a symmetrical momentum distribution in the cooling channel of theNF [1]. In the MICE beamline pions are captured by a quadrupole triplet, beam momentum is selected by dipole 1 (D1) before the beam traverses the decay solenoid. After the decay solenoid the beam momentum is selected by dipole 2 (D2), the beam is focused in two quadrupole triplets and characterised by time-of-flight (TOF) detectors TOF0 and TOF1 before entering the cooling channel. By doing a so-called D1-scan, where the optics parameters are scaled according to the upstream beam momentum, the purity and momentum distribution of the decay muons are changed. In this paper simulation results from G4Beamline (G4BL) [2] and data from MICE are presented and compared.

Personal cooling with phase change materials to improve thermal comfort from a heat wave perspective.

Science.gov (United States)

Gao, C; Kuklane, K; Wang, F; Holmér, I

2012-12-01

The impact of heat waves arising from climate change on human health is predicted to be profound. It is important to be prepared with various preventive measures for such impacts on society. The objective of this study was to investigate whether personal cooling with phase change materials (PCM) could improve thermal comfort in simulated office work at 34°C. Cooling vests with PCM were measured on a thermal manikin before studies on human subjects. Eight male subjects participated in the study in a climatic chamber (T(a) = 34°C, RH = 60%, and ν(a) = 0.4 m/s). Results showed that the cooling effect on the manikin torso was 29.1 W/m(2) in the isothermal condition. The results on the manikin using a constant heating power mode reflect directly the local cooling effect on subjects. The results on the subjects showed that the torso skin temperature decreased by about 2-3°C and remained at 33.3°C. Both whole body and torso thermal sensations were improved. The findings indicate that the personal cooling with PCM can be used as an option to improve thermal comfort for office workers without air conditioning and may be used for vulnerable groups, such as elderly people, when confronted with heat waves. Wearable personal cooling integrated with phase change materials has the advantage of cooling human body's micro-environment in contrast to stationary personalized cooling and entire room or building cooling, thus providing greater mobility and helping to save energy. In places where air conditioning is not usually used, this personal cooling method can be used as a preventive measure when confronted with heat waves for office workers, vulnerable populations such as the elderly and disabled people, people with chronic diseases, and for use at home. © 2012 John Wiley & Sons A/S.

Possible demonstration of ionization cooling using absorbers in a solenoidal field

International Nuclear Information System (INIS)

Fernow, R.C.; Gallardo, J.C.; Kirk, H.G.

1995-12-01

Ionization cooling may play an important role in reducing the phase space volume of muons for a future muon-muon collider. We describe a possible experiment to demonstrate transverse emittance cooling using a muon beam at the AGS at Brookhaven National Laboratory. The experiment uses device dimensions and parameters and beam conditions similar to what is expected in an actual muon-muon collider

On the suitability of Peltier cooled Si-PIN detectors in transmission experiments

International Nuclear Information System (INIS)

Murty, V.R.K.; Devan, K.R.S.

2001-01-01

The performance of a Peltier cooled Si-PIN detector is compared with that for a Freolectric cooled Si(Li) detector, references being made to transmission experiments that evaluate total cross sections at low photon energies. The results of these measurements are discussed. (author)

Using multi-shell phase change materials layers for cooling a lithium-ion battery

Directory of Open Access Journals (Sweden)

Nasehi Ramin

2016-01-01

Full Text Available One of the cooling methods in engineering systems is usage of phase change materials. Phase change materials or PCMs, which have high latent heats, are usually used where high energy absorption in a constant temperature is required. This work presents a numerical analysis of PCMs effects on cooling Li-ion batteries and their decrease in temperature levels during intense discharge. In this study, three PCM shells with different thermo-physical specifications located around a battery pack is examined. The results of each possible arrangement are compared together and the best arrangement leading to the lowest battery temperature during discharge is identified. In addition, the recovery time for the system which is the time required for the PCMs to refreeze is investigated.

Experimental investigation of a two-phase closed thermosyphon assembly for passive containment cooling system

Energy Technology Data Exchange (ETDEWEB)

Nam, Kyung Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Sang Nyung [Kyunghee Univ., Gyeonggi-do (Korea, Republic of)

2017-06-15

After the Fukushima accident, increasing interest has been raised in passive safety systems that maintain the integrity of the containment building. To improve the reliability and safety of nuclear power plants, long-term passive cooling concepts have been developed for advanced reactors. In a previous study, the proposed design was based on an ordinary cylindrical Two-Phase Closed Thermosyphon (TPCT). The exact assembly size and number of TPCTs should be elaborated upon through accurate calculations based on experiments. While the ultimate goal is to propose an effective MPHP design for the PCCS and experimentally verify its performance, a TPCT assembly that was manufactured based on the conceptual design in this paper was tested.

Summary and implications of out-of-pile investigations of local cooling disturbances in LMFBR subassembly geometry under single-phase and boiling conditions

International Nuclear Information System (INIS)

Huber, F.; Peppler, W.

1985-05-01

The consequences of local cooling disturbances in subassemblies of LMFBRs have been investigated out-of-pile at KfK. Flow and temperature distributions in the disturbed region as well as cooling under boiling conditions up to loss of cooling were investigated. Fission gas release was simulated by gas injection. A total of 16 different blockages in 20 test set-ups were used, four of them under sodium and the rest under water conditions. Mainly planar plates of different sizes and arrangements were used as blockages. In some of the experiments performed in water also porous blockages were investigated. The test sections consisted of electrically heated pin bundles with a thermal-hydraulic characteristic corresponding to that of an SNR 300 subassembly. With different parameter settings the single-phase tests in water furnished a multitude of test results on flow and temperature fields and on the behaviour of gas in the recirculation zone. In the experiments involving boiling two boiling patterns were observed: steady-state boiling and oscillating boiling. With increasing boiling intensity the boiling region grew to some extent, but it remained always confined to the blocked zone because of the relatively cold sodium flow around this zone. In the experiments simulating fission gas release it was found that under certain conditions gas accumulates in the reverse flow region behind a blockage and leads to loss of cooling. (orig./GL) [de

Cooling tower plume - model and experiment

Science.gov (United States)

Cizek, Jan; Gemperle, Jiri; Strob, Miroslav; Nozicka, Jiri

The paper discusses the description of the simple model of the, so-called, steam plume, which in many cases forms during the operation of the evaporative cooling systems of the power plants, or large technological units. The model is based on semi-empirical equations that describe the behaviour of a mixture of two gases in case of the free jet stream. In the conclusion of the paper, a simple experiment is presented through which the results of the designed model shall be validated in the subsequent period.

Laser-Cooled Ions and Atoms in a Storage Ring

International Nuclear Information System (INIS)

Kleinert, J.; Hannemann, S.; Eike, B.; Eisenbarth, U.; Grieser, M.; Grimm, R.; Gwinner, G.; Karpuk, S.; Saathoff, G.; Schramm, U.; Schwalm, D.; Weidemueller, M.

2003-01-01

We review recent experiments at the Heidelberg Test Storage Ring which apply advanced laser cooling techniques to stored ion beams. Very high phase-space densities are achieved by three-dimensional laser cooling of a coasting 9 Be + beam at 7.3 MeV. Laser-cooled, trapped Cs atoms are used as an ultracold precision target for the study of ion-atom interactions with a 74 MeV beam of 12 C 6+ ions.

French gas cooled reactor experience with moisture ingress

International Nuclear Information System (INIS)

Bastien, D.; Brie, M.

1995-01-01

During the history of operation of six gas cooled reactors in France, some experience has been gained with accidental water ingress into the primary system. This occurred as a result of leaks in steam generators. This paper describes the cause of the leaks, and the resulting consequences. (author). 2 refs, 8 figs

Liquid cooling applications on automotive exterior LED lighting

Science.gov (United States)

Aktaş, Mehmet; Şenyüz, Tunç; Şenyıldız, Teoman; Kılıç, Muhsin

2018-02-01

In this study cooling of a LED unit with heatsink and liquid cooling block which is used in automotive head lamp applications has been investigated numerically and experimentally. Junction temperature of a LED which is cooled with heatsink and liquid cooling block obtained in the experiment. 23°C is used both in the simulation and the experiment phase. Liquid cooling block material is choosed aluminium (Al) and polyamide. All tests and simulation are performed with three different flow rate. Temperature distribution of the designed product is investigated by doing the numerical simulations with a commercially software. In the simulations, fluid flow is assumed to be steady, incompressible and laminar and 3 dimensional (3D) Navier-Stokes equations are used. According to the calculations it is obtained that junction temperature is higher in the heatsink design compared to block cooled one. By changing the block material, it is desired to investigate the variation on the LED junction temperature. It is found that more efficient cooling can be obtained in block cooling by using less volume and weight. With block cooling lifetime of LED can be increased and flux loss can be decreased with the result of decreased junction temperature.

Stochastic cooling in muon colliders

International Nuclear Information System (INIS)

Barletta, W.A.; Sessler, A.M.

1993-09-01

Analysis of muon production techniques for high energy colliders indicates the need for rapid and effective beam cooling in order that one achieve luminosities > 10 30 cm -2 s -1 as required for high energy physics experiments. This paper considers stochastic cooling to increase the phase space density of the muons in the collider. Even at muon energies greater than 100 GeV, the number of muons per bunch must be limited to ∼10 3 for the cooling rate to be less than the muon lifetime. With such a small number of muons per bunch, the final beam emittance implied by the luminosity requirement is well below the thermodynamic limit for beam electronics at practical temperatures. Rapid bunch stacking after the cooling process can raise the number of muons per bunch to a level consistent with both the luminosity goals and with practical temperatures for the stochastic cooling electronics. A major advantage of our stochastic cooling/stacking scheme over scenarios that employ only ionization cooling is that the power on the production target can be reduced below 1 MW

Experimental Studies of Phase Change and Microencapsulated Phase Change Materials in a Cold Storage/Transportation System with Solar Driven Cooling Cycle

Directory of Open Access Journals (Sweden)

Lin Zheng

2017-11-01

Full Text Available The paper presents the different properties of phase change material (PCM and Microencapsulated phase change material (MEPCM employed to cold storage/transportation system with a solar-driven cooling cycle. Differential Scanning Calorimeter (DSC tests have been performed to analyze the materials enthalpy, melting temperature range, and temperature range of solidification. KD2 Pro is used to test the thermal conductivities of phase change materials slurry and the results were used to compare the materials heat transfer performance. The slurry flow characteristics of MEPCM slurry also have been tested. Furthermore, in order to analyze the improvement effect on stability, the stability of MEPCM slurry with different surfactants have been tested. The researches of the PCM and MEPCM thermal properties revealed a more prospective application for phase change materials in energy storage/transportation systems. The study aims to find the most suitable chilling medium to further optimize the design of the cold storage/transportation systems with solar driven cooling cycles.

Measurement of spectral phase noise in a cryogenically cooled Ti:Sa amplifier (Conference Presentation)

Science.gov (United States)

Nagymihaly, Roland S.; Jójárt, Péter; Börzsönyi, Ádám.; Osvay, Károly

2017-05-01

In most of cases the drift of the carrier envelope phase (CEP) of a chirped pulse amplifier (CPA) system is determined only [1], being the relevant parameter at laser-matter interactions. The need of coherent combination of multiple amplifier channels to further increase the peak power of pulses requires interferometric precision [2]. For this purpose, the stability of the group delay of the pulses may become equally important. Further development of amplifier systems requires the investigation of phase noise contributions of individual subsystems, like amplifier stages. Spectrally resolved interferometry (SRI), which is a completely linear optical method, makes the measurement of spectral phase noise possible of basically any part of a laser system [3]. By utilizing this method, the CEP stability of water-cooled Ti:Sa based amplifiers was investigated just recently, where the effects of seed and pump energy, repetition rate, and the cooling crystal mounts were thoroughly measured [4]. We present a systematic investigation on the noise of the spectral phase, including CEP, of laser pulses amplified in a cryogenically-cooled Ti:Sa amplifier of a CPA chain. The double-pass amplifier was built in the sample arm of a compact Michelson interferometer. The Ti:Sa crystal was cooled below 30 °K. The inherent phase noise was measured for different operation modes, as at various repetition rates, and pump depletion. Noise contributions of the vacuum pumps and the cryogenic refrigerator were found to be 43 and 47 mrad, respectively. We have also identified CEP noise having thermal as well as mechanical origin. Both showed a monotonically decreasing tendency towards higher repetition rates. We found that the widths of the noise distributions are getting broader towards lower repetition rates. Spectral phase noise with and without amplification was measured, and we found no significant difference in the phase noise distributions. The mechanical vibration was also measured in

Cooling tower plume - model and experiment

Directory of Open Access Journals (Sweden)

Cizek Jan

2017-01-01

Full Text Available The paper discusses the description of the simple model of the, so-called, steam plume, which in many cases forms during the operation of the evaporative cooling systems of the power plants, or large technological units. The model is based on semi-empirical equations that describe the behaviour of a mixture of two gases in case of the free jet stream. In the conclusion of the paper, a simple experiment is presented through which the results of the designed model shall be validated in the subsequent period.

Numerical analysis of experiments modeling LWR sump cooling by natural convection

International Nuclear Information System (INIS)

2002-01-01

An optional sump cooling concept for the European pressurized water reactor EPR was investigated at the Research Center Karlsruhe. This concept foresees to utilize single phase natural convection in water to remove the decay heat from the core melt. The natural convection was investigated by the SUCOS-2D and -3D scaled experiments. A numerical investigation and interpretation of these experiments was performed by means of the computer code FLUTAN. In this paper, the numerical investigation of SUCOS-3D is summarized. Following the results of the former 2d experiments and the numerical analysis of both experiments, an unexpected temperature distribution is found in this 3d experiment. Basing on the experimental data it had to be postulated that one of the horizontal coolers was slightly tilled against the main flow direction. Additional numerical investigations show that a slope of only one percent would explain the experimental flow field. Conclusions are also drawn on the limits of scalability and transferability of the experimental results to a reactor sump. A detailed transformation will only be possible by applying well validated CFD-codes and experienced code users. As the flow in the reactor sump will be turbulent and this flow is strongly three-dimensional and time-dependent, only the method of Large Eddy Simulation is considered of being an adequate tool for reliable trans formation of the gained experience to analyses for the reactor sump at 1:1 scales. (author)

Facility for electron cooling experiments

International Nuclear Information System (INIS)

Budker, G.I.; Dikanskij, N.S.; Kudelajnen, V.I.

1982-01-01

The NAP-M proton storage ring intended for electron cooling experiments is described. The NAP-M magnetic system comprises four bending magnets and eight correction elements. located at the ends of rectilinear gaps. An electron beam facility is located in one of the rectilinear gaps. An 1.5 MeV electrostatic accelerator is used as a proton injector. The NAP-M accelerating system includes a driving generator, a power amplifier and a resonator. The proton beam lifetime (at the RF-system switched-off) up to 7 s has been obtained at the NAP-N at the injection energy, and up to 600 s at 65 MeV and the proton current of 120 μA

Laser-Cooled Ions and Atoms in a Storage Ring

Energy Technology Data Exchange (ETDEWEB)

Kleinert, J.; Hannemann, S.; Eike, B.; Eisenbarth, U.; Grieser, M.; Grimm, R.; Gwinner, G.; Karpuk, S.; Saathoff, G.; Schramm, U.; Schwalm, D.; Weidemueller, M., E-mail: m.weidemueller@mpi-hd.mpg.de [Max-Planck-Insitut fuer Kernphysik (Germany)

2003-03-15

We review recent experiments at the Heidelberg Test Storage Ring which apply advanced laser cooling techniques to stored ion beams. Very high phase-space densities are achieved by three-dimensional laser cooling of a coasting {sup 9}Be{sup +} beam at 7.3 MeV. Laser-cooled, trapped Cs atoms are used as an ultracold precision target for the study of ion-atom interactions with a 74 MeV beam of {sup 12}C{sup 6+} ions.

Coupled Analysis of Change in Fracture Permeability during the Cooling Phase of the Yucca Mountain Drift Scale Test

International Nuclear Information System (INIS)

Rutqvist, Jonny; Rutqvist, J.; Freifeld, B.; Tsang, Y.W.; Min, K.B.; Elsworth, D.

2008-01-01

This paper presents results from a coupled thermal, hydrological and mechanical analysis of thermally-induced permeability changes during heating and cooling of fractured volcanic rock at the Drift Scale Test at Yucca Mountain, Nevada. The analysis extends the previous analysis of the four-year heating phase to include newly available data from the subsequent four year cooling phase. The new analysis of the cooling phase shows that the measured changes in fracture permeability follows that of a thermo-hydro-elastic model on average, but at several locations the measured permeability indicates (inelastic) irreversible behavior. At the end of the cooling phase, the air-permeability had decreased at some locations (to as low as 0.2 of initial), whereas it had increased at other locations (to as high as 1.8 of initial). Our analysis shows that such irreversible changes in fracture permeability are consistent with either inelastic fracture shear dilation (where permeability increased) or inelastic fracture surface asperity shortening (where permeability decreased). These data are important for bounding model predictions of potential thermally-induced changes in rock-mass permeability at a future repository at Yucca Mountain

Ferrite morphology and residual phases in continuously cooled low carbon steels

International Nuclear Information System (INIS)

Dunne, D.P.

1999-01-01

Although much research has been conducted on the isothermal transformation products of medium to high carbon hardenable steels, relatively little has been reported for transformation of low carbon structural steels under continuous cooling conditions. The trend towards reduced carbon levels (less than about 0.1 wt% C) has been driven by demands for formability and weldability, challenging steel designers to maintain strength by microalloying and/or thermomechanical controlled processing. Although control of the ferritic products formed in low carbon steels after hot rolling, normalising and welding is essential in order to ensure adequate strength and toughness, understanding of the microstructures formed on continuous cooling is still limited. In addition, transformation mechanisms remain controversial because of polarisation of researchers into groups championing diffusional and displacive theories for the transformation of austenite over a wide range of cooling rates. The present review compares and draws together the main ferrite classification schemes, and discusses some critical issues on kinetics and mechanisms, in an attempt to rationalise the effects of cooling rate, prior austenite structure and composition on the resulting ferrite structure and its mechanical properties. It is concluded that with increasing cooling rate the ferritic product becomes finer, more plate-like, more dislocated, more carbon supersaturated, more likely to be formed by a displacive mechanism, harder and stronger. Other conclusions are that: (i) 'bainitic ferrite', which is a pervasive form of ferrite in continuously cooled low carbon steels, is different from the conventional upper and lower bainites observed in higher carbon steels, insofar as the co-product 'phase' is typically martensite-austenite islands rather than cementite; and (ii) low carbon bainite rather than martensite is the dominant product at typical fast cooling rates (<500K/s) associated with commercial

Daytime space cooling with phase change material ceiling panels discharged using rooftop photovoltaic/thermal panels and night-time ventilation

DEFF Research Database (Denmark)

Bourdakis, Eleftherios; Pean, Thibault Quentin; Gennari, Luca

2016-01-01

The possibility of using photovoltaic/thermal panels for producing cold water through the process of night-time radiative cooling was experimentally examined. The cold water was used to discharge phase change material in ceiling panels in a climatic chamber. Both night-time radiative cooling...... the photovoltaic/thermal varied from 56% to 122%. The phase change material ceiling panels were thus, capable of providing an acceptable thermal environment and the photovoltaic/thermal panels were able to provide most of the required electricity and cold water needed for cooling....

Constructal tree-shaped two-phase flow for cooling a surface

Energy Technology Data Exchange (ETDEWEB)

Zamfirescu, C.; Bejan, A. [Duke University, Durham, NC (United States). Dept. of Mechanical Engineering and Materials Science

2003-07-01

This paper documents the strong relation that exists between the changing architecture of a complex flow system and the maximization of global performance under constraints. The system is a surface with uniform heating per unit area, which is cooled by a network with evaporating two-phase flow. Illustrations are based on the design of the cooling network for a skating rink. The flow structure is optimized as a sequence of building blocks, which starts with the smallest (elemental volume of fixed size), and continues with assemblies of stepwise larger sizes (first construct, second construct, etc.). The optimized flow network is tree shaped. Three features of the elemental volume are optimized: the cross-sectional shape, the elemental tube diameter, and the shape of the elemental area viewed from above. The tree that emerges at larger scales is optimized for minimal amount of header material and fixed pressure drop. The optimal number of constituents in each new (larger) construct decreases as the size and complexity of the construct increase. Constructs of various levels of complexity compete: the paper shows how to select the optimal flow structure subject to fixed size (cooled surface), pressure drop and amount of header material. (author)

Gravity driven emergency core cooling experiments with the PACTEL facility

International Nuclear Information System (INIS)

Munther, R.; Kalli, H.; Kouhia, J.

1996-01-01

PACTEL (Parallel Channel Test Loop) is an experimental out-of-pile facility designed to simulated the major components and system behaviour of a commercial Pressurized Water Reactor (PWR) during different postulated LOCAs and transients. The reference reactor to the PACTEL facility is Loviisa type WWER-440. The recently made modifications enable experiments to be conducted also on the passive core cooling. In these experiments the passive core cooling system consisted of one core makeup tank (CMT) and pressure balancing lines from the pressurizer and from a cold leg connected to the top of the CMT in order to maintain the tank in pressure equilibrium with the primary system during ECC injection. The line from the pressurizer to the core makeup tank was normally open. The ECC flow was provided from the CMT located at a higher elevation than the main part of the primary system. A total number of nine experiments have been performed by now. 4 refs, 7 figs, 3 tabs

Gravity driven emergency core cooling experiments with the PACTEL facility

Energy Technology Data Exchange (ETDEWEB)

Munther, R; Kalli, H [University of Technology, Lappeenranta (Finland); Kouhia, J [Technical Research Centre of Finland, Lappeenranta (Finland)

1996-12-01

PACTEL (Parallel Channel Test Loop) is an experimental out-of-pile facility designed to simulated the major components and system behaviour of a commercial Pressurized Water Reactor (PWR) during different postulated LOCAs and transients. The reference reactor to the PACTEL facility is Loviisa type WWER-440. The recently made modifications enable experiments to be conducted also on the passive core cooling. In these experiments the passive core cooling system consisted of one core makeup tank (CMT) and pressure balancing lines from the pressurizer and from a cold leg connected to the top of the CMT in order to maintain the tank in pressure equilibrium with the primary system during ECC injection. The line from the pressurizer to the core makeup tank was normally open. The ECC flow was provided from the CMT located at a higher elevation than the main part of the primary system. A total number of nine experiments have been performed by now. 4 refs, 7 figs, 3 tabs.

Capillary-Driven Heat Transfer Experiment: Keeping It Cool in Space

Science.gov (United States)

Lekan, Jack F.; Allen, Jeffrey S.

1998-01-01

Capillary-pumped loops (CPL's) are devices that are used to transport heat from one location to another--specifically to transfer heat away from something. In low-gravity applications, such as satellites (and possibly the International Space Station), CPL's are used to transfer heat from electrical devices to space radiators. This is accomplished by evaporating one liquid surface on the hot side of the CPL and condensing the vapor produced onto another liquid surface on the cold side. Capillary action, the phenomenon that causes paper towels to absorb spilled liquids, is used to "pump" the liquid back to the evaporating liquid surface (hot side) to complete the "loop." CPL's require no power to operate and can transfer heat over distances as large as 30 ft or more. Their reliance upon evaporation and condensation to transfer heat makes them much more economical in terms of weight than conventional heat transfer systems. Unfortunately, they have proven to be unreliable in space operations, and the explanation for this unreliability has been elusive. The Capillary-Driven Heat Transfer (CHT) experiment is investigating the fundamental fluid physics phenomena thought to be responsible for the failure of CPL's in low-gravity operations. If the failure mechanism can be identified, then appropriate design modifications can be developed to make capillary phase-change heat-transport devices a more viable option in space applications. CHT was conducted onboard the Space Shuttle Columbia during the first Microgravity Science Laboratory (MSL-1) mission, STS-94, which flew from July 1 to 17, 1997. The CHT glovebox investigation, which was conceived by Dr. Kevin Hallinan and Jeffrey Allen of the University of Dayton, focused on studying the dynamics associated with the heating and cooling at the evaporating meniscus within a capillary phase-change device in a low-gravity environment. The CHT experimental hardware was designed by a small team of engineers from Aerospace Design

Development of TPNCIRC code for Evaluation of Two-Phase Natural Circulation Flow Performance under External Reactor Vessel Cooling Conditions

International Nuclear Information System (INIS)

Choi, A-Reum; Song, Hyuk-Jin; Park, Jong-Woon

2015-01-01

During a severe accident, corium is relocated to the lower head of the nuclear reactor pressure vessel (RPV). Design concept of retaining the corium inside a nuclear reactor pressure vessel (RPV) through external cooling under hypothetical core melting accidents is called external reactor vessel cooling (ERVC). In this respect, validated two-phase natural circulation flow (TPNC) model is necessary to determine the adequacy of the ERVC design and operating conditions such as inlet area, form losses, gap distance, riser length and coolant conditions. The most important model generally characterizing the TPNC are void fraction and two-phase friction factors. Typical experimental and analytical studies to be referred to on two-phase circulation flow characteristics are those by Reyes, Gartia et al. based on Vijayan et al., Nayak et al. and Dubey et al. In the present paper, two-phase natural circulation (TPNC) flow characteristics under external reactor vessel cooling (ERVC) conditions are studied using two existing TPNC flow models of Reyes and Gartia et al. incorporating more improved void fraction and two-phase friction models. These models and correlations are integrated into a computer program, TPNCIRC, which can handle candidate ERVC design parameters, such as inlet, riser and downcomer flow lengths and areas, gap size between reactor vessel and surrounding insulations, minor loss factors and operating parameters of decay power, pressure and subcooling. Accuracy of the TPNCIRC program is investigated with respect to the flow rate and void fractions for existing measured data from a general experiment and ULPU specifically designed for the AP1000 in-vessel retention. Also, the effect of some important design parameters are examined for the experimental and plant conditions. Using the flow models and correlations are integrated into a computer program, TPNCIRC, a number of correlations have been examined. This seems coming from the differences of void fractions

Electron cooling and recombination experiments with an adiabatically expanded electron beam

International Nuclear Information System (INIS)

Pastuszka, S.; Heidelberg Univ.; Schramm, U.; Heidelberg Univ.; Grieser, M.; Heidelberg Univ.; Broude, C.; Heidelberg Univ.; Grimm, R.; Heidelberg Univ.; Habs, D.; Heidelberg Univ.; Kenntner, J.; Heidelberg Univ.; Miesner, H.J.; Heidelberg Univ.; Schuessler, T.; Heidelberg Univ.; Schwalm, D.; Heidelberg Univ.; Wolf, A.; Heidelberg Univ.

1996-01-01

Magnetically guided electron beams with transverse temperatures reduced with respect to the cathode temperature by a factor of more than 7 were realized in the electron cooling device of the heavy-ion storage ring TSR and the effect of the reduced transverse temperature in recombination and electron cooling experiments was studied. Measured dielectronic recombination resonances at low relative energy and spectra of laser-stimulated recombination indicate that transverse electron temperatures of about 17 meV have been obtained at cathode temperatures of about 110 meV. The temperature dependence of the spontaneous electron-ion recombination rate during electron cooling was investigated and found to follow the inverse square-root law expected from the theory of radiative recombination, although the measured absolute rates are higher than predicted. A new method based on analyzing the intensity of the fluorescence light emitted during simultaneous laser and electron cooling is used to measure the longitudinal electron cooling force in a range of relative velocities extending over two orders of magnitude (10 5 -10 7 cm/s). The results confirm the occurrence of 'magnetized electron cooling' also at the reduced transverse temperature and show that, compared to earlier measurements at the high transverse temperature, the cooling force increases by about a factor of 2; a considerably larger increase by a factor of ∼5 would be expected if 'magnetized electron cooling' would not exist. (orig.)

A combined heating cooling stage for cluster thermalization in the gas phase

International Nuclear Information System (INIS)

Ievlev, D.N.; Kuester, A.; Enders, A.; Malinowski, N.; Schaber, H.; Kern, K.

2003-01-01

We report on the design and performance of a combined heating/cooling stage for the thermalization of clusters in a gas phase time-of-flight mass spectrometer. With this setup the cluster temperature can sensitively be adjusted within the range from 100 up to 800 K and higher. The unique combination of a heating stage with a subsequent cooling stage allows us to perform thermodynamic investigations on clusters at very high temperatures without quality losses in the spectra due to delayed fragmentation in the drift tube of the mass spectrometer. The performance of the setup is demonstrated by the example of (C 60 ) n clusters

Lattice design of the integrable optics test accelerator and optical stochastic cooling experiment at Fermilab

Energy Technology Data Exchange (ETDEWEB)

Kafka, Gene [Illinois Inst. of Technology, Chicago, IL (United States)

2015-05-01

The Integrable Optics Test Accelerator (IOTA) storage ring at Fermilab will serve as the backbone for a broad spectrum of Advanced Accelerator R&D (AARD) experiments, and as such, must be designed with signi cant exibility in mind, but without compromising cost e ciency. The nonlinear experiments at IOTA will include: achievement of a large nonlinear tune shift/spread without degradation of dynamic aperture; suppression of strong lattice resonances; study of stability of nonlinear systems to perturbations; and studies of di erent variants of nonlinear magnet design. The ring optics control has challenging requirements that reach or exceed the present state of the art. The development of a complete self-consistent design of the IOTA ring optics, meeting the demands of all planned AARD experiments, is presented. Of particular interest are the precise control for nonlinear integrable optics experiments and the transverse-to-longitudinal coupling and phase stability for the Optical Stochastic Cooling Experiment (OSC). Since the beam time-of- ight must be tightly controlled in the OSC section, studies of second order corrections in this section are presented.

Altering the cooling rate dependence of phase formation during rapid solidification in the Nd{sub 2}Fe{sub 14}B system

Energy Technology Data Exchange (ETDEWEB)

Branagan, D.J. [USDOE, Ames, IA (United States). Ames Lab.]|[Iowa State Univ. of Science and Technology, Ames, IA (United States). Dept. of Materials Science and Engineering; McCallum, R.W. [USDOE, Ames, IA (United States). Ames Lab.]|[Iowa State Univ. of Science and Technology, Ames, IA (United States). Dept. of Materials Science and Engineering

1995-04-26

In order to evaluate the effects of additions on the solidification behavior of Nd{sub 2}Fe{sub 14}B, a stoichiometric alloy was modified with elemental additions of Ti or C and a compound addition of Ti with C. For each alloy, a series of wheel speed runs was undertaken, from which the optimum wheel speeds and optimum energy products were determined. On the BH{sub max} versus wheel speed plots, regions were identified in order to analyze the changes with cooling rates leading to phase formation brought about by the alloy modifications. The compilation of the regional data of the modified alloys showed their effects on altering the cooling rate dependence of phase formation. It was found that the regions of properitectic iron formation, glass formation, and the optimum cooling rate can be changed by more than a factor of two through appropriate alloying additions. The effects of the alloy modifications can be visualized in a convenient fashion through the use of a model continuous cooling transformation (CCT) diagram which represents phase formation during the solidification process under continuous cooling conditions for a wide range of cooling rates from rapid solidification to equilibrium cooling. ((orig.)).

Experimental Studies of Phase Change and Microencapsulated Phase Change Materials in a Cold Storage/Transportation System with Solar Driven Cooling Cycle

OpenAIRE

Lin Zheng; Wei Zhang; Fei Liang; Shuang Lin; Xiangyu Jin

2017-01-01

The paper presents the different properties of phase change material (PCM) and Microencapsulated phase change material (MEPCM) employed to cold storage/transportation system with a solar-driven cooling cycle. Differential Scanning Calorimeter (DSC) tests have been performed to analyze the materials enthalpy, melting temperature range, and temperature range of solidification. KD2 Pro is used to test the thermal conductivities of phase change materials slurry and the results were used to compar...

Phase-IIC experiments of the JAERI/USDOE collaborative program on fusion blanket neutronics

International Nuclear Information System (INIS)

Oyama, Yukio

1992-12-01

Neutronics experiments on two types of heterogeneous blankets have been performed as the Phase-IIC experiment of JAERI/USDOE collaborative program on fusion blanket neutronics. The experimental system was used in the same geometry as the previous Phase-IIA series which was a closed geometry using neutron source enclosure of lithium carbonate. The heterogeneous blankets selected here are the beryllium edge-on and the water coolant channel assemblies. In the former the beryllium and lithium-oxide layers are piled up alternately in the front part of test blanket. In the latter, the three simulated water cooling channels are settled in the Li 2 O blanket. These are producing steep gradient of neutron flux around material boundary. The calculation accuracy and measurement method for these features is a key of interest in the experiments. The measurements were performed for tritium production rate and the other nuclear parameters as well as the previous experiments. This report describes the experimental detail and the results enough to use for the benchmark data for testing the data and method of design calculation of fusion reactors. (author)

A combined capillary cooling system for cooling fuel cells

Energy Technology Data Exchange (ETDEWEB)

Silva, Ana Paula; Pelizza, Pablo Rodrigo; Galante, Renan Manozzo; Bazzo, Edson [Universidade Federal de Santa Catarina (LabCET/UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica. Lab. de Combustao e Engenharia de Sistemas Termicos], Emails: ana@labcet.ufsc.br, pablo@labcet.ufsc.br, renan@labcet.ufsc.br, ebazzo@emc.ufsc.br

2010-07-01

The operation temperature control has an important influence over the PEMFC (Proton Exchange Membrane Fuel Cell) performance. A two-phase heat transfer system is proposed as an alternative for cooling and thermal control of PEMFC. The proposed system consists of a CPL (Capillary Pumped Loop) connected to a set of constant conductance heat pipes. In this work ceramic wick and stainless mesh wicks have been used as capillary structure of the CPL and heat pipes, respectively. Acetone has been used as the working fluid for CPL and deionized water for the heat pipes. Experimental results of three 1/4 inch stainless steel outlet diameter heats pipes and one CPL have been carried out and presented in this paper. Further experiments are planned coupling the proposed cooling system to a module which simulates the fuel cell. (author)

Two-phase jet impingement cooling for high heat flux wide band-gap devices using multi-scale porous surfaces

International Nuclear Information System (INIS)

Joshi, Shailesh N.; Dede, Ercan M.

2017-01-01

Highlights: • Jet impingement with phase change on multi-scale porous surfaces is investigated. • Porous coated flat, pin-fin, open tunnel, and closed tunnel structures are studied. • Boiling curve, heat transfer coefficient, and pressure drop metrics are reported. • Flow visualization shows vapor removal from the surface is a key aspect of design. • The porous coated pin-fin surface exhibits superior two-phase cooling performance. - Abstract: In the future, wide band-gap (WBG) devices such as silicon carbide and gallium nitride will be widely used in automotive power electronics due to performance advantages over silicon-based devices. The high heat fluxes dissipated by WBG devices pose extreme cooling challenges that demand the use of advanced thermal management technologies such as two-phase cooling. In this light, we describe the performance of a submerged two-phase jet impingement cooler in combination with porous coated heat spreaders and multi-jet orifices. The cooling performance of four different porous coated structures was evaluated using R-245fa as the coolant at sub-cooling of 5 K. The results show that the boiling performance of a pin-fin heat spreader is the highest followed by that for an open tunnel (OPT), closed tunnel (CLT), and flat heat spreader. Furthermore, the flat heat spreader demonstrated the lowest critical heat flux (CHF), while the pin-fin surface sustained a heat flux of 218 W/cm 2 without reaching CHF. The CHF values of the OPT and CLT surfaces were 202 W/cm 2 and 194 W/cm 2 , respectively. The pin-fin heat spreader has the highest two-phase heat transfer coefficient of 97,800 W/m 2 K, while the CLT surface has the lowest heat transfer coefficient of 69,300 W/m 2 K, both at a heat flux of 165 W/cm 2 . The variation of the pressure drop of all surfaces is similar for the entire range of heat fluxes tested. The flat heat spreader exhibited the least pressure drop, 1.73 kPa, while the CLT surface had the highest, 2.17 kPa at a

Electron cooling application for luminosity preservation in an experiment with internal targets at COSY

CERN Document Server

Meshkov, I N; Maier, R; Prasuhn, D; Sidorin, A O; Smirnov, A V; Stein, H J; Stockhorst, H; Trubnikov, G V

2003-01-01

This report is an investigation of the beam parameter evolution in the experiments with internal target. In calculations of the proton and deuteron beams we concentrated on cluster, atomic beam, storage cell and pellet targets at ANKE experiment mainly. In these calculations electron and stochastic cooling, intrabeam scattering, scattering on the target and residual gas atoms are taken into account. Beam parameter evolution is investigated in the long-term time scale, up to one hour, at different beam energies in the range from 1.0 to 2.7 GeV for proton beam and from 1 to 2.11 GeV for deuteron beam. The results of numerical simulations of the proton and deuteron beam parameters at different energies obtained using new version of BETACOOL program (elaborated at the first stage of this work [1]) are presented. Optimum parameters of the electron cooling system are estimated. The COSY experiment requirements can be satisfied even when electron cooling time is rather long. That allows to apply an electron cooling ...

Thermal characteristics of manganese (II) nitrate hexahydrate as a phase change material for cooling systems

International Nuclear Information System (INIS)

Nagano, K.; Mochida, T.; Takeda, S.; Domanski, R.; Rebow, M.

2003-01-01

The imbalance of electrical demand in summer due to cooling system demand is a big problem in many countries. One promising solution is shifting peak demand from early afternoon to night by utilizing natural cold energy resources such as cool outside air during night or running a refrigerator driven by midnight power. In these cases, using the thermal energy storage (TES) of phase change material (PCM) which has a melting point from 15 to 25 deg. C is one of the most effective ideas. However, few suitable PCMs for this temperature range are at present commercially available. This study aims to evaluate the potential of Mn(NO 3 ) 2 · 6H 2 O (manganese (II) nitrate hexahydrate) as a new PCM for the TES of cooling systems. First, experiments on the modulation of the melting point of Mn(NO 3 ) 2 · 6H 2 O and reduction of supercooling were made by dissolving small amounts of salts in the material. Consequently, MnCl 2 · 4H 2 O was found to have good performance with regard to both modulation of the melting temperature and the heat of fusion. Next, a thermal response test was carried out by using a small cylindrical vessel. Results showed that the required temperature levels for charging and discharging the heat of this mixture were clarified. In addition, the price and safety of this material as a PCM are discussed

Hybrid Cooling Loop Technology for Robust High Heat Flux Cooling, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Advanced Cooling Technologies, Inc. (ACT) proposes to develop a hybrid cooling loop and cold plate technology for space systems thermal management. The proposed...

Heat transfer during phase change. Evaporation. Application to cooling towers

International Nuclear Information System (INIS)

Merigoux, J.

1973-01-01

Evaporation near a water sheet, without convection, is considered. The displacement of water molecules in the gaseous phase, due to concentration gradients, is especially studied. This displacement governs the development of evaporation. The calculation is made to derive the velocity of water evaporation as a function of the partial pressure of the surrounding air, the temperature and physical properties of the air and steam. Diffusion laws are used. The calculation is applied to cooling towers, according to Merkel theory [fr

Experiments for the premixing phase (QUEOS)

International Nuclear Information System (INIS)

Meyer, L.; Huber, R.; Haessler, M.; Kirstahler, M.; Kuhn, D.; Rehme, K.; Schumacher, G.; Schwall, M.; Wachter, E.; Woerner, G.

1995-01-01

Experiments are performed with solid spheres at high temperatures to establish a data base for the premixing phase of a steam explosion, which will be used for code improvement and validation. The hot spheres (T≤2600 K) are being dropped into saturated water at 1 bar pressure. The objective of the experiments is to obtain data on the cooling rate of the spheres, their distribution in the water, the amount of generated steam and its distribution with respect to the spheres. The spheres have a diameter of 4.2 mm, 4.8 mm and 10 mm, respectively, depending on the material used. Molybdenum coated with Rhenium to inhibit oxidation and ZrO 2 are used. The experimental parameters are the mass flow of the spheres, their density and their temperature. The QUEOS test facility has been set up and tested. A series of first tests has been performed with cold spheres and spheres at 1000 C. The main results are the distribution of the spheres during the fall through the water and their distribution at the bottom of the water vessel. A large air bubble is being entrained into the water in both the cold and hot tests. (orig./HP)

Effect of Drawer Master Modeling of ZPPR15 Phase A Reactor Physics Experiment on Integral Parameter

International Nuclear Information System (INIS)

Yoo, Jae Woon; Kim, Sang Ji

2011-01-01

As a part of an International-Nuclear Engineering Research Initiative (I-NERI) Project, KAERI and ANL are analyzing the ZPPR-15 reactor physics experiments. The ZPPR-15 experiments were carried out in support of the Integral Fast Reactor (IFR) project. Because of lack of the experimental data, verifying and validating the core neutronics analysis code for metal fueled sodium cooled fast reactors (SFR) has been one of the big concerns. KAERI is developing the metal fuel loaded SFR and plans to construct the demonstration SFR by around 2028. Database built through this project and its result of analysis will play an important role in validating the SFR neutronics characteristics. As the first year work of I-NERI project, KAERI analyzed ZPPR-15 Phase A experiment among four phases (Phase A to D). The effect of a drawer master modeling on the integral parameter was investigated. The approximated benchmark configurations for each loading were constructed to be used for validating a deterministic code

Problems of two-phase flows in water cooled and moderated reactors

International Nuclear Information System (INIS)

Syu, Yu.

1984-01-01

Heat exchange in two-phase flows of coolant in loss of coolant accidents in PWR and BWR reactors has been investigated. Three main stages of accident history are considered: blowdown, reflooding using emergency core cooling system and rewetting. Factors, determining the rate of coolant leakage and the rate of temperature increase in fuel cladding during blowdown, processes of vapour during reflooding and liquid priming by vapour during rewetting, are discussed

Identification of gap cooling phenomena from LAVA-4 experiment using MELCOR

International Nuclear Information System (INIS)

Park, Jong-Hwa; Kim, Dong-Ha; Kim, See-Darl; Kim, Sang-Baik; Kim, Hee-Dong

2000-01-01

During the severe accident, whether the hot debris in. lower head will be cool-down or not is the important issue concerning the plant safety. KAERI has launched the 'LAVA' experimental program to examine the existence of initial gap and its effect on the cooling of hot debris. The objective of this study is to identify the gap cooling phenomena from the analysis of simulation results on LAVA-4 experiment using MELCOR1.8.4 code. Three parameters on the debris coolability in MELCOR are the quenching heat transfer coefficient for the interaction between molten Al 2 O 3 and water, the heat transfer coefficient from debris to wall and the diameter of the particulate debris for calculating the available heat transfer area with water. The sensitivity study was performed with these three parameters. However it was believed that there must be a gap between debris and inside wall during the transient. MELCOR1.8.4 does not consider these gap-cooling phenomena. Therefore a conceptual gap-cooling model has been developed and implemented into the lower plenum model in MELCOR to take into account the gap effect in the lower plenum. When the 'gap model' is implemented, the peak temperature of the vessel wall was reduced and its cooling rate was increased. (author)

A device for emergency cooling visualization

International Nuclear Information System (INIS)

Rezende, Hugo Cesar; Ladeira, Luiz Carlos Duarte

1995-01-01

A test facility for rewetting experiments, Emergency Cooling Visualization Device, has been erected at CDTN, with the objective of Emergency Cooling visualization device performing visual observations of basic phenomena that occur during the reflood phase of a Loss of Coolant Accident (LOCA), in a Pressurised Water Reactor (PWR), utilizing annular test sections. It permits to film or photograph the advance of a wetting front and the flow and heat transfer conditions. Then it is possible to observe the heat transfer regions and flow zones: steam convection, fog cooling, film boiling, nucleate boiling and fluid convection. Finally, this facility is the first test facility, in the Thermohydraulics Laboratory of CDTN, that uses a indirectly heated fuel rod simulator. (author). 3 refs, 5 figs

Experimental study on two-phase flow natural circulation in a core catcher cooling channel for EU-APR1400 using air-water system

Energy Technology Data Exchange (ETDEWEB)

Song, Ki Won [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Korea Atomic Energy Research Institute, Daejeon 34057 (Korea, Republic of); Nguyen, Thanh Hung [School of Nuclear Engineering, Purdue University, West Lafayette, IN 47906 (United States); Ha, Kwang Soon; Kim, Hwan Yeol; Song, Jinho [Korea Atomic Energy Research Institute, Daejeon 34057 (Korea, Republic of); Park, Hyun Sun [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Revankar, Shripad T., E-mail: shripad@postech.ac.kr [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); School of Nuclear Engineering, Purdue University, West Lafayette, IN 47906 (United States); Kim, Moo Hwan [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Korea Institute of Nuclear Safety, Daejeon 305-338 (Korea, Republic of)

2017-05-15

Highlights: • Two-phase flow regimes and transition behavior were observed in the coolant channel. • Test were conducted for natural circulation with air-water. • Data were obtained on flow regime, void fraction, flow rates and re-wetting time. • The data were related to a cooling capability of core catcher system. - Abstract: Ex-vessel core catcher cooling system driven by natural circulation is designed using a full scaled air-water system. A transparent half symmetric section of a core catcher coolant channel of a pressurized water reactor was designed with instrumentations for local void fraction measurement and flow visualization. Two designs of air-water top separator water tanks are studied including one with modified ‘super-step’ design which prevents gas entrainment into down-comer. In the experiment air flow rates are set corresponding to steam generation rate for given corium decay power. Measurements of natural circulation flow rate, spatial local void fraction distribution and re-wetting time near the top wall are carried out for various air flow rates which simulate boiling-induced vapor generation. Since heat transfer and critical heat flux are strongly dependent on the water mass flow rate and development of two-phase flow on the heated wall, knowledge of two-phase flow characteristics in the coolant channel is essential. Results on flow visualization showing two phase flow structure specifically near the high void accumulation regions, local void profiles, rewetting time, and natural circulation flow rate are presented for various air flow rates that simulate corium power levels. The data are useful in assessing the cooling capability of and safety of the core catcher system.

Cooling of molecular ion beams

International Nuclear Information System (INIS)

Wolf, A.; Krohn, S.; Kreckel, H.; Lammich, L.; Lange, M.; Strasser, D.; Grieser, M.; Schwalm, D.; Zajfman, D.

2004-01-01

An overview of the use of stored ion beams and phase space cooling (electron cooling) is given for the field of molecular physics. Emphasis is given to interactions between molecular ions and electrons studied in the electron cooler: dissociative recombination and, for internally excited molecular ions, electron-induced ro-vibrational cooling. Diagnostic methods for the transverse ion beam properties and for the internal excitation of the molecular ions are discussed, and results for phase space cooling and internal (vibrational) cooling are presented for hydrogen molecular ions

Phase Change Material Heat Sink for an ISS Flight Experiment

Science.gov (United States)

Quinn, Gregory; Stieber, Jesse; Sheth, Rubik; Ahlstrom, Thomas

2015-01-01

A flight experiment is being constructed to utilize the persistent microgravity environment of the International Space Station (ISS) to prove out operation of a microgravity compatible phase change material (PCM) heat sink. A PCM heat sink can help to reduce the overall mass and volume of future exploration spacecraft thermal control systems (TCS). The program is characterizing a new PCM heat sink that incorporates a novel phase management approach to prevent high pressures and structural deformation that often occur with PCM heat sinks undergoing cyclic operation in microgravity. The PCM unit was made using brazed aluminum construction with paraffin wax as the fusible material. It is designed to be installed into a propylene glycol and water cooling loop, with scaling consistent with the conceptual designs for the Orion Multipurpose Crew Vehicle. This paper reports on the construction of the PCM heat sink and on initial ground test results conducted at UTC Aerospace Systems prior to delivery to NASA. The prototype will be tested later on the ground and in orbit via a self-contained experiment package developed by NASA Johnson Space Center to operate in an ISS EXPRESS rack.

Ventilative Cooling

DEFF Research Database (Denmark)

Heiselberg, Per Kvols; Kolokotroni, Maria

This report, by venticool, summarises the outcome of the work of the initial working phase of IEA ECB Annex 62 Ventilative Cooling and is based on the findings in the participating countries. It presents a summary of the first official Annex 62 report that describes the state-of-the-art of ventil......This report, by venticool, summarises the outcome of the work of the initial working phase of IEA ECB Annex 62 Ventilative Cooling and is based on the findings in the participating countries. It presents a summary of the first official Annex 62 report that describes the state......-of-the-art of ventilative cooling potentials and limitations, its consideration in current energy performance regulations, available building components and control strategies and analysis methods and tools. In addition, the report provides twenty six examples of operational buildings using ventilative cooling ranging from...

Monoclinic MB phase and phase instability in [110] field cooled Pb(Zn1/3Nb2/3)O3-4.5%PbTiO3 single crystals

Science.gov (United States)

Yao, Jianjun; Cao, Hu; Ge, Wenwei; Li, Jiefang; Viehland, D.

2009-08-01

We report the finding of a monoclinic MB phase in Pb(Zn1/3Nb2/3)O3-4.5%PbTiO3 single crystals. High precision x-ray diffraction investigations of [110] field cooled crystals have shown a transformation sequence of cubic(C)→tetragonal(T)→orthorhombic(O)→monoclinic(MB), which is different from that previously reported [A.-E. Renault et al., J. Appl. Phys. 97, 044105 (2005)]. Beginning in the zero-field-cooled condition at 383 K, a rhombohedral (R)→MB→O sequence was observed with increasing field. Coexisting MB and O phases were then found upon removal of field, which fully transformed to MB on cooling to room temperature.

Experiments on Quantum Hall Topological Phases in Ultra Low Temperatures

International Nuclear Information System (INIS)

Du, Rui-Rui

2015-01-01

This project is to cool electrons in semiconductors to extremely low temperatures and to study new states of matter formed by low-dimensional electrons (or holes). At such low temperatures (and with an intense magnetic field), electronic behavior differs completely from ordinary ones observed at room temperatures or regular low temperature. Studies of electrons at such low temperatures would open the door for fundamental discoveries in condensed matter physics. Present studies have been focused on topological phases in the fractional quantum Hall effect in GaAs/AlGaAs semiconductor heterostructures, and the newly discovered (by this group) quantum spin Hall effect in InAs/GaSb materials. This project consists of the following components: 1) Development of efficient sample cooling techniques and electron thermometry: Our goal is to reach 1 mK electron temperature and reasonable determination of electron temperature; 2) Experiments at ultra-low temperatures: Our goal is to understand the energy scale of competing quantum phases, by measuring the temperature-dependence of transport features. Focus will be placed on such issues as the energy gap of the 5/2 state, and those of 12/5 (and possible 13/5); resistive signature of instability near 1/2 at ultra-low temperatures; 3) Measurement of the 5/2 gaps in the limit of small or large Zeeman energies: Our goal is to gain physics insight of 5/2 state at limiting experimental parameters, especially those properties concerning the spin polarization; 4) Experiments on tuning the electron-electron interaction in a screened quantum Hall system: Our goal is to gain understanding of the formation of paired fractional quantum Hall state as the interaction pseudo-potential is being modified by a nearby screening electron layer; 5) Experiments on the quantized helical edge states under a strong magnetic field and ultralow temperatures: our goal is to investigate both the bulk and edge states in a quantum spin Hall insulator under

Simple material physics experiment for studying phase diagrams and solid state transformations in alloys

Energy Technology Data Exchange (ETDEWEB)

Kaur, S; Kamal, R [Punjabi Univ., Patiala (India). Dept. of Physics

1977-09-01

Study of phase diagram and accompanying solid state transformations is essential to determine the best possible composition, manufacturing techniques and physical properties of an alloy. A simple technique having wide applications in metallurgical industry is to study the temperature--time curve of the alloy undergoing cooling with an uniform rate. An experiment which uses this technique is described. It is widely applicable in the fields of materials science, applied solid state physics, physical metallurgy and physical chemistry.

A novel personal cooling system (PCS) incorporated with phase change materials (PCMs) and ventilation fans: An investigation on its cooling efficiency.

Science.gov (United States)

Lu, Yehu; Wei, Fanru; Lai, Dandan; Shi, Wen; Wang, Faming; Gao, Chuansi; Song, Guowen

2015-08-01

Personal cooling systems (PCS) have been developed to mitigate the impact of severe heat stress for humans working in hot environments. It is still a great challenge to develop PCSs that are portable, inexpensive, and effective. We studied the performance of a new hybrid PCS incorporating both ventilation fans and phase change materials (PCMs). The cooling efficiency of the newly developed PCS was investigated on a sweating manikin in two hot conditions: hot humid (HH, 34°C, 75% RH) and hot dry (HD, 34°C, 28% RH). Four test scenarios were selected: fans off with no PCMs (i.e., Fan-off, the CONTROL), fans on with no PCMs (i.e., Fan-on), fans off with fully solidified PCMs (i.e., PCM+Fan-off), and fans on with fully solidified PCMs (i.e., PCM+Fan-on). It was found that the addition of PCMs provided a 54∼78min cooling in HH condition. In contrast, the PCMs only offered a 19-39min cooling in HD condition. In both conditions, the ventilation fans greatly enhanced the evaporative heat loss compared with Fan-off. The hybrid PCS (i.e., PCM+Fan-on) provided a continuous cooling effect during the three-hour test and the average cooling rate for the whole body was around 111 and 315W in HH and HD conditions, respectively. Overall, the new hybrid PCS may be an effective means of ameliorating symptoms of heat stress in both hot-humid and hot-dry environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cold storage with phase change material for building ventilation

OpenAIRE

Butala, Vincenc; Stritih, Uroš

2015-01-01

This paper presents an experimental and numerical analysis of building coolingusing night-time cold accumulation in phase change material (PCM), otherwise known as the "free-cooling" or "passive-cooling" principle. The phase change materials were used in ceilings and floors. The free-cooling principle is explained and some of the types of PCMs suitable for summer cooling are listed. An experiment was conducted using paraffin with a melting point of 22 °C as the PCM to store cold during the ni...

Experimental investigations on the cooling of a motorcycle helmet with phase change material (PCM

Directory of Open Access Journals (Sweden)

Fok S.C.

2011-01-01

Full Text Available The thermal comfort of motorcycle helmet during hot weather is important as it can affect the physiological and psychological condition of the rider. This paper examines the use of phase change material (PCM to cool a motorcycle helmet and presents the experimental investigations on the influences of the simulated solar radiation, wind speed, and heat generation rate on the cooling system. The result shows that the PCM-cooled helmet is able to prolong the thermal comfort period compared to a normal helmet. The findings also indicate that the heat generation from the head is the predominant factor that will affect the PCM melting time. Simulated solar radiation and ram-air due to vehicle motion under adiabatic condition can have very little influences on the PCM melting time. The results suggested that the helmet usage time would be influenced by the amount of heat generated from the head. Some major design considerations based on these findings have been included. Although this investigation focuses on the cooling of a motorcyclist helmet, the findings would also be useful for the development of PCM-cooling systems in other applications.

Effects of Undercooling and Cooling Rate on Peritectic Phase Crystallization Within Ni-Zr Alloy Melt

Science.gov (United States)

Lü, P.; Wang, H. P.

2018-04-01

The liquid Ni-16.75 at. pct Zr peritectic alloy was substantially undercooled and containerlessly solidified by an electromagnetic levitator and a drop tube. The dependence of the peritectic solidification mode on undercooling was established based on the results of the solidified microstructures, crystal growth velocity, as well as X-ray diffraction patterns. Below a critical undercooling of 124 K, the primary Ni7Zr2 phase preferentially nucleates and grows from the undercooled liquid, which is followed by a peritectic reaction of Ni7Zr2+L → Ni5Zr. The corresponding microstructure is composed of the Ni7Zr2 dendrites, peritectic Ni5Zr phase, and inter-dendritic eutectic. Nevertheless, once the liquid undercooling exceeds the critical undercooling, the peritectic Ni5Zr phase directly precipitates from this undercooled liquid. However, a negligible amount of residual Ni7Zr2 phase still appears in the microstructure, indicating that nucleation and growth of the Ni7Zr2 phase are not completely suppressed. The micromechanical property of the peritectic Ni5Zr phase in terms of the Vickers microhardness is enhanced, which is ascribed to the transition of the peritectic solidification mode. To suppress the formation of the primary phase completely, this alloy was also containerlessly solidified in free fall experiments. Typical peritectic solidified microstructure forms in large droplets, while only the peritectic Ni5Zr phase appears in smaller droplets, which gives an indication that the peritectic Ni5Zr phase directly precipitates from the undercooled liquid by completely suppressing the growth of the primary Ni7Zr2 phase and the peritectic reaction due to the combined effects of the large undercooling and high cooling rate.

Shock and vibration protection of submerged jet impingement cooling systems: Theory and experiment

International Nuclear Information System (INIS)

Haji Hosseinloo, Ashkan; Tan, Siow Pin; Yap, Fook Fah; Toh, Kok Chuan

2014-01-01

In the recent years, advances in high power density electronics and computing systems have pushed towards more advanced thermal management technologies and higher-capacity cooling systems. Among different types of cooling systems, jet impingement technology has gained attention and been widely used in different industries for its adaptability, cooling uniformity, large heat capacity, and ease of its localization. However, these cooling systems may not function properly in dynamically harsh environment inherent in many applications such as land, sea and air transportation. In this research article, a novel double-chamber jet impingement cooling system is fabricated and its performance is studied in harsh environment. Using the authors' previous studies, isolators with optimum properties are selected to ruggedize the chassis containing the cooling chamber against shock and random vibration. Experiments are conducted on both hard-mounted and isolated chassis and the cooling performance of the system is assessed using the inlet, and impingement surface temperatures of the cooling chamber. The experimental results show the isolation system prevents any failure that otherwise would occur, and also does not compromise the thermal performance of the system. - Highlights: • A novel double-chamber jet impingement cooling system was designed and fabricated. • Comprehensive set of random vibration and shock tests are conducted. • The isolation system proved to protect the cooling system properly against mechanical failure. • Cooling system performance was not significantly affected by the input random vibration and shock

Four foot septifoil cooling experiment unrestricted inlet/outlet case

International Nuclear Information System (INIS)

Foti, D.J.; Randolph, H.W.; Geiger, G.T.; Verebelyi, D.T.; Wooten, L.A.

1992-02-01

The ability to predict the behavior of reactor components to varying coolant flow scenarios constitutes a necessary skill for assessing reactor safety. One tool for performing these calculations is the Transient Reactor Analysis Code (TRAC). In order to benchmark the code, the Safety Analysis Group of SRL requested the Equipment Engineering Section (EES) of SRL to conduct a series of experiments to provide measurements of cooling parameters in a well defined physical system utilizing SRS reactor components. The configuration selected consisted of a short length of septifoil with both top and bottom fittings containing five simulated control rods in an open-quotes unseatedclose quotes configuration. Varying power levels were to be supplied to the rods with 3.5 kilowatts per foot the value targeted for modelling during the computer runs. The septifoil segment was to be operated with no forced flow in order to evaluate thermal-hydraulic cooling. Parameters to be measured for comparison with code predictions were basic cooling phenomena, incidence of film boiling, water flow rate, pressure rise, and ratio of heat transfer through the wall of the assembly vs. heat transfer to axial water flow through the assembly. This report documents testing done with unimpeded flow into and out of the septifoil in order to assess basic cooling phenomena, incidence of film boiling and pressure rise. Previous tests have evaluated water flow rate and the ratio of axial to azimuthal heat transfer

Liquid-liquid phase separation and solidification behavior of Al55Bi36Cu9 monotectic alloy with different cooling rates

Science.gov (United States)

Bo, Lin; Li, Shanshan; Wang, Lin; Wu, Di; Zuo, Min; Zhao, Degang

2018-03-01

The cooling rate has a significant effect on the solidification behavior and microstructure of monotectic alloy. In this study, different cooling rate was designed through casting in the copper mold with different bore diameters. The effects of different cooling rate on the solidification behavior of Al55Bi36Cu9 (at.%) immiscible alloy have been investigated. The liquid-liquid phase separation of Al55Bi36Cu9 immiscible alloy melt was investigated by resistivity test. The solidification microstructure and phase analysis of Al55Bi36Cu9 immiscible alloy were performed by the SEM and XRD, respectively. The results showed that the liquid-liquid phase separation occurred in the solidification of Al55Bi36Cu9 monotectic melt from 917 °C to 653 °C. The monotectic temperature, liquid phase separation temperature and immiscibility zone of Al55Bi36Cu9 monotectic alloy was lower than those of Al-Bi binary monotectic alloy. The solidification morphology of Al55Bi36Cu9 monotectic alloy was very sensitive to the cooling rate. The Al/Bi core-shell structure formed when Al55Bi36Cu9 melt was cast in the copper mold with a 8 mm bore diameter.

Phase change based cooling for high burst mode heat loads with temperature regulation above the phase change temperature

Science.gov (United States)

The United States of America as represented by the United States Department of Energy

2009-12-15

An apparatus and method for transferring thermal energy from a heat load is disclosed. In particular, use of a phase change material and specific flow designs enables cooling with temperature regulation well above the fusion temperature of the phase change material for medium and high heat loads from devices operated intermittently (in burst mode). Exemplary heat loads include burst mode lasers and laser diodes, flight avionics, and high power space instruments. Thermal energy is transferred from the heat load to liquid phase change material from a phase change material reservoir. The liquid phase change material is split into two flows. Thermal energy is transferred from the first flow via a phase change material heat sink. The second flow bypasses the phase change material heat sink and joins with liquid phase change material exiting from the phase change material heat sink. The combined liquid phase change material is returned to the liquid phase change material reservoir. The ratio of bypass flow to flow into the phase change material heat sink can be varied to adjust the temperature of the liquid phase change material returned to the liquid phase change material reservoir. Varying the flowrate and temperature of the liquid phase change material presented to the heat load determines the magnitude of thermal energy transferred from the heat load.

Advanced phase change materials and systems for solar passive heating and cooling of residential buildings

Energy Technology Data Exchange (ETDEWEB)

Salyer, I.O.; Sircar, A.K.; Dantiki, S.

1988-01-01

During the last three years under the sponsorship of the DOE Solar Passive Division, the University of Dayton Research Institute (UDRI) has investigated four phase change material (PCM) systems for utility in thermal energy storage for solar passive heating and cooling applications. From this research on the basis of cost, performance, containment, and environmental acceptability, we have selected as our current and most promising series of candidate phase change materials, C-15 to C-24 linear crystalline alkyl hydrocarbons. The major part of the research during this contract period was directed toward the following three objectives. Find, test, and develop low-cost effective phase change materials (PCM) that melt and freeze sharply in the comfort temperature range of 73--77{degree}F for use in solar passive heating and cooling of buildings. Define practical materials and processes for fire retarding plasterboard/PCM building products. Develop cost-effective methods for incorporating PCM into building construction materials (concrete, plasterboard, etc.) which will lead to the commercial manufacture and sale of PCM-containing products resulting in significant energy conservation.

Onderzoeksrapportage duurzaam koelen : EOS Renewable Cooling

NARCIS (Netherlands)

Broeze, J.; Sluis, van der S.; Wissink, E.

2010-01-01

For reducing energy use for cooling, alternative methods (that do not rely on electricity) are needed. Renewable cooling is based on naturally available resources such as evaporative cooling, free cooling, phase change materials, ground subcooling, solar cooling, wind cooling, night radiation &

Performance analysis of phase-change material storage unit for both heating and cooling of buildings

Science.gov (United States)

Waqas, Adeel; Ali, Majid; Ud Din, Zia

2017-04-01

Utilisation of solar energy and the night ambient (cool) temperatures are the passive ways of heating and cooling of buildings. Intermittent and time-dependent nature of these sources makes thermal energy storage vital for efficient and continuous operation of these heating and cooling techniques. Latent heat thermal energy storage by phase-change materials (PCMs) is preferred over other storage techniques due to its high-energy storage density and isothermal storage process. The current study was aimed to evaluate the performance of the air-based PCM storage unit utilising solar energy and cool ambient night temperatures for comfort heating and cooling of a building in dry-cold and dry-hot climates. The performance of the studied PCM storage unit was maximised when the melting point of the PCM was ∼29°C in summer and 21°C during winter season. The appropriate melting point was ∼27.5°C for all-the-year-round performance. At lower melting points than 27.5°C, declination in the cooling capacity of the storage unit was more profound as compared to the improvement in the heating capacity. Also, it was concluded that the melting point of the PCM that provided maximum cooling during summer season could be used for winter heating also but not vice versa.

Bi-phase CO{sub 2} cooling of the CBM STS detector

Energy Technology Data Exchange (ETDEWEB)

Lavrik, Evgeny [Physikalisches Institut der Universitaet Tuebingen (Germany); Collaboration: CBM-Collaboration

2016-07-01

The Compressed Baryonic Matter (CBM) experiment aims to study the properties of nuclear matter at high net-baryon densities. The Silicon Tracking System (STS) is the key detector to reconstruct charged particle tracks created in heavy-ion interactions. The foreseen interaction rate of up to 10 MHz requires radiation hard detectors as well as efficient cooling of the silicon sensors. To avoid thermal runaway the system must be kept at -5 C or below all the time. This is rather challenging because the overall thermal load in the 2 m{sup 3} STS enclosure is up to 40 kW. Because of these requirements liquid CO{sub 2} is used as a cooling agent as it is superior in terms of volumetric heat transfer coefficient compared to other agents. This contribution shows the thermal simulations and measurement results of the STS front-end electronic boxes as well as an overview of 1 kW TRACI-XL cooling plant developed at GSI and its use to perform thermal measurements of a fully heat loaded STS quarter station.

A self-regulating valve for single-phase liquid cooling of microelectronics

International Nuclear Information System (INIS)

Donose, Radu; De Volder, Michaël; Peirs, Jan; Reynaerts, Dominiek

2011-01-01

This paper reports on the design, optimization and testing of a self-regulating valve for single-phase liquid cooling of microelectronics. Its purpose is to maintain the integrated circuit (IC) at constant temperature and to reduce power consumption by diminishing flow generated by the pump as a function of the cooling requirements. It uses a thermopneumatic actuation principle that combines the advantages of zero power consumption and small size in combination with a high flow rate and low manufacturing costs. The valve actuation is provided by the thermal expansion of a liquid (actuation fluid) which, at the same time, actuates the valve and provides feed-back sensing. A maximum flow rate of 38 kg h −1 passes through the valve for a heat load up to 500 W. The valve is able to reduce the pumping power by up to 60% and it has the capability to maintain the IC at a more uniform temperature.

Numerical modelling of phase-change material used for PV panels cooling

Science.gov (United States)

Sellami, Assia; Elotmani, Rabie; Kandoussi, Khalid; Eljouad, Mohamed; Hajjaji, Abdelowahed; Boutaous, M'Hamed

2017-12-01

Passive cooling of a PV solar panel using phase-change material (PCM) may play an important role in increasing efficiency of PV cells. Because it does not need a maintenance and does not release greenhouses gases, PCM seems to be a good way to decrease the among of overheating of PV cell. The aims of this paper describes a detailed multiphysical issue in order to understand the effect of PCM (RT25) in keeping PV cell temperature close to ambient. The study is focused on modeling the heat and mass transfer in a PCM domain by modifying the buoyancy term in momentum equation. Due to a phase-change and free convection, transient incompressible flow is taken into account to explain the dynamic variations of the velocity profile and viscosity distribution. With standard condition of irradiation and heat flux on both sides of the PV panel, a melt front has been tracked by the energy equation, which gives a good argument for the temperature evolution during phase-change.

Stochastic cooling at Fermilab

International Nuclear Information System (INIS)

Marriner, J.

1986-08-01

The topics discussed are the stochastic cooling systems in use at Fermilab and some of the techniques that have been employed to meet the particular requirements of the anti-proton source. Stochastic cooling at Fermilab became of paramount importance about 5 years ago when the anti-proton source group at Fermilab abandoned the electron cooling ring in favor of a high flux anti-proton source which relied solely on stochastic cooling to achieve the phase space densities necessary for colliding proton and anti-proton beams. The Fermilab systems have constituted a substantial advance in the techniques of cooling including: large pickup arrays operating at microwave frequencies, extensive use of cryogenic techniques to reduce thermal noise, super-conducting notch filters, and the development of tools for controlling and for accurately phasing the system

Experimental study of efficiency of solar panel by phase change material cooling

Science.gov (United States)

Wei, Nicholas Tan Jian; Nan, Wong Jian; Guiping, Cheng

2017-07-01

The dependence of efficiency of photovoltaic panels on their temperature during operation is a major concern for developers and users. In this paper, a phase change material (PCM) cooling system was designed for a 60W mono-crystalline solar panel. Tealights candle was selected as the cooling medium. The solar irradiance was recorded using Kipp & Zonen CMP3 pyranometer and Meteon data logger. Temperature distribution on the surface of solar panel, output voltage and output current of solar panel were measured. The average irradiance throughout data collection was found to be 705W/m2 and highest irradiance was 1100 W/m2. The average solar panel temperature was 43.6°C and a maximum temperature of 53°C was at the center of solar panel. Results showed that average power output and efficiency of the solar panel were 44.4W and 15%, respectively. It was found that the higher the solar irradiance, the lower the efficiency of solar panel and the higher the temperature and power output of solar panel. This is due to the fact that high irradiance results in high power input and high solar panel temperature. But high PV panel temperature reduces its power output. Therefore, the increase of power input outweighs that of power output, which leads to the decrease of efficiency of solar panel with the increase of solar irradiance. Compared with solar panel without cooling, the power output and efficiency of solar panel did not increase with PCM cooling. It indicates that Tealights candle as PCM cooling is not efficient in improving the efficiency of solar panel in this study.

Standardinng initial cooling of sheep semen before freezing

African Journals Online (AJOL)

sheep semen before freezing. C. Kemp. Animal and Dairy Science Research Institute, Private Bag X2,. Irene, 1675 Republic of South Africa. Received 6 June 1985. A practical and repeatable method for the cooling, during the processing phase, of sheep semen, with the aim of minimizing inter-experiment variation is ...

Cryogenic system with the sub-cooled liquid nitrogen for cooling HTS power cable

Energy Technology Data Exchange (ETDEWEB)

Fan, Y.F. [Chinese Academy of Sciences, Beijing (China). Technical Institute of Physics and Chemistry; Graduate School of Chinese Academy of Sciences, Beijing (China); Gong, L.H.; Xu, X.D.; Li, L.F.; Zhang, L. [Chinese Academy of Sciences, Beijing (China). Technical Institute of Physics and Chemistry; Xiao, L.Y. [Chinese Academy of Sciences, Beijing (China). Institute of Electrical Engineering

2005-04-01

A 10 m long, three-phase AC high-temperature superconducting (HTS) power cable had been fabricated and tested in China August 2003. The sub-cooled liquid nitrogen (LN{sub 2}) was used to cool the HTS cable. The sub-cooled LN{sub 2} circulation was built by means of a centrifugal pump through a heat exchanger in the sub-cooler, the three-phase HTS cable cryostats and a LN{sub 2} gas-liquid separator. The LN{sub 2} was cooled down to 65 K by means of decompressing, and the maximum cooling capacity was about 3.3 kW and the amount of consumed LN{sub 2} was about 72 L/h at 1500 A. Cryogenic system design, test and some experimental results would be presented in this paper. (author)

Cooling of wood briquettes

Directory of Open Access Journals (Sweden)

Adžić Miroljub M.

2013-01-01

Full Text Available This paper is concerned with the experimental research of surface temperature of wood briquettes during cooling phase along the cooling line. The cooling phase is an important part of the briquette production technology. It should be performed with care, otherwise the quality of briquettes could deteriorate and possible changes of combustion characteristics of briquettes could happen. The briquette surface temperature was measured with an IR camera and a surface temperature probe at 42 sections. It was found that the temperature of briquette surface dropped from 68 to 34°C after 7 minutes spent at the cooling line. The temperature at the center of briquette, during the 6 hour storage, decreased to 38°C.

A Technology Demonstration Experiment for Laser Cooled Atomic Clocks in Space

Science.gov (United States)

Klipstein, W. M.; Kohel, J.; Seidel, D. J.; Thompson, R. J.; Maleki, L.; Gibble, K.

2000-01-01

We have been developing a laser-cooling apparatus for flight on the International Space Station (ISS), with the intention of demonstrating linewidths on the cesium clock transition narrower than can be realized on the ground. GLACE (the Glovebox Laser- cooled Atomic Clock Experiment) is scheduled for launch on Utilization Flight 3 (UF3) in 2002, and will be mounted in one of the ISS Glovebox platforms for an anticipated 2-3 week run. Separate flight definition projects funded at NIST and Yale by the Micro- gravity Research Division of NASA as a part of its Laser Cooling and Atomic Physics (LCAP) program will follow GLACE. Core technologies for these and other LCAP missions are being developed at JPL, with the current emphasis on developing components such as the laser and optics subsystem, and non-magnetic vacuum-compatible mechanical shutters. Significant technical challenges in developing a space qualifiable laser cooling apparatus include reducing the volume, mass, and power requirements, while increasing the ruggedness and reliability in order to both withstand typical launch conditions and achieve several months of unattended operation. This work was performed at the Jet Propulsion Laboratory under a contract with the National Aeronautics and Space Administration.

Past Experiences and Future Trends on Vertex Detector Cooling at LHC

CERN Document Server

Petagna, Paolo

2014-01-01

Substantially different approaches have been ad opted for the refrigeration plants of the first generation of vertex detectors at LHC: those of ALICE, ATLAS and CMS use PFC fluids, either in single phase or in a traditional Joule-Thomson cycle, while carbon dioxide in a pumped two-phase loop has been selected for the LHCb VELO. For what concerns the on-board thermal management of the sensors and related electronics, a traditional design has been followed, based on a common general approach and only differing in the specific choices related to the local configuration. Although the global performance of the detectors in this first phase of LHC operation can be claimed as fully satisfactory, it appears that the additional challenges posed by the coming upgrade phases can only be tackled through an effort on technology innovation and, in particular on much stronger and earlier integration of all the cooling-related aspects in the detector conception. Carbon dioxide seems to be the preferred choice for the refrige...

Thermal performance experiments on ultimate heat sinks, spray ponds, and cooling ponds

International Nuclear Information System (INIS)

Hadlock, R.K.

1976-12-01

A program of measurement on a Battelle-Northwest (BNW) spray pond has been completed to prove an integrated instrumentation system for application in future field experiments. The measurement programs in the field will produce data of relevance to the design and understanding of performance for ultimate heat sinks as components of emergency core cooling systems. In the absence of active emergency cooling systems, the data will be obtained on analog systems--prime candidates among these are the naturally-occurring hot ponds at Yellowstone National Park and man-made hot cooling ponds at Savannah River National Laboratory as well as spray ponds at various industrial facilities. The proof experiment has provided data that not only illustrate the effectiveness of the instrumentation system but also display interesting site-specific heat transfer processes. The data to be obtained in the field will also be site specific but must be of generic applicability in modeling for design and performance purposes. The integrated instrumentation system will evolve, through modest modifications and substantial supplementation, to provide the requisite data for the more demanding situation of work in and about hot water

Two-dimensional modeling of water spray cooling in superheated steam

Directory of Open Access Journals (Sweden)

Ebrahimian Vahid

2008-01-01

Full Text Available Spray cooling of the superheated steam occurs with the interaction of many complex physical processes, such as initial droplet formation, collision, coalescence, secondary break up, evaporation, turbulence generation, and modulation, as well as turbulent mixing, heat, mass and momentum transfer in a highly non-uniform two-phase environment. While it is extremely difficult to systematically study particular effects in this complex interaction in a well defined physical experiment, the interaction is well suited for numerical studies based on advanced detailed models of all the processes involved. This paper presents results of such a numerical experiment. Cooling of the superheated steam can be applied in order to decrease the temperature of superheated steam in power plants. By spraying the cooling water into the superheated steam, the temperature of the superheated steam can be controlled. In this work, water spray cooling was modeled to investigate the influences of the droplet size, injected velocity, the pressure and velocity of the superheated steam on the evaporation of the cooling water. The results show that by increasing the diameter of the droplets, the pressure and velocity of the superheated steam, the amount of evaporation of cooling water increases. .

Effect of cooling rate on the phase structure and magnetic properties of Fe{sub 26.7}Co{sub 28.5}Ni{sub 28.5}Si{sub 4.6}B{sub 8.7}P{sub 3} high entropy alloy

Energy Technology Data Exchange (ETDEWEB)

Wei, Ran; Sun, Huan; Chen, Chen [School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Han, Zhenhua [School of Materials Science and Engineering, Xi’an University of Technology, Xi’an 710068 (China); Li, Fushan, E-mail: fsli@zzu.edu.cn [School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001 (China)

2017-08-01

Highlights: • High entropy alloy with amorphous phase and FCC solid solution phase are successfully developed respectively. • The amorphous phase exhibits better soft magnetic properties than that of the solid solution phase. • The BCC phase transformed into FCC phase, and then into BCC phase was found in this HEA. - Abstract: The effect of cooling rate on phase structure and magnetic properties of the Fe{sub 26.7}Co{sub 28.5}Ni{sub 28.5}Si{sub 4.6}B{sub 8.7}P{sub 3} high entropy alloy (HEA) was investigated. The HEA forms into amorphous phase by melt spinning method at high cooling rate and FCC solid solution phase at low cooling rate. The soft magnetic properties of the amorphous phase (saturation magnetization B{sub s} of 1.07T and coercivity H{sub c} of 4 A/m) are better than that of the solid solution phase (B{sub s} of 1.0 T and H{sub c} of 168 A/m). In order to study the phase evolution of the present HEA, anneal experiments were conducted. It is found that crystallization products of amorphous phase are solid solution phase which constitute much of FCC and a small amount of BCC. BCC phase transforms into FCC phase, and then into BCC phase with the increase of annealing temperature.

Second sector cool down

CERN Multimedia

2007-01-01

At the beginning of July, cool-down is starting in the second LHC sector, sector 4-5. The cool down of sector 4-5 may occasionally generate mist at Point 4, like that produced last January (photo) during the cool-down of sector 7-8.Things are getting colder in the LHC. Sector 7-8 has been kept at 1.9 K for three weeks with excellent stability (see Bulletin No. 16-17 of 16 April 2007). The electrical tests in this sector have got opt to a successful start. At the beginning of July the cryogenic teams started to cool a second sector, sector 4-5. At Point 4 in Echenevex, where one of the LHC’s cryogenic plants is located, preparations for the first phase of the cool-down are underway. During this phase, the sector will first be cooled to 80 K (-193°C), the temperature of liquid nitrogen. As for the first sector, 1200 tonnes of liquid nitrogen will be used for the cool-down. In fact, the nitrogen circulates only at the surface in the ...

Evaluation of the effect of Bi, Sb, Sr and cooling condition on eutectic phases in an Al–Si–Cu alloy (ADC12) by in situ thermal analysis

International Nuclear Information System (INIS)

Farahany, S.; Ourdjini, A.; Idrsi, M.H.; Shabestari, S.G.

2013-01-01

Highlights: • Combined effect of Bi, Sb and Sr additions, and cooling condition was evaluated. • Two different scenarios of recalecense in response to cooling rate were observed. • Fraction solid increased in the order of Sr > Bi > Sb, corresponds to Si morphologies. • Only Bi decreased the nucleation temperature of Al 2 Cu eutectic phase. - Abstract: Al–Si and Al–Cu eutectic phases strongly affect the properties of Al–Si–Cu cast alloys. The characteristic parameters of these two eutectic phases with addition of bismuth, antimony and strontium under different cooling rates (0.6–2 °C/s) were investigated in ADC12 alloy using in situ thermal analysis. Results show that additives affect the Al–Si phase more than the Al–Cu (Al 2 Cu) phase. Addition elements showed two different scenarios in response to cooling rate in terms of recalescence of the Al–Si eutectic phase. Both Bi and Sb caused an increase in recalescence with increased cooling rate but Sr addition reduced the recalescence. Additions of Sb and Sr increased the nucleation temperature of Al 2 Cu, but addition of Bi produced an opposite effect. There seems to be relationship between the solidification temperature range and fraction solid of Al–Si and Al 2 Cu eutectic phases. As the cooling rate increases the fraction solid of Al–Si decreased and that of Al 2 Cu increased

Design study on sodium-cooled middle-scale modular reactor

International Nuclear Information System (INIS)

Shimakawa, Yoshio; Nibe, Nobuaki; Hori, Toru

2002-05-01

In Phase 1 of the 'Feasibility Study on Commercialized Fast Reactor Cycle Systems (F/S)', an advanced loop type reactor has been selected as a promising concept of sodium-cooled middle-scale modular reactor, which has a possibility to fulfill the design requirements of the F/S. In Phase 2 of the F/S, it is planed to precede a preliminary conceptual design of a sodium-cooled middle-scale modular reactor based on the design of the advanced loop type reactor. Through the design study, it is intended to construct such a plant concept that can show its attraction and competitiveness as a commercialized reactor. This report summarizes the results of the design study on the sodium-cooled middle-scale modular reactor performed in JFY2001, which is the first year of Phase 2. As the construction cost of the sodium-cooled middle-scale modular reactor, which has been constructed in Phase 1, was about 10% higher than that of the sodium-cooled large-scale reactor, a new concept of the middle-scale modular reactor, which is expected to be equal to the large-scale reactor from a viewpoint of economic competitiveness, has been re-constructed based on the design of the advanced loop type reactor. After that, fundamental specifications of main systems and components for the new concept have been set, and critical subjects related to safety, structural integrity, thermal hydraulics, operability, maintainability and economy have been examined and evaluated. As a result of this study, the plant concept of the sodium-cooled middle-scale modular reactor has been constructed, which has a prospect to satisfy the economic goal (construction cost: less than 200,000 yens/kWe, etc.) and has a prospect to solve the critical subjects. From now on, reflecting the results of elemental experiments, the preliminary conceptual design of this plant will be preceded toward the selection for narrowing down candidate concepts at the end of Phase 2. (author)

Experiments on novel solar heating and cooling system

International Nuclear Information System (INIS)

Wang Yiping; Cui Yong; Zhu Li; Han Lijun

2008-01-01

Solar heating and nocturnal radiant cooling techniques are united to produce a novel solar heating and cooling system. The radiant panel with both heating and cooling functions can be used as structural materials for the building envelope, which realizes true building integrated utilization of solar energy. Based on the natural circulation principle, the operation status can be changed automatically between the heating cycle and the cooling cycle. System performances under different climate conditions using different covers on the radiant panel are studied. The results show that the novel solar heating and cooling system has good performance of heating and cooling. For the no cover system, the daily average heat collecting efficiency is 52% with the maximum efficiency of 73%, while at night, the cooling capacity is about 47 W/m 2 on a sunny day. On a cloudy day, the daily average heat collecting efficiency is 47% with the maximum of 84%, while the cooling capacity is about 33 W/m 2 . As a polycarbonate (PC) panel or polyethylene film are used as covers, the maximum heat collecting efficiencies are 75% and 72% and the daily average heat collecting efficiencies are 61% and 58%, while the cooling capacities are 50 W/m 2 and 36 W/m 2 , respectively

A Modified Cooling Method and Its Application in "Drosophila" Experiments

Science.gov (United States)

Qu, Wen-hui; Zhu, Tong-bo; Yang, Da-Xiang

2015-01-01

Chilling is a cost-effective and safe method of immobilising flies in "Drosophila" experiments. However, should condensation form on the plate, it would be fatal to the flies. Here we describe a modified cooling method using reusable commercial ice pack(s) (ca. 400 ml, 2-3 cm tall) rather than crushed ice. The ice pack is covered with a…

Flow and Heat Transfer in Cooling Microchannels with Phase-Change

Energy Technology Data Exchange (ETDEWEB)

Peles, Y P; Yarin, L P; Hetsroni, G [Technion, Israel Institute of Technology, Haifa (Israel) Faculty of Engineering

1998-05-19

The subject of the present work is the parametrical investigation of hydrodynamic and thermal characteristics of laminar flow with phase-change in a heating microchannels. The study is based on the quasi-one-dimensional model of non-isothermal capillary flow. This model takes into account the evolution of flow, heating and evaporation of the liquid, as well as the influence of capillary, inertia, friction and gravity forces. The effect of various parameters (sizes of microchannel, initial temperature of cooling liquid, wall heat flux etc.) on hydrodynamic and thermal structures of the flow, the length of heating, evaporation and superheat regions is studied. Thc specific features of the phenomena is discussed.

Flow and Heat Transfer in Cooling Microchannels with Phase-Change

International Nuclear Information System (INIS)

Peles, Y.P.; Yarin, L.P.; Hetsroni, G.

1998-01-01

The subject of the present work is the parametrical investigation of hydrodynamic and thermal characteristics of laminar flow with phase-change in a heating microchannels. The study is based on the quasi-one-dimensional model of non-isothermal capillary flow. This model takes into account the evolution of flow, heating and evaporation of the liquid, as well as the influence of capillary, inertia, friction and gravity forces. The effect of various parameters (sizes of microchannel, initial temperature of cooling liquid, wall heat flux etc.) on hydrodynamic and thermal structures of the flow, the length of heating, evaporation and superheat regions is studied. Thc specific features of the phenomena is discussed

The ATLAS IBL CO2 Cooling System

CERN Document Server

Verlaat, Bartholomeus; The ATLAS collaboration

2016-01-01

The Atlas Pixel detector has been equipped with an extra B-layer in the space obtained by a reduced beam pipe. This new pixel detector called the ATLAS Insertable B-Layer (IBL) is installed in 2014 and is operational in the current ATLAS data taking. The IBL detector is cooled with evaporative CO2 and is the first of its kind in ATLAS. The ATLAS IBL CO2 cooling system is designed for lower temperature operation (<-35⁰C) than the previous developed CO2 cooling systems in High Energy Physics experiments. The cold temperatures are required to protect the pixel sensors for the high expected radiation dose up to 550 fb^-1 integrated luminosity. This paper describes the design, development, construction and commissioning of the IBL CO2 cooling system. It describes the challenges overcome and the important lessons learned for the development of future systems which are now under design for the Phase-II upgrade detectors.

A study of the cool gas in the Large Magellanic Cloud. I. Properties of the cool atomic phase - a third H i absorption survey

Science.gov (United States)

Marx-Zimmer, M.; Herbstmeier, U.; Dickey, J. M.; Zimmer, F.; Staveley-Smith, L.; Mebold, U.

2000-02-01

The cool atomic interstellar medium of the Large Magellanic Cloud (LMC) seems to be quite different from that in the Milky Way. In a series of three papers we study the properties of the cool atomic hydrogen in the LMC (Paper I), its relation to molecular clouds using SEST-CO-observations (Paper II) and the cooling mechanism of the atomic gas based on ISO-[\\CII]-investigations (Paper III). In this paper we present the results of a third 21 cm absorption line survey toward the LMC carried out with the Australia Telescope Compact Array (ATCA). 20 compact continuum sources, which are mainly in the direction of the supergiant shell LMC 4, toward the surroundings of 30 Doradus and toward the eastern steep \\HI\\ boundary, have been chosen from the 1.4 GHz snapshot continuum survey of Marx et al. We have identified 20 absorption features toward nine of the 20 sources. The properties of the cool \\HI\\ clouds are investigated and are compared for the different regions of the LMC taking the results of Dickey et al. (survey 2) into account. We find that the cool \\HI\\ gas in the LMC is either unusually abundant compared to the cool atomic phase of the Milky Way or the gas is clearly colder (\\Tc\\ ~ 30 K) than that in our Galaxy (\\Tc\\ ~ 60 K). The properties of atomic clouds toward 30 Doradus and LMC 4 suggest a higher cooling rate in these regions compared to other parts of the LMC, probably due to an enhanced pressure near the shock fronts of LMC 4 and 30 Doradus. The detected cool atomic gas toward the eastern steep \\HI\\ boundary might be the result of a high compression of gas at the leading edge. The Australia Telescope is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO.

Experiments indicating a second hydrogen ordered phase of ice VI.

Science.gov (United States)

Gasser, Tobias M; Thoeny, Alexander V; Plaga, Lucie J; Köster, Karsten W; Etter, Martin; Böhmer, Roland; Loerting, Thomas

2018-05-14

In the last twelve years five new ice phases were experimentally prepared. Two of them are empty clathrate hydrates and three of them represent hydrogen ordered counterparts of previously known disordered ice phases. Here, we report on hydrogen ordering in ice VI samples produced by cooling at pressures up to 2.00 GPa. Based on results from calorimetry, dielectric relaxation spectroscopy, Raman spectroscopy, and powder X-ray diffraction the existence of a second hydrogen ordered polymorph related to ice VI is suggested. Powder X-ray data show the oxygen network to be the one of ice VI. For the 1.80 GPa sample the activation energy from dielectric spectroscopy is 45 kJ mol -1 , which is much larger than for the known hydrogen ordered proxy of ice VI, ice XV. Raman spectroscopy indicates the 1.80 GPa sample to be more ordered than ice XV. It is further distinct from ice XV in that it experiences hydrogen disordering above ≈103 K which is 26 K below the ice XV to ice VI disordering transition. Consequently, below 103 K it is thermodynamically more stable than ice XV, adding a stability region to the phase diagram of water. For the time being we suggest to call this new phase ice β-XV and to relabel it ice XVIII once its crystal structure is known.

Effect of Cooling Rate on the Longitudinal Modulus of Cu3Sn Phase of Ag-Sn-Cu Amalgam Alloy (Part II

Directory of Open Access Journals (Sweden)

R. H. Rusli

2015-10-01

Full Text Available Effects of cooling rate (at the time of solidification on the elastic constants of Cu3Sn phase of Ag-Sn-Cu dental amalgam alloy were studied. In this study, three types of alloys were made, with the composition Cu-38-37 wt% Sn by means of casting, where each alloy was subjected to different cooling rate, such as cooling on the air (AC, air blown (AB, and quenched in the water (WQ. X-ray diffraction, metallography, and Scanning Electron Microscopy with Energy Dispersive Spectroscopy studies of three alloys indicated the existence of Cu3Sn phase. Determination of the modulus of elasticity of Cu3Sn (ε phase was carried out by the measurement of longitudinal and transversal waves velocity using ultrasonic technique. The result shows that Cu3Sn (ε phase on AC gives higher modulus of elasticity values than those of Cu3Sn (ε on AB and WQ. The high modulus of elasticity value will produce a strong Ag-Sn-Cu dental amalagam alloy.

Study on direct-contact phase-change liquid immersion cooling dense-array solar cells under high concentration ratios

International Nuclear Information System (INIS)

Kang, Xue; Wang, Yiping; Huang, Qunwu; Cui, Yong; Shi, Xusheng; Sun, Yong

2016-01-01

Highlights: • Direct-contact phase-change liquid immersion cooling for solar cells was proposed. • A self-regulating system investigated the feasibility in temperature control. • Temperature was well controlled between 87.3 °C and 88.5 °C. • Surface heat transfer coefficient was up to 23.49 kW/(m"2·K) under 398.4×. • A model illustrated the interface function was the main reason to affect light. - Abstract: A new cooling method by directly immersing the solar cells into phase-change liquid was put forward to cool dense-array solar cells in high concentrating photovoltaic system. A self-running system was built to study the feasibility of temperature control and the effect of bubbles generated by ethanol phase change under concentration ratio ranged between 219.8× and 398.4×. The results show that the cooling system is self-regulating without consuming extra energy and ethanol flow rate reaches up to 180.6 kg/(s·m"2) under 398.4×. The temperature of solar cells distributes in the range between 87.3 °C and 88.5 °C, the surface heat transfer coefficient of electric heating plate is up to 23.49 kW/(m"2·K) under 398.4×. The bubble effect on electrical performance of triple-junction solar cells is reported and the results show that I_s_c and P_m_a_x decline 10.2% and 7.3%, respectively. A model based on bubble images illustrates that light loss at the interface between ethanol and bubble is the main reason to cut down the electrical performance.

Evaluation of the effect of Bi, Sb, Sr and cooling condition on eutectic phases in an Al–Si–Cu alloy (ADC12) by in situ thermal analysis

Energy Technology Data Exchange (ETDEWEB)

Farahany, S., E-mail: saeedfarahany@gmail.com [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia (UTM), 81310 Johor Bahru (Malaysia); Ourdjini, A.; Idrsi, M.H. [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia (UTM), 81310 Johor Bahru (Malaysia); Shabestari, S.G. [Center of Excellence for High Strength Alloys Technology (CEHSAT), School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), 16846-13114 Tehran (Iran, Islamic Republic of)

2013-05-10

Highlights: • Combined effect of Bi, Sb and Sr additions, and cooling condition was evaluated. • Two different scenarios of recalecense in response to cooling rate were observed. • Fraction solid increased in the order of Sr > Bi > Sb, corresponds to Si morphologies. • Only Bi decreased the nucleation temperature of Al{sub 2}Cu eutectic phase. - Abstract: Al–Si and Al–Cu eutectic phases strongly affect the properties of Al–Si–Cu cast alloys. The characteristic parameters of these two eutectic phases with addition of bismuth, antimony and strontium under different cooling rates (0.6–2 °C/s) were investigated in ADC12 alloy using in situ thermal analysis. Results show that additives affect the Al–Si phase more than the Al–Cu (Al{sub 2}Cu) phase. Addition elements showed two different scenarios in response to cooling rate in terms of recalescence of the Al–Si eutectic phase. Both Bi and Sb caused an increase in recalescence with increased cooling rate but Sr addition reduced the recalescence. Additions of Sb and Sr increased the nucleation temperature of Al{sub 2}Cu, but addition of Bi produced an opposite effect. There seems to be relationship between the solidification temperature range and fraction solid of Al–Si and Al{sub 2}Cu eutectic phases. As the cooling rate increases the fraction solid of Al–Si decreased and that of Al{sub 2}Cu increased.

Supercritical Helium Cooling of the LHC Beam Screens

CERN Document Server

Hatchadourian, E; Tavian, L

1998-01-01

The cold mass of the LHC superconducting magnets, operating in pressurised superfluid helium at 1.9 K, must be shielded from the dynamic heat loads induced by the circulating particle beams, by means of beam screens maintained at higher temperature. The beam screens are cooled between 5 and 20 K by forced flow of weakly supercritical helium, a solution which avoids two-phase flow in the long, narr ow cooling channels, but still presents a potential risk of thermohydraulic instabilities. This problem has been studied by theoretical modelling and experiments performed on a full-scale dedicated te st loop.

Experimental analysis of ex-vessel core catcher cooling system performance for EU-APR1400 during severe accident

Energy Technology Data Exchange (ETDEWEB)

Song, K. W.; Park, H. S.; Revankar, S. T. [POSTECH, Pohang (Korea, Republic of); Kim, H. Y. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

In the coolant channel which has a unique design and large scale flow paths, natural circulation is passively activated by buoyancy driven force. Since two-phase flow behavior in a large scale channel is different from that in a small scale channel, the two-phase flow affecting the cooling capability is difficult to be predicted in the large channel. Therefore, cooling experiment in the core catcher coolant path is necessary. Cooling Experiment - Passive Ex-vessel corium retaining and Cooling System(CE-PECS) is constructed in full scale(in height and width) slice of half prototype. It actually simulates steam-water flow in the coolant channel for different decay heat condition of the corium. In this study, thermal power considering of total amount of decay heat 190 kW which corresponds to 40MW of thermal power in the prototype is loaded on the top wall of the CE-PECS coolant channel. Natural circulation flow rate and pressure drops at the two-phase region are measured in various power level. Temperatures of heater block and working fluid in various position along the flow path enable to calculate heat fluxes and heat transfer coefficients distribution. These results are used for evaluating heat removal capability of core catcher facility. Two-phase natural circulation experiment is carried out in CE-PECS facility. Based on the prototypic condition, 190 kW of total power is supplied to the top of the coolant path. Uniform distribution of heat load on the downward facing heater bock produces -300 kW/m2 at 100 % power ratio. Although the experiment should consider the heat loss and heat flux uniformity, several noticeable conclusions have been made as followings; 1. Mass flow rate and two-phase pressure drop are measured in various power conditions. 2. Slightly inclined top wall at the downstream of the channel shows better heat exchange performance than horizontal top wall because enhanced convection due to the increase of void fraction improves local cooling. This

Medium-size high-temperature gas-cooled reactor

International Nuclear Information System (INIS)

Peinado, C.O.; Koutz, S.L.

1980-08-01

This report summarizes high-temperature gas-cooled reactor (HTGR) experience for the 40-MW(e) Peach Bottom Nuclear Generating Station of Philadelphia Electric Company and the 330-MW(e) Fort St. Vrain Nuclear Generating Station of the Public Service Company of Colorado. Both reactors are graphite moderated and helium cooled, operating at approx. 760 0 C (1400 0 F) and using the uranium/thorium fuel cycle. The plants have demonstrated the inherent safety characteristics, the low activation of components, and the high efficiency associated with the HTGR concept. This experience has been translated into the conceptual design of a medium-sized 1170-MW(t) HTGR for generation of 450 MW of electric power. The concept incorporates inherent HTGR safety characteristics [a multiply redundant prestressed concrete reactor vessel (PCRV), a graphite core, and an inert single-phase coolant] and engineered safety features

Onderzoeksrapportage duurzaam koelen : EOS Renewable Cooling

OpenAIRE

Broeze, J.; Sluis, van der, S.; Wissink, E.

2010-01-01

For reducing energy use for cooling, alternative methods (that do not rely on electricity) are needed. Renewable cooling is based on naturally available resources such as evaporative cooling, free cooling, phase change materials, ground subcooling, solar cooling, wind cooling, night radiation & storage. The project was aimed to create innovative combinations of these renewable cooling technologies and sophisticated control systems, to design renewable climate systems for various applicati...

System for fast and accurate filling of a two-phase cooling device, notably a heat pipe, adapted for use in an automated process

NARCIS (Netherlands)

Wits, Wessel Willems; Ten Hoeve, Harm Jan; Te Riele Gert, Jan; Van Es, Johannes

2013-01-01

The current invention relates to a system for fast and accurate filling of a two-phase cooling device, comprising a binding device (30) intended to be hermetically mounted onto the cooling device, the binding device (30) comprising a through-hole (32) able to be in fluid contact with the cooling

SYSTEM FOR FAST AND ACCURATE FILLING OF A TWO-PHASE COOLING DEVICE, NOTABLY A HEAT PIPE, ADAPTED FOR USE IN AN AUTOMATED PROCESS

NARCIS (Netherlands)

Wits, Wessel Willems; Ten Hoeve, Harm Jan; Te Riele Gert, Jan; Van Es, Johannes

2013-01-01

The current invention relates to a system for fast and accurate filling of a two- phase cooling device, comprising a binding device (30) intended to be hermetically mounted onto the cooling device, the binding device (30) comprising a through-hole (32) able to be in fluid contact with the cooling

SYSTEM FOR FAST AND ACCURATE FILLING OF A TWO-PHASE COOLING DEVICE, NOTABLY A HEAT PIPE, ADAPTED FOR USE IN AN AUTOMATED PROCESS

NARCIS (Netherlands)

Wits, Wessel Willems; Ten Hoeve, Harm Jan; Te Riele Gert, Jan; Van Es, Johannes; Wits, Wessel Willems; Ten Hoeve, Harm Jan; Te Riele, Gerhardus Wilhelmus; Van Es, Johannes

2014-01-01

The current invention relates to a system for fast and accurate filling of a two-phase cooling device, comprising a binding device (30) intended to be hermetically mounted onto the cooling device, the binding device (30) comprising a through-hole (32) able to be in fluid contact with the cooling

Design study on sodium-cooled large-scale reactor

International Nuclear Information System (INIS)

Shimakawa, Yoshio; Nibe, Nobuaki; Hori, Toru

2002-05-01

In Phase 1 of the 'Feasibility Study on Commercialized Fast Reactor Cycle Systems (F/S)', an advanced loop type reactor has been selected as a promising concept of sodium-cooled large-scale reactor, which has a possibility to fulfill the design requirements of the F/S. In Phase 2 of the F/S, it is planed to precede a preliminary conceptual design of a sodium-cooled large-scale reactor based on the design of the advanced loop type reactor. Through the design study, it is intended to construct such a plant concept that can show its attraction and competitiveness as a commercialized reactor. This report summarizes the results of the design study on the sodium-cooled large-scale reactor performed in JFY2001, which is the first year of Phase 2. In the JFY2001 design study, a plant concept has been constructed based on the design of the advanced loop type reactor, and fundamental specifications of main systems and components have been set. Furthermore, critical subjects related to safety, structural integrity, thermal hydraulics, operability, maintainability and economy have been examined and evaluated. As a result of this study, the plant concept of the sodium-cooled large-scale reactor has been constructed, which has a prospect to satisfy the economic goal (construction cost: less than 200,000yens/kWe, etc.) and has a prospect to solve the critical subjects. From now on, reflecting the results of elemental experiments, the preliminary conceptual design of this plant will be preceded toward the selection for narrowing down candidate concepts at the end of Phase 2. (author)

Cooling Li-ion batteries of racing solar car by using multiple phase change materials

International Nuclear Information System (INIS)

Moraga, Nelson O.; Xamán, Jesús P.; Araya, Ricardo H.

2016-01-01

Highlights: • Thermal efficiency of Li-ion batteries improved by use of phase change materials. • Multiple layers of PCM provides good cooling capabilities for solar car batteries. • Evolution of temperature of solar car batteries described by Finite Volume Method. • Thermal control in discharge mode of lithium battery for solar car achieved by PCM. - Abstract: A numerical study of the unsteady phase change convection-conduction heat transfer of an ion-lithium battery with volumetric heat generation used in solar vehicles is presented. The cooling process is investigated for a total of seven arrays of phase change material (PCM): capric acid (PCM 1), eicosane (PCM 2), decahydrated sodium carbonate (PCM 3) and octadecane (PCM 4) located in one or three layers around the battery. The results show that heat conduction predominates in the battery with a PCM and the liquid phase fraction of the PCM indicates that the melting initiates after 7 min, reaching totally liquid state after 14.25 min. From the different configurations of PCM around the battery, the configuration “B” (multiple PCM: PCM 1 (5 mm) + PCM 3 (2.9 mm) + PCM 2 (4.3 mm)) and the configuration with a single layer of PCM 3 (14.3 mm) respectively reduce the maximum temperature of the battery about 20.9 and 23.2 K compared with the temperature reached by the battery without PCM. This result occurs because of the Decahydrated Sodium Carbonate PCM, since it has the highest latent heat and has a low melting point.

Brazing of the Tore Supra actively cooled Phase III Limiter

International Nuclear Information System (INIS)

Nygren, R.E.; Walker, C.A.; Lutz, T.J.; Hosking, F.M.; McGrath, R.T.

1993-01-01

The head of the water-cooled Tore Supra Phase 3 Limiter is a bank of 14 round OFHC copper tubes, curved to fit the plasma radius, onto which several hundred pyrolytic graphite (PG) tiles and a lesser number of carbon fiber composite tiles are brazed. The small allowable tolerances for fitting the tiles to the tubes and mating of compound curvatures made the brazing and fabrication extremely challenging. The paper describes the fabrication process with emphasis on the procedure for brazing. In the fixturing for vacuum furnace brazing, the tiles were each independently clamped to the tube with an elaborate set of window frame clamps. Braze quality was evaluated with transient heating tests. Some rebrazing was necessary

Investigation of the thermal performance of a vertical two-phase closed thermosyphon as a passive cooling system for a nuclear reactor spent fuel storage pool

Energy Technology Data Exchange (ETDEWEB)

Kusuma, Mukhsinun Hadi; Putra, Nandy; Imawan, Ficky Augusta [Heat Transfer Laboratory, Department of Mechanical Engineering Universitas Indonesia, Kampus (Indonesia); Antariksawan, Anhar Riza [Centre for Nuclear Reactor Safety and Technology, National Nuclear Energy Agency of Indonesia (BATAN), Kawasan Puspiptek Serpong (Indonesia)

2017-04-15

The decay heat that is produced by nuclear reactor spent fuel must be cooled in a spent fuel storage pool. A wickless heat pipe or a vertical two-phase closed thermosyphon (TPCT) is used to remove this decay heat. The objective of this research is to investigate the thermal performance of a prototype model for a large-scale vertical TPCT as a passive cooling system for a nuclear research reactor spent fuel storage pool. An experimental investigation and numerical simulation using RELAP5/MOD 3.2 were used to investigate the TPCT thermal performance. The effects of the initial pressure, filling ratio, and heat load were analyzed. Demineralized water was used as the TPCT working fluid. The cooled water was circulated in the water jacket as a cooling system. The experimental results show that the best thermal performance was obtained at a thermal resistance of 0.22°C/W, the lowest initial pressure, a filling ratio of 60%, and a high evaporator heat load. The simulation model that was experimentally validated showed a pattern and trend line similar to those of the experiment and can be used to predict the heat transfer phenomena of TPCT with varying inputs.

Development of the design of the High Temperature Gas Cooled Reactor experiment

International Nuclear Information System (INIS)

Lockett, G.E.; Huddle, R.A.U.

1960-01-01

Early in 1956 a small team was formed at the Atomic Energy Research Establishment, Harwell, to investigate the possibilities of the High Temperature Gas Cooled (H.T.G.C.) Reactor System. Although the primary objective of this team was to carry out a feasibility study of the system as a whole, it soon became apparent that, in addition to design studies and economic surveys of power producing reactors, the most appropriate approach to such a novel system was to carry out a design study of a relatively small (10 to 20 M.W.) Reactor Experiment, together with the necessary research and development work associated with such a reactor. This work proceeded within the U.K.A.E.A. during the three following years, and it was felt that realistic design proposals could be put forward with sufficient confidence to justify the detailed design and construction of a 20 M.W. Reactor Experiment. In April 1959 responsibility for this Reactor Experiment was taken over by the O.E.E.C. High Temperature Gas Cooled Reactor Project, the DRAGON Project, at the Atomic Energy Establishment, Winfrith, Dorset. In this Paper the research, development, and design work is reviewed, and the proposals for the Reactor Experiment are summarised. (author)

Flow-induced and acoustically induced vibration experience in operating gas-cooled reactors

International Nuclear Information System (INIS)

Halvers, L.J.

1977-03-01

An overview has been presented of flow-induced and acoustically induced vibration failures that occurred in the past in gas-cooled graphite-moderated reactors, and the importance of this experience for the Gas-Cooled Fast-Breeder Reactor (GCFR) project has been assessed. Until now only failures in CO 2 -cooled reactors have been found. No problems with helium-cooled reactors have been encountered so far. It is shown that most of the failures occurred because flow-induced and acoustically induced dynamic loads were underestimated, while at the same time not enough was known about the influence of environmental parameters on material behavior. All problems encountered were solved. The comparison of the influence of the gas properties on acoustically induced and flow-induced vibration phenomena shows that the interaction between reactor design and the thermodynamic properties of the primary coolant precludes a general preference for either carbon dioxide or helium. The acoustic characteristics of CO 2 and He systems are different, but the difference in dynamic loadings due to the use of one rather than the other remains difficult to predict. A slight preference for helium seems, however, to be justified

Cooling tower drift: experiment design for comprehensive case study

International Nuclear Information System (INIS)

Laulainen, N.S.

1978-01-01

A drift experiment program to develop a data base which can be used for validation of drift deposition models has been formulated. The first field effort is designed for a suitable mechanical-draft cooling tower to be selected after site visits have been conducted. The discussion here demonstrates the importance of characterizing the droplet size spectrum emitted from the tower and to accurately account for droplet evaporation, because the downwind droplet deposition patterns and near-surface airborne concentrations are extremely sensitive to these parameters

Requirements for the GCFR plenum streaming experiment

International Nuclear Information System (INIS)

Perkins, R.G.; Rouse, C.A.; Hamilton, C.J.

1980-09-01

This report gives the experiment objectives and generic descriptions of experimental configurations for the gas-cooled fast breeder reactor (GCFR) plenum shield experiment. This report defines four experiment phases. Each phase represents a distinct area of uncertainty in computing radiation transport from the GCFR core to the plenums, through the upper and lower plenum shields, and ultimately to the prestressed concrete reactor vessel (PCRV) liner: (1) the shield heterogeneity phase; (2) the exit shield simulation phase; (3) the plenum streaming phase; and (4) the plenum shield simulation phase

Stochastic Cooling at the CERN Antiproton Decelerator

CERN Document Server

Carli, Christian

2000-01-01

When transforming the CERN Antiproton Collector (AC) into the Antiproton Decelerator (AD), the stochastic cooling systems were rebuilt to cope with the new requirements. Instead of using the original three frequency bands, (0.9-1.6 GHz, 1.6-2.45 GHz and 2.4-3.2 GHz) only the first of these was used due to lattice limitations and other constraints. The same pick-ups and kickers are in use at two different energies. As in the AC, simultaneous cooling in all three phase planes is required. Switching between two transmission paths (at 3.5 GeV/c and 2.0 GeV/c) became necessary, including separate notch filters and delay compensation for the kicker sections. The tanks has to be rendered bakeable (150 C) to make the vacuum properties (<10-10 Torr) compatible with deceleration to low energies. Further improvements included programmable, phase-invariant electronic attenuators and amplitude-invariant delays. Experience during commissioning showed that careful optimization (depth and periodicity) of the notch filters...

Power-Cooling-Mismatch Test Series Test PCM-7. Experiment operating specifications

International Nuclear Information System (INIS)

Sparks, D.T.; Smith, R.H.; Stanley, C.J.

1979-02-01

The experiment operating specifications for the Power-Cooling-Mismatch (PCM) Test PCM-7 to be conducted in the Power Burst Facility are described. The PCM Test Series was designed on the basis of a parametric evaluation of fuel behavior response with cladding temperature, rod internal pressure, time in film boiling, and test rod power being the variable parameters. The test matrix, defined in the PCM Experiment Requirements Document (ERD), encompasses a wide range of situations extending from pre-CHF (critical heat flux) PCMs to long duration operation in stable film boiling leading to rod failure

Validation of Friction Models in MARS-MultiD Module with Two-Phase Cross Flow Experiment

International Nuclear Information System (INIS)

Choi, Chi-Jin; Yang, Jin-Hwa; Cho, Hyoung-Kyu; Park, Goon-Cher; Euh, Dong-Jin

2015-01-01

In the downcomer of Advanced Power Reactor 1400 (APR1400) which has direct vessel injection (DVI) lines as an emergency core cooling system, multidimensional two-phase flow may occur due to the Loss-of-Coolant-Accident (LOCA). The accurate prediction about that is high relevance to evaluation of the integrity of the reactor core. For this reason, Yang performed an experiment that was to investigate the two-dimensional film flow which simulated the two-phase cross flow in the upper downcomer, and obtained the local liquid film velocity and thickness data. From these data, it could be possible to validate the multidimensional modules of system analysis codes. In this study, MARS-MultiD was used to simulate the Yang's experiment, and obtained the local variables. Then, the friction models used in MARS-MultiD were validated by comparing the two-phase flow experimental results with the calculated local variables. In this study, the two-phase cross flow experiment was modeled by the MARS-MultiD. Compared with the experimental results, the calculated results by the code properly presented mass conservation which could be known from the relation between the liquid film velocity and thickness at the same flow rate. The magnitude and direction of the liquid film, however, did not follow well with experimental results. According to the results of Case-2, wall friction should be increased, and interfacial friction should be decreased in MARS-MultiD. These results show that it is needed to modify the friction models in the MARS-MultiD to simulate the two-phase cross flow

Encyclopedia of two-phase heat transfer and flow IV modeling methodologies, boiling of CO₂, and micro-two-phase cooling

CERN Document Server

2018-01-01

Set IV is a new addition to the previous Sets I, II and III. It contains 23 invited chapters from international specialists on the topics of numerical modeling of pulsating heat pipes and of slug flows with evaporation; lattice Boltzmann modeling of pool boiling; fundamentals of boiling in microchannels and microfin tubes, CO2 and nanofluids; testing and modeling of micro-two-phase cooling systems for electronics; and various special topics (flow separation in microfluidics, two-phase sensors, wetting of anisotropic surfaces, ultra-compact heat exchangers, etc.). The invited authors are leading university researchers and well-known engineers from leading corporate research laboratories (ABB, IBM, Nokia Bell Labs). Numerous "must read" chapters are also included here for the two-phase community. Set IV constitutes a "must have" engineering and research reference together with previous Sets I, II and III for thermal engineering researchers and practitioners.

Novel two-phase jet impingement heat sink for active cooling of electronic devices

International Nuclear Information System (INIS)

Oliveira, Pablo A. de; Barbosa, Jader R.

2017-01-01

Highlights: • Novel jet-based heat sink integrates the evaporator and the expansion device. • The system was tested with a small-scale oil-free R-134a compressor. • The thermodynamic performance of the cooling system was evaluated experimentally. • The single-jet maximum cooling capacity was 160 W, with a COP of 2.3 and a η 2nd of 8%. • Maximum heat transfer coefficient of 15 kW m −2 K −1 and surface temperature of 30 °C. - Abstract: This work presents a compact vapor compression cooling system equipped with a small-scale oil-free R-134a compressor and a jet-impingement-based heat sink that integrates the evaporator and the expansion device into a single unit. At the present stage of the development, a single orifice was used to generate the high-speed two-phase impinging jet on the heated surface. The effects of the compressor piston stroke, applied thermal load and orifice diameter on the system performance were quantified. The thermodynamic performance of the system was evaluated in terms of the temperature of the heated surface, impinging jet heat transfer coefficient, several system thermal resistances, coefficient of performance, second-law efficiency and second-law ratio. The coefficient of performance of the new refrigeration system increased with the cooling capacity, justifying its application in the removal of large thermal loads. The maximum system cooling capacity with a single jet was approximately 160 W, which was achieved with an orifice diameter of 500 μm and operation at a full compressor piston stroke. This condition corresponded to a COP of 2.3, a second-law efficiency of 8.0%, a jet impingement heat transfer coefficient above 15 kW m −2 K −1 and a heater surface temperature of approximately 30 °C.

Comparative Effectiveness of Different Phase Change Materials to Improve Cooling Performance of Heat Sinks for Electronic Devices

Directory of Open Access Journals (Sweden)

Ahmad Hasan

2016-08-01

Full Text Available This paper thermo-physically characterizes salt hydrate, paraffin wax and milk fat as phase change materials (PCMs. The three PCMs are compared in terms of improving heat sink (HS performance for cooling electronic packaging. An experimental study is carried out on commercially available finned HS with and without PCM under natural ventilation (NV and forced ventilation (FV at different heat loads (4 W to 10 W. The results indicate that integration of all of the PCMs into the HS improves its cooling performance; however, milk fat lags behind the other two PCMs in terms of cooling produced. A three-dimensional pressure-based conjugate heat transfer model has been developed and validated with experimental results. The model predicts the parametric influence of PCM melting range, thermal conductivity and density on HS thermal management performance. The HS cooling performance improves with increased density and conductivity while it deteriorates with the wider melting range of the PCMs.

Contribution to the study of the thermal and hydrodynamical properties of a two-phase natural circulation flow of normal helium (He I) for the cooling of superconducting magnets

International Nuclear Information System (INIS)

Benkheira, L.

2007-06-01

The method of cooling based on the thermosyphon principle is of great interest because of its simplicity, its passivity and its low cost. It is adopted to cool down to 4,5 K the superconducting magnet of the CMS particles detector of the Large Hadron Collider (LHC) experiment under construction at CERN, Geneva. This work studies heat and mass transfer characteristics of two phase He I in a natural circulation loop. The experimental set-up consists of a thermosyphon single branch loop mainly composed of a phase separator, a downward tube, and a test section. The experiments were conducted with varying several parameters such as the diameter of the test section (10 mm or 14 mm) and the applied heat flux up to the appearance of the boiling crisis. These experiments have permitted to determine the laws of evolution of the various parameters characterizing the flow (circulation mass flow rate, vapour mass flow rate, vapour quality, friction coefficient, two phase heat transfer coefficient and the critical heat flux) as a function of the applied heat flux. On the base of the obtained results, we discuss the validity of the various existing models in the literature. We show that the homogeneous model is the best model to predict the hydrodynamical properties of this type of flow in the vapour quality range 0≤x≤30%. Moreover, we propose two models for the prediction of the two phase heat transfer coefficient and the density of the critical heat flux. The first one considers that the effects of the forced convection and nucleate boiling act simultaneously and contribute to heat transfer. The second one correlates the measured critical heat flux density with the ratio altitude to diameter. (author)

Analysis of OECD/CSNI ISP-42 phase A PANDA experiment using coupled code R5G (RELAP5-GOTHIC)

International Nuclear Information System (INIS)

Bencik, V.; Debrecin, N.; Grgic, D.; Bajs, T.

2010-01-01

In the paper, the results of the analysis of OECD/CSNI ISP-42 Phase A experiment at PANDA facility using stand-alone codes RELAP5/mod3.3 and GOTHIC 7.2b as well as coupled code R5G (RELAP5/mod3.3-GOTHIC 7.2b) are presented. PANDA is a large-scale thermal-hydraulic test facility installed at PSI (Paul Scherrer Institute) in Switzerland. The OECD/CSNI ISP-42 test consists of six sequential phases (Phase A through F). The present work deals with the post-test calculation of the Phase A, including the break of the main steam line and the Passive Containment Cooling (PCC) System Start-Up. The objective of the test is to investigate the start-up phenomenology of passive cooling system when steam is injected into cold vessel filled with air. The calculation was performed using stand-alone RELAP5/mod3.3 and GOTHIC 7.2b models, and then the same calculation was performed using coupled code with RELAP5 being responsible for reactor part of the model and GOTHIC being responsible for containment part of the model. The prediction capability, running time and modeling aspects were discussed for all three cases. (authors)

Comparison of simulated and experimental results of temperature distribution in a closed two-phase thermosyphon cooling system

Science.gov (United States)

Shaanika, E.; Yamaguchi, K.; Miki, M.; Ida, T.; Izumi, M.; Murase, Y.; Oryu, T.; Yanamoto, T.

2017-12-01

Superconducting generators offer numerous advantages over conventional generators of the same rating. They are lighter, smaller and more efficient. Amongst a host of methods for cooling HTS machinery, thermosyphon-based cooling systems have been employed due to their high heat transfer rate and near-isothermal operating characteristics associated with them. To use them optimally, it is essential to study thermal characteristics of these cryogenic thermosyphons. To this end, a stand-alone neon thermosyphon cooling system with a topology resembling an HTS rotating machine was studied. Heat load tests were conducted on the neon thermosyphon cooling system by applying a series of heat loads to the evaporator at different filling ratios. The temperature at selected points of evaporator, adiabatic tube and condenser as well as total heat leak were measured. A further study involving a computer thermal model was conducted to gain further insight into the estimated temperature distribution of thermosyphon components and heat leak of the cooling system. The model employed boundary conditions from data of heat load tests. This work presents a comparison between estimated (by model) and experimental (measured) temperature distribution in a two-phase cryogenic thermosyphon cooling system. The simulation results of temperature distribution and heat leak compared generally well with experimental data.

Survey of natural-circulation cooling in U.S. pressurized water reactors

International Nuclear Information System (INIS)

Boyack, B.E.

1985-01-01

Literature describing natural circulation analyses, experiments, and plant operation have been obtained from the Nuclear Regulatory Commission, reactor vendors, utility-sponsored research groups, utilities, national laboratories, and foreign sources. These have been reviewed and significant results and conclusions identified. Three modes of natural-circulation cooling are covered: single phase, two-phase, and reflux condensation. Single-phase natural circulation is amply verified by plant operational data, test data from scaled experimental facilities, and analysis with assessed computer codes. Ample evidence also exists that two-phase natural circulation can successfully cool pressurized water reactors. This mode occurs during certain events such as small-break loss-of-coolant accidents. The data base for reflux condensation is primarily from tests in scaled experimental facilities. There are no plant operational data and only limited assessment of thermal-hydraulic systems codes has been performed. Further work is needed before this mode of natural circulation can be confidently used

Cavity Cooling of Nanoparticles: Towards Matter-Wave experiments

Science.gov (United States)

Millen, James; Kuhn, Stefan; Arndt, Markus

2016-05-01

Levitated systems are a fascinating addition to the world of optically-controlled mechanical resonators. It is predicted that nanoparticles can be cooled to their c.o.m. ground state via the interaction with an optical cavity. By freeing the oscillator from clamping forces dissipation and decoherence is greatly reduced, leading to the potential to produce long-lived, macroscopically spread, mechanical quantum states, allowing tests of collapse models and any mass limit of quantum physics. Reaching the low pressures required to cavity-cool to the ground state has proved challenging. Our approach is to cavity cool a beam of nanoparticles in high vacuum. We can cool the c.o.m. motion of nanospheres a few hundred nanometers in size. Looking forward, we will utilize novel microcavities to enhance optomechanical cooling, preparing particles in a coherent beam ideally suited to ultra-high mass interferometry at 107 a.m.u.

Cooling Scenario for the HESR Complex

International Nuclear Information System (INIS)

Stockhorst, H.; Prasuhn, D.; Maier, R.; Lorentz, B.

2006-01-01

The High-Energy Storage Ring (HESR) of the future International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt is planned as an anti-proton cooler ring in the momentum range from 1.5 to 15 GeV/c. An important and challenging feature of the new facility is the combination of phase space cooled beams with internal targets. The required beam parameters and intensities are prepared in two operation modes: the high luminosity mode with beam intensities up to 1011 anti-protons, and the high resolution mode with 1010 anti-protons cooled down to a relative momentum spread of only a few 10-5. Consequently, powerful phase space cooling is needed, taking advantage of high-energy electron cooling and high-bandwidth stochastic cooling. Both cooling techniques are envisaged here theoretically, including the effect of beam-target interaction and intra-beam scattering to find especially for stochastic cooling the best system parameters

Construction and commissioning experience of evolutionary water cooled nuclear power plants

International Nuclear Information System (INIS)

2004-04-01

Electricity market liberalization is an established fact in several countries and there is a trend to adopt it in other countries. The essential aim of market liberalization is to improve the overall economic efficiency. In order that nuclear power remains a viable option for electricity generation, its costs should be competitive with alternative sources while, at the same time, it should have a safe and reliable operation record. The capital cost of nuclear power plants (NPPs) generally accounts for 43-70% of the total nuclear electricity generation costs, compared to 26-48% for coal plants and 13-32% for gas plants. Most of these expenditures are incurred during the construction phase of a NPP. The achievement of shorter construction periods using improved technology and construction methods has a significant benefit on the costs incurred prior to any production of electricity. This document is intended to make the recent worldwide experience on construction and commissioning of evolutionary water cooled NPPs available to Member States and especially to those with nuclear power plants under construction/planning, and to those seriously considering nuclear power projects in the future. The final aim is to assist utilities and other organizations in Member States to improve the construction of nuclear power plants and achieve shortened schedules and reduced costs without compromising quality and safety. This document aims to provide an overview of the most advanced technologies, methods and processes used in construction and commissioning of recent nuclear projects. To better achieve this objective the presentation is selectively focused more on the new developments rather than providing a full review of all issues related to construction and commissioning. The experience described in this TECDOC applies to managers, engineers, supervisors, technicians and workers in various organizations dealing with the site construction and commissioning of nuclear power plants

Spray cooling

International Nuclear Information System (INIS)

Rollin, Philippe.

1975-01-01

Spray cooling - using water spraying in air - is surveyed as a possible system for make-up (peak clipping in open circuit) or major cooling (in closed circuit) of the cooling water of the condensers in thermal power plants. Indications are given on the experiments made in France and the systems recently developed in USA, questions relating to performance, cost and environmental effects of spray devices are then dealt with [fr

Relating hydrogen-bonding interactions with the phase behavior of naproxen/PVP K 25 solid dispersions: evaluation of solution-cast and quench-cooled films.

Science.gov (United States)

Paudel, Amrit; Nies, Erik; Van den Mooter, Guy

2012-11-05

In this work, we investigated the relationship between various intermolecular hydrogen-bonding (H-bonding) interactions and the miscibility of the model hydrophobic drug naproxen with the hydrophilic polymer polyvinylpyrrolidone (PVP) across an entire composition range of solid dispersions prepared by quasi-equilibrium film casting and nonequilibrium melt quench cooling. The binary phase behavior in solid dispersions exhibited substantial processing method dependence. The solid state solubility of crystalline naproxen in PVP to form amorphous solid dispersions was 35% and 70% w/w naproxen in solution-cast films and quench-cooled films, respectively. However, the presence of a single mixed phase glass transition indicated the amorphous miscibility to be 20% w/w naproxen for the films, beyond which amorphous-amorphous and/or crystalline phase separations were apparent. This was further supported by the solution state interactions data such as PVP globular size distribution and solution infrared spectral profiles. The borderline melt composition showed cooling rate dependence of amorphization. The glass transition and melting point depression profiles of the system were treated with the analytical expressions based on Flory-Huggins mixing theory to interpolate the equilibrium solid solubility. FTIR analysis and subsequent spectral deconvolution revealed composition and miscibility dependent variations in the strength of drug-polymer intermolecular H-bonding. Two types of H-bonded populations were evidenced from 25% w/w and 35% w/w naproxen in solution-cast films and quench-cooled films, respectively, with the higher fraction of strongly H-bonded population in the drug rich domains of phase separated amorphous film compositions and highly drug loaded amorphous quench-cooled dispersions.

Extending the applicability of an open-ring trap to perform experiments with a single laser-cooled ion

Energy Technology Data Exchange (ETDEWEB)

Cornejo, J. M.; Colombano, M.; Doménech, J.; Rodríguez, D., E-mail: danielrodriguez@ugr.es [Departamento de Física Atómica, Molecular y Nuclear, Universidad de Granada, 18071 Granada (Spain); Block, M. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Helmholtz-Institut Mainz, 55099 Mainz (Germany); Institut für Kernchemie, University of Mainz, 55099 Mainz (Germany); Delahaye, P. [Grand Accélérateur National d’Ions Lourds, 14000 Caen (France)

2015-10-15

A special ion trap was initially built up to perform β-ν correlation experiments with radioactive ions. The trap geometry is also well suited to perform experiments with laser-cooled ions, serving for the development of a new type of Penning trap, in the framework of the project TRAPSENSOR at the University of Granada. The goal of this project is to use a single {sup 40}Ca{sup +} ion as detector for single-ion mass spectrometry. Within this project and without any modification to the initial electrode configuration, it was possible to perform Doppler cooling on {sup 40}Ca{sup +} ions, starting from large clouds and reaching single ion sensitivity. This new feature of the trap might be important also for other experiments with ions produced at radioactive ion beam facilities. In this publication, the trap and the laser system will be described, together with their performance with respect to laser cooling applied to large ion clouds down to a single ion.

Influence of cooling rate on phase formation in spray-formed H13 tool steel

Energy Technology Data Exchange (ETDEWEB)

McHugh, K.M. [Industrial Technology Department, Idaho National Laboratory, Idaho Falls, ID 83415-2050 (United States)], E-mail: kevin.mchugh@inl.gov; Lin, Y.; Zhou, Y.; Lavernia, E.J. [Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616 (United States)

2008-03-25

Spray forming is an effective way to process many tool steels into near-net-shape molds, dies, and related tooling. The general approach involves depositing atomized droplets onto a refractory pattern in order to image the pattern's features. The pattern is removed and the die insert is mounted in a standard mold base or holding block. This approach results in significant cost and lead-time savings compared to conventional machining. Spray-formed dies perform well in many industrial forming operations, oftentimes exhibiting extended die life compared to conventional dies of the same material and design. Care must be exercised when spray forming tool steel dies to minimize porosity and control the nature and distribution of phases and residual stresses. Selection of post-deposition heat treatment is important to tailor the die's properties (hardness, strength, impact energy, etc.) for a particular application. This paper examines how the cooling rate during spray processing and heat treatment of H13 tool steel influences phase formation. Porosity and hardness were evaluated over a range of deposit cooling rates and residual stresses were evaluated for a die in the as-deposited condition. Finally, the performance of spray-formed dies during production runs in forging, extrusion, and die casting is described.

Influence of cooling rate on phase formation in spray-formed H13 tool steel

International Nuclear Information System (INIS)

McHugh, K.M.; Lin, Y.; Zhou, Y.; Lavernia, E.J.

2008-01-01

Spray forming is an effective way to process many tool steels into near-net-shape molds, dies, and related tooling. The general approach involves depositing atomized droplets onto a refractory pattern in order to image the pattern's features. The pattern is removed and the die insert is mounted in a standard mold base or holding block. This approach results in significant cost and lead-time savings compared to conventional machining. Spray-formed dies perform well in many industrial forming operations, oftentimes exhibiting extended die life compared to conventional dies of the same material and design. Care must be exercised when spray forming tool steel dies to minimize porosity and control the nature and distribution of phases and residual stresses. Selection of post-deposition heat treatment is important to tailor the die's properties (hardness, strength, impact energy, etc.) for a particular application. This paper examines how the cooling rate during spray processing and heat treatment of H13 tool steel influences phase formation. Porosity and hardness were evaluated over a range of deposit cooling rates and residual stresses were evaluated for a die in the as-deposited condition. Finally, the performance of spray-formed dies during production runs in forging, extrusion, and die casting is described

Effects of deep cryogenic treatment on the solid-state phase transformation of Cu-Al alloy in cooling process

Science.gov (United States)

Wang, Yuhui; Liao, Bo; Liu, Jianhua; Chen, Shuqing; Feng, Yu; Zhang, Yanyan; Zhang, Ruijun

2012-07-01

The solid-state phase transformation temperature and duration of deep cryogenic treated and untreated Cu-Al alloys in cooling process were measured by differential scanning calorimetry measurement. The solid-state phase transformation activation energy and Avrami exponent were calculated according to these measurements. The effects of deep cryogenic treatment on the solid-state phase transformation were investigated based on the measurement and calculation as well as the observation of alloy's microstructure. The results show that deep cryogenic treatment can increase the solid-phase transformation activation energy and shorten the phase transformation duration, which is helpful to the formation of fine grains in Cu-Al alloy.

Effect of cooling rate on the phase transformation behavior and mechanical properties of Ni-rich NiTi shape memory alloy

Energy Technology Data Exchange (ETDEWEB)

Motemani, Y. [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Nili-Ahmadabadi, M. [School of Metallurgy and Materials Engineering, Faculty of Engineering, University of Tehran, 14395-731 Tehran (Iran, Islamic Republic of); Tan, M.J. [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore)], E-mail: mmjtan@ntu.edu.sg; Bornapour, M.; Rayagan, Sh. [School of Metallurgy and Materials Engineering, Faculty of Engineering, University of Tehran, 14395-731 Tehran (Iran, Islamic Republic of)

2009-02-05

TiNi alloy is a well-known shape memory alloy and has been widely used for bio-medical, mechanical and electrical applications. In this study, a Ni-rich NiTi alloy was prepared by vacuum arc melting in a water-cooled copper crucible. Three samples of this alloy were heated to 1000 deg. C and cooled in three media: furnace, water, and dry-ice bath. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), hardness measurement and tensile test were carried out to investigate the effect of cooling rate on transformation temperature and mechanical properties. The results show that Ni{sub 3}Ti intermetallic compounds have a great influence on martensitic phase transformation temperature. These tests clearly showed the correlation between cooling rate and properties of the alloy.

Influence of Solution-Annealing Parameters on the Continuous Cooling Precipitation of Aluminum Alloy 6082

Directory of Open Access Journals (Sweden)

Hannes Fröck

2018-04-01

Full Text Available We use a systematic approach to investigate the influence of the specific solution condition on quench-induced precipitation of coarse secondary phase particles during subsequent cooling for a wide range of cooling rates. Commercially produced plate material of aluminum alloy EN AW-6082 was investigated and the applied solution treatment conditions were chosen based on heating differential scanning calorimetry experiments of the initial T651 condition. The kinetics of the quench-induced precipitation were investigated by in situ cooling differential scanning calorimetry for a wide range of cooling rates. The nature of those quench-induced precipitates was analyzed by electron microscopy. The experimental data was evaluated with respect to the detrimental effect of incomplete dissolution on the age-hardening potential. We show that if the chosen solution temperature and soaking duration are too low or short, the solution treatment results in an incomplete dissolution of secondary phase particles. This involves precipitation during subsequent cooling to start concurrently with the onset of cooling, which increases the quench sensitivity. However, if the solution conditions allow the formation of a complete solid solution, precipitation will start after a certain degree of undercooling, thus keeping the upper critical cooling rate at the usual alloy-specific level.

A study on corium melt pool behavior under external vessel cooling : investigation of the first phase research results in the OECD RASPLAV project

Energy Technology Data Exchange (ETDEWEB)

Park, Rae Joon; Kim, Sang Baik; Kim, Hee Dong; Yoo, Kun Joong

1998-04-01

The scope and contents of the OECD RASPLAV program are to investigate natural convection heat transfer in the corium, chemical and mechanical interaction between the corium and the reactor vessel, crust formation of the corium, and thermal behaviour of the corium by experiments and model development during external vessel cooling to prevent reactor vessel failure in severe accidents of nuclear power plant. This study includes evaluation and analysis of the RASPLAV V phase I results for three years between July 1, 1994 and June 30, 1997. These results supply technical basis for our experimental program on severe accident research. Two large-scale experiments of RASPLAV-AW-between the corium and the reactor vessel. Several small-scale experiments were conducted to analyze thermal stratification in the corium. The salt experiments were conducted to estimate the crust and the mushy region formation, and natural convection heat transfer in the corium. In the analytical studies, pre and post analysis of the RASPLAV-AW-200 experiments and evaluation of the salt test results have been performed using CONV 2 and 3D computer codes, which were developed during RASPLAV program phase I. Low density corium was separated from the high density corium during the RASPLAV-AW-200 tests and the TULPAN test, which was a new finding in the RASPLAV project phase I. From the salts test, heat flux distribution in the side wall heating case is similar to the direct internal heat generation case, and the crust formation is a little effect on heat transfer rate. The results of CONV 2 and 3 D were very well with with the experimental results. The results of RASLAV project phase I, such as furnace design and the techniques on fuel melting, are very helpful to our severe accident experimental program. (author). 57 refs., 13 tabs., 52 figs.

TEM study on a new Zr-(Fe, Cu) phase in furnace-cooled Zr-1.0Sn-0.3Nb-0.3Fe-0.1Cu alloy

Science.gov (United States)

Liu, Yushun; Qiu, Risheng; Luan, Baifeng; Hao, Longlong; Tan, Xinu; Tao, Boran; Zhao, Yifan; Li, Feitao; Liu, Qing

2018-06-01

A new Zr-(Fe, Cu) phase was found in furnace-cooled Zr-1.0Sn-0.3Nb-0.3Fe- 0.1Cu alloy and alloys aged at 580 °C for 10min, 2 h and 10 h. Electron diffraction experiment shows the crystal structure of this phase to be body-centered tetragonal with unit cell dimensions determined to be a = b = 6.49 Å, c = 5.37 Å. Its possible space groups have been discussed and the reason accounting for its formation is believed to be the addition of Cu according to the atom-level images. In addition, no crystal structural or chemical composition changes were observed throughout the aging process.

Phase-Field Modeling of Sigma-Phase Precipitation in 25Cr7Ni4Mo Duplex Stainless Steel

Science.gov (United States)

Malik, Amer; Odqvist, Joakim; Höglund, Lars; Hertzman, Staffan; Ågren, John

2017-10-01

Phase-field modeling is used to simulate the formation of sigma phase in a model alloy mimicking a commercial super duplex stainless steel (SDSS) alloy, in order to study precipitation and growth of sigma phase under linear continuous cooling. The so-called Warren-Boettinger-McFadden (WBM) model is used to build the basis of the multiphase and multicomponent phase-field model. The thermodynamic inconsistency at the multiple junctions associated with the multiphase formulation of the WBM model is resolved by means of a numerical Cut-off algorithm. To make realistic simulations, all the kinetic and the thermodynamic quantities are derived from the CALPHAD databases at each numerical time step, using Thermo-Calc and TQ-Interface. The credibility of the phase-field model is verified by comparing the results from the phase-field simulations with the corresponding DICTRA simulations and also with the empirical data. 2D phase-field simulations are performed for three different cooling rates in two different initial microstructures. A simple model for the nucleation of sigma phase is also implemented in the first case. Simulation results show that the precipitation of sigma phase is characterized by the accumulation of Cr and Mo at the austenite-ferrite and the ferrite-ferrite boundaries. Moreover, it is observed that a slow cooling rate promotes the growth of sigma phase, while a higher cooling rate restricts it, eventually preserving the duplex structure in the SDSS alloy. Results from the phase-field simulations are also compared quantitatively with the experiments, performed on a commercial 2507 SDSS alloy. It is found that overall, the predicted morphological features of the transformation and the composition profiles show good conformity with the empirical data.

Extended analysis of cooling curves

International Nuclear Information System (INIS)

Djurdjevic, M.B.; Kierkus, W.T.; Liliac, R.E.; Sokolowski, J.H.

2002-01-01

Thermal Analysis (TA) is the measurement of changes in a physical property of a material that is heated through a phase transformation temperature range. The temperature changes in the material are recorded as a function of the heating or cooling time in such a manner that allows for the detection of phase transformations. In order to increase accuracy, characteristic points on the cooling curve have been identified using the first derivative curve plotted versus time. In this paper, an alternative approach to the analysis of the cooling curve has been proposed. The first derivative curve has been plotted versus temperature and all characteristic points have been identified with the same accuracy achieved using the traditional method. The new cooling curve analysis also enables the Dendrite Coherency Point (DCP) to be detected using only one thermocouple. (author)

RCCS Experiments and Validation for High Temperature Gas-Cooled Reactor

International Nuclear Information System (INIS)

Chang Oh; Cliff Davis; Goon C. Park

2007-01-01

A reactor cavity cooling system (RCCS), an air-cooled helical coil RCCS unit immersed in the water pool, was proposed to overcome the disadvantages of the weak cooling ability of air-cooled RCCS and the complex structure of water-cooled RCCS for the high temperature gas-cooled reactor (HTGR). An experimental apparatus was constructed to investigate the various heat transfer phenomena in the water pool type RCCS, such as the natural convection of air inside the cavity, radiation in the cavity, the natural convection of water in the water pool and the forced convection of air in the cooling pipe. The RCCS experimental results were compared with published correlations. The CFX code was validated using data from the air-cooled portion of the RCCS. The RELAP5 code was validated using measured temperatures from the reactor vessel and cavity walls

Multilayer composite material and method for evaporative cooling

Science.gov (United States)

Buckley, Theresa M. (Inventor)

2002-01-01

A multilayer composite material and method for evaporative cooling of a person employs an evaporative cooling liquid that changes phase from a liquid to a gaseous state to absorb thermal energy. The evaporative cooling liquid is absorbed into a superabsorbent material enclosed within the multilayer composite material. The multilayer composite material has a high percentage of the evaporative cooling liquid in the matrix. The cooling effect can be sustained for an extended period of time because of the high percentage of phase change liquid that can be absorbed into the superabsorbent. Such a composite can be used for cooling febrile patients by evaporative cooling as the evaporative cooling liquid in the matrix changes from a liquid to a gaseous state to absorb thermal energy. The composite can be made with a perforated barrier material around the outside to regulate the evaporation rate of the phase change liquid. Alternatively, the composite can be made with an imperveous barrier material or semipermeable membrane on one side to prevent the liquid from contacting the person's skin. The evaporative cooling liquid in the matrix can be recharged by soaking the material in the liquid. The multilayer composite material can be fashioned into blankets, garments and other articles.

Immersion Cooling of Electronics in DoD Installations

Science.gov (United States)

2016-05-01

2012). Bitcoin Mining Electronics Cooling Development In January 2013, inventor/consultant Mark Miyoshi began development of a two-phase cooling...system using Novec 649 to be used for cooling bitcoin mining hardware. After a short trial period, hardware power supply and logic-board failures...are reports of bitcoin mining companies vertically stacking two-phase immersion baths to improve the floor space density, but this approach is likely

Electron cooling and elementary particle physics

International Nuclear Information System (INIS)

Budker, G.I.; Skrinskij, A.N.

1978-01-01

This review is devoted to a new method in experimental physics - the electron cooling. This method opens possibilities in storing the intense and highly monochromatic beams of heavy particles and allows to carry out a wide series of experiments of a high luminocity and resolution. The method is based on the beam cooling by an accompanying flux of electrons. The cooling is due to Coulomb collisions of the beam particles with electrons. In the first part the theoretical aspects of the method are considered shortly. The layout of the NAP-M installation with electron cooling and results of successful experiments on cooling the proton beam are given. In the second part the new possibilities are discussed which appear due to application of electron cooling: storing the intense antiproton beams and realization of the proton - antiproton colliding beams, carrying out experiments with the super fine targets in storage rings, experiments with particles and antiparticles at ultimately low energies, storing the polarized antiprotons and other particles, production of antiatoms, antideuton storing, experiments with ion beams

Passive decay heat removal by sump cooling after core meltdown

International Nuclear Information System (INIS)

Knebel, J.U.; Mueller, U.

1996-01-01

This article presents the basic physical phenomena and scaling criteria of decay heat removal from a large coolant pool by single-phase and two-phase natural circulation flow. The physical significance of the dimensionless similarity groups derived is evaluated. The above results are applied to the SUCO program that is performed at the Forschungszentrum Karlsruhe. The SUCO program is a three-step series of scaled model experiments investigating the possibility of a sump cooling concept for future light water reactors. The sump cooling concept is based on passive safety features within the containment. The work is supported by the German utilities and the Siemens AG. The article gives first measurement results of the 1:20 linearly scaled plane two-dimensional SUCOS-2D test facility. The experimental results of the model geometry are transformed to prototype conditions

Prehospital cooling of severe burns: Experience of the Emergency ...

African Journals Online (AJOL)

Only cooling performed by the patient, their family, bystanders or prehospital staff was recorded. Cooling performed by the Edendale Hospital ED staff was not included. Duration of cooling with water was documented as per the report given by the patient. Variables assessed included age, gender, time of burn, day of week,.

Vertical sampling flights in support of the 1981 ASCOT cooling tower experiments: field effort and data

Energy Technology Data Exchange (ETDEWEB)

Gay, G.T.

1982-03-01

During the month of August 1981, three nights of experimental sampling of tracers released into the cooling tower plume of a geothermal power plant were conducted. In these experiments a tethered balloon was used to lift a payload so as to obtain vertical profiles of the cooling tower plume and the entrained tracers. A description of the equipment used, the field effort and the data acquired are presented here.

Design study on sodium cooled large-scale reactor

International Nuclear Information System (INIS)

Murakami, Tsutomu; Hishida, Masahiko; Kisohara, Naoyuki

2004-07-01

In Phase 1 of the 'Feasibility Studies on Commercialized Fast Reactor Cycle Systems (F/S)', an advanced loop type reactor has been selected as a promising concept of sodium-cooled large-scale reactor, which has a possibility to fulfill the design requirements of the F/S. In Phase 2, design improvement for further cost reduction of establishment of the plant concept has been performed. This report summarizes the results of the design study on the sodium-cooled large-scale reactor performed in JFY2003, which is the third year of Phase 2. In the JFY2003 design study, critical subjects related to safety, structural integrity and thermal hydraulics which found in the last fiscal year has been examined and the plant concept has been modified. Furthermore, fundamental specifications of main systems and components have been set and economy has been evaluated. In addition, as the interim evaluation of the candidate concept of the FBR fuel cycle is to be conducted, cost effectiveness and achievability for the development goal were evaluated and the data of the three large-scale reactor candidate concepts were prepared. As a results of this study, the plant concept of the sodium-cooled large-scale reactor has been constructed, which has a prospect to satisfy the economic goal (construction cost: less than 200,000 yens/kWe, etc.) and has a prospect to solve the critical subjects. From now on, reflecting the results of elemental experiments, the preliminary conceptual design of this plant will be preceded toward the selection for narrowing down candidate concepts at the end of Phase 2. (author)

An experimental investigation of the effect of clad ballooning on the effectiveness of PWR emergency cooling

International Nuclear Information System (INIS)

Cooper, C.A.; Pearson, K.G.; Jowitt, D.

1985-01-01

A series of single phase cooling, forced reflood, gravity reflood and level swell experiments has been performed on a full length, electrically heated 7x7 rod fuel cluster (in the THETIS Rig) containing a blockage simulating very severe clad ballooning. The single phase cooling experiments provided data on the level of heat transfer within the cluster and the enhancement produced by turbulence created by the spacer grids. The forced reflood experiments have led to a better understanding of the rewetting processes during bottom reflooding, the very important influence of spacer grids in two-phase flow and the complicated heat transfer processes within the blockage. The insight obtained has been used to develop a mechanistic model. The gravity reflood experiments investigated steam binding and inlet flow oscillation effects. The variation in inlet flow produced by the variations in system parameters was the dominant influence. The inlet flow oscillations which occurred in gravity reflood appeared not to influence overall rewetting or heat removal performance. The level swell experiments investigated the relationship between void fraction and superficial steam velocity at pressures up to 40 bar and compared the data with various correlations. The correlation of Gardner was found to be most satisfactory. 107 refs., 252 figs.

A feasibility experiment for assessing the efficacy of ex-vessel cooling through the external gap structure

International Nuclear Information System (INIS)

Kang, K. H.; Kim, J. H.; Park, L. J.; Kim, S. B.; Hwang, I. S.

1999-01-01

This paper presents the results of a feasibility experiment for assessing the efficacy of ex-vessel cooling through the external gap structure during a severe accident. In this study, a 1/8 linear scale mockup of a lower plenum was used with Al2O3/Fe thermite melt as a corium simulant. The results show that in dry case test conducted without cooling the outside of the vessel, after about thirty second from the thermite ignition the vessel was heated to cause a complete melt penetration at about 30 degree upper position from the bottom. Whereas in wet case test conducted cooling the outside of the vessel with 0.85 kg/s of water flow rate using 2.5 cm of uniform gap structure, the vessel effectively cooled down with 23.7 K/s of cooling rate by nucleate boiling at the surface of the vessel. The results of two-dimensional analyses using FLUENT code show a similar trend of vessel thermal behavior presented in the tests. Synthesized the results of the tests and analyses work, a natural convection of the melt pool could cause the formation of hot spot at the upper portion of the vessel, but the vessel could effectively cool down by heat removal with ex-vessel cooling

A very cool cooling system

CERN Multimedia

Antonella Del Rosso

2015-01-01

The NA62 Gigatracker is a jewel of technology: its sensor, which delivers the time of the crossing particles with a precision of less than 200 picoseconds (better than similar LHC detectors), has a cooling system that might become the precursor to a completely new detector technique.   The 115 metre long vacuum tank of the NA62 experiment. The NA62 Gigatracker (GTK) is composed of a set of three innovative silicon pixel detectors, whose job is to measure the arrival time and the position of the incoming beam particles. Installed in the heart of the NA62 detector, the silicon sensors are cooled down (to about -20 degrees Celsius) by a microfluidic silicon device. “The cooling system is needed to remove the heat produced by the readout chips the silicon sensor is bonded to,” explains Alessandro Mapelli, microsystems engineer working in the Physics department. “For the NA62 Gigatracker we have designed a cooling plate on top of which both the silicon sensor and the...

Cooling of particulate debris beds: analysis of the initial D-series experiments

International Nuclear Information System (INIS)

Rivard, J.B.

1978-01-01

In an effort to provide basic data on the cooling of fast reactor debris, three in-pile experiments employing oxide fuel particulate in liquid sodium were completed in late 1977. Preliminary results from these experiments were reported shortly after their completion at the Third Post-Accident Heat Removal Information Exchange, at Argonne National Laboratory. In these experiments, a distribution of 100 μm to 1000 μm-sized particles of enriched UO 2 was fission-heated to simulate decay-heated debris. In each experiment, the UO 2 particles were contained in a closed, flat-bottomed vessel 012 mm in diameter which was insulated on the diameter and bottom. Sufficient sodium was included to saturate the bed of particles and to provide a volume of bulk sodium above the bed at a controlled temperature. Parameters of interest in the experiments are given

Design study on sodium-cooled middle-scale modular reactor

International Nuclear Information System (INIS)

Kisohara, Naoyuki; Hishida, Masahiko; Nibe, Nobuaki

2003-09-01

In Phase 1 of the 'Feasibility Study on Commercialized Fast Reactor Cycle Systems (F/S)', an advanced loop type reactor has been selected as a promising concept of sodium-cooled middle-scale modular reactor, which has a possibility to fulfill the design requirements of the F/S. This report summarizes the results of the design study on the sodium-cooled middle-scale modular reactor performed in JFY2002, which is the second year of Phase 2. The construction cost of the sodium-cooled middle-scale modular reactor, which has been constructed in JFY2002, was almost achieved the economical goal. But its achievability was not sufficient to accept the concept. In order to reduce the construction cost, the plant concept has been re-constructed based on the 50 MWe plant studied in JFY2002. After that, fundamental specifications of main systems and components for the new concept have been set, and critical subjects have been examined and evaluated. In addition, in order to achieve the further cost reduction, the plant with simplified secondary system, the plant with electric magnetic pump in secondary system, and the fuel handling system are examined and evaluated. As a result of this study, the plant concept of the sodium-cooled middle-scale modular reactor has been constructed, which has a prospect to satisfy the economic goal (construction cost: less than 200,000 yens/kWe, etc.) and has a prospect to solve the critical subjects. From now on, reflecting the results of elemental experiments, the preliminary conceptual design of this plant will be preceded toward the selection for narrowing down candidate concepts at the end of Phase 2. (author)

Helical muon beam cooling channel engineering design

International Nuclear Information System (INIS)

Johnson, Rolland

2015-01-01

The Helical Cooling Channel (HCC) achieves effective ionization cooling of the six-dimensional (6d) phase space of a muon beam by means of a series of 21st century inventions. In the HCC, hydrogen-pressurized RF cavities enable high RF gradients in strong external magnetic fields. The theory of the HCC, which requires a magnetic field with solenoid, helical dipole, and helical quadrupole components, demonstrates that dispersion in the gaseous hydrogen energy absorber provides effective emittance exchange to enable longitudinal ionization cooling. The 10-year development of a practical implementation of a muon-beam cooling device has involved a series of technical innovations and experiments that imply that an HCC of less than 300 m length can cool the 6d emittance of a muon beam by six orders of magnitude. We describe the design and construction plans for a prototype HCC module based on oxygen-doped hydrogen-pressurized RF cavities that are loaded with dielectric, fed by magnetrons, and operate in a superconducting helical solenoid magnet. The first phase of this project saw the development of a conceptual design for the integration of 805 MHz RF cavities into a 10 T Nb 3 Sn-based HS test section. Two very novel ideas are required to realize the design. The first idea is the use of dielectric inserts in the RF cavities to make them smaller for a given frequency so that the cavities and associated plumbing easily fit inside the magnet cryostat. Calculations indicate that heat loads will be tolerable, while RF breakdown of the dielectric inserts will be suppressed by the pressurized hydrogen gas. The second new idea is the use of a multi-layer Nb 3 Sn helical solenoid. The technology demonstrations for the two aforementioned key components of a 10T, 805 MHz HCC were begun in this project. The work load in the Fermilab Technical Division made it difficult to test a multi-layer Nb 3 Sn solenoid as originally planned. Instead, a complementary project was approved by the

Helical muon beam cooling channel engineering design

Energy Technology Data Exchange (ETDEWEB)

Johnson, Rolland [Muons, Inc., Batavia, IL (United States)

2015-08-07

The Helical Cooling Channel (HCC) achieves effective ionization cooling of the six-dimensional (6d) phase space of a muon beam by means of a series of 21st century inventions. In the HCC, hydrogen-pressurized RF cavities enable high RF gradients in strong external magnetic fields. The theory of the HCC, which requires a magnetic field with solenoid, helical dipole, and helical quadrupole components, demonstrates that dispersion in the gaseous hydrogen energy absorber provides effective emittance exchange to enable longitudinal ionization cooling. The 10-year development of a practical implementation of a muon-beam cooling device has involved a series of technical innovations and experiments that imply that an HCC of less than 300 m length can cool the 6d emittance of a muon beam by six orders of magnitude. We describe the design and construction plans for a prototype HCC module based on oxygen-doped hydrogen-pressurized RF cavities that are loaded with dielectric, fed by magnetrons, and operate in a superconducting helical solenoid magnet. The first phase of this project saw the development of a conceptual design for the integration of 805 MHz RF cavities into a 10 T Nb₃Sn-based HS test section. Two very novel ideas are required to realize the design. The first idea is the use of dielectric inserts in the RF cavities to make them smaller for a given frequency so that the cavities and associated plumbing easily fit inside the magnet cryostat. Calculations indicate that heat loads will be tolerable, while RF breakdown of the dielectric inserts will be suppressed by the pressurized hydrogen gas. The second new idea is the use of a multi-layer Nb₃Sn helical solenoid. The technology demonstrations for the two aforementioned key components of a 10T, 805 MHz HCC were begun in this project. The work load in the Fermilab Technical Division made it difficult to test a multi-layer Nb₃Sn solenoid as originally planned. Instead, a complementary

Cooling rates and intensity limitations for laser-cooled ions at relativistic energies

Science.gov (United States)

Eidam, Lewin; Boine-Frankenheim, Oliver; Winters, Danyal

2018-04-01

The ability of laser cooling for relativistic ion beams is investigated. For this purpose, the excitation of relativistic ions with a continuous wave and a pulsed laser is analyzed, utilizing the optical Bloch equations. The laser cooling force is derived in detail and its scaling with the relativistic factor γ is discussed. The cooling processes with a continuous wave and a pulsed laser system are investigated. Optimized cooling scenarios and times are obtained in order to determine the required properties of the laser and the ion beam for the planed experiments. The impact of beam intensity effects, like intrabeam scattering and space charge are analyzed. Predictions from simplified models are compared to particle-in-cell simulations and are found to be in good agreement. Finally two realistic example cases of Carbon ions in the ESR and relativistic Titanium ions in SIS100 are compared in order to discuss prospects for future laser cooling experiments.

Fuel assembly cooling experience at the FFTF/IEM cell

International Nuclear Information System (INIS)

McGuinness, P.W.

1985-01-01

In the Fast Flux Test Facility (FFTF), sodium wetted irradiated fuel assemblies are discharged to the Interim Examination and Maintenance (IEM) Cell for disassembly and post-irradiation examination in an inert argon atmosphere. While in the IEM Cell, fuel assemblies are cooled by the IEM Cell Subassembly Cooling System. This paper describes the cooling system design, performance, and lessons learned, including a discussion of two overtemperature incidents. 2 refs., 6 figs

Application of analytical capability to predict rapid cladding cooling and quench during the blowdown phase of a large break loss-of-coolant accident

International Nuclear Information System (INIS)

Aksan, S.N.; Tolman, E.L.; Nelson, R.A.

1983-01-01

Large-break Experiments L2-2 and L2-3 conducted in the Loss-of-Fluid Test (LOFT) facility experienced core-wide rapid quenches early in the blowdown transients. To further investigate rapid cladding quenches, separate effects experiments using Semiscale solid-type electric heater rods were conducted in the LOFT Test Support Facility (LTSF) over a wide range of inlet coolant conditions. The analytical capability to predict the cladding temperature response from selected LTSF experiments estimated to bound the hydraulic conditions causing the LOFT early blowdown quenches was investigated using the RELAP4 computer code and was shown to be acceptable over the film boiling cooldown phase. This analytical capability was then used to investigate the behavior of nuclear fuel rods under the same hydraulic conditions. The calculations show that, under rapid cooling conditions, the behaviors of nuclear and electrical heater rods are significantly different because the nuclear rods are conduction limited, while the electrical rods are convection limited

Role and status of scaled experiments in the development of fluoride-salt-cooled, high-temperature reactors - 15185

International Nuclear Information System (INIS)

Zweibaum, N.; Huddar, L.; Laufer, M.R.; Peterson, P.F.; Hughes, J.T.; Blandford, E.D.; Scarlat, R.O.

2015-01-01

Development of fluoride-salt-cooled, high-temperature reactor (FHR) technology requires a better understanding of key hydrodynamic and heat transfer phenomena associated with this novel class of reactors. The use of simulant fluids that can match the most important non dimensional numbers between scaled experiments and prototypical FHR systems enables integral effects tests (IETs) to be performed at reduced cost and difficulty for FHR code validation. The University of California at Berkeley (UCB) and the University of New Mexico (UNM) have built a number of IETs and separate effects tests to investigate pebble-bed FHR (PB-FHR) phenomenology using water or simulant oils such as Dowtherm A. PB-FHR pebble motion and porous media flow dynamics have been investigated with UCB's pebble recirculation experiments using water and plastic spheres. Transient flow of high-Prandtl-number fluids around hot spheres has also been investigated by UCB to measure Nusselt numbers in pebble-bed cores, using simulant oils and copper spheres. Finally, single-phase forced/natural circulation has been investigated using the scaled height, reduced flow area loops of the Compact Integral Effects Test facility at UCB and a multi-flow regime loop at UNM, using Dowtherm A oil. The scaling methodology and status of these ongoing experiments are described here

Demonstration of Super Cooled Ice as a Phase Change Material Heat Sink for Portable Life Support Systems

Science.gov (United States)

Leimkuehler, Thomas O.; Bue, Grant C.

2009-01-01

A phase change material (PCM) heat sink using super cooled ice as a nontoxic, nonflammable PCM is being developed. The latent heat of fusion for water is approximately 70% larger than most paraffin waxes, which can provide significant mass savings. Further mass reduction is accomplished by super cooling the ice significantly below its freezing temperature for additional sensible heat storage. Expansion and contraction of the water as it freezes and melts is accommodated with the use of flexible bag and foam materials. A demonstrator unit has been designed, built, and tested to demonstrate proof of concept. Both testing and modeling results are presented along with recommendations for further development of this technology.

Cooling System for the Merit High-Power Target Experiment

CERN Document Server

Haug, F; Silva, P; Pezzeti, M; Pavlov, O; Pirotte, O; Metselaar, J; Efthymiopoulos, I; Fabich, A; Lettry, J; Kirk, H G; McDonald, K T; Titus, P; Bennett, J R J

2010-01-01

MERIT is a proof-of-principle experiment of a target station suitable as source for future muon colliders or neutrino factories. When installed at the CERN (European Organization for Nuclear Research) PS (Proton Synchrotron)complex fast-extracted high-intensity proton beams intercepted a free mercury jet inside a normal-conducting, pulsed 15-T capture solenoid magnet cooled with liquid nitrogen. Up to 25 MJ of Joule heat was dissipated in the magnet during a pulse. The fully automated, remotely controlled cryogenic system of novel design permitted the transfer of nitrogen by the sole means of differential pressures inside the vessels. This fast cycling system permitted several hundred tests in less than three weeks during the 2007 data taking campaign.

Emergency cooling of presurized water reactor

International Nuclear Information System (INIS)

Sykora, D.

1981-01-01

The method described of emergency core cooling in the pressurized water reactor is characterized by the fact that water is transported to the disturbed primary circuit or direct to the reactor by the action of the energy and mass of the steam and/or liquid phase of the secondary circuit coolant, which during emergency core cooling becomes an emergency cooling medium. (B.S.)

Experiments for the premixing phase (QUEOS); Experimente zur Vorvermischungsphase (QUEOS)

Energy Technology Data Exchange (ETDEWEB)

Meyer, L.; Huber, R.; Haessler, M.; Kirstahler, M.; Kuhn, D.; Rehme, K.; Schumacher, G.; Schwall, M.; Wachter, E.; Woerner, G.

1995-08-01

Experiments are performed with solid spheres at high temperatures to establish a data base for the premixing phase of a steam explosion, which will be used for code improvement and validation. The hot spheres (T{<=}2600 K) are being dropped into saturated water at 1 bar pressure. The objective of the experiments is to obtain data on the cooling rate of the spheres, their distribution in the water, the amount of generated steam and its distribution with respect to the spheres. The spheres have a diameter of 4.2 mm, 4.8 mm and 10 mm, respectively, depending on the material used. Molybdenum coated with Rhenium to inhibit oxidation and ZrO{sub 2} are used. The experimental parameters are the mass flow of the spheres, their density and their temperature. The QUEOS test facility has been set up and tested. A series of first tests has been performed with cold spheres and spheres at 1000 C. The main results are the distribution of the spheres during the fall through the water and their distribution at the bottom of the water vessel. A large air bubble is being entrained into the water in both the cold and hot tests. (orig./HP)

The HypHI Phase 0 experiment

Energy Technology Data Exchange (ETDEWEB)

Saito, T.R. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Inst. fuer Kernphysik, Johannes Gutenberg Univ. Mainz, J.J.Becherweg 45, 55099 Mainz (Germany)], E-mail: t.saito@gsi.de; Bianchin, S. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Borodina, O. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Inst. fuer Kernphysik, Johannes Gutenberg Univ. Mainz, J.J. Becherweg 45, 55099 Mainz (Germany); Bozkurt, V.; Goekuezuem, B. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Dept. of Physics, Nigde Univ., 51100 Nigde (Turkey); Kavatsyuk, M. [KVI, Zernikelaan 25, NL-9747 AA Groningen (Netherlands); Kim, E. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Dept. of Physics and Astronomy, Seoul National Univ., Gwanakro Sillim-dong, Gwanak-gu, Seoul 151-747 (Korea, Republic of); Minami, S. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Nakajima, D. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Dept. of Physics, Graduate School of Science, Univ. of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Ozel-Tashenov, B. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Rappold, C. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Univ. Louis Pasteur Strasbourg, 4 rue Blaise Pascal, 67070 Strasbourg Cedex (France); Achenbach, P. [Inst. fuer Kernphysik, Johannes Gutenberg Univ. Mainz, J.J.Becherweg 45, 55099 Mainz (Germany); Ajimura, S. [Research Center for Nuclear Physics (RCNP), 10-1 Mihogaoka, Ibaraki, Osaka, 567-0047 (Japan); Aumann, T.; Caesar, C. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany)] (and others)

2010-04-01

The HypHI Phase 0 experiment to demonstrate the feasibility of precise hypernuclear spectroscopy with induced reactions of heavy ion beams was performed at GSI in August and October in 2009, with a projectile of {sup 6}Li at 2 A GeV impinged on carbon graphite target with a thickness of 8 g/cm{sup 2}. The experiment mainly aims to reconstruct events of {sup 3}{sub {lambda}}H, {sup 4}{sub {lambda}}H and {sup 5}{sub {lambda}}He by observing the {pi}{sup -} decay channel. Details of the HypHI Phase 0 experiment performed in August in 2009 will be discussed.

Design of the cooling systems for the multiplicity and vertex detector

International Nuclear Information System (INIS)

Bernardin, J.D.; Cunningham, R.

1997-11-01

The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory is being constructed to investigate a phase of matter termed the quark-gluon plasma. The plasma will be produced through the collision of two heavy ions. The multiplicity and vertex detector (MVD) located in the center of PHENIX will characterize the events, determine the collision point, and act as a central trigger. This report presents the final mechanical designs of the cooling systems for the Multiplicity and Vertex Detector (MVD). In particular, the design procedure and layouts are discussed for two different air cooling systems for the multichip modules and MVD enclosure, and a liquid cooling system for the low dropout voltage regulators. First of all, experimental prototype cooling system test results used to drive the final mechanical designs are summarized and discussed. Next, the cooling system requirements and design calculation for the various subsystem components are presented along with detailed lists of supply vendors, components, and costs. Finally, safety measures incorporated in the final mechanical design and operation procedures for each of the subsystems are detailed

Super-cool Dark Matter arXiv

CERN Document Server

Hambye, Thomas; Teresi, Daniele

In dimension-less theories of dynamical generation of the weak scale, the Universe can undergo a period of low-scale inflation during which all particles are massless and super-cool. This leads to a new mechanism of generation of the cosmological Dark Matter (DM) relic density: super-cooling can easily suppress the amount of DM to the desired level. This is achieved for TeV-scale DM, if super-cooling ends when quark condensates form at the QCD phase transition. Along this scenario, the baryon asymmetry can be generated either at the phase transition or through leptogenesis. We show that the above mechanism takes place in old and new dimension-less models.

Evaporative cooling of cold atoms in a surface trap

International Nuclear Information System (INIS)

Hammes, M.; Rychtarik, D.; Grimm, R.

2001-01-01

Full text: Trapping cold atom close to a surface is a promising route for attaining a two-dimensional quantum gas. We present our gravito-optical surface trap (LOST), which consists of a horizontal evanescent-wave atom mirror in combination with a blue-detuned hollow beam for transverse confinement. Optical pre-cooling based on inelastic reflections from the evanescent wave provides good starting conditions for subsequent evaporative cooling, which can be realized by ramping down the optical potentials of the trap. Already our preliminary experiments (performed at the MPI fuer Kernphysik in Heidelberg) show a 100-fold increase in phase-space density and temperature reduction to 300 nK. Substantial further improvements can be expected in our greatly improved set-up after the recent transfer of the experiment to Innsbruck. By eliminating heating processes, optimizing the evaporation ramp, polarizing the atoms and by using an additional far red-detuned laser beam we expect to soon reach the conditions of quantum degeneracy and/or two-dimensionality. (author)

EFFECT OF COOLING RATES ON THE MICROSTRUCTURE AND ...

African Journals Online (AJOL)

... eutectic under three cooling conditions were proposed. In the DTA mode (slow cooling), the relationship between the two phases was stable. However as the cooling rates increased ( quenching and meltspun modes), the relationship tended towards metastability. KEY WORDS: alloy, solidification, microstructure, eutectic, ...

Analysis of the heat transfer mechanisms during energy storage in a Phase Change Material filled vertical finned cylindrical unit for free cooling application

International Nuclear Information System (INIS)

Solomon, Gnanadurai Ravikumar; Velraj, Ramalingam

2013-01-01

Highlights: • Freezing behavior of a PCM, in a cylinder with annular longitudinal fins is presented. • Among various fin heights, 20 mm fin contribute maximum heat transfer enhancement. • Addition of fins plays a contradictory role during the sensible cooling of liquid PCM. • The fin effect along with external cooling, vary the sensible cooling rate of liquid PCM. • The surface convective resistance dominated over the conductive resistance of PCM. - Abstract: The heat transfer performance of the Phase Change Material (PCM) used in free cooling application is low due to poor thermal conductivity. The addition of fins to enhance the heat transfer during solidification process is commonly employed, to address this. However for application such as free cooling, where the driving temperature potential is very less, the present experimental study is intended to investigate the sensible and subcooling phenomena during the outward cylindrical solidification of the PCM stored on the annulus side, along with 8 longitudinal uniformly spaced copper fins of different heights. The performance of the fins during solidification is analyzed, and the best suitable height is arrived at. The addition of fins plays a contradicting role during the sensible cooling of the liquid PCM, due to the suppression of free convection. The external cooling conditions along with the effect of the fin, vary the sensible cooling rate of the liquid PCM, that influences the subcooling effect, and also drifts the temperature at which major phase change occurs. In addition, the effects due to the inlet velocity of the heat transfer fluid, and its temperature on heat transfer are investigated and reported. The increase in velocity decreases the duration of solidification, and this effect is more pronounced towards the entry region, due to the higher local convective heat transfer co-efficient and a comparatively higher driving temperature potential

Experience gained from high heat flux actively cooled PFCs in Tore Supra

International Nuclear Information System (INIS)

Grosman, A.; Bayetti, P.; Brosset, C.; Bucalossi, J.; Cordier, J.J.; Durocher, A.; Escourbiac, F.; Ghendrih, Ph.; Guilhem, D.; Gunn, J.; Loarer, T.; Lipa, M.; Mitteau, R.; Pegourie, B.; Reichle, R.; Schlosser, J.; Tsitrone, E.; Vallet, J.C.

2005-01-01

The implementation of actively cooled high heat flux plasma facing components (PFCs) is one of the major ingredients required for operating the Tore Supra tokamak with very long pulses. A pioneering activity has been developed in this field from the very beginning of the device operation that is today culminating with the routine operation of an actively cooled toroidal pumped limiter (TPL) capable to sustain up to 10 MW/m 2 of nominal convected heat flux. Technical information is drawn from the whole development up to the industrialisation and focuses on a number of critical issues, such as bonding technology analysis, manufacture processes, repair processes, destructive and non-destructive testing. The actual experience in Tore Supra allows to address the question of D retention on carbon walls. Redeposition on surfaces without plasma flux is suspected to cause the final 'burial' of about half of the injected gas during long discharges

Emergency reactor container cooling facility

International Nuclear Information System (INIS)

Suzuki, Hiroaki; Matsumoto, Tomoyuki.

1992-01-01

The present invention concerns an emergency cooling facility for a nuclear reactor container having a pressure suppression chamber, in which water in the suppression chamber is effectively used for cooling the reactor container. That is, the lower portion of a water pool in the pressure suppression chamber and the inside of the reactor container are connected by a pipeline. The lower end of the pipeline and a pressurized incombustible gas tank disposed to the outside of the reactor container are connected by a pipeline by way of valves. Then, when the temperature of the lower end of the pressure vessel exceeds a predetermined value, the valves are opened. If the valves are opened, the incombustible gas flows into the lower end of the pipeline connecting the lower portion of the water pool in the pressure suppression chamber and the inside of the reactor container. Since the inside of the pipeline is a two phase flow comprising a mixture of a gas phase and a liquid phase, the average density is decreased. Therefore, the water level of the two phase flow is risen by the level difference between the inside and the outside of the pipeline and, finally, the two phase mixture is released into the reactor container. As a result, the reactor container can be cooled by water in the suppression chamber by a static means without requiring pumps. (I.S.)

The final cool down

CERN Multimedia

Thursday 29th May, the cool-down of the final sector (sector 4-5) of LHC has begun, one week after the start of the cool-down of sector 1-2. It will take five weeks for the sectors to be cooled from room temperature to 5 K and a further two weeks to complete the cool down to 1.9 K and the commissioning of cryogenic instrumentation, as well as to fine tune the cryogenic plants and the cooling loops of cryostats.Nearly a year and half has passed since sector 7-8 was cooled for the first time in January 2007. For Laurent Tavian, AT/CRG Group Leader, reaching the final phase of the cool down is an important milestone, confirming the basic design of the cryogenic system and the ability to operate complete sectors. “All the sectors have to operate at the same time otherwise we cannot inject the beam into the machine. The stability and reliability of the cryogenic system and its utilities are now very important. That will be the new challenge for the coming months,” he explains. The status of the cool down of ...

Electron cooling of PB$^{54+}$ ions in the low energy ion ring (LEIR)

CERN Document Server

Bosser, Jacques; Chanel, M; MacCaferri, R; Maury, S; Möhl, D; Molinari, G; Tranquille, G

1998-01-01

For the preparation of dense bunches of lead ions for the LHC, electron cooling will be essential for accumula tion in a storage ring at 4.2 MeV/u. Tests have been carried out on the LEAR ring (renamed LEIR for Low Energy Ion Ring) in order to determine the optimum parameters for a future state-of-the-art electron cooling device which would be able to cool linac pulses of lead ions in less than 100 ms. The experiments focused on the generation of a stable high intensity electron beam that is needed to free space in both longitudinal and transverse phase space for incoming pulses. Investigations on the ion beam lifetime in the presence of the electron beam and on the dependency of the cooling times on the optical settings of the storage ring will also be discussed. This paper concentrates on the cooling aspects with the multiturn injection, vacuum, and high intensity aspects discussed in a companion paper at this conference.

Cryogenic systems for proof of the principle experiment of coherent electron cooling at RHIC

Energy Technology Data Exchange (ETDEWEB)

Huang, Yuenian; Belomestnykh, Sergey; Brutus, Jean Clifford; Lederle, Dewey; Orfin, Paul; Skaritka, John; Soria, Victor; Tallerico, Thomas; Than, Roberto [Collider Accelerator Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2014-01-29

The Coherent electron Cooling (CeC) Proof of Principle (PoP) experiment is proposed to be installed in the Relativistic Heavy Ion Collider (RHIC) to demonstrate proton and ion beam cooling with this new technique that may increase the beam luminosity in certain cases, by as much as tenfold. Within the scope of this project, a 112 MHz, 2MeV Superconducting Radio Frequency (SRF) electron gun and a 704 MHz 20MeV 5-cell SRF cavity will be installed at IP2 in the RHIC ring. The superconducting RF electron gun will be cooled in a liquid helium bath at 4.4 K. The 704 MHz 5-cell SRF cavity will be cooled in a super-fluid helium bath at 2.0 K. This paper discusses the cryogenic systems designed for both cavities. For the 112 MHz cavity cryogenic system, a condenser/boiler heat exchanger is used to isolate the cavity helium bath from pressure pulses and microphonics noise sources. For the 704 MHz 5-cell SRF cavity, a heat exchanger is also used to isolate the SRF cavity helium bath from noise sources in the sub-atmospheric pumping system operating at room temperature. Detailed designs, thermal analyses and discussions for both systems will be presented in this paper.

Stochastic cooling of bunched beams from fluctuation and kinetic theory

International Nuclear Information System (INIS)

Chattopadhyay, S.

1982-09-01

A theoretical formalism for stochastic phase-space cooling of bunched beams in storage rings is developed on the dual basis of classical fluctuation theory and kinetic theory of many-body systems in phase-space. The physics is that of a collection of three-dimensional oscillators coupled via retarded nonconservative interactions determined by an electronic feedback loop. At the heart of the formulation is the existence of several disparate time-scales characterizing the cooling process. Both theoretical approaches describe the cooling process in the form of a Fokker-Planck transport equation in phase-space valid up to second order in the strength and first order in the auto-correlation of the cooling signal. With neglect of the collective correlations induced by the feedback loop, identical expressions are obtained in both cases for the coherent damping and Schottky noise diffusion coefficients. These are expressed in terms of Fourier coefficients in a harmonic decomposition in angle of the generalized nonconservative cooling force written in canonical action-angle variables of the particles in six-dimensional phase-space. Comparison of analytic results to a numerical simulation study with 90 pseudo-particles in a model cooling system is presented

Fast cooling phenomena with ice pellet injection in the JIPP T-IIU Tokamak

International Nuclear Information System (INIS)

Sakamoto, M.; Sato, K.N.; Ogawa, Y.

1991-01-01

Ice pellet injection experiments were carried out in the JIPP T-IIU Tokamak in order to study thermal (cooling) transport just after injection. The cut-off problem of ECE signals due to the rise in density has been resolved by careful measurements of the temperature profile at a high time resolution (Δt = 2μs) during its decay phase. The phenomenon of ultra-fast cooling (so-called pre-cooling) has been identified using the two different methods of ECE and soft X-ray (SXR) measurements. In the outer region (r > r q=1 ) of the plasma the cooling propagation velocity is comparable to or slightly greater than the pellet velocity, while in the central region (r q=1 ) the propagation velocity is significantly greater than the pellet velocity. Ice pellets were injected into various kinds of JIPP T-IIU plasmas, the current and sawtooth phase of which had different values, including a no-sawtooth plasma. The existence of the q = 1 surface and arrival of a pellet near the q = 1 surface have turned out to be necessary conditions for pre-cooling, and even just after the sawtooth crash the pre-cooling starts around the q = 1 surface, not at the plasma center. Simultaneous measurements of electron temperature and density profiles indicate that the central temperature always decreases before the central density increases. Some anomalous transport might be induced by pellet injection at the central region. (Author)

The research of materials and water chemistry for supercritical water-cooled reactors in Research Centre Rez

International Nuclear Information System (INIS)

Zychova, Marketa; Fukac, Rostislav; Vsolak, Rudolf; Vojacek, Ales; Ruzickova, Mariana; Vonkova, Katerina

2012-09-01

Research Centre Rez (CVR) is R and D company based in the Czech Republic. It was established as the subsidiary of the Nuclear Research Institute Rez plc. One of the main activities of CVR is the research of materials and chemistry for the generation IV reactor systems - especially the supercritical water-cooled one. For these experiments is CVR equipped by a supercritical water loop (SCWL) and a supercritical water autoclave (SCWA) serving for research of material and Supercritical Water-cooled Reactor (SCWR) environment compatibility experiments. SCWL is a research facility designed to material, water chemistry, radiolysis and other testing in SCWR environment, SCWA serves for complementary and supporting experiments. SCWL consists of auxiliary circuits (ensuring the required parameters as temperature, pressure and chemical conditions in the irradiation channel, purification and measurements) and irradiation channel (where specimens are exposed to the SCWR environment). The design of the loop is based on many years of experience with loop design for various types of corrosion/water chemistry experiments. Designed conditions in the test area of SCWL are 600 deg. C and 25 MPa. SCWL was designed in 2008 within the High Performance Light Water Reactor Phase 2 project and built during 2008 and 2009. The trial operations were performed in 2010 and 2011 and were divided into three phases - the first phase to verify the functionality of auxiliary circuits of the loop, the second phase to verify the complete facility (auxiliary circuits and functional irradiation channel internals) and the third phase to verify the feasibility of corrosion tests with the complete equipment and specimens. All three trial operations were very successful - designed conditions and parameters were reached. (authors)

Phase Change Material Based Accumulation Panels in Combination with Renewable Energy Sources and Thermoelectric Cooling

Directory of Open Access Journals (Sweden)

Jan Skovajsa

2017-01-01

Full Text Available The article deals with the use of modern materials and technologies that can improve the thermal comfort in buildings. The article describes the design and usage of a special accumulation device, which is composed of thermal panels based on phase change materials (PCMs. The thermal panels have an integrated tube heat exchanger and heating foils. The technology can be used as a passive or active system for heating and cooling. It is designed as a “green technology”, so it is able to use renewable energy sources, e.g., photovoltaic (PV panels, solar thermal collectors and heat pumps. Moreover, an interesting possibility is the ability to use thermoelectric coolers. In the research, measurements of the different operating modes were made, and the results are presented in the text. The measurement approves that the technology improves the thermal capacity of the building, and it is possible to use it for active heating and cooling.

Mathematical Model of Two Phase Flow in Natural Draft Wet-Cooling Tower Including Flue Gas Injection

Directory of Open Access Journals (Sweden)

Hyhlík Tomáš

2016-01-01

Full Text Available The previously developed model of natural draft wet-cooling tower flow, heat and mass transfer is extended to be able to take into account the flow of supersaturated moist air. The two phase flow model is based on void fraction of gas phase which is included in the governing equations. Homogeneous equilibrium model, where the two phases are well mixed and have the same velocity, is used. The effect of flue gas injection is included into the developed mathematical model by using source terms in governing equations and by using momentum flux coefficient and kinetic energy flux coefficient. Heat and mass transfer in the fill zone is described by the system of ordinary differential equations, where the mass transfer is represented by measured fill Merkel number and heat transfer is calculated using prescribed Lewis factor.

Effects of surface deposition and droplet injection on film cooling

International Nuclear Information System (INIS)

Wang, Jin; Cui, Pei; Vujanović, Milan; Baleta, Jakov; Duić, Neven; Guzović, Zvonimir

2016-01-01

Highlights: • Cooling effectiveness is significantly affected by the deposition size. • Coverage area for model without mist is reduced by increasing the deposition height. • Wall temperature is decreased by 15% with 2% mist injection. • Cooling coverage is increased by more than three times with 2% mist injection. • Cooling effectiveness for mist models is improved by increasing deposition height. - Abstract: In the present research, the influence of the particle dispersion onto the continuous phase in film cooling application was analysed by means of numerical simulations. The interaction between the water droplets and the main stream plays an important role in the results. The prediction of two-phase flow is investigated by employing the discrete phase model (DPM). The results present heat transfer characteristics in the near-wall region under the influence of mist cooling. The local wall temperature distribution and film cooling effectiveness are obtained, and results show that the film cooling characteristics on the downstream wall are affected by different height of surface deposits. It is also found that smaller deposits without mist injection provide a lower wall temperature and a better cooling performance. With 2% mist injection, evaporation of water droplets improves film cooling effectiveness, and higher deposits cause lateral and downstream spread of water droplets. The results indicate that mist injection can significantly enhance film cooling performance.

ONKALO POSE experiment. Phase 3: acoustic and ultrasonic monitoring

International Nuclear Information System (INIS)

Reyes-Montes, J.; Flynn, W.; Huang, J.

2014-01-01

The objectives of the third phase of the POSE experiment are to determine the in situ state of stress at Olkiluoto and the spalling strength of Olkiluoto rock, by internal heating of the experimental hole (ONK-EH3) using 8 vertically installed heaters. This report presents the results from the Acoustic and ultrasonic monitoring carried out around the third experimental hole of the POSE niche between November 2012 and May 2013. The experiment was monitored using an array of 24 transducers installed along 4 monitoring drillholes and data was automatically acquired and processed using the system installed at the niche by Applied Seismology Consultants in May 2012. Daily ultrasonic surveys were carried out between 14 th November 2012 and 21 st May 2013, monitoring the changes in transmission velocities of P and S-waves with an estimated error of ±2 m x s -1 (ASC, 2013). Changes in transmission velocities closely follow the evolution of the temperature profile in the hole wall. An increase in both P-and S-wave transmission velocities is observed at all depth levels and surveyed raypaths during the heating phase, with the highest changes observed in raypaths skimming the hole surface and depths between 2.33 m and 3.7 m. This observation indicates the closure of in situ and excavation-induced microcracks due to thermal stress. After the heaters were switched off, P-wave velocities show a marked decrease, in all raypaths reaching values below those measured at the start of the monitoring approximately 4 weeks after the heaters were switched off. The highest decrease was observed along raypaths surveying the region skimming the hole wall. This decrease below original background values indicates the induction of rock degradation as microcracking induced through the heating-cooling cycle. Changes in P- and S-wave transmission velocity were used to calculate changes in Young's modulus and Poisson's ratio along the different raypaths and depth levels. An overall

Advanced Pumps and Cold Plates for Two-Phase Cooling Loops, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Advanced instruments used for earth science missions require improved cooling systems to remove heat from high power electronic components and maintain tight...

H/He demixing and the cooling behavior of Saturn

Science.gov (United States)

Püstow, Robert; Nettelmann, Nadine; Lorenzen, Winfried; Redmer, Ronald

2016-03-01

The description of the interior structure and evolution of the Solar System giant planets continues to be a serious challenge. The most prominent example is Saturn for which simple homogeneous evolution models yield ages between 2 and 3 billion years (Gyr), i.e. much shorter than the age of the Solar System of τ⊙ = 4.56 Gyr. It has long been suggested that H/He demixing might occur in the interior of Saturn after the planet has cooled off sufficiently. This incident would mark the begin of an inhomogeneous evolution period in which He droplets sink down and accumulate above the planetary core. The corresponding release of gravitational energy contributes to the intrinsic luminosity of the planet, thereby prolonging its cooling time, perhaps towards the correct value. Such scenarios have been studied in the past on the basis of rather approximate assumptions for the H-He phase diagram. Recently, various ab initio simulations have revealed details of the H-He phase diagram but also of remaining uncertainties (Morales, M.A. et al. [2009]. Proc. Nat. Acad. Sci. USA 106, 1324; Morales, M.A. et al. [2013a]. Phys. Rev. B 87, 174105; Lorenzen, W. et al. [2011]. Phys. Rev. B 84, 235109). In this paper we use the new predictions by Lorenzen et al. and modifications thereof to study the inhomogeneous evolution period of Saturn, with resulting values for the onset of H/He phase separation ts , the cooling time τ , and the atmospheric helium abundance y1 . For the planetary interior during the inhomogeneous evolution we assume adiabatic, convective envelopes. We find ts = 1 Gyr, τ = 5.8 Gyr, and y1 = 0.18 , while ts ≊ 2 Gyr for the Morales et al. data, for which we also estimate τ ≈ 5.1 Gyr. On the other hand, reasonable cooling times τ ≈τ⊙ are obtained for shifts of the Lorenzen et al. phase diagram by respectively -1300 K and +500 K, yielding y1 = 0.22 and y1 = 0.06 . More accurate knowledge of H-He phase diagram is necessary to understand cool gas giant

Design of a two-phase loop thermosyphon for telecommunications system(I): experiments and visualization

Energy Technology Data Exchange (ETDEWEB)

Kim, Won Tae [Kongju National Univ., Kongju (Korea, Republic of); Song, Kyu Sub [Electronics and Telecommunications Research Institute, Taejon (Korea, Republic of); Lee, Young [Univ. of Ottawa, Ontario (Canada)

1998-10-01

A two-phase loop thermosyphon system is developed for the B-ISDN telecommunications system and its performance is evaluated both experimentally and by visualization techniques. The design of the thermosyphon system proposed is aimed to cool MultiChip Modules (MCM) upto heat flux of 8 W/cm{sup 2}. The results indicate that in the loop thermosyphon system cooling heat flux is capable of 12 W/cm{sup 2} with two condensers under the forced convection cooling of the condenser section with acetone or FC-87 as the working fluid. The instability of the working fluid flow within the loop is observed using the visualization techniques and temperature fluctuation is stabilized with orifice insertion.

Design of a two-phase loop thermosyphon for telecommunications system(I): experiments and visualization

International Nuclear Information System (INIS)

Kim, Won Tae; Song, Kyu Sub; Lee, Young

1998-01-01

A two-phase loop thermosyphon system is developed for the B-ISDN telecommunications system and its performance is evaluated both experimentally and by visualization techniques. The design of the thermosyphon system proposed is aimed to cool MultiChip Modules (MCM) upto heat flux of 8 W/cm 2 . The results indicate that in the loop thermosyphon system cooling heat flux is capable of 12 W/cm 2 with two condensers under the forced convection cooling of the condenser section with acetone or FC-87 as the working fluid. The instability of the working fluid flow within the loop is observed using the visualization techniques and temperature fluctuation is stabilized with orifice insertion

Single- and two-phase flow modeling for coupled neutronics / thermal-hydraulics transient analysis of advanced sodium-cooled fast reactors

International Nuclear Information System (INIS)

Chenu, A.

2011-10-01

Nuclear power is nowadays in the front rank as regards helping to meet the growing worldwide energy demand while avoiding an excessive increase in greenhouse gas emissions. However, the operating nuclear power plants are mainly thermal-neutron reactors and, as such, can not be maintained on the basis of the currently identified uranium resources beyond one century at the present consumption rate. Sustainability of nuclear power thus involves closure of the fuel cycle through breeding. With a uranium-based fuel, breeding can only be achieved using a fast-neutron reactor. Sodium-cooled fast reactor (SFR) technology benefits from 400 reactor-years of accumulated experience and is thus a prime candidate for the implementation of so-called Generation-IV nuclear energy systems. In this context, the safety demonstration of SFRs remains a major Research and Development related issue. The current research aims at the development of a computational tool for the in-depth understanding of SFR core behaviour during accidental transients, particularly those including boiling of the coolant. An accurate modelling of the core physics during such transients requires the coupling between 3D neutron kinetics and thermal-hydraulics in the core, to account for the strong interactions between the two-phase coolant flow and power variations caused by the sodium void effect. The present study is specifically focused upon models for the representation of sodium two-phase flow. The extension of the thermal-hydraulics TRACE code, previously limited to the simulation of single-phase sodium flow, has been carried out through the implementation of equations-of-state and closure relations specific to sodium. The different correlations have then been implemented as options. From the validation study carried out, it has been possible to recommend a set of models which provide satisfactory results, while considering annular flow as the dominant regime up to dryout and a smooth breakdown of the

Continuous parametric feedback cooling of a single atom in an optical cavity

Science.gov (United States)

Sames, C.; Hamsen, C.; Chibani, H.; Altin, P. A.; Wilk, T.; Rempe, G.

2018-05-01

We demonstrate a feedback algorithm to cool a single neutral atom trapped inside a standing-wave optical cavity. The algorithm is based on parametric modulation of the confining potential at twice the natural oscillation frequency of the atom, in combination with fast and repetitive atomic position measurements. The latter serve to continuously adjust the modulation phase to a value for which parametric excitation of the atomic motion is avoided. Cooling is limited by the measurement backaction which decoheres the atomic motion after only a few oscillations. Nonetheless, applying this feedback scheme to an ˜5 -kHz oscillation mode increases the average storage time of a single atom in the cavity by a factor of 60 to more than 2 s. In contrast to previous feedback schemes, our algorithm is also capable of cooling a much faster ˜500 -kHz oscillation mode within just microseconds. This demonstrates that parametric cooling is a powerful technique that can be applied in all experiments where optical access is limited.

Research Proposal for the Design and Engineering Phase of a Solar Heating and Cooling System Experiment at the Warner Robins Public Library, Warner Robins, Georgia. Submitted to the United States Energy Research and Development Administration.

Science.gov (United States)

Phillips, Warren H.; And Others

A number of reasons are advanced to include a solar heating and cooling experiment in a library building. The unique aspects of the experiment are to be a seasonally adjustable collector tilt and testing of a new generation of absorption air conditioners. After a brief description of the proposed experiment, the proposal contains forms filed by…

Quality assurance for CORAL and COOL within the LCG software stack for the LHC experiments

CERN Multimedia

CERN. Geneva

2015-01-01

CORAL and COOL are software packages used by the LHC experiments for managing different categories of physics data using a variety of relational database technologies. The core components are written in C++, but Python bindings are also provided. CORAL is a generic relational access layer, while COOL includes the implementation of a specific relational data model and optimization of SQL queries for "conditions data". The software is the result of more than 10 years of development in colaboration between the IT department and the LHC experiments. The packages are built and released within the LCG software stack, for which automatic nightly builds and release installations are provided by PH-SFT (cmake, jenkins, cdash) for many different platforms, compilers and software version configurations. Test-driven development and functional tests of both C++ and Python components (CppUnit, unittest) have been key elements in the success of the projects. Dedicated test suites have also been prepared to commission and ma...

Conceptual design study on simplified and safer cooling systems for sodium cooled FBRs

International Nuclear Information System (INIS)

Hayafune, Hiroki; Shimakawa, Yoshio; Ishikawa, Hiroyasu; Kubota, Kenichi; Kobayashi, Jun; Kasai, Shigeo

2000-06-01

The objective of this study is to create the FBR plant concepts increasing economy and safety for the Phase-I 'Feasibility Studies on Commercialized Fast Reactor System'. In this study, various concepts of simplified 2ry cooling system for sodium cooled FBRs are considered and evaluated from the view points of technological feasibility, economy, and safety. The concepts in the study are considered on the basis of the following points of view. 1. To simplify 2ry cooling system by moderating and localizing the sodium-water reaction in the steam generator of the FBRs. 2. To simplify 2ry cooling system by eliminating the sodium-water reaction using integrated IHX-SG unit. 3. To simplify 2ry cooling system by eliminating the sodium-water reaction using a power generating system other than the steam generator. As the result of the study, 12 concepts and 3 innovative concepts are proposed. The evaluation study for those concepts shows the following technical prospects. 1. 2 concepts of integrated IHX-SG unit can eliminate the sodium-water reaction. Separated IHX and SG tubes unit using Lead-Bismuth as the heat transfer medium. Integrated IHX-SG unit using copper as the heat transfer medium. 2. Cost reduction effect by simplified 2ry cooling system using integrated IHX-SG unit is estimated 0 to 5%. 3. All of the integrated IHX-SG unit concepts have more weight and larger size than conventional steam generator unit. The weight of the unit during transporting and lifting would limit capacity of heat transfer system. These evaluation results will be compared with the results in JFY 2000 and used for the Phase-II study. (author)

Innovative low-mass cooling systems for the ALICE ITS Upgrade detector at CERN

OpenAIRE

Gomez Marzoa, Manuel; Thome, John

2016-01-01

The Phase-1 upgrade of the LHC to full design luminosity, planned for 2019 at CERN, requires the modernisation of the experiments around the accelerator. The Inner Tracking System (ITS), the innermost detector at the ALICE experiment, will be upgraded by replacing the current apparatus by new silicon pixels arranged in 7 cylindrical layers. Each layer is composed by multiple independent modules, named staves, which provide mechanical support and cooling to the chips. This thesis aims to devel...

Direct transmission electron microscopy observations of martensitic transformations in Ni-rich NiTi single crystals during in situ cooling and straining

International Nuclear Information System (INIS)

Kroeger, A.; Dziaszyk, S.; Frenzel, J.; Somsen, Ch.; Dlouhy, A.; Eggeler, G.

2008-01-01

We investigate martensitic transformations using transmission electron microscopy (TEM) in compression aged Ni-rich NiTi single crystals with one family of Ni 4 Ti 3 precipitates. Small cylinders from a Ni-rich NiTi single crystal with a Ni content of 51.0 at.% were compression aged at 550 deg. C in the [1 1 1] B2 direction for different aging times. Differential scanning calorimetry (DSC) investigations show that a three-step martensitic transformation (three DSC peaks on cooling from the high temperature regime) can be observed for aging times of 4 ks. In situ cooling TEM investigations reveal that the first peak on cooling is associated with a transformation from B2 to R-phase, starting from all precipitate/matrix interfaces. On further cooling, the B19'-phase appears and grows along precipitate/matrix interfaces (second step). With further decreasing temperature, the remaining R-phase between the precipitates transforms to B19' (third peak). In situ TEM straining experiments of B2 above the martensitic start temperature reveal that first some microstructural regions directly transform in microscopic burst like events from B2 to B19'. On further straining, the B19'-phase grows along precipitate/matrix interfaces. However, no formation of R-phase precedes the formation of stress-induced B19'

Two-phase alkali-metal experiments in reduced gravity

International Nuclear Information System (INIS)

Antoniak, Z.I.

1986-06-01

Future space missions envision the use of large nuclear reactors utilizing either a single or a two-phase alkali-metal working fluid. The design and analysis of such reactors require state-of-the-art computer codes that can properly treat alkali-metal flow and heat transfer in a reduced-gravity environment. A literature search of relevant experiments in reduced gravity is reported on here, and reveals a paucity of data for such correlations. The few ongoing experiments in reduced gravity are noted. General plans are put forth for the reduced-gravity experiments which will have to be performed, at NASA facilities, with benign fluids. A similar situation exists regarding two-phase alkali-metal flow and heat transfer, even in normal gravity. Existing data are conflicting and indequate for the task of modeling a space reactor using a two-phase alkali-metal coolant. The major features of past experiments are described here. Data from the reduced-gravity experiments with innocuous fluids are to be combined with normal gravity data from the two-phase alkali-metal experiments. Analyses undertaken here give every expectation that the correlations developed from this data base will provide a valid representation of alkali-metal heat transfer and pressure drop in reduced gravity

The effect of lower body cooling on the changes in three core temperature indices

International Nuclear Information System (INIS)

Basset, F A; Cahill, F; Handrigan, G; DuCharme, M B; Cheung, S S

2011-01-01

Rectal (T re ), ear canal (T ear ) and esophageal (T es ) temperatures have been used in the literature as core temperature indices in humans. The aim of the study was to investigate if localized lower body cooling would have a different effect on each of these measurements. We hypothesized that prolonged lower body surface cooling will result in a localized cooling effect for the rectal temperature not reflected in the other core measurement sites. Twelve participants (mean ± SD; 26.8 ± 6.0 years; 82.6 ± 13.9 kg; 179 ± 10 cm, BSA = 2.00 ± 0.21 m 2 ) attended one experimental session consisting of sitting on a rubberized raft floor surface suspended in 5 °C water in a thermoneutral air environment (∼21.5 ± 0.5 °C). Experimental conditions were (a) a baseline phase during which participants were seated for 15 min in an upright position on an insulated pad (1.408 K . m 2 . W −1 ); (b) a cooling phase during which participants were exposed to the cooling surface for 2 h, and (c) an insulation phase during which the baseline condition was repeated for 1 h. Temperature data were collected at 1 Hz, reduced to 1 min averages, and transformed from absolute values to a change in temperature from baseline (15 min average). Metabolic data were collected breath-by-breath and integrated over the same temperature epoch. Within the baseline phase no significant change was found between the three indices of core temperature. By the end of the cooling phase, T re was significantly lower (Δ = −1.0 ± 0.4 °C) from baseline values than from T ear (Δ = −0.3 ± 0.3 °C) and T es (Δ = −0.1 ± 0.3 °C). T re continued to decrease during the insulation phase from Δ −1.0 ± 0.4 °C to as low as Δ −1.4 ± 0.5 °C. By the end of the insulation phase T re had slightly risen back to Δ −1.3 ± 0.4 °C but remained significantly different from baseline values and from the other two core measures. Metabolic data showed no variation throughout the experiment. In

Fabrication and Properties of Micro-Nanoencapsulated Phase Change Materials for Internally-Cooled Liquid Desiccant Dehumidification

Directory of Open Access Journals (Sweden)

Xiaofeng Niu

2017-04-01

Full Text Available Micro-nanoencapsulated phase change materials (M-NEPCMs are proposed to be useful in liquid desiccant dehumidification by restraining the temperature rise in the moisture-removal process and improving the dehumidification efficiency. In this paper, the n-octadecane M-NEPCMs with desirable thermal properties for internally-cooled dehumidification were fabricated by using compound emulsifiers through the in-situ polymerization method. Melamine-formaldehyde resin was used as the shell material. The effects of the mixing ratio, emulsification methods and amount of the compound emulsifiers on the morphology, size and thermal properties of the M-NEPCMs were investigated experimentally. The optimum weight mixing ratio of the compound emulsifiers is SDS (sodium dodecyl sulfate:Tween80 (polyoxyethylene sorbitan monooleate:Span80 (sorbitan monooleate = 0.1:0.6:0.3, which achieves the best stability of the n-octadecane emulsion. When the compound emulsifiers are 10 wt. % of the core material, the melting enthalpy of M-NEPCMs reaches its maximum of 145.26 J/g of capsules, with an encapsulation efficiency of 62.88% and a mean diameter of 636 nm. The sub-cooling of the prepared M-NEPCMs is lower than 3 °C, with an acceptable thermal reliability after the thermal cycling test. A pre-emulsification prior to the addition of deionized water in the emulsification is beneficial to the morphology of the capsules, as the phase change enthalpy can be increased by 123.7%.

Fabrication and Properties of Micro-Nanoencapsulated Phase Change Materials for Internally-Cooled Liquid Desiccant Dehumidification.

Science.gov (United States)

Niu, Xiaofeng; Xu, Qing; Zhang, Yi; Zhang, Yue; Yan, Yufeng; Liu, Tao

2017-04-29

Micro-nanoencapsulated phase change materials (M-NEPCMs) are proposed to be useful in liquid desiccant dehumidification by restraining the temperature rise in the moisture-removal process and improving the dehumidification efficiency. In this paper, the n -octadecane M-NEPCMs with desirable thermal properties for internally-cooled dehumidification were fabricated by using compound emulsifiers through the in-situ polymerization method. Melamine-formaldehyde resin was used as the shell material. The effects of the mixing ratio, emulsification methods and amount of the compound emulsifiers on the morphology, size and thermal properties of the M-NEPCMs were investigated experimentally. The optimum weight mixing ratio of the compound emulsifiers is SDS (sodium dodecyl sulfate):Tween80 (polyoxyethylene sorbitan monooleate):Span80 (sorbitan monooleate) = 0.1:0.6:0.3, which achieves the best stability of the n -octadecane emulsion. When the compound emulsifiers are 10 wt. % of the core material, the melting enthalpy of M-NEPCMs reaches its maximum of 145.26 J/g of capsules, with an encapsulation efficiency of 62.88% and a mean diameter of 636 nm. The sub-cooling of the prepared M-NEPCMs is lower than 3 °C, with an acceptable thermal reliability after the thermal cycling test. A pre-emulsification prior to the addition of deionized water in the emulsification is beneficial to the morphology of the capsules, as the phase change enthalpy can be increased by 123.7%.

Heat pipe with PCM for electronic cooling

International Nuclear Information System (INIS)

Weng, Ying-Che; Cho, Hung-Pin; Chang, Chih-Chung; Chen, Sih-Li

2011-01-01

This article experimentally investigates the thermal performances of a heat pipe with phase change material for electronic cooling. The adiabatic section of heat pipe is covered by a storage container with phase change material (PCM), which can store and release thermal energy depending upon the heating powers of evaporator and fan speeds of condenser. Experimental investigations are conducted to obtain the system temperature distributions from the charge, discharge and simultaneous charge/discharge performance tests. The parameters in this study include three kinds of PCMs, different filling PCM volumes, fan speeds, and heating powers in the PCM cooling module. The cooling module with tricosane as PCM can save 46% of the fan power consumption compared with the traditional heat pipe.

An efficient continuous flow helium cooling unit for Moessbauer experiments

International Nuclear Information System (INIS)

Herbert, I.R.; Campbell, S.J.

1976-01-01

A Moessbauer continuous flow cooling unit for use with liquid helium over the temperature range 4.2 to 300K is described. The cooling unit can be used for either absorber or source studies in the horizontal plane and it is positioned directly on top of a helium storage vessel. The helium transfer line forms an integral part of the cooling unit and feeds directly into the storage vessel so that helium losses are kept to the minimum. The helium consumption is 0.12 l h -1 at 4.2 K decreasing to 0.055 l h -1 at 40 K. The unit is top loading and the exchange gas cooled samples can be changed easily and quickly. (author)

Cool PDO phase leads to recent rebound in coastal southern California fog

Directory of Open Access Journals (Sweden)

Witiw, Michael R.

2015-12-01

Full Text Available The relationship between coastal fog in southern California and the Pacific Decadal Oscillation (PDO is investigated during the last decade. Fog occurrence was examined at two locations in southern California: San Diego and Los Angeles international airports. Both locations are located near the Pacific coast with strong marine influences. The period looked at was 2001 through 2012. The cool season (October-March and warm season (April-September were examined separately because of the different types of fog that prevail in each season. Previous studies have shown a relation between fog and the Pacific Decadal Oscillation (PDO. However, a switch in polarity in the PDO in the mid-1970s (from a cool to a warm phase coupled with a sharp decrease in particulate concentrations calls into question the strong relationship shown. Further studies suggest that the decrease in dense fog seen from the 1960s through the 1990s was largely due to increasing urban heat island effects coupled with a decrease in atmospheric particulate matter. Since 1998, the PDO again changed polarity and fog frequencies began to rise. However, urban heat island and particulate effects were relatively constant making it easier to isolate any effects of the PDO on fog occurrence. Previous studies examined the occurrence of dense fog (visibility less than 400 meters, but because of the decrease in fog in this category, 800 meters was chosen this time. That also corresponds to the 0.5 mile visibility which triggers special reports at the California airports when visibility moves through this threshold. Although there was no strong relationship between fog and PDO in the most recent period, Pacific Ocean oscillations were found to show significant relationships with fog frequencies historically. Upwelling indices show a significant relationship with fog frequencies when examined by the phase of the PDO. Even stronger relationships are found when selecting La Niña and El Niño events.

Effect of heating and cooling rate on the kinetics of allotropic phase changes in uranium: A differential scanning calorimetry study

International Nuclear Information System (INIS)

Rai, Arun Kumar; Raju, S.; Jeyaganesh, B.; Mohandas, E.; Sudha, R.; Ganesan, V.

2009-01-01

The kinetic aspects of allotropic phase changes in uranium are studied as a function of heating/cooling rate in the range 10 0 -10 2 K min -1 by isochronal differential scanning calorimetry. The transformation arrest temperatures revealed a remarkable degree of sensitivity to variations of heating and cooling rate, and this is especially more so for the transformation finish (T f ) temperatures. The results obtained for the α → β and β → γ transformations during heating confirm to the standard Kolmogorov-Johnson-Mehl-Avrami (KJMA) model for a nucleation and growth mediated process. The apparent activation energy Q eff for the overall transformation showed a mild increase with increasing heating rate. In fact, the heating rate normalised Arrhenius rate constant, k/β reveals a smooth power law decay with increasing heating rate (β). For the α → β phase change, the observed DSC peak profile for slower heating rates contained a distinct shoulder like feature, which however is absent in the corresponding profiles found for higher heating rates. The kinetics of γ → β phase change on the other hand, is best described by the two-parameter Koistinen-Marburger empirical relation for the martensitic transformation

Conductive cooling of high-power RIB targets

International Nuclear Information System (INIS)

Talbert, W.L.; Drake, D.M.; Wilson, M.T.; Lenz, J.W.; Hsu, H.-H.

2002-01-01

A short review is presented of target cooling approaches suggested for targets irradiated by intense high-energy proton beams to produce radioactive species for use in a broad range of physics studies. This work reports on conductive cooling approaches for operation at temperatures lower than effective for radiative cooling. The possibilities for conductive cooling are discussed, and a prototype test target is described. This target was constructed for an experiment, designed to validate the numerical analysis approaches, at the TRIUMF/ISAC facility. Fabrication issues and the results of the experiment are presented, followed by a discussion of the implications of the experiment outcome for future development of targets to produce intense beams of radioactive ions

Electrode Cooling Effect on Out-Of-Phase Electrothermal Streaming in Rotating Electric Fields

Directory of Open Access Journals (Sweden)

Weiyu Liu

2017-11-01

Full Text Available In this work, we focus on investigating electrothermal flow in rotating electric fields (ROT-ETF, with primary attention paid to the horizontal traveling-wave electrothermal (TWET vortex induced at the center of the electric field. The frequency-dependent flow profiles in the microdevice are analyzed using different heat transfer models. Accordingly, we address in particular the importance of electrode cooling in ROT-ETF as metal electrodes of high thermal conductivity, while substrate material of low heat dissipation capability is employed to develop such microfluidic chips. Under this circumstance, cooling of electrode array due to external natural convection on millimeter-scale electrode pads for external wire connection occurs and makes the internal temperature maxima shift from the electrode plane to a bit of distance right above the cross-shaped interelectrode gaps, giving rise to reversal of flow rotation from a typical repulsion-type to attraction-type induction vortex, which is in good accordance with our experimental observations of co-field TWET streaming at frequencies in the order of reciprocal charge relaxation time of the bulk fluid. These results point out a way to make a correct interpretation of out-of-phase electrothermal streaming behavior, which holds great potential for handing high-conductivity analytes in modern microfluidic systems.

Cooling water for SSC experiments: Supplemental Conceptual Design Report (SCDR)

International Nuclear Information System (INIS)

Doyle, R.E.

1989-01-01

This paper discusses the following topics on cooling water design on the superconducting super collider; low conductivity water; industrial cooling water; chilled water systems; and radioactive water systems

Characterisation of the Muon Beams for the Muon Ionisation Cooling Experiment

CERN Document Server

Adams, D.; Alekou, A.; Apollonio, M.; Asfandiyarov, R.; Back, J.; Barber, G.; Barclay, P.; de Bari, A.; Bayes, R.; Bayliss, V.; Bertoni, R.; Blackmore, V.J.; Blondel, A.; Blot, S.; Bogomilov, M.; Bonesini, M.; Booth, C.N.; Bowring, D.; Boyd, S.; Bradshaw, T.W.; Bravar, U.; Bross, A.D.; Capponi, M.; Carlisle, T.; Cecchet, G.; Charnley, G.; Cobb, J.H.; Colling, D.; Collomb, N.; Coney, L.; Cooke, P.; Courthold, M.; Cremaldi, L.M.; DeMello, A.; Dick, A.; Dobbs, A.; Dornan, P.; Fayer, S.; Filthaut, F.; Fish, A.; Fitzpatrick, T.; Fletcher, R.; Forrest, D.; Francis, V.; Freemire, B.; Fry, L.; Gallagher, A.; Gamet, R.; Gourlay, S.; Grant, A.; Graulich, J.S.; Griffiths, S.; Hanlet, P.; Hansen, O.M.; Hanson, G.G.; Harrison, P.; Hart, T.L.; Hartnett, T.; Hayler, T.; Heidt, C.; Hills, M.; Hodgson, P.; Iaciofano, A.; Ishimoto, S.; Kafka, G.; Kaplan, D.M.; Karadzhov, Y.; Kim, Y.K.; Kolev, D.; Kuno, Y.; Kyberd, P.; Lau, W.; Leaver, J.; Leonova, M.; Li, D.; Lintern, A.; Littlefield, M.; Long, K.; Lucchini, G.; Luo, T.; Macwaters, C.; Martlew, B.; Martyniak, J.; Middleton, S.; Moretti, A.; Moss, A.; Muir, A.; Mullacrane, I.; Nebrensky, J.J.; Neuffer, D.; Nichols, A.; Nicholson, R.; Nugent, J.C.; Onel, Y.; Orestano, D.; Overton, E.; Owens, P.; Palladino, V.; Palmer, R.B.; Pasternak, J.; Pastore, F.; Pidcott, C.; Popovic, M.; Preece, R.; Prestemon, S.; Rajaram, D.; Ramberger, S.; Rayner, M.A.; Ricciardi, S.; Richards, A.; Roberts, T.J.; Robinson, M.; Rogers, C.; Ronald, K.; Rubinov, P.; Rucinski, R.; Rusinov, I.; Sakamoto, H.; Sanders, D.A.; Santos, E.; Savidge, T.; Smith, P.J.; Snopok, P.; Soler, F.J.P.; Stanley, T.; Summers, D.J.; Takahashi, M.; Tarrant, J.; Taylor, I.; Tortora, L.; Torun, Y.; Tsenov, R.; Tunnell, C.D.; Vankova, G.; Verguilov, V.; Virostek, S.; Vretenar, M.; Walaron, K.; Watson, S.; White, C.; Whyte, C.G.; Wilson, A.; Wisting, H.; Zisman, M.

2013-01-01

A novel single-particle technique to measure emittance has been developed and used to characterise seventeen different muon beams for the Muon Ionisation Cooling Experiment (MICE). The muon beams, whose mean momenta vary from 171 to 281 MeV/c, have emittances of approximately 1.5--2.3 \\pi mm-rad horizontally and 0.6--1.0 \\pi mm-rad vertically, a horizontal dispersion of 90--190 mm and momentum spreads of about 25 MeV/c. There is reasonable agreement between the measured parameters of the beams and the results of simulations. The beams are found to meet the requirements of MICE.

Characterisation of the muon beams for the Muon Ionisation Cooling Experiment

Energy Technology Data Exchange (ETDEWEB)

Adams, D.; et al.,

2013-10-01

A novel single-particle technique to measure emittance has been developed and used to characterise seventeen different muon beams for the Muon Ionisation Cooling Experiment (MICE). The muon beams, whose mean momenta vary from 171 to 281 MeV/c, have emittances of approximately 1.5--2.3 \\pi mm-rad horizontally and 0.6--1.0 \\pi mm-rad vertically, a horizontal dispersion of 90--190 mm and momentum spreads of about 25 MeV/c. There is reasonable agreement between the measured parameters of the beams and the results of simulations. The beams are found to meet the requirements of MICE.

Application of a two-phase thermosyphon loop with minichannels and a minipump in computer cooling

Directory of Open Access Journals (Sweden)

Bieliński Henryk

2016-03-01

Full Text Available This paper focuses on the computer cooling capacity using the thermosyphon loop with minichannels and minipump. The one-dimensional separate model of two-phase flow and heat transfer in a closed thermosyphon loop with minichannels and minipump has been used in calculations. The latest correlations for minichannels available in literature have been applied. This model is based on mass, momentum, and energy balances in the evaporator, rising tube, condenser and the falling tube. A numerical analysis of the mass flux and heat transfer coefficient in the steady state has been presented.

Effects of Cooling Rate on 6.5% Silicon Steel Ordering

Energy Technology Data Exchange (ETDEWEB)

Cui, Jun [Ames Lab. and Iowa State Univ., Ames, IA (United States); Macziewski, Chad [Iowa State Univ., Ames, IA (United States); Jensen, Brandt [Ames Lab., Ames, IA (United States); Ouyang, Gaoyuan [Iowa State Univ., Ames, IA (United States); Zhou, Lin [Ames Lab., Ames, IA (United States); Dennis, Kevin [Ames Lab., Ames, IA (United States); Zarkevich, Nikolai [Ames Lab., Ames, IA (United States); Jiang, Xiujuan [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tang, Wei [Ames Lab., Ames, IA (United States); Zhou, Shihuai [Ames Lab., Ames, IA (United States); Simsek, Emrah [Ames Lab., Ames, IA (United States); Napolitano, Ralph [Iowa State Univ., Ames, IA (United States); Kramer, Matt [Ames Lab., Ames, IA (United States)

2017-03-02

Increasing Si content improves magnetic and electrical properties of electrical steel, with 6.5% Si as the optimum. Unfortunately, when Si content approaches 5.7%, the Fe-Si alloy becomes brittle. At 6.5%, the steel conventional cold rolling process is no longer applicable. The heterogeneous formation of B2 and D03 ordered phases is responsible for the embrittlement. The formation of these ordered phases can be impeded by rapid cooling. However, only the cooling rates of water and brine water were investigated. A comprehensive study of the effect of rapid cooling rate on the formation of the ordered phases was carried out by varying wheel speed and melt-injection rate. Thermal imaging employed to measure cooling rates while microstructures of the obtained ribbons are characterized using X-ray diffraction and TEM. The electrical, magnetic and mechanical properties are characterized using 4-pt probe, VSM, and macro-indentation methods. The relations between physical properties and ordered phases are established.

Thermohydraulics in a high-temperature gas-cooled reactor primary loop during early phases of unrestricted core-heatup accidents

International Nuclear Information System (INIS)

Kroeger, P.G.; Colman, J.; Hsu, C.J.

1983-01-01

In High Temperature Gas Cooled Reactor (HTGR) siting considerations, the Unrestricted Core Heatup Accidents (UCHA) are considered as accidents of highest consequence, corresponding to core meltdown accidents in light water reactors. Initiation of such accidents can be, for instance, due to station blackout, resulting in scram and loss of all main loop forced circulation, with none of the core auxiliary cooling system loops being started. The result is a slow but continuing core heatup, extending over days. During the initial phases of such UCHA scenarios, the primary loop remains pressurized, with the system pressure slowly increasing until the relief valve setpoint is reached. The major objectives of the work described here were to determine times to depressurization as well as approximate loop component temperatures up to depressurization

EVAPORATIVE COOLING - CONCEPTUAL DESIGN FOR ATLAS SCT

CERN Document Server

Niinikoski, T O

1998-01-01

The conceptual design of an evaporative two-phase flow cooling system for the ATLAS SCT detector is described, using perfluorinated propane (C3F8) as a coolant. Comparison with perfluorinated butane (C4F10) is made, although the detailed design is presented only for C3F8. The two-phase pressure drop and heat transfer coefficient are calculated in order to determine the dimensions of the cooling pipes and module contacts for the Barrel SCT. The region in which the flow is homogeneous is determined. The cooling cycle, pipework, compressor, heat exchangers and other main elements of the system are calculated in order to be able to discuss the system control, safety and reliability. Evaporative cooling appears to be substantially better than the binary ice system from the point of view of safety, reliability, detector thickness, heat transfer coefficient, cost and simplicity.

Experimental study of the thermal characteristics of phase change slurries for active cooling

International Nuclear Information System (INIS)

Lu, W.; Tassou, S.A.

2012-01-01

Highlights: ► Tween 60 and hexadecanol can be employed to produce paraffin-in-water emulsions. ► Paraffin with longer carbon chain than the paraffin in the emulsion can act as nucleate agent to reduce supercooling. ► Increasing the quantity of paraffin increases the viscosity of the emulsion. ► Antifreeze and traces of thickener can cause a significant increase to the viscosity of the emulsion. ► Well prepared emulsions are stable with storage and thermal cycles. -- Abstract: Phase change materials (PCMs) are increasingly being used for thermal energy storage in buildings and industry to produce energy savings and reduce carbon dioxide emissions. PCM slurries are also being investigated for active thermal energy storage or as alternatives to conventional single phase fluids because they are pumpable and have advanced heat transport performance with phase change. The present study investigates several types of phase change materials for the preparation of PCM slurries which have potential for cooling applications. The thermophysical properties of paraffin in water emulsions, such as latent heat of fusion, melting and freezing temperature ranges, viscosity and the effect of surfactants, have been tested using appropriate experimental techniques. It has been identified that the use of small quantities of higher melting temperature paraffin and surfactants in the emulsion can reduce the effect of supercooling and increase the useful heat of fusion. However there are negative impacts on viscosity which should be considered in heat transport applications.

Influence of cooling modes on purity of solid-state synthesized tetracalcium phosphate

International Nuclear Information System (INIS)

Guo Dagang; Xu Kewei; Han Yong

2005-01-01

Pure tetracalcium phosphate powder (TTCP) was prepared by a solid-state phase reaction at 1500 deg. C. Effects of cooling modes on the synthesizing process of TTCP powder and its thermal behavior at different heating temperatures were investigated by XRD and FTIR. The results show that cooling in dry air tends to promote formation of single phase TTCP, while in situ cooling in furnace results in a mixture of hydroxyapatite (HAP) and CaO. The examination of the thermal behavior of TTCP indicates that there exists a decomposing zone in the range of 500 deg. C-1200 deg. C, in which the high-temperature synthesized TTCP phase is transformed during the subsequent cooling process. This was confirmed by three additional cooling treatment routes that provide significant experimental evidence to the cooling modes effect on the purity of TTCP. The phase transformation course of starting materials heated to elevated temperatures was further studied by TGA-DSC analysis with the aid of XRD and FTIR, in order to fully understand the complicated synthesizing process of TTCP

Concept of the Cooling System of the ITS for ALICE: Technical Proposals, Theoretical Estimates, Experimental Results

CERN Document Server

Godisov, O N; Yudkin, M I; Gerasimov, S F; Feofilov, G A

1994-01-01

Contradictory demands raised by the application of different types of sensitive detectors in 5 layers of the Inner Tracking System (ITS) for ALICE stipulate the simultaneous use of different schemes of heat drain: gaseous cooling of the 1st layer (uniform heat production over the sensitive surface) and evaporative cooling for the 2nd-5th layers (localised heat production). The last system is also a must for the thermostabilization of Si-drift detectors within 0.1 degree C. Theoretical estimates of gaseous, evaporative and liquid cooling systems are done for all ITS layers. The results of the experiments done for evaporative and liquid heat drain systems are presented and discussed. The major technical problems of the evaporative systems' design are being considered: i) control of liquid supply; ii) vapour pressure control. Two concepts of the evaporative systems are proposed: 1) One channel system for joint transfer of two phases (liquid + gas); 2) Two channels system with separate transfer of phases. Both sy...

Investigations on sump cooling after core melt down

Energy Technology Data Exchange (ETDEWEB)

Knebel, J.U. [Forschungeszentrum Karlsruhe - Technik und Umwelt Institut fuer Angewandte Thermo- und Fluiddynamik, Karlsruhe (Germany)

1995-09-01

This article presents the basic physical phenomena and scaling criteria of decay heat removal from a large coolant pool by single-phase and two-phase natural circulation flow. The physical significance of the dimensionless similarity groups derived is evaluated. The above results are applied to the SUCO program that is performed at the Forschungszentrum Karlsruhe. The SUCO program is a three-step series of scaled model experiments investigating the possibility of an optional sump cooling concept for the European Pressurized Water Reactor EPR. This concept is entirely based on passive safety features within the containment. The work is supported by the German utilities and the Siemens dimensional SUCOS-2D test facility. The experimental results of the model geometry are transformed to prototypic conditions.

Investigations on sump cooling after core melt down

International Nuclear Information System (INIS)

Knebel, J.U.

1995-01-01

This article presents the basic physical phenomena and scaling criteria of decay heat removal from a large coolant pool by single-phase and two-phase natural circulation flow. The physical significance of the dimensionless similarity groups derived is evaluated. The above results are applied to the SUCO program that is performed at the Forschungszentrum Karlsruhe. The SUCO program is a three-step series of scaled model experiments investigating the possibility of an optional sump cooling concept for the European Pressurized Water Reactor EPR. This concept is entirely based on passive safety features within the containment. The work is supported by the German utilities and the Siemens dimensional SUCOS-2D test facility. The experimental results of the model geometry are transformed to prototypic conditions

Thermal and stability considerations for a supercritical water-cooled fast reactor during power-raising phase of plant startup

International Nuclear Information System (INIS)

Cai, Jiejin; Ishiwatari, Yuki; Oka, Yoshiaki; Ikejiri, Satoshi

2009-01-01

This paper describes thermal analyses and linear stability analyses of the Supercritical Water-cooled Fast Reactor with 'two-path' flow scheme during the power-raising phase of plant startup. For thermal consideration, the same criterion of the maximum cladding surface temperature (MCST) as applied to the normal operating condition is used. For thermal-hydraulic stability consideration, the decay ratio of 0.5 is applied, which is taken from BWRs. Firstly, we calculated the flow rate distribution among the parallel flow paths from the reactor vessel inlet nozzles to the mixing plenum below the core using a system analysis code. The parallel flow paths consist of the seed fuel assemblies cooled by downward flow, the blanket fuel assemblies cooled by downward flow and the downcomer. Then, the MCSTs are estimated for various reactor powers and feedwater flow rates with system analyses. The decay ratios are estimated with linear stability analyses. The available range of the reactor power and feedwater flow rate to satisfy the thermal and stability criteria is obtained. (author)

The cryogenic helium cooling system for the Tokamak physics experiment

International Nuclear Information System (INIS)

Felker, B.; Slack, D.S.; Wendland, C.R.

1995-01-01

The Tokamak Physics Experiment (TPX) will use supercritical helium to cool all the magnets and supply helium to the Vacuum cryopumping subsystem. The heat loads will come from the standard steady state conduction and thermal radiation sources and from the pulsed loads of the nuclear and eddy currents caused by the Central Solenoid Coils and the plasma positioning coils. The operations of the TPX will begin with pulses of up to 1000 seconds in duration every 75 minutes. The helium system utilizes a pulse load leveling scheme to buffer out the effects of the pulse load and maintain a constant cryogenic plant operation. The pulse load leveling scheme utilizes the thermal mass of liquid and gaseous helium stored in a remote dewar to absorb the pulses of the tokamak loads. The mass of the stored helium will buffer out the temperature pulses allowing 5 K helium to be delivered to the magnets throughout the length of the pulse. The temperature of the dewar will remain below 5 K with all the energy of the pulse absorbed. This paper will present the details of the heat load sources, of the pulse load leveling scheme operations, a partial helium schematic, dewar temperature as a function of time, the heat load sources as a function of time and the helium temperature as a function of length along the various components that will be cooled

INVESTIGATION OF THE PERFORMANCE OF AN ATMOSPHERIC COOLING TOWER USING FRESH AND SALTED WATER

Directory of Open Access Journals (Sweden)

A Haddad

2012-01-01

Full Text Available Cooling towers are extensively used to evacuate large quantities of heat at modest temperatures through a change of phase of the flowing cooling fluid. Based on this classical principle, the present study investigates the influence of salty water on the heat exchange produced. For that purpose, experiments are carried out using fresh and salty water. Furthermore, a comparison with the results produced through an approach involving the solution of energy equation involving the flow of air on an evaporating film of fluid. The detailed results show a preponderance of fresh water over the salty.

Environmental effects of large discharges of cooling water. Experiences from Swedish nuclear power plants

International Nuclear Information System (INIS)

Ehlin, Ulf; Lindahl, Sture; Neuman, Erik; Sandstroem, Olof; Svensson, Jonny

2009-07-01

variations caused by changing weather and climate. When cooling water discharges began, the monitoring of effects started, mapping environmental impacts. To ensure that observed environmental changes were caused by cooling water discharges and not by natural variations, parallel measurements were carried out in undisturbed reference areas. The focus of the biological investigations has been directed towards fish using test fishing and daily records of commercial fishing. Age distributions, reproduction, growth, and the prevalence of disease and parasites have been analysed. Fish movements and behaviour related to cooling-water were mapped using mark-recapture experiments. The monitoring of effects included mapping the shape and size of the cooling-water plume and the temperature distribution in the discharge area. For certain biological variables, such as the movement of fish in relation to the cooling water plume, great efforts were made during the first years of power plant operation. In conjunction with the start of the plants, studies were also initiated to estimate the loss of fish on the cooling-water intake screens. Meteorological research projects investigated among other things, the risks for increased fog formation due to the discharge of warm water, while hydrography projects mainly concerned the development of methods for calculating the size and form of the cooling water plumes. Ecological studies were directed to the effects of increasing temperature on the production and degradation of biological material, on the benthic fauna responses, on the risk of fish parasite and disease outbreaks as well as on the combined effects of toxic substances and heat. The possibility of using cooling-water to improve fish recruitment was also studied. In conjunction with the construction of the Forsmark nuclear power plant, an artificial enclosure was made using rock excavated from the cooling water tunnels. Cooling water is led through this basin before discharge into the

History Dependence of the Microstructure on Time-Dependent Deformation During In-Situ Cooling of a Nickel-Based Single-Crystal Superalloy

Science.gov (United States)

Panwisawas, Chinnapat; D'Souza, Neil; Collins, David M.; Bhowmik, Ayan; Roebuck, Bryan

2018-05-01

Time-dependent plastic deformation through stress relaxation and creep deformation during in-situ cooling of the as-cast single-crystal superalloy CMSX-4® has been studied via neutron diffraction, transmission electron microscopy, electro-thermal miniature testing, and analytical modeling across two temperature regimes. Between 1000 °C and 900 °C, stress relaxation prevails and gives rise to softening as evidenced by a decreased dislocation density and the presence of long segment stacking faults in γ phase. Lattice strains decrease in both the γ matrix and γ' precipitate phases. A constitutive viscoplastic law derived from in-situ isothermal relaxation test under-estimates the equivalent plastic strain in the prediction of the stress and strain evolution during cooling in this case. It is thereby shown that the history dependence of the microstructure needs to be taken into account while deriving a constitutive law and which becomes even more relevant at high temperatures approaching the solvus. Higher temperature cooling experiments have also been carried out between 1300 °C and 1150 °C to measure the evolution of stress and plastic strain close to the γ' solvus temperature. In-situ cooling of samples using ETMT shows that creep dominates during high-temperature deformation between 1300 °C and 1220 °C, but below a threshold temperature, typically 1220 °C work hardening begins to prevail from increasing γ' fraction and resulting in a rapid increase in stress. The history dependence of prior accumulated deformation is also confirmed in the flow stress measurements using a single sample while cooling. The saturation stresses in the flow stress experiments show very good agreement with the stresses measured in the cooling experiments when viscoplastic deformation is dominant. This study demonstrates that experimentation during high-temperature deformation as well as the history dependence of the microstructure during cooling plays a key role in deriving

Upgrade for Phase II of the Gerda experiment

Science.gov (United States)

Agostini, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; Di Marco, N.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Hiller, R.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Ioannucci, L.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; Kermaïdic, Y.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Medinaceli, E.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Nisi, S.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Ransom, C.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Salathe, M.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schütz, A.-K.; Schulz, O.; Schwingenheuer, B.; Selivanenko, O.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zsigmond, A. J.; Zuber, K.; Zuzel, G.

2018-05-01

The Gerda collaboration is performing a sensitive search for neutrinoless double beta decay of ^{76}Ge at the INFN Laboratori Nazionali del Gran Sasso, Italy. The upgrade of the Gerda experiment from Phase I to Phase II has been concluded in December 2015. The first Phase II data release shows that the goal to suppress the background by one order of magnitude compared to Phase I has been achieved. Gerda is thus the first experiment that will remain "background-free" up to its design exposure (100 kg year). It will reach thereby a half-life sensitivity of more than 10^{26} year within 3 years of data collection. This paper describes in detail the modifications and improvements of the experimental setup for Phase II and discusses the performance of individual detector components.

In-vessel core debris retention experiments. Final report

International Nuclear Information System (INIS)

1998-10-01

The in-vessel cooling experimental program (Phase 1 and 2) was motivated by the survivability of the TMI lower vessel head during the TMI-2 accident. During that accident, molten debris relocation into the water filled lower head resulted in a localized hot spot in the lower head, but no lower head failure occurred. A postulated set of mechanisms which could be involved in and responsible for the survivability of the TMI lower head were identified and experimentally investigated as part of this program. These mechanisms included: the formation of a gap (contact resistance) between the relocated and frozen debris and the vessel wall was a key aspect of the in-vessel cooling mechanism; wall heatup due to the relocated debris in the presence of wall stress due to a pressure gradient across the vessel wall; gap growth due to a lack of debris adherence to the vessel wall and material creep of the heated vessel wall; and the potential for enhanced wall cooling due to gap growth. Each of these postulated mechanisms was investigated in this experimental program. This report summarizes the several insights and conclusions that were obtained from this experimental program. This report documents the entire set of five experiments completed in Phase 2 of this experimental program. Results from the Phase 1 effort were used to plan and select the Phase 2 test matrix. Conclusions from the Phase 1 and 2 experiments are identified and recommendations for future work are provided

Low-noise wide-band amplifiers for stochastic beam cooling experiments

International Nuclear Information System (INIS)

Leskovar, B.; Lo, C.C.

1982-01-01

Noise characteristics of the continuous-wave wide-band amplifier systems for stochastic beam cooling experiments are presented. Also, the noise performance, bandwidth capability and gain stability of components used in these amplifiers are summarized and compared in the 100 MHz to 40 GHz frequency range. This includes bipolar and field-effect transistors, parametric amplifier, Schottky diode mixer and maser. Measurements of the noise characteristics and scattering parameters of variety GaAs FETs as a function of ambient temperature are also given. Performance data and design information are presented on a broadband 150-500 MHz preamplifier having noise temperature of approximately 35 0 K at ambient temperature of 20 0 K. An analysis of preamplifier stability based on scattering parameters concept is included

Experiencies of corrosion and corrosion protection in seawater-cooling systems in the Nordic countries

International Nuclear Information System (INIS)

Henriksson, S.

1984-10-01

This report summarizes the experience of the corrosion resistance of pumps, heat exchangers, valves, and pipings in different seawater-cooling system. For pumps and heat exchangers the experience has been so extensive that a clear picture of todays status can be given. Owing to more scanty data concerning valves and pipes the survey of the corrosion in these components is less well substantiated. The most common pumps in the cooling systems of power stations are vertically extended shaft pumps. To counteract corrosion on column and casing with organic surface coating and on stainless steel shafts and impellers under shutdown conditions, these should be provided with internal and external cathodic protection. The experience of tin and aluminium bronzes in impellers and shafts in such pumps has been so poor - erosion and cavitaion damage - that a change has usually been made to preferentially ferritic-austenitic Mo-alloyd stainless steels. The combination of stainless steel/Ni-Resist 2 D has been found unsatisfactory owing to the occurrence of galvanic corrosion on the latter material. For heat exchangers, titanium has proved to be far and away the best choice. In the optimal blanket solution for a titanium heat exchangers the tubes are seal-welded to tube sheets of explosion-bonded titanium clad steel. For retubing of old condensers a similar procedure with tubes of high-alloy stainless steel in tube sheets of stainless clad steel is of economic interest. The effect of chlorination of the cooling water, however, remains to be clarified before such a procedure can be unreservedly recommended. Pipings of rubber-lined carbon steel or with thick coatings of solvent-free opoxy resin have shown very good corrosion resistance. Tar-epoxy-resin-coated pipes, however, should usually be provided with internal cathodic protection. Cement-lined carbon steel pipes are used with varying results in the offshore industry. Recently, however, pipes of the high slloy stainless steel

Acoustic emission characterization of the tetragonal-monoclinic phase transformation in zirconia

International Nuclear Information System (INIS)

Clarke, D.R.; Arora, A.

1983-01-01

The processes accompanying the tetragonal-monoclinic phase transformation in zirconia (ZrO 2 ) have been studied using acoustic emission and electron microscopy in an attempt to characterize the different mechanisms by which the transformation can be accommodated in bulk materials. Experiments in which the acoustic emission is detected as specimens are cooled through the transformation, following densification by sintering, are described. For comparison, the acoustic emission from free, nominally unconstrained powders similarly cooled through the transformation is reported. The existence of distinct processes accompanying the phase transformation is established on the basis of postexperiment multiparametric correlation analysis of the acoustic emission

Steam generator tube failures: experience with water-cooled nuclear power reactors during 1976

International Nuclear Information System (INIS)

Tatone, O.S.; Pathania, R.S.

1978-02-01

A survey was conducted of experience with steam generator tubes at nuclear power stations during 1976. Failures were reported at 25 out of 68 water-cooled reactors. The causes of these failures and the repair and inspection procedures designed to cope with them are summarized. Examination of the data indicates that corrosion was the major cause of steam generator tube failures. Improvements are needed in steam generator design, condenser integrity and secondary water chemistry control. (author)

Phase transition stability within ceramics

International Nuclear Information System (INIS)

Wang, E.; Wang, D.

1992-01-01

Irreversible thermodynamics is applied to analyse nucleation, both in metals and ceramics, in order to distinguish the stability of metastable under cooled melts. The hypothesis of local equilibrium has been used to apply research results from equilibrium thermodynamics, for the study of irreversible processes. The under cooling equation for homogenous nucleation only depends on a coefficient which is not related to the melting point of the material. The calculated critical under cooling values for metals are compared with experimental data. The metastable phase formation of plasma-sprayed alumina and zircon coatings has been discussed based on irreversible thermodynamics. A critical under cooling parameter (β) is defined. The metastable phase formation of plasma-sprayed alumina and zircon has been discussed. The analysis shows that γ-Al 2 O 3 is first formed in the coating since it has a lower β value than α-Al 2 O 3 . Zircon dissociates into ZrO 2 and SiO 2 , and rapid quenching of plasma spraying prevents their re association. The cooling rate determines whether t-ZrO 2 or c-ZrO 2 will form in the sprayed coating. It can be confirmed by the experiments that the content of t-ZrO 2 will increase correspondingly as the sprayed particle size decreases. At high transition temperatures, c-ZrO 2 will be formed because of the anisotropic thermal expansion behaviour in the crystal structure. 22 refs., 2 tabs

High quality actively cooled plasma facing components for fusion

International Nuclear Information System (INIS)

Nygren, R.

1993-01-01

This paper interweaves some suggestions for developing actively-cooled PFCs (plasma facing components) for future fusion devices with supporting examples taken from the design, fabrication and operation of Tore Supra's Phase III Outboard Pump Limiter (OPL). This actively-cooled midplane limiter, designed for heat and particle removal during long pulse operation, has been operated in essentially thermally steady state conditions. From experience with testing to identify braze flaws in the OPL, recommendations are made to analyze the impact of joining flaws on thermal-hydraulic performance of PFCs and to validate a method of inspection for such flaws early in the design development. Capability for extensive in-service monitoring of future PFCs is also recommended and the extensive calorimetry and IR thermography used to confirm and update safe operating limits for power handling of the OPL are reviewed

Longitudinal dynamics of laser-cooled fast ion beams

DEFF Research Database (Denmark)

Weidemüller, M.; Eike, B.; Eisenbarth, U.

1999-01-01

We present recent results of our experiments on laser cooling of fast stored ion beams at the Heidelberg Test Storage Ring. The longitudinal motion of the ions is directly cooled by the light pressure force, whereas efficient transverse cooling is obtained indirectly by longitudinal-transverse co......We present recent results of our experiments on laser cooling of fast stored ion beams at the Heidelberg Test Storage Ring. The longitudinal motion of the ions is directly cooled by the light pressure force, whereas efficient transverse cooling is obtained indirectly by longitudinal....... When applying laser cooling in square-well buckets over long time intervals, hard Coulomb collisions suddenly disappear and the longitudinal temperature drops by about a factor of three. The observed longitudinal behaviour of the beam shows strong resemblance with the transition to an Coulomb...

Characterisation of the muon beams for the Muon Ionisation Cooling Experiment

Energy Technology Data Exchange (ETDEWEB)

Adams, D.; Barclay, P.; Bayliss, V.; Bradshaw, T.W.; Courthold, M.; Francis, V.; Fry, L.; Hayler, T.; Hills, M.; Lintern, A.; Macwaters, C.; Nichols, A.; Preece, R.; Ricciardi, S.; Rogers, C.; Stanley, T.; Tarrant, J.; Watson, S.; Wilson, A. [Harwell Oxford, STFC Rutherford Appleton Laboratory, Didcot (United Kingdom); Adey, D.; Back, J.; Boyd, S.; Harrison, P.; Pidcott, C.; Taylor, I. [University of Warwick, Department of Physics, Coventry (United Kingdom); Alekou, A.; Apollonio, M.; Barber, G.; Colling, D.; Dobbs, A.; Dornan, P.; Fayer, S.; Fish, A.; Hunt, C.; Leaver, J.; Long, K.; Martyniak, J.; Middleton, S.; Pasternak, J.; Richards, A.; Santos, E.; Savidge, T.; Takahashi, M. [Imperial College London, Department of Physics, Blackett Laboratory, London (United Kingdom); Asfandiyarov, R.; Blondel, A.; Graulich, J.S.; Karadzhov, Y.; Verguilov, V.; Wisting, H. [Universite de Geneve, DPNC, Section de Physique, Geneva (Switzerland); De Bari, A.; Cecchet, G. [Sezione INFN Pavia (Italy); Dipartimento di Fisica Nucleare e Teorica, Pavia (Italy); Bayes, R.; Forrest, D.; Nugent, J.C.; Soler, F.J.P.; Walaron, K. [The University of Glasgow, School of Physics and Astronomy, Glasgow (United Kingdom); Bertoni, R.; Bonesini, M.; Lucchini, G. [Sezione INFN Milano Bicocca (Italy); Dipartimento di Fisica G. Occhialini, Milano (Italy); Blackmore, V.J.; Carlisle, T.; Cobb, J.H.; Lau, W.; Rayner, M.A.; Tunnell, C.D. [University of Oxford, Department of Physics, Oxford (United Kingdom); Blot, S.; Kim, Y.K. [University of Chicago, Enrico Fermi Institute, Chicago, IL (United States); Bogomilov, M.; Kolev, D.; Rusinov, I.; Tsenov, R.; Vankova, G. [St. Kliment Ohridski University of Sofia, Department of Atomic Physics, Sofia (Bulgaria); Booth, C.N.; Hodgson, P.; Nicholson, R.; Overton, E.; Robinson, M.; Smith, P.J. [University of Sheffield, Department of Physics and Astronomy, Sheffield (United Kingdom); Bowring, D.; DeMello, A.; Gourlay, S.; Li, D.; Prestemon, S.; Virostek, S.P.; Zisman, M.S. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Bravar, U. [University of New Hampshire, Durham, NH (United States); Bross, A.D.; Fitzpatrick, T.; Leonova, M.; Moretti, A.; Neuffer, D.; Popovic, M.; Rubinov, P.; Rucinski, R. [Fermilab, Batavia, IL (United States); Capponi, M.; Iaciofano, A.; Orestano, D.; Pastore, F.; Tortora, L. [Sezione INFN Roma Tre e Dipartimento di Fisica, Roma (Italy); Charnley, G.; Collomb, N.; Gallagher, A.; Grant, A.; Griffiths, S.; Hartnett, T.; Martlew, B.; Moss, A.; Muir, A.; Mullacrane, I.; Owens, P.; White, C. [STFC Daresbury Laboratory, Cheshire (United Kingdom); Coney, L.; Fletcher, R.; Hanson, G.G.; Heidt, C. [University of California, Riverside, CA (United States); Cooke, P.; Gamet, R. [University of Liverpool, Department of Physics, Liverpool (United Kingdom); Cremaldi, L.M.; Hart, T.L.; Luo, T.; Sanders, D.A.; Summers, D.J. [University of Mississippi, Oxford, MS (United States); Dick, A.J.; Ronald, K.; Whyte, C.G. [University of Strathclyde, Department of Physics, Glasgow (United Kingdom); Filthaut, F. [NIKHEF, Amsterdam (Netherlands); Freemire, B.; Hanlet, P.; Kafka, G.; Kaplan, D.M.; Rajaram, D.; Snopok, P.; Torun, Y. [Illinois Institute of Technology, Chicago, IL (United States); Hansen, O.M.; Ramberger, S.; Vretenar, M. [CERN, Geneva (Switzerland); Ishimoto, S. [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Kuno, Y.; Sakamoto, H. [Osaka University, Graduate School of Science, Department of Physics, Toyonaka, Osaka (Japan); Kyberd, P.; Littlefield, M.; Nebrensky, J.J. [Brunel University, Uxbridge (United Kingdom); Onel, Y. [University of Iowa, Department of Physics and Astronomy, Iowa City, IA (United States); Palladino, V. [Universita Federico II, Sezione INFN Napoli (Italy); Dipartimento di Fisica, Napoli (Italy); Palmer, R.B. [Brookhaven National Laboratory, Upton, NY (US); Roberts, T.J. [Muons, Inc., Batavia, IL (US); Collaboration: The MICE Collaboration

2013-10-15

A novel single-particle technique to measure emittance has been developed and used to characterise seventeen different muon beams for the Muon Ionisation Cooling Experiment (MICE). The muon beams, whose mean momenta vary from 171 to 281 MeV/c, have emittances of approximately 1.2-2.3 {pi} mm-rad horizontally and 0.6-1.0 {pi} mm-rad vertically, a horizontal dispersion of 90-190 mm and momentum spreads of about 25 MeV/c. There is reasonable agreement between the measured parameters of the beams and the results of simulations. The beams are found to meet the requirements of MICE. (orig.)

Characterisation of the muon beams for the Muon Ionisation Cooling Experiment

International Nuclear Information System (INIS)

Adams, D.; Barclay, P.; Bayliss, V.; Bradshaw, T.W.; Courthold, M.; Francis, V.; Fry, L.; Hayler, T.; Hills, M.; Lintern, A.; Macwaters, C.; Nichols, A.; Preece, R.; Ricciardi, S.; Rogers, C.; Stanley, T.; Tarrant, J.; Watson, S.; Wilson, A.; Adey, D.; Back, J.; Boyd, S.; Harrison, P.; Pidcott, C.; Taylor, I.; Alekou, A.; Apollonio, M.; Barber, G.; Colling, D.; Dobbs, A.; Dornan, P.; Fayer, S.; Fish, A.; Hunt, C.; Leaver, J.; Long, K.; Martyniak, J.; Middleton, S.; Pasternak, J.; Richards, A.; Santos, E.; Savidge, T.; Takahashi, M.; Asfandiyarov, R.; Blondel, A.; Graulich, J.S.; Karadzhov, Y.; Verguilov, V.; Wisting, H.; De Bari, A.; Cecchet, G.; Bayes, R.; Forrest, D.; Nugent, J.C.; Soler, F.J.P.; Walaron, K.; Bertoni, R.; Bonesini, M.; Lucchini, G.; Blackmore, V.J.; Carlisle, T.; Cobb, J.H.; Lau, W.; Rayner, M.A.; Tunnell, C.D.; Blot, S.; Kim, Y.K.; Bogomilov, M.; Kolev, D.; Rusinov, I.; Tsenov, R.; Vankova, G.; Booth, C.N.; Hodgson, P.; Nicholson, R.; Overton, E.; Robinson, M.; Smith, P.J.; Bowring, D.; DeMello, A.; Gourlay, S.; Li, D.; Prestemon, S.; Virostek, S.P.; Zisman, M.S.; Bravar, U.; Bross, A.D.; Fitzpatrick, T.; Leonova, M.; Moretti, A.; Neuffer, D.; Popovic, M.; Rubinov, P.; Rucinski, R.; Capponi, M.; Iaciofano, A.; Orestano, D.; Pastore, F.; Tortora, L.; Charnley, G.; Collomb, N.; Gallagher, A.; Grant, A.; Griffiths, S.; Hartnett, T.; Martlew, B.; Moss, A.; Muir, A.; Mullacrane, I.; Owens, P.; White, C.; Coney, L.; Fletcher, R.; Hanson, G.G.; Heidt, C.; Cooke, P.; Gamet, R.; Cremaldi, L.M.; Hart, T.L.; Luo, T.; Sanders, D.A.; Summers, D.J.; Dick, A.J.; Ronald, K.; Whyte, C.G.; Filthaut, F.; Freemire, B.; Hanlet, P.; Kafka, G.; Kaplan, D.M.; Rajaram, D.; Snopok, P.; Torun, Y.; Hansen, O.M.; Ramberger, S.; Vretenar, M.; Ishimoto, S.; Kuno, Y.; Sakamoto, H.; Kyberd, P.; Littlefield, M.; Nebrensky, J.J.; Onel, Y.; Palladino, V.; Palmer, R.B.; Roberts, T.J.

2013-01-01

A novel single-particle technique to measure emittance has been developed and used to characterise seventeen different muon beams for the Muon Ionisation Cooling Experiment (MICE). The muon beams, whose mean momenta vary from 171 to 281 MeV/c, have emittances of approximately 1.2-2.3 π mm-rad horizontally and 0.6-1.0 π mm-rad vertically, a horizontal dispersion of 90-190 mm and momentum spreads of about 25 MeV/c. There is reasonable agreement between the measured parameters of the beams and the results of simulations. The beams are found to meet the requirements of MICE. (orig.)

The Proposed Heating and Cooling System in the CH2 Building and Its Impact on Occupant Productivity

Directory of Open Access Journals (Sweden)

Lu Aye

2012-11-01

Full Text Available Melbourne's climatic conditions demand that its buildings require both heating and cooling systems. In a multi-storey office building , however, cooling requirements will dominate. How the internal space is cooled and ventilation air is delivered will significantly impact on occupant comfort. This paper discusses the heating and cooling systems proposed for the CH2building. The paper critiques the proposed systems against previous experience, both internationally and in Australia. While the heating system employs proven technologies, less established techniques are proposed for the cooling system. Air movement in the shower towers, for example, is to be naturally induced and this has not always been successful elsewhere. Phase change material for storage of "coolth" does not appear to have been demonstrated previously in a commercial building, so the effectiveness of the proposed system is uncertain. A conventional absorption chiller backs up the untried elements of the cooling system, so that ultimately occupant comfort should not be compromised .

Development of Low Carbon Niobium Bearing High Strength F-B Dual Phase Steel with High Hole Expansion Property

Science.gov (United States)

Zhang, Lin; Xia, Ming-sheng; Xiong, Zi-liu; Du, Yan-bing; Qiao, Zhi-ming; Zhang, Hong-bo

In the study a low carbon niobium bearing high strength F-B dual phase automobile steel with high hole expansion property has been investigated. Steels of different chemical composition have been investigated by simulation experiments of controlled rolling and cooling process to study the influences of chemical elements, especially for C,Nb and Ti, and cooling pattern on the mechanical properties, flangeability and microstructure of strips. So-called 3-stages cooling pattern was adopted in simulation experiments, combining ultra fast cooling in first stage, air cooling in middle stage and fast cooling in the last stage, and at the end of run-out table the temperature of rolled pieces drop to below Bs point. Optical microstructure and SEM morphology have been observed. Results indicate that it is possible to obtain dual phase microstructure of polygonal ferrite plus bainite in adopting 3-stages cooling pattern. The low temperature coiling method using 3-step controlled cooling pattern after hot rolling is effective to produce low carbon Nb bearing steel with high balance of strength-ductility-flangeability, in addition, higher carbon content of steel tend to be detrimental to flangeability of steel, due to much carbide precipitation at ferrite boundary. Based on the results of simulation experiments mill trial has been carried out and hot rolled high strength steel with tensile strength higher as 600Mpa and hole expansion ratio higher as 100% has been developed successfully.

Cooled heavy ion beams at the ESR

International Nuclear Information System (INIS)

Steck, M.; Beckert, K.; Bosch, F.; Eickhoff, H.; Franzke, B.; Klepper, O.; Nolden, F.; Reich, H.; Schlitt, B.; Spaedtke, P.; Winkler, T.

1996-01-01

The storage ring ESR has been used in various operational modes for experiments with electron cooled heavy ion beams. Besides the standard storage mode including injection and beam accumulation the deceleration of highly charged ions has been demonstrated. Beams of highly charged ions have been injected and accumulated and finally decelerated to a minimum energy of 50 MeV/u. An ultraslow extraction method using charge changing processes is now also available for cooled beams of highly charged ions. For in ring experiments the internal gas jet and the cold electron beam of the cooling system are applied as targets. High precision mass spectrometry by Schottky noise detection has been demonstrated. Operation at transition energy has been achieved with cooled beams opening the field for experiments which require an isochronous revolution of the ions. (orig.)

Newton's law of cooling revisited

International Nuclear Information System (INIS)

Vollmer, M

2009-01-01

The cooling of objects is often described by a law, attributed to Newton, which states that the temperature difference of a cooling body with respect to the surroundings decreases exponentially with time. Such behaviour has been observed for many laboratory experiments, which led to a wide acceptance of this approach. However, the heat transfer from any object to its surrounding is not only due to conduction and convection but also due to radiation. The latter does not vary linearly with temperature difference, which leads to deviations from Newton's law. This paper presents a theoretical analysis of the cooling of objects with a small Biot number. It is shown that Newton's law of cooling, i.e. simple exponential behaviour, is mostly valid if temperature differences are below a certain threshold which depends on the experimental conditions. For any larger temperature differences appreciable deviations occur which need the complete nonlinear treatment. This is demonstrated by results of some laboratory experiments which use IR imaging to measure surface temperatures of solid cooling objects with temperature differences of up to 300 K.

Intensity limitations of cooled heavy ion beams in the ESR

International Nuclear Information System (INIS)

Hofmann, I.; Meyer-Pruessner, R.

1985-06-01

We consider the possibility of achieving maximum intensity and phase space density of heavy ions cooled by electrons in the Experimental Storage Ring to be built at GSI. Intrabeam scattering and the longitudinal microwave instability are found to be important limiting effects particularly at low energies. They are evaluated in diagrams, which can serve as a preliminary orientation for the expected performance of experiments. Examples have been calculated for U 92+ at 50 and 500 MeV/u; in the latter case we find that 9 ions at Δp/p=2x10 -4 and epsilon=0.2π mm mrad are on the safe side for an assumed cooling time of 100 msec. We have also analyzed I 20+ as a candidate for generating high energy density in matter. (orig.)

Preparation and cooling of magnesium ion crystals for sympathetic cooling of highly charged ions in a Penning trap

Energy Technology Data Exchange (ETDEWEB)

Murboeck, Tobias

2017-07-01

In this work, laser-cooled ion crystals containing 10{sup 3} to 10{sup 5} singly charged magnesium ions (Mg{sup +}) were prepared in a Penning trap. The properties of the ion crystals and their structure displaying long-range ordering were analyzed by various nondestructive techniques. After creation of the Mg{sup +} ions in the form of ion bunches in an external source, the ions were injected into the Penning trap where their temperature was reduced by eight orders of magnitude within seconds using a combination of buffer gas cooling and Doppler laser cooling. The achieved temperatures in the millikelvin-regime were close to the theoretical Doppler-cooling limit and sufficiently low to induce the transition to a crystal phase exhibiting long-range ordering. The structure of these mesoscopic ion crystals is in agreement with a model describing the crystal as a set of planar shells. This allows for a derivation of properties such as the charge density or the temperature of the observed crystals. For the process of combined buffer-gas and Doppler laser cooling an analytical model has been developed, which explains the time development of the temperature and the fluorescence signal in agreement with the experimental results. The external ion source for the production of singly charged magnesium ions was developed and characterized. A SIMION simulation of the ion creation and extraction process allows to describe the ion bunch structure and to increase the Mg{sup +} number by three orders of magnitude to 10{sup 6} Mg{sup +} ions per bunch. Other ion species with charge states between one (H{sup +}{sub 2}, C{sup +}, N{sup +}{sub 2}, CO{sup +}{sub 2}) and three (Ar{sup 3+}) were injected into the Mg{sup +} crystals. Ion crystals containing more than one ion species were observed with structures in agreement with the theory of centrifugal separation, which indicates sympathetic cooling of the non-fluorescing ion species. This preparation of mixed ion crystals is an

Gas Reactor International Cooperative Program. Interim report. Construction and operating experience of selected European Gas-Cooled Reactors

International Nuclear Information System (INIS)

1978-09-01

The construction and operating experience of selected European Gas-Cooled Reactors is summarized along with technical descriptions of the plants. Included in the report are the AVR Experimental Pebble Bed Reactor, the Dragon Reactor, AGR Reactors, and the Thorium High Temperature Reactor (THTR). The study demonstrates that the European experience has been favorable and forms a good foundation for the development of Advanced High Temperature Reactors

Improving prediction accuracy of cooling load using EMD, PSR and RBFNN

Science.gov (United States)

Shen, Limin; Wen, Yuanmei; Li, Xiaohong

2017-08-01

To increase the accuracy for the prediction of cooling load demand, this work presents an EMD (empirical mode decomposition)-PSR (phase space reconstruction) based RBFNN (radial basis function neural networks) method. Firstly, analyzed the chaotic nature of the real cooling load demand, transformed the non-stationary cooling load historical data into several stationary intrinsic mode functions (IMFs) by using EMD. Secondly, compared the RBFNN prediction accuracies of each IMFs and proposed an IMF combining scheme that is combine the lower-frequency components (called IMF4-IMF6 combined) while keep the higher frequency component (IMF1, IMF2, IMF3) and the residual unchanged. Thirdly, reconstruct phase space for each combined components separately, process the highest frequency component (IMF1) by differential method and predict with RBFNN in the reconstructed phase spaces. Real cooling load data of a centralized ice storage cooling systems in Guangzhou are used for simulation. The results show that the proposed hybrid method outperforms the traditional methods.

Traveling-wave tube amplifier characteristics study for stochastic beam-cooling experiments

International Nuclear Information System (INIS)

Leskovar, B.; Lo, C.C.

1982-03-01

The characteristics of continuous-wave wideband traveling-wave tube amplifiers have been experimentally investigated over a frequency range of 1.5 to 4.5 GHz. We present measurements of characteristics important for stochastic beam cooling systems that are generally not available from manufacturers' data sheets. The amplifers measured include models 1177 H01 and 1277 H01 having output power capabilities of 10 to 20 W, respectively, at frequencies of 2 to 4 GHz. The power transfer characteristics, the phase-shift characteristics as functions of frequency and the input power level, the voltage standing-wave ratio, noise drive transfer characteristics, harmonics and intermodulation products content were accurately measured and are discussed. Measurement procedures and description of measuring systems, which include measuring system error corrections, are given in detail. Also several approaches are discussed for the reduction of harmonics and intermodulation products

Immersion Cooling of Electronics in DoD Installations

Energy Technology Data Exchange (ETDEWEB)

Coles, Henry [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Herrlin, Magnus [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2017-08-15

A considerable amount of energy is consumed to cool electronic equipment in data centers. A method for substantially reducing the energy needed for this cooling was demonstrated. The method involves immersing electronic equipment in a non-conductive liquid that changes phase from a liquid to a gas. The liquid used was 3M Novec 649. Two-phase immersion cooling using this liquid is not viable at this time. The primary obstacles are IT equipment failures and costs. However, the demonstrated technology met the performance objectives for energy efficiency and greenhouse gas reduction. Before commercialization of this technology can occur, a root cause analysis of the failures should be completed, and the design changes proven.

Hybrid cooling tower Neckarwestheim 2 cooling function, emission, plume dispersion

International Nuclear Information System (INIS)

Braeuning, G.; Ernst, G.; Maeule, R.; Necker, P.

1990-01-01

The fan-assisted hybrid cooling tower of the 1300 MW power plant Gemeinschafts-Kernkraftwerk Neckarwestheim 2 was designed and constructed based on results from theoretical and experimental studies and experiences from a smaller prototype. The wet part acts in counterflow. The dry part is arranged above the wet part. Each part contains 44 fans. Special attention was payed to the ducts which mix the dry into the wet plume. The cooling function and state, mass flow and contents of the emission were measured. The dispersion of the plume in the atmosphere was observed. The central results are presented in this paper. The cooling function corresponds to the predictions. The content of drifted cooling water in the plume is extremely low. The high velocity of the plume in the exit causes an undisturbed flow into the atmosphere. The hybrid operation reduces visible plumes strongly, especially in warmer and drier ambient air

Phase transition traced by conductivity measurements: quantitative analysis

DEFF Research Database (Denmark)

Keding, Ralf; Ruessel, Christian; Tauch, Diana

2008-01-01

to the electrodes, all in a cylindrical geometry. The electrical resistivity of a sample in the system BaAl2B2O7 was measured during cooling between liquidus temperature (T-l) and transformation temperature (T-g) using a fixed frequency of 3.7 Hz. The melt crystallised in this temperature range during cooling...... of conductivity and the resistance changes caused by phase transformation. This enables to determine the crystal growth velocity in the temperature range between 750 and 860 degrees C in a single experiment....

A method and device for cooling

International Nuclear Information System (INIS)

Gautier, Daniel.

1974-01-01

The invention relates to a method and a device for cooling steam. The invention refers to a method for cooling steam from a turbine, e.g. a turbine coupled to a high power nuclear reactor, in which a fluid F in the state of a two-phase mixture (steam and condensation liquid) is circulated, in a closed circuit, in conduits passing through a condenser associated with the turbine in which fluid F contained in said conduits vaporizes by heat-exchange with the condenser hot steam, then through a cooling tower wherein the fluid condenses by heat-exchange with a coolant. This can be applied to cooling the steam in a turbine associated with a nuclear reactor [fr

Steam generator tube performance: experience with water-cooled nuclear power reactors during 1978

International Nuclear Information System (INIS)

Tatone, O.S.; Pathania, R.S.

1980-02-01

The performance of steam generator tubes in water-cooled nuclear power reactors has been reviewed for 1978. Tube failures occurred at 31 of the 86 reactors surveyed. Causes of these failures and procedures designed to deal with them are described. A dramatic decrease in the number of tubes plugged was evident in 1978 compared to the previous year. This is attributed to diligent application of techniques developed from in-plant experience and research and development programs over the past several years. (auth)

Ultracold molecules for the masses: Evaporative cooling and magneto-optical trapping

Science.gov (United States)

Stuhl, B. K.

While cold molecule experiments are rapidly moving towards their promised benefits of precision spectroscopy, controllable chemistry, and novel condensed phases, heretofore the field has been greatly limited by a lack of methods to cool and compress chemically diverse species to temperatures below ten millikelvin. While in atomic physics these needs are fulfilled by laser cooling, magneto-optical trapping, and evaporative cooling, until now none of these techniques have been applicable to molecules. In this thesis, two major breakthroughs are reported. The first is the observation of evaporative cooling in magnetically trapped hydroxyl (OH) radicals, which potentially opens a path all the way to Bose-Einstein condensation of dipolar radicals, as well as allowing cold- and ultracold-chemistry studies of fundamental reaction mechanisms. Through the combination of an extremely high gradient magnetic quadrupole trap and the use of the OH Λ-doublet transition to enable highly selective forced evaporation, cooling by an order of magnitude in temperature was achieved and yielded a final temperature no higher than 5mK. The second breakthrough is the successful application of laser cooling and magneto-optical trapping to molecules. Motivated by a proposal in this thesis, laser cooling of molecules is now known to be technically feasible in a select but substantial pool of diatomic molecules. The demonstration of not only Doppler cooling but also two-dimensional magneto-optical trapping in yttrium (II) oxide, YO, is expected to enable rapid growth in the availability of ultracold molecules—just as the invention of the atomic magneto-optical trap stimulated atomic physics twenty-five years ago.

History of nuclear cooling

International Nuclear Information System (INIS)

Kuerti, M.

1998-01-01

The historical development of producing extreme low temperatures by magnetic techniques is overviewed. With electron spin methods, temperatures down to 1 mK can be achieved. With nuclear spins theoretically 10 -9 K can be produced. The idea of cooling with nuclear demagnetization is not new, it is a logical extension of the concept of electron cooling. Using nuclear demagnetization experiment with 3 T water cooled solenoids 3 mK could be produced. The cold record is held by Olli Lounasmaa in Helsinki with temperatures below 10 -9 K. (R.P.)

Steady-state heat and particle removal with the actively cooled Phase III outboard pump limiter in Tore Supra

International Nuclear Information System (INIS)

Nygren, R.; Koski, J.; Lutz, T.; McGrath; Miller, J.; Watkins, J.; Guilhem, D.; Chappuis, P.; Cordier, J.; Loarer, T.

1995-01-01

Tore Supra's Phase III outboard pump limiter (OPL) is a modular actively-cooled mid-plane limiter, designed for heat and particle removal during long pulse operation. During its initial operation in 1993, the OPL successfully removed about 1 MW of power during ohmicly heated shots of up to 10 s duration and reached (steady state) thermal equilibrium. The particle pumping of the Phase III OPL was found to be about 50% greater than the Phase II OPL which had a radial distance between the last closed flux surface and the entrance of the pumping throat of 3.5 cm compared with only 2.5 cm for the Phase III OPL. This paper gives examples of power distribution over the limiter from IR measurements of surface temperature and from extensively calorimetry (34 thermocouples and 10 flow meters) and compares the distributions with values predicted by a 3D model (HF3D) with a detailed magnetic configuration (e.g., includes field ripple). ((orig.))

Experiments with stored heavy ions

International Nuclear Information System (INIS)

Fick, D.; Habs, D.; Jaeschke, E.

1985-02-01

The success of newly-developed methods of phase space cooling in proton and antiproton storage rings was sufficient for an examination of whether these methods could also be applied in storage rings for heavy ions. An expansion of these methods to heavy ion beams seems attractive for all sorts of reasons. Recently, this area was extensively discussed in a series of working meetings with the result that heavy ion storage rings are to be built for use in atomic and nuclear physics, with integrated radiation cooling and stochastic cooling, but primarily electron cooling. The current state of research and planning for the storage experiment is described. It is not intended to be a structural specification worked out in detail. The general design of the ring, however, has been established, and experimental details have deliberately been kept flexible, to thereby allow very different sorts of experiments to be conducted. The ring described with a maximum magnetic rigidity of Bp = 1.5 Tm, is designed in quadripartite symmetry. The total circumference is approximately 35 m, and there are four straight sections each 3.5 m long for the electron cooling sections, the experimental equipment, as well as HF system and injection. One of the most desirable properties of the reservoir is the multi-charge mode, which will significantly improve the operation which heavy ion beams, which reverse charge in electron cooling sections, target and residual vacuum. Initial considerations are presented with regard to stochastic and electron cooling. A review of possible classes of experiments is given and the schedule and financing of the project is outlined. 46 refs

Microstructure evolution of ASTM 335 P91 steel, subjected to continuous cooling

International Nuclear Information System (INIS)

Carrizo, D.A; Danon, C.A; Ramos, C.P

2012-01-01

This paper studies the influence of the cooling rate on an isothermal phase transformations in ASTM A335 P91 steel, by the analysis of the resulting microstructure after several continuous cooling cycles under fixed austenization conditions. The CCT (Continuous Cooling Transformation) diagram of this material has already been reported in the literature, so the main phase fields are known, and they depend on the austenitic grain size and the cooling rate. Five samples were tested in a dilatometer, they were austenized and then cooled at different rates between 50 o C/h and 300 o C/h. The identification and characterization of the resulting phases was carried out by using Scanning Electron Microscopy, X-ray Diffraction and Mossbauer Spectroscopy. The obtained results allowed to add information about the presence of retained austenite and (Fe,Cr) 3 C - type carbides to the CCT diagram of the material (author)

Status report of the GERDA experiment phase I

International Nuclear Information System (INIS)

Riboldi, Stefano

2013-01-01

Phase I of GERDA, aimed at investigating neutrino-less double beta decay of 76 Ge is in the active phase since November 2011 at the Gran Sasso National Laboratory of INFN—Italy. GERDA Ge detectors are non-encapsulated and operate immersed in liquid argon, equipped with a front-end readout electronics consisting of cryogenic charge sensitive preamplifiers designed and manufactured to cope with the characteristics of the GERDA experiment (radio-purity, long and resistive cables, etc.). The presentation will report on the current status of the GERDA experiment phase I, focusing on Ge detectors performance in terms of energy resolution, stability over time, counting rate and related issues

Status report of the GERDA experiment phase I

Energy Technology Data Exchange (ETDEWEB)

Riboldi, Stefano, E-mail: stefano.riboldi@mi.infn.it [Universita' degli Studi di Milano and INFN, Milano (Italy)

2013-08-01

Phase I of GERDA, aimed at investigating neutrino-less double beta decay of {sup 76}Ge is in the active phase since November 2011 at the Gran Sasso National Laboratory of INFN—Italy. GERDA Ge detectors are non-encapsulated and operate immersed in liquid argon, equipped with a front-end readout electronics consisting of cryogenic charge sensitive preamplifiers designed and manufactured to cope with the characteristics of the GERDA experiment (radio-purity, long and resistive cables, etc.). The presentation will report on the current status of the GERDA experiment phase I, focusing on Ge detectors performance in terms of energy resolution, stability over time, counting rate and related issues.

Status report of the GERDA experiment phase I

Science.gov (United States)

Riboldi, Stefano; Gerda Collaboration

2013-08-01

Phase I of GERDA, aimed at investigating neutrino-less double beta decay of 76Ge is in the active phase since November 2011 at the Gran Sasso National Laboratory of INFN-Italy. GERDA Ge detectors are non-encapsulated and operate immersed in liquid argon, equipped with a front-end readout electronics consisting of cryogenic charge sensitive preamplifiers designed and manufactured to cope with the characteristics of the GERDA experiment (radio-purity, long and resistive cables, etc.). The presentation will report on the current status of the GERDA experiment phase I, focusing on Ge detectors performance in terms of energy resolution, stability over time, counting rate and related issues.

Development of a CO{sub 2} cooling system for the CBM silicon tracking system

Energy Technology Data Exchange (ETDEWEB)

Sanchez Rosado, Jorge; Degirmenciler, Burak; Heuser, Johann; Sturm, Christian [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH (Germany); Lymanets, Anton; Schmidt, Hans Rudolf [Eberhard Karls Universitaet Tuebingen (Germany)

2015-07-01

The demanding requirements of current high-energy physics experiments curiously bring back the idea of using a well-known and present refrigerant in nature: CO{sub 2}. As an outcome of previous studies and effort made within the current upgrade programs of detectors like ATLAS or CMS, this refrigerant is the optimum solution. Due to its highest volumetric heat transfer coefficient, it fulfills the requirements in this kind of detectors such as reduction of mass budget and the use of smaller diameter for cooling pipes. A two-phase (evaporative) CO{sub 2} cooling system is taken as the first choice to extract the 42 kW dissipated by the electronics of the Silicon Tracking System, the central detector of the CBM experiment at FAIR that will be installed in the gap of the 1 T super-conducting dipole magnet in a confined volume of 2 m{sup 3}. As a step towards the final design of this a cooling system, a 1 kW cooling unit called TRACI-XL was conceived at GSI in cooperation with CERN. This scaled prototype allows gaining insight into the behavior of the full system with valuable conclusions in terms of thermodynamics, process engineering and automation.

Theory of semiconductor laser cooling

Science.gov (United States)

Rupper, Greg

Recently laser cooling of semiconductors has received renewed attention, with the hope that a semiconductor cooler might be able to achieve cryogenic temperatures. In order to study semiconductor laser cooling at cryogenic temperatures, it is crucial that the theory include both the effects of excitons and the electron-hole plasma. In this dissertation, I present a theoretical analysis of laser cooling of bulk GaAs based on a microscopic many-particle theory of absorption and luminescence of a partially ionized electron-hole plasma. This theory has been analyzed from a temperature 10K to 500K. It is shown that at high temperatures (above 300K), cooling can be modeled using older models with a few parameter changes. Below 200K, band filling effects dominate over Auger recombination. Below 30K excitonic effects are essential for laser cooling. In all cases, excitonic effects make cooling easier then predicted by a free carrier model. The initial cooling model is based on the assumption of a homogeneous undoped semiconductor. This model has been systematically modified to include effects that are present in real laser cooling experiments. The following modifications have been performed. (1) Propagation and polariton effects have been included. (2) The effect of p-doping has been included. (n-doping can be modeled in a similar fashion.) (3) In experiments, a passivation layer is required to minimize non-radiative recombination. The passivation results in a npn heterostructure. The effect of the npn heterostructure on cooling has been analyzed. (4) The effect of a Gaussian pump beam was analyzed and (5) Some of the parameters in the cooling model have a large uncertainty. The effect of modifying these parameters has been analyzed. Most of the extensions to the original theory have only had a modest effect on the overall results. However we find that the current passivation technique may not be sufficient to allow cooling. The passivation technique currently used appears

In service experience feed back of the tore supra actively cooled inner first wall

International Nuclear Information System (INIS)

Schlosser, J.; Chappuis, P.; Chatelier, M.; Cordier, J.J.; Deschamps, P.; Garampon, L.; Guilhem, D.; Lipa, M.; Mitteau, R.

1994-01-01

Over 12000 plasma shots (some of them up to 8 MW of additional power and same as long as 60 s) have been achieved in TORE SUPRA (TS) with a significant number of them limited by thr inner first wall. This actively water cooled wall is covered with brazed graphite tiles. High power - high energy experiments have shown that a reliability of the graphite tile/heat sink joint and an accurate alignment of the wall are needed. This paper summarizes the experience gained with this component and developments in progress in order to improve the performance of such a inner first wall. (authors). 9 refs., 13 figs., 2 tabs

In service experience feed back of the tore supra actively cooled inner first wall

Energy Technology Data Exchange (ETDEWEB)

Schlosser, J; Chappuis, P; Chatelier, M; Cordier, J J; Deschamps, P; Garampon, L; Guilhem, D; Lipa, M; Mitteau, R

1994-12-31

Over 12000 plasma shots (some of them up to 8 MW of additional power and same as long as 60 s) have been achieved in TORE SUPRA (TS) with a significant number of them limited by thr inner first wall. This actively water cooled wall is covered with brazed graphite tiles. High power - high energy experiments have shown that a reliability of the graphite tile/heat sink joint and an accurate alignment of the wall are needed. This paper summarizes the experience gained with this component and developments in progress in order to improve the performance of such a inner first wall. (authors). 9 refs., 13 figs., 2 tabs.

An operational experience with cooling tower water system in chilling plant

International Nuclear Information System (INIS)

Rajan, Manju B.; Roy, Ankan; Ravi, K.V.

2015-01-01

Cooling towers are popular in industries as a very effective evaporative cooling technology for air conditioning. Supply of chilled water to air conditioning equipments of various plant buildings and cooling tower water to important equipments for heat removal is the purpose of chilling plant at PRPD. The cooling medium used is raw water available at site. Water chemistry is maintained by make-up and blowdown. In this paper, various observations made during plant operation and equipment maintenance are discussed. The issues observed was scaling and algal growth affecting the heat transfer and availability of the equipment. Corrosion related issues were observed to be less significant. Scaling indices were calculated to predict the behavior. (author)

Experimental investigation of single-phase microjet cooling of microelectronics

Directory of Open Access Journals (Sweden)

Rusowicz Artur

2015-09-01

Full Text Available Development of electronics, which aims to improve the functionality of electronic devices, aims at increasing the packing of transistors in a chip and boosting clock speed (the number of elementary operations per second. While pursuing this objective, one encounters the growing problem of thermal nature. Each switching of the logic state at the elementary level of an integrated circuit is associated with the generation of heat. Due to a large number of transistors and high clock speeds, higher heat flux is emitted by the microprocessor to a level where the component needs to be intensively cooled, or otherwise it will become overheated. This paper presents the cooling of microelectronic components using microjets.

Experimental investigation of single-phase microjet cooling of microelectronics

Science.gov (United States)

Rusowicz, Artur; Leszczyński, Maciej; Grzebielec, Andrzej; Laskowski, Rafał

2015-09-01

Development of electronics, which aims to improve the functionality of electronic devices, aims at increasing the packing of transistors in a chip and boosting clock speed (the number of elementary operations per second). While pursuing this objective, one encounters the growing problem of thermal nature. Each switching of the logic state at the elementary level of an integrated circuit is associated with the generation of heat. Due to a large number of transistors and high clock speeds, higher heat flux is emitted by the microprocessor to a level where the component needs to be intensively cooled, or otherwise it will become overheated. This paper presents the cooling of microelectronic components using microjets.

Numerical investigation of mist/air impingement cooling on ribbed blade leading-edge surface.

Science.gov (United States)

Bian, Qingfei; Wang, Jin; Chen, Yi-Tung; Wang, Qiuwang; Zeng, Min

2017-12-01

The working gas turbine blades are exposed to the environment of high temperature, especially in the leading-edge region. The mist/air two-phase impingement cooling has been adopted to enhance the heat transfer on blade surfaces and investigate the leading-edge cooling effectiveness. An Euler-Lagrange particle tracking method is used to simulate the two-phase impingement cooling on the blade leading-edge. The mesh dependency test has been carried out and the numerical method is validated based on the available experimental data of mist/air cooling with jet impingement on a concave surface. The cooling effectiveness on three target surfaces is investigated, including the smooth and the ribbed surface with convex/concave columnar ribs. The results show that the cooling effectiveness of the mist/air two-phase flow is better than that of the single-phase flow. When the ribbed surfaces are used, the heat transfer enhancement is significant, the surface cooling effectiveness becomes higher and the convex ribbed surface presents a better performance. With the enhancement of the surface heat transfer, the pressure drop in the impingement zone increases, but the incremental factor of the flow friction is smaller than that of the heat transfer enhancement. Copyright © 2017 Elsevier Ltd. All rights reserved.

TASK 2.5.7 FIELD EXPERIMENTS TO EVALUATE COOL-COLORED ROOFING

Energy Technology Data Exchange (ETDEWEB)

Miller, William A [ORNL; Cherry, Nigel J [ORNL; Allen, Richard Lowell [ORNL; Childs, Phillip W [ORNL; Atchley, Jerald Allen [ORNL; Ronnen, Levinson [Lawrence Berkeley National Laboratory (LBNL); Akbari, Hashem [Lawrence Berkeley National Laboratory (LBNL); Berhahl, Paul [Lawrence Berkeley National Laboratory (LBNL)

2010-03-01

counter battens, providing a nailing surface for the concrete tile. This double batten construction forms an inclined air channel running from the soffit to the ridge. The bottom surface of the channel is formed by the roof decking and is relatively flat and smooth. The top surface is created by the underside of the roofing tiles, and is designed to be an air permeable covering to alleviate the underside air pressure and minimize wind uplift on the tiles. The resulting air flows also have a cooling influence which further complicates prediction of the heat penetrating through the deck because an accurate measure of the airflow is required to predict the heat transfer. Measured temperatures and heat flows at the roof surface, within the attic and at the ceiling of the houses are discussed as well as the power usage to help gauge the benefit of cool-pigmented reflective roof products fitted with and without ventilation above the roof deck. Ventilation occurring above the deck is an inherent feature for tile roof assemblies, and is formed by an air space between the exterior face of the roof sheathing and the underside of the tile. The greater the tile s profile the greater is the effect of the ventilation which herein is termed above-sheathing ventilation (ASV). However, because of the complexity of the thermally induced flow, little credit is allowed by state and federal building codes. ASHRAE (2005) provides empirical data for the effective thermal resistance of plane air spaces. A -in. (0.0191-m) plane air space inclined at 45 with the horizontal has an RUS-0.85 (RSI-0.15) . Our intent is to help further deploy cool color pigments in roofs by conducting field experiments to evaluate the new cool-colored roofing materials in the hot climate of Southern California. The collected data will be used to showcase and market the performance of new cool-roof products and also to help formulate and validate computer codes capable of calculating the heat transfer occurring within

Evaporative Cooling of Antiprotons to Cryogenic Temperatures

CERN Document Server

Andresen, G B; Baquero-Ruiz, M; Bertsche, W; Bowe, P D; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Hangst, J S; Hardy, W N; Hayano, R S; Hayden, M E; Humphries, A; Hydomako, R; Jonsell, S; Kurchaninov, L; Lambo, R; Madsen, N; Menary, S; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Silveira, D M; So, C; Storey, J W; Thompson, R I; van der Werf, D P; Wilding, D; Wurtele, J S; Yamazaki, Y

2010-01-01

We report the application of evaporative cooling to clouds of trapped antiprotons, resulting in plasmas with measured temperature as low as 9~K. We have modeled the evaporation process for charged particles using appropriate rate equations. Good agreement between experiment and theory is observed, permitting prediction of cooling efficiency in future experiments. The technique opens up new possibilities for cooling of trapped ions and is of particular interest in antiproton physics, where a precise CPT test on trapped antihydrogen is a long-standing goal.

Experimental investigation of electron cooling and stacking of lead ions in a low energy accumulation ring

CERN Document Server

Bosser, Jacques; Chanel, M; Hill, C; Lombardi, A M; MacCaferri, R; Maury, S; Möhl, D; Molinari, G; Rossi, S; Tanke, E; Tranquille, G; Vretenar, Maurizio

1999-01-01

This report gives the results of a programme of experimental investigations, which were carried out to test stacking of lead ions in a storage ring (the former Low Energy Antiproton Ring, LEAR) at 4.2 MeV per nucleon. The motivation was to demonstrate the feasibility of gaining the large factor in the phase-space density required for injection into the LHC. In the first part of the report, the layout of the experiments is described, the choice of the parameters of the electron cooling system used for stacking is reported and the multi-turn injection using horizontal- and longitudinal- (and in the final project also vertical-) phase space is discussed. In the second part the experimental results are presented. Factors of vital importance are the stacking efficiency, the beam life-time and the cooling time of the ions. The beam decay owing to charge exchange with the residual gas and to recombination by the capture of cooling electrons was intensively studied. Beam instabilities and space-charge effects in the ...

Evaporative cooling in polymer electrolyte fuel cell

Energy Technology Data Exchange (ETDEWEB)

Shimotori, S; Sonai, A [Toshiba Corp. Tokyo (Japan)

1996-06-05

The concept of the evaporative cooling for the internally humidified PEFC was confirmed by the experiment. The evaporative cooling rates at the anode and the cathode were mastered under the various temperatures and air utilizations. At a high temperature the proportion of the evaporative cooling rate to the heat generation rate got higher, the possibility of the evaporative cooling was demonstrated. 2 refs., 7 figs., 1 tab.

The active phasing experiment: Part II. Design and developments

Science.gov (United States)

Gonte, F.; Yaitskova, N.; Derie, F.; Araujo, C.; Brast, R.; Delabre, B.; Dierickx, P.; Dupuy, C.; Frank, C.; Guisard, S.; Karban, R.; Noethe, L.; Sedghi, B.; Surdej, I.; Wilhelm, R.; Reyes, M.; Esposito, S.; Langlois, M.

2006-06-01

The purpose of the Active Phasing Experiment, designed under the lead of ESO, is to validate wavefront control concepts for ELT class telescopes. This instrument includes an Active Segmented Mirror, located in a pupil image. It will be mounted at a Nasmyth focus of one of the Unit Telescopes of the ESO VLT. APE contains four different types of phasing sensors, which are developed by Istituto Nazionale di Astrofisica in Arcetri, Instituto Astrofisica Canarias, Laboratoire d'Astrophysique de Marseille and ESO. These phasing sensors can be compared simultaneously under identical optical and environmental conditions. All sensors receive telecentric F/15 beams with identical optical quality and intensity. Each phasing sensor can measure segmentation errors of the active segmented mirror and correct them in closed loop. The phasing process is supervised by an Internal Metrology system developed by FOGALE Nanotech and capable of measuring piston steps with an accuracy of a few nanometers. The Active Phasing Experiment is equipped with a turbulence generator to simulate atmospheric seeing between 0.45 and 0.85 arcsec in the laboratory. In addition, the Active Phasing Experiment is designed to control simultaneously with the phasing corrections the guiding and the active optics of one of the VLT Unit Telescopes. This activity is supported by the European Community (Framework Programme 6, ELT Design Study, contract No 011863).

Ultrasound-guided percutaneous treatment of hepatocellular carcinoma by radiofrequency hyperthermia with a 'cooled-tip needle'. A preliminary clinical experience.

Science.gov (United States)

Francica, G; Marone, G

1999-05-01

Radiofrequency hyperthermia using the newly-developed 'cooled-tip' needle has recently been proposed as a therapeutic modality for hepatocellular carcinoma (HCC). Herein we report our preliminary results on feasibility and effectiveness of the thermal ablation of mono- or pauci-focal hepatocellular carcinoma with the cooled-tip needle. We treated 15 cirrhotic patients (mean age 68.8 years; 12 males; 14 HCV-positive; 13 in Child's Class A and 2 in Class B) with 20 hepatocellular carcinoma nodules (mean diameter 28.1 mm; range 10-43 mm; nine lesions with diameter greater than 3 cm). None of the patients had portal thrombosis and/or extrahepatic spread. We used a radiofrequency generator (100 W of power) connected to a 18 g perfusion electrode needle with an exposed tip of 2-3 cm. The circuit was closed through a dispersive electrode positioned under the patient's thighs. A peristaltic pump infused a chilled (2-5 degrees C) saline solution to guarantee the continuous cooling of the needle tip. The needle was placed into target lesions under US guidance. The interventional procedure was carried out in general anesthesia without intubation. Dynamic helical CT was carried out 15-20 days after thermal ablation to assess therapeutic efficacy. In all, 38 areas of coagulation necrosis (at 1000-1200 mA for 10-15 min) were generated in 24 sessions in the 20 hepatocellular carcinoma nodules (mean 1.9 lesions per nodule and 1.2 sessions per nodule). Complete necrosis as assessed at dynamic CT (lack of enhancement during the arteriographic phase) was achieved in 75% of cases in a single session; after a second RF session success rate was 90% (18 out of 20 nodules). A self-limited pleurisy along with a 5-fold increase in transaminases occurred in one patient; a 3-fold elevation of transaminases was encountered in three other patients. During the follow-up (median 15 months) five patients had recurrent hepatocellular carcinoma with a 1-year disease free interval of 64%. Of the

Active (air-cooled) vs. passive (phase change material) thermal management of high power lithium-ion packs: Limitation of temperature rise and uniformity of temperature distribution

Energy Technology Data Exchange (ETDEWEB)

Sabbah, Rami; Kizilel, R.; Selman, J.R.; Al-Hallaj, S. [Center for Electrochemical Science and Engineering, Department of Chemical and Biological Engineering, Illinois Institute of Technology, 10 W. 33rd Street, Chicago, IL 60616 (United States)

2008-08-01

The effectiveness of passive cooling by phase change materials (PCM) is compared with that of active (forced air) cooling. Numerical simulations were performed at different discharge rates, operating temperatures and ambient temperatures of a compact Li-ion battery pack suitable for plug-in hybrid electric vehicle (PHEV) propulsion. The results were also compared with experimental results. The PCM cooling mode uses a micro-composite graphite-PCM matrix surrounding the array of cells, while the active cooling mode uses air blown through the gaps between the cells in the same array. The results show that at stressful conditions, i.e. at high discharge rates and at high operating or ambient temperatures (for example 40-45 C), air-cooling is not a proper thermal management system to keep the temperature of the cell in the desirable operating range without expending significant fan power. On the other hand, the passive cooling system is able to meet the operating range requirements under these same stressful conditions without the need for additional fan power. (author)

Active (air-cooled) vs. passive (phase change material) thermal management of high power lithium-ion packs: Limitation of temperature rise and uniformity of temperature distribution

Science.gov (United States)

Sabbah, Rami; Kizilel, R.; Selman, J. R.; Al-Hallaj, S.

The effectiveness of passive cooling by phase change materials (PCM) is compared with that of active (forced air) cooling. Numerical simulations were performed at different discharge rates, operating temperatures and ambient temperatures of a compact Li-ion battery pack suitable for plug-in hybrid electric vehicle (PHEV) propulsion. The results were also compared with experimental results. The PCM cooling mode uses a micro-composite graphite-PCM matrix surrounding the array of cells, while the active cooling mode uses air blown through the gaps between the cells in the same array. The results show that at stressful conditions, i.e. at high discharge rates and at high operating or ambient temperatures (for example 40-45 °C), air-cooling is not a proper thermal management system to keep the temperature of the cell in the desirable operating range without expending significant fan power. On the other hand, the passive cooling system is able to meet the operating range requirements under these same stressful conditions without the need for additional fan power.

The ultra low mass cooling system of the Belle II DEPFET detector

International Nuclear Information System (INIS)

Ruiz-Valls, P.; Marinas, C.

2013-01-01

The new Japanese Super Flavor Factory Belle II is designed with high precision in mind, making a good vertex resolution a necessity. In order to achieve the required resolution in the vertex reconstruction, besides highly segmented pixel detectors, the material budget has to be kept at very low levels, since more material results in multiple scattering and degrades the resolution. As a consequence, there is a direct impact on the cooling system, that has to be carefully designed, not allowing active cooling pipes inside the acceptance region. In this asymmetric e + e − experiment the angular acceptance ranges from 17° to 150°, leaving room for support structures outside this range. The Belle II vertex detector includes DEPFET technology in its vertex detector the front end electronics (FEE) of which, placed outside the acceptance, can be cooled by 2-phase CO 2 through massive support structures while the sensitive area relies on forced convection with cold nitrogen gas

The influence of cooling rate and Fe/Cr content on the evolution of Fe-rich compounds in a secondary Al-Si-Cu diecasting alloy

Science.gov (United States)

Fabrizi, A.; Timelli, G.

2016-03-01

This study investigates the morphological evolution of primary α-Al(Fe,Mn,Cr)Si phase in a secondary Al-Si-Cu alloy with respect to the initial Fe and Cr contents as well as to the cooling rate. The solidification experiments have been designed in order to cover a wide range of cooling rates, and the Fe and Cr contents have been varied over two levels. Metallographic and image analysis techniques have been used to quantitatively examine the microstructural changes occurring at different experimental conditions. The morphological evolution of the α-Fe phase has been also analysed by observing deep etched samples. By changing the cooling rate, α-Al15(Fe,Mn,Cr)3Si2 dodecahedron crystals, as well as Chinese- script, branched structures and dendrites form, while primary coarse β-Al5(Fe,Mn)Si needles appear in the alloy with the highest Fe content at low cooling rates.

Dustproof cooling of the electrical box

Directory of Open Access Journals (Sweden)

Nemec Patrik

2018-01-01

Full Text Available In present are electrical boxes cooled by air through the intake hole on the bottom electrical box to the box space with electrotechnical elements and exhaust through the hole at the top to the surrounding by natural convection. This cooling method is effective but operate with the risk of contamination electrotechnical elements by dust sucking from surrounding air. The goal of this work is solution of the dustproof cooling of the electrical box by natural convection. The work deal with design of the device with the heat transfer by the phase change of the working fluid and experimental measuring its thermal performance at the cooling electrotechnical elements loaded by heat 1 200 W in the dustproof electrical box.

Long-time dynamics of laser-cooled ions in the TSR storage ring

International Nuclear Information System (INIS)

Mudrich, M.

2000-01-01

This diploma thesis studies experimentally the long-time dynamics of laser-cooled 9 Be + -beams at the TSR under different cooling conditions. The goal is to enlarge the understanding of ultra-cold, non-neutral plasma at high center-of-mass energies. By means of improved measurement capabilities one can now for the first time monitor the entire phase-space over a long time. This makes it possible to quantitatively analyse the possibilities and limitations of laser cooling at a storage ring. Under optimum cooling conditions a regime of high phase-space density is reached, close to the region where influences of Coulomb coupling are expected. Furthermore, a Monte-Carlo model is worked out that qualitatively describes the beam dynamics. The model includes the influence of transverse-longitudinal coupling due to intra beam scattering on the longitudinal phase-space distribution. At high phase-space density a sudden disappearance of intra beam collisions is observed experimentally and possible interpretations are given. (orig.)

Theoretical investigations on improving performance of cooling systems for fuel cell vehicles; Theoretische Untersuchungen zur Kuehlleistungssteigerung durch innovative Kuehlsysteme fuer Brennstoffzellen-Elektrofahrzeuge

Energy Technology Data Exchange (ETDEWEB)

Reichler, Mark

2008-04-01

In this work theoretical investigations are carried out for cooling systems, which are used in fuel cell vehicles. This work focuses mainly on the capability of increasing the heat rejection rate by using new alternative cooling systems and by improving the conventional cooling system. Fuel cell vehicles have a higher demand of heat rejection to the ambient than comparable vehicles with combustion engine. The performance of conventional liquid cooling systems, especially at high loads and high ambient temperatures, is often not sufficient anymore. Hence, cooling systems with improved performance are necessary for fuel cell vehicles. The investigations in this work are based on DaimlerChrysler's ''A-Class'' having a PEM-Fuel Cell system integrated. Specific computational models are developed for radiators and condensers to evaluate the performance of different cooling concepts. The models are validated with experimental data. Based on an intensive investigation in the open literature the state of the art of cooling systems for fuel cell vehicles is depicted. Furthermore new cooling concepts as an alternative to the liquid cooling system are presented. The method of cooling the fuel cell by using two-phase transition shows the greatest capability to increase the cooling performance. Hence, this concept is investigated in detail. Two different concepts with three different refrigerants (R113, R245fa und R236fa) are analyzed. Cooling performance of this concept shows improvement of 18.2 up to 32.6 % compared to the conventional liquid cooling system. Thus, a two phase cooling system represents an alternative cooling system for fuel cell vehicles, which should be closer investigated by experiments. (orig.)

Adopted Methodology for Cool-Down of SST-1 Superconducting Magnet System: Operational Experience with the Helium Refrigerator

Science.gov (United States)

Sahu, A. K.; Sarkar, B.; Panchal, P.; Tank, J.; Bhattacharya, R.; Panchal, R.; Tanna, V. L.; Patel, R.; Shukla, P.; Patel, J. C.; Singh, M.; Sonara, D.; Sharma, R.; Duggar, R.; Saxena, Y. C.

2008-03-01

The 1.3 kW at 4.5 K helium refrigerator / liquefier (HRL) was commissioned during the year 2003. The HRL was operated with its different modes as per the functional requirements of the experiments. The superconducting magnets system (SCMS) of SST-1 was successfully cooled down to 4.5 K. The actual loads were different from the originally predicted boundary conditions and an adjustment in the thermodynamic balance of the refrigerator was necessary. This led to enhanced capacity, which was achieved without any additional hardware. The required control system for the HRL was tuned to achieve the stable thermodynamic balance, while keeping the turbines' operating parameters at optimized conditions. An extra mass flow rate requirement was met by exploiting the margin available with the compressor station. The methodology adopted to modify the capacity of the HRL, the safety precautions and experience of SCMS cool down to 4.5 K, are discussed.

Phase-field modelling and synchrotron validation of phase transformations in martensitic dual-phase steel

International Nuclear Information System (INIS)

Thiessen, R.G.; Sietsma, J.; Palmer, T.A.; Elmer, J.W.; Richardson, I.M.

2007-01-01

A thermodynamically based method to describe the phase transformations during heating and cooling of martensitic dual-phase steel has been developed, and in situ synchrotron measurements of phase transformations have been undertaken to support the model experimentally. Nucleation routines are governed by a novel implementation of the classical nucleation theory in a general phase-field code. Physically-based expressions for the temperature-dependent interface mobility and the driving forces for transformation have also been constructed. Modelling of martensite was accomplished by assuming a carbon supersaturation of the body-centred-cubic ferrite lattice. The simulations predict kinetic aspects of the austenite formation during heating and ferrite formation upon cooling. Simulations of partial austenitising thermal cycles predicted peak and retained austenite percentages of 38.2% and 6.7%, respectively, while measurements yielded peak and retained austenite percentages of 31.0% and 7.2% (±1%). Simulations of a complete austenitisation thermal cycle predicted the measured complete austenitisation and, upon cooling, a retained austenite percentage of 10.3% while 9.8% (±1%) retained austenite was measured

Manufacturing experiment on a cooling plate for a blanket breeder unit

International Nuclear Information System (INIS)

Weth, A. von der; Aktaa, J.

2008-01-01

Plates with curved cooling channels will be used as structural elements in a breeding blanket of a future fusion power plant. Such power plants are a promising attempt for future electrical energy production. The central manufacturing process of such cooling plates is a diffusion welding process. Such a process has been 'available' on a laboratory scale for years. But this diffusion welding process has not yet been applied on an industrial scale. This contribution documents our first attempt to transfer this to industry, a so-called uniaxial diffusion welding setup. The industrial transfer was attempted in two steps: (1) On a small cooling plate mock-up and (2) On a true-scale cooling plate. The problems with the technical transfer of the diffusion welding process from the laboratory scale to the true scale were outlined

Experimental study of proton stochastic cooling in the NAP-M

International Nuclear Information System (INIS)

Dement'ev, E.N.; Zinevich, N.I.; Medvedko, A.S.; Parkhomchuk, V.V.; Pestrikov, D.V.

1983-01-01

Experimental results on stochastic cooling of a proton beam in the NAP-M are presented. The estimation of the possibility or the cooling method usage in antiproton accumulator rings and also for the study of the cooling peculiarities is the aim of the experiments. Two systems for stochastic cooling have been studied: the wide-band width one and the system with a resonance filter at the input. The experiments are conducted at the energy of 62 MeV. The experiments conducted have shown the possibility of antiproton accumulation. Thermal noises of the feedback system limit the cooling time to approximately 150 s for the single channel system. To attain the cooling time of approximately 1s about one hundred systems operating in parallel connection is required. Mutual effect of particles and coherent instabilities limit the maximum intensity of the particle beam cooled during approximately 1s with the value of approximately 10 7 particles at technically attainable values of the frequency bandwidth

Two-phase LMMHD mixer-development experiments

International Nuclear Information System (INIS)

Fabris, G.; Dunn, P.F.; Chow, J.C.F.

1978-01-01

The results of a series of experiments conducted to evaluate the fluid mechanical performance of various two-phase LMMHD mixer designs are presented. The results from both flow visualization studies of the local two-phase flows downstream from various mixer-element configurations and local measurements performed to characterize these flows are presented. A conceptual LMMHD mixer design is described that insures the generation of small bubbles, prevents the formation of gas slugs and separated regions, and favors the stabilization of a homogeneous foam flow

Reactor-core isolation cooling system with dedicated generator

International Nuclear Information System (INIS)

Nazareno, E.V.; Dillmann, C.W.

1992-01-01

This patent describes a nuclear reactor complex. It comprises a dual-phase nuclear reactor; a main turbine for converting phase-conversion energy stored by vapor into mechanical energy for driving a generator; a main generator for converting the mechanical energy into electricity; a fluid reservoir external to the reactor; a reactor core isolation cooling system with several components at least some of which require electrical power. It also comprises an auxiliary pump for pumping fluid from the reservoir into the reactor pressure vessel; an auxiliary turbine for driving the pump; control means for regulating the rotation rate of the auxiliary turbine; cooling means for cooling the control means; and an auxiliary generator coupled to the auxiliary turbine for providing at least a portion of the electrical power required by the components during a blackout condition

PANDA experiment and International Standard Problem for passive cooling systems for afterheat removal

International Nuclear Information System (INIS)

Yadigaroglu, G.; Aksan, N.S.

1999-01-01

In the context of OECD/NEA, Paul Scherrer Institut (PSI) is working on an International Standard Problem which is to provide information on the efficiency and use of computer program systems for passive afterheat removal systems. The PANDA test facility of PSI was designed for these investigations. A six-phase PANDA experiment provides a basis for pre-calculation and recalculation of selected phases covering a limited number of system-typical operating states and phenomena. The experiment was specified and carried out in the year under report [de

The contrasting roles of creep and stress relaxation in the time-dependent deformation during in-situ cooling of a nickel-base single crystal superalloy.

Science.gov (United States)

Panwisawas, Chinnapat; D'Souza, Neil; Collins, David M; Bhowmik, Ayan

2017-09-11

Time dependent plastic deformation in a single crystal nickel-base superalloy during cooling from casting relevant temperatures has been studied using a combination of in-situ neutron diffraction, transmission electron microscopy and modelling. Visco-plastic deformation during cooling was found to be dependent on the stress and constraints imposed to component contraction during cooling, which mechanistically comprises creep and stress relaxation. Creep results in progressive work hardening with dislocations shearing the γ' precipitates, a high dislocation density in the γ channels and near the γ/γ' interface and precipitate shearing. When macroscopic contraction is restricted, relaxation dominates. This leads to work softening from a decreased dislocation density and the presence of long segment stacking faults in γ phase. Changes in lattice strains occur to a similar magnitude in both the γ and γ' phases during stress relaxation, while in creep there is no clear monotonic trend in lattice strain in the γ phase, but only a marginal increase in the γ' precipitates. Using a visco-plastic law derived from in-situ experiments, the experimentally measured and calculated stresses during cooling show a good agreement when creep predominates. However, when stress relaxation dominates accounting for the decrease in dislocation density during cooling is essential.

Newton's Law of Cooling Revisited

Science.gov (United States)

Vollmer, M.

2009-01-01

The cooling of objects is often described by a law, attributed to Newton, which states that the temperature difference of a cooling body with respect to the surroundings decreases exponentially with time. Such behaviour has been observed for many laboratory experiments, which led to a wide acceptance of this approach. However, the heat transfer…

Natural-circulation-cooling characteristics during PWR accident simulations

International Nuclear Information System (INIS)

Adams, J.P.; McCreery, G.E.; Berta, V.T.

1983-01-01

A description of natural circulation cooling characteristics is presented. Data were obtained from several pressurized water reactor accident simulations in the Loss-of-Fluid Test (LOFT) pressurized water reactor (PWR). The reliability of natural circulation cooling, its cooling effectiveness, and the effect of changing system conditions are described. Quantitative comparison of flow rates and time constants with theory for both single- and two-phase fluid conditions were made. It is concluded that natural circulation cooling can be relied on in plant recovery procedures in the absence of forced convection whenever the steam generator heat sink is available

SIMMER-II analysis of transition-phase experiments

International Nuclear Information System (INIS)

Wehner, T.R.; Bell, C.R.

1985-01-01

Analyses of Los Alamos transition-phase experiments with the SIMMER-II computer code are reported. These transient boilup experiments simulated the recriticality-induced transient motion of a boiling pool of molten fuel, molten steel and steel vapor, within a subassembly duct in a liquid-metal fast breeder reactor during the transition phase of a core-disruptive accident. The two purposes of these experiments were to explore and reach a better understanding of fast reactor safety issues, and to provide data for SIMMER-II verification. Experimental data, consisting of four pressure traces and a high-speed movie, were recorded for four sets of initial conditions. For three of the four cases, SIMMER-II-calculated pressures compared reasonably well with the experimental pressures. After a modification to SIMMER-II's liquid-vapor drag correlation, the comparison for the fourth case was reasonable also. 12 refs., 4 figs

A cool present for LEIR

CERN Multimedia

2005-01-01

LEIR (Low Energy Ion Ring), which will supply lead ions to the LHC experiments, has taken delivery of one of its key components, its electron cooling system. From left to right, Gérard Tranquille, Virginia Prieto and Roland Sautier, in charge of the electron cooling system for LEIR at CERN, and Christian Lacroix, in charge of installation for the LEIR machine. On 16 December, the day before CERN's annual closure, the LEIR teams received a rather impressive Christmas present. The "parcel" from Russia, measuring 7 metres in length and 4 metres in height, weighed no less than 20 tonnes! The component will, in fact, be one of the key elements of the future LEIR, namely its electron cooling system. LEIR is one of the links in the injector chain that will supply lead ions to the LHC experiments, in particular ALICE (see Bulletin No. 28/2004 of 5 July 2004), within the framework of the I-LHC Project. The electron cooling system is designed to reduce and standardise transverse ion velocity. This focuses the bea...

Intermediate energy electron cooling for antiproton sources using a Pelletron accelerator

International Nuclear Information System (INIS)

Cline, D.B.; Adney, J.; Ferry, J.; Kells, W.; Larson, D.J.; Mills, F.E.; Sundquist, M.

1983-01-01

It has been shown at FNAL that the electron cooling of protons is a very efficient method for reaching high luminosity in a proton beam. The emittance of the 120 KeV electron beam used at Fermilab corresponds to a cathode temperature of 0.1 eV. In order to apply cooling techniques to GeV proton beams the electron energies required are in the MeV range. In the experiment reported in this paper the emittance of a 3-MeV Pelletron electron accelerator was measured to determine that its emittance scaled to a value appropriate for electron cooling. The machine tested was jointly owned and operated by the University of California at Santa Barbara and National Electrostatics Corporation for research into free-electron lasers which also require low emittance beams for operation. This paper describes the thermal emittance of the beam to be the area in phase space in which 90% of the beam trajectories lie and goes on to describe the emittance-measurement method both in theory and application

Innovative low-mass cooling systems for the ALICE ITS Upgrade detector at CERN

CERN Document Server

Gomez Marzoa, Manuel

The Phase-1 upgrade of the LHC to full design luminosity, planned for 2019 at CERN, requires the modernisation of the experiments around the accelerator. The Inner Tracking System (ITS), the innermost detector at the ALICE experiment, will be upgraded by replacing the current apparatus by new silicon pixels arranged in 7 cylindrical layers. Each layer is composed by multiple independent modules, named staves, which provide mechanical support and cooling to the chips. This thesis aims to develop and validate experimentally an ultra-lightweight stave cooling system for the ITS Upgrade. The moderate thermal requirements, with a nominal power density of 0.15 W/cm^2 and a maximum chip temperature of 30ºC, are counterweighted by extreme low-mass restrictions, obliging to resort to lightweight, non-metallic materials, such as carbon fibre-reinforced polymers and plastics. Novel lightweight stave concepts were developed and experimentally validated, meeting the thermal requirements with minimal material inventory. T...

Cryogenic Loop Heat Pipes for the Cooling of Small Particle Detectors at CERN

CERN Document Server

Pereira, H; Silva, P; Wu, J; Koettig, T

2010-01-01

The loop heat pipe (LHP) is among the most effective heat transfer elements. Its principle is based on a continuous evaporation/condensation process and its passive nature does not require any mechanical devices such as pumps to circulate the cooling agent. Instead a porous wick structure in the evaporator provides the capillary pumping forces to drive the fluid [1]. Cryogenic LHP are investigated as potential candidates for the cooling of future small-scale particle detectors and upgrades of existing ones. A large spectrum of cryogenic temperatures can be covered by choosing appropriate working fluids. For high luminosity upgrades of existing experiments installed at the Large Hadron Collider (LHC) (TOTEM) and planned ones (FP420) [2-3] being in the design phase, radiation-hard solutions are studied with noble gases as working fluids to limit the radiolysis effect on molecules detrimental to the functioning of the LHP. The installation compactness requirement of experiments such as the CAST frame-store CCD d...

Status of the Gerda phase II experiment

Energy Technology Data Exchange (ETDEWEB)

Lazzaro, Andrea [Physik-Department and Excellence Cluster Universe, Technische Universitaet Muenchen (Germany); Collaboration: GERDA-Collaboration

2016-07-01

The Gerda experiment searches for the neutrinoless double beta decay (0νββ) in {sup 76}Ge. The first phase of the experiment collected 21.6 kg. yr of exposure with a background index (BI) of 0.01 cts/(keV . kg . yr). No signal was observed and a lower limit for the 0νββ half-life was set to T{sup 0νββ}{sub 1/2} < 2.1 . 10{sup 25} yr (90% C.L). The apparatus has now been upgraded to the Phase II configuration. In Phase II 38 kg of HPGe detectors will be operated to reach an exposure of 100 kg . yr. The goal of Gerda Phase II is to lower the BI to 10{sup -3} cts/(keV . kg . y), in order to reach the sensitivity for T{sup 0νββ}{sub 1/2} = O(10{sup 26}) yr. The additional target mass is constituted of 30 custom made BEGe detectors with higher energy resolution and better pulse shape discrimination performance. The detectors are operated in new radio-pure low-mass holders. The liquid argon surrounding the detectors has been instrumented to veto the background events which produce scintillation light. In this talk the current status and the performance of the Gerda Phase II are presented.

The influence of cooling rate and Fe/Cr content on the evolution of Fe-rich compounds in a secondary Al-Si-Cu diecasting alloy

International Nuclear Information System (INIS)

Fabrizi, A; Timelli, G

2016-01-01

This study investigates the morphological evolution of primary α-Al(Fe,Mn,Cr)Si phase in a secondary Al-Si-Cu alloy with respect to the initial Fe and Cr contents as well as to the cooling rate. The solidification experiments have been designed in order to cover a wide range of cooling rates, and the Fe and Cr contents have been varied over two levels. Metallographic and image analysis techniques have been used to quantitatively examine the microstructural changes occurring at different experimental conditions. The morphological evolution of the α-Fe phase has been also analysed by observing deep etched samples. By changing the cooling rate, α-Al 15 (Fe,Mn,Cr) 3 Si 2 dodecahedron crystals, as well as Chinese- script, branched structures and dendrites form, while primary coarse β-Al 5 (Fe,Mn)Si needles appear in the alloy with the highest Fe content at low cooling rates. (paper)

Overnight storage of whole blood: cooling and transporting blood at room temperature under extreme temperature conditions.

Science.gov (United States)

Thibault, L; Beauséjour, A; Jacques, A; Ducas, E; Tremblay, M

2014-02-01

Many countries allow the overnight storage of whole blood (WB) at ambient temperature. Some countries, such as Canada, also require a rapid cooling of WB with an active cooling system. Given the significant operational constraints associated with current cooling systems, an alternative method for cooling and transporting WB at 20-24°C was evaluated. Phase 22 cooling packs (TCP Reliable Inc., USA) were used in combination with vacuum-insulated panel (VIP) boxes. Temperature profiles of simulated WB units were studied in extreme temperatures (-35 and 40°C). The quality of blood components prepared using Phase 22 packs and CompoCool-WB (Fresenius HemoCare, Germany) was studied. Phase 22 packs reduced the temperature of simulated WB bags from 37 to 24°C in 1·7 ± 0·2 h. Used in combination with VIP boxes, Phase 22 packs maintain the temperature of bags between 20 and 24°C for 15 and 24 h, compared to 2 and 11 h with CompoCool-WB, when exposed at -35 and 40°C, respectively. The quality of platelet concentrates and plasma was comparable, regardless of the cooling system used. For red blood cell units, per cent haemolysis on day 42 was slightly higher in products prepared after cooling with Phase 22 packs compared to CompoCool-WB (0·33 ± 0·15% vs. 0·21 ± 0·06%; P environmental conditions. © 2013 International Society of Blood Transfusion.

High quality actively cooled plasma-facing components for fusion

International Nuclear Information System (INIS)

Nygren, R.E.

1995-01-01

This paper interweaves some suggestions for developing actively cooled plasma-facing components (PFCs) for future fusion devices, with supporting examples taken from the design, fabrication and operation of Tore Supra's Phase III outboard pump limiter (OPL). This actively cooled midplane limiter, designed for heat and particle removal during long-pulse operation, has been operated under essentially thermally steady state conditions. Testing to identify braze flaws, analysis of the impact of joining flaws on the thermal-hydraulic performance of the OPL, and the extensive calorimetry and IR thermography used to confirm and update safe operating limits for power handling of the OPL are reviewed. This experience suggests that, for PFCs in future fusion devices, flaw-tolerant designs are possible; analyses of the impacts of flaws on performance can provide criteria for quality assurance; and validating appropriate methods of inspection for such flaws early in the design development of PFCs is prudent. The need for in-service monitoring is also discussed. (orig.)

Steam-generator tube performance: world experience with water-cooled nuclear power reactors during 1978

International Nuclear Information System (INIS)

Tatone, O.S.; Pathania, R.S.

1980-01-01

The performance of steam-generator tubes in water-cooled nuclear power reactors during 1978 is reviewed. Tube failures occurred at 31 of the 86 reactors surveyed. The causes of these failures and the procedures designed to deal with them are described. The number of tubes plugged has decreased dramatically in 1978 compared to the previous year. This is attributed to the diligent application of techniques developed through in-plant experience and research and development programs over the past several years

Investigation/evaluation of water cooled fast reactor in the feasibility study on commercialized fast reactor cycle systems. Intermediate evaluation of phase-II study

International Nuclear Information System (INIS)

Kotake, Syoji; Nishikawa, Akira

2005-01-01

Feasibility study on commercialized fast reactor cycle systems aims at investigation and evaluation of FBR design requirement's attainability, operation and maintenance, and technical feasibility of the candidate system. Development targets are 1) ensuring safety, 2) economic competitiveness, 3) efficient utilization of resources, 4) reduction of environmental load and 5) enhancement of nuclear non-proliferation. Based on the selection of the promising concepts in the first phase, conceptual design for the plant system has proceeded with the following plant system: a) sodium cooled reactors at large size and medium size module reactors, b) a lead-bismuth cooled medium size reactor, c) a helium gas cooled large size reactor and d) a BWR type large size FBR. Technical development and feasibility has been assessed and the study considers the need of respective key technology development for the confirmation of the feasibility study. (T. Tanaka)

Hysteresis in the phase transition of chocolate

Science.gov (United States)

Ren, Ruilong; Lu, Qunfeng; Lin, Sihua; Dong, Xiaoyan; Fu, Hao; Wu, Shaoyi; Wu, Minghe; Teng, Baohua

2016-01-01

We designed an experiment to reproduce the hysteresis phenomenon of chocolate appearing in the heating and cooling process, and then established a model to relate the solidification degree to the order parameter. Based on the Landau-Devonshire theory, our model gave a description of the hysteresis phenomenon in chocolate, which lays the foundations for the study of the phase transition behavior of chocolate.

Development and application of online Stelmor Controlled Cooling System

International Nuclear Information System (INIS)

Yu Wanhua; Chen Shaohui; Kuang Yonghai; Cao Kaichao

2009-01-01

An online Stelmor Controlled Cooling System (SCCS) has been developed successfully for the Stelmor production line, which can communicate with the material flow management system and Program Logic Control System (PLCs) automatically through local network. This online model adopts Implicit Finite Difference Time Domain (FDTD) method to calculate temperature evolution and phase transformation during the production process and predicts final properties. As Continuous Cooling Temperature (CCT) curves of various steels can be coupled in the model, it can predict the latent heat rise and range of phase transformation for various steels, which can provide direct guidance for new steel development and optimization of present Stelmor cooling process. This unique online system has been installed in three Stelmor production lines at present with good results.

Memory coherence of a sympathetically cooled trapped-ion qubit

International Nuclear Information System (INIS)

Home, J. P.; McDonnell, M. J.; Szwer, D. J.; Keitch, B. C.; Lucas, D. M.; Stacey, D. N.; Steane, A. M.

2009-01-01

We demonstrate sympathetic cooling of a 43 Ca + trapped-ion 'memory' qubit by a 40 Ca + 'coolant' ion sufficiently near the ground state of motion for fault-tolerant quantum logic, while maintaining coherence of the qubit. This is an essential ingredient in trapped-ion quantum computers. The isotope shifts are sufficient to suppress decoherence and phase shifts of the memory qubit due to the cooling light which illuminates both ions. We measure the qubit coherence during ten cycles of sideband cooling, finding a coherence loss of 3.3% per cooling cycle. The natural limit of the method is O(10 -4 ) infidelity per cooling cycle.

Construction progress of the cooling & ventilation in the LHC project

CERN Document Server

Body, Y; Josa, F; Monsted, A; Pirollet, B; CERN. Geneva. ST Division

2002-01-01

After the LEP dismantling Phase the Cooling and Ventilation Group has started the LHC construction work. Year 2001 through to 2004 will certainly be the most important period of activity for the CV group in the erection phase The author will report on the current works that are in progress on the different LHC Points distinguishing between the Ventilation and the Water Cooling installations. The Ventilation work completed in the new surface buildings in Points 1, 4,5,6 and 8. The work for the Cooling plants comprehend to the pumping stations, the cooling towers and the chilled water production stations in Points 1 and 5, For all of these activities, an updated report of the progress the work, the planning and of the expenses are given. Finally, a brief overview of the future activities is presented.

Review of ORNL-TSF shielding experiments for the gas-cooled Fast Breeder Reactor Program

International Nuclear Information System (INIS)

Abbott, L.S.; Ingersoll, D.T.; Muckenthaler, F.J.; Slater, C.O.

1982-01-01

During the period between 1975 and 1980 a series of experiments was performed at the ORNL Tower Shielding Facility in support of the shield design for a 300-MW(e) Gas Cooled Fast Breeder Demonstration Plant. This report reviews the experiments and calculations, which included studies of: (1) neutron streaming in the helium coolant passageways in the GCFR core; (2) the effectiveness of the shield designed to protect the reactor grid plate from radiation damage; (3) the adequacy of the radial shield in protecting the PCRV (prestressed concrete reactor vessel) from radiation damage; (4) neutron streaming between abutting sections of the radial shield; and (5) the effectiveness of the exit shield in reducing the neutron fluxes in the upper plenum region of the reactor

Experience in handling core subassemblies in sodium cooled reactor KNK and test rigs

International Nuclear Information System (INIS)

Althaus; Jansing; Kesseler; Kirchner; Menck

1974-01-01

Compared with a water cooled reactor plant a sodium cooled reactor plant presents a number of problems which result from the specific nature of sodium. These problems that must be faced during all handling operations are mainly: 1. The rapid reaction of sodium in air requires handling to be done only under cover gas. 2. The temperature of all sodium-wetted components is to be kept above the melting point of sodium. 3. Poor draining of removed reactor components due to the high surface tension of sodium and the associated danger of dripping radioactive sodium may produce radiation or contamination problems. 4. Sodium is not transparent. The sum of these and further influences dictate that the general handling usually is carried out without visual means, though a method is under development in the USA to use ultrasonic for under sodium 'viewing'. These limitations to sodium component handling are applicable to all sodium reactor plants, several of which are discussed in this report. After the description of the handling systems of the KNK plant now operating at Karlsruhe, the experience with the SNR test rig and finally the handling systems for SNR 300 and SNR 2 are discussed

Changes in copper sulfate crystal habit during cooling crystallization

Science.gov (United States)

Giulietti, M.; Seckler, M. M.; Derenzo, S.; Valarelli, J. V.

1996-09-01

The morphology of technical grade copper(II) sulfate pentahydrate crystals produced from batch cooling experiments in the temperature range of 70 to 30°C is described and correlated with the process conditions. A slow linear cooling rate (batch time of 90 min) predominantly caused the appearance of well-formed crystals. Exponential cooling (120 min) resulted in the additional formation of agglomerates and twins. The presence of seeds for both cooling modes led to round crystals, agglomerates and twins. Fast linear cooling (15 min) gave rise to a mixture of the former types. Broken crystals and adhering fragments were often found. Growth zoning was pronounced in seeded and linear cooling experiments. Fluid inclusions were always found and were more pronounced for larger particles. The occurrence of twinning, zoning and fluid inclusions was qualitatively explained in terms of fundamental principles.

Experimental Tests of Cooling: Expectations and Additional Needs

International Nuclear Information System (INIS)

Zisman, Michael S

2008-01-01

Cooling is a critical aspect for a high-performance Neutrino Factory or a Muon Collider. For this reason, considerable effort is being put toward the experimental verification of this technique. The international Muon Ionization Cooling Experiment, MICE, was approved to operate at Rutherford Appleton Laboratory (RAL) in the UK and beam line commissioning commenced in March, 2008. The MICE collaboration comprises about 130 scientists and engineers from Asia, Europe, and the U.S. In this paper we present the motivation and goals for this experiment and describe its present status. MICE is scheduled for completion in 2011. We will also indicate the prospects for a future 6D muon cooling experiment and discuss its possible time schedule

State machine operation of the MICE cooling channel

International Nuclear Information System (INIS)

Hanlet, Pierrick

2014-01-01

The Muon Ionization Cooling Experiment (MICE) is a demonstration experiment to prove the feasibility of cooling a beam of muons for use in a Neutrino Factory and/or Muon Collider. The MICE cooling channel is a section of a modified Study II cooling channel which will provide a 10% reduction in beam emittance. In order to ensure a reliable measurement, MICE will measure the beam emittance before and after the cooling channel at the level of 1%, a relative measurement of 0.001. This renders MICE a precision experiment which requires strict controls and monitoring of all experimental parameters in order to control systematic errors. The MICE Controls and Monitoring system is based on EPICS and integrates with the DAQ, Data monitoring systems, and a configuration database. The cooling channel for MICE has between 12 and 18 superconductnig solenoid coils in 3 to 7 magnets, depending on the staged development of the experiment. The magnets are coaxial and in close proximity which requires coordinated operation of the magnets when ramping, responding to quench conditions, and quench recovery. To reliably manage the operation of the magnets, MICE is implementing state machines for each magnet and an over-arching state machine for the magnets integrated in the cooling channel. The state machine transitions and operating parameters are stored/restored to/from the configuration database and coupled with MICE Run Control. Proper implementation of the state machines will not only ensure safe operation of the magnets, but will help ensure reliable data quality. A description of MICE, details of the state machines, and lessons learned from use of the state machines in recent magnet training tests will be discussed.

Challenges and Opportunities in Gen3 Embedded Cooling with High-Quality Microgap Flow

Science.gov (United States)

Bar-Cohen, Avram; Robinson, Franklin L.; Deisenroth, David C.

2018-01-01

Gen3, Embedded Cooling, promises to revolutionize thermal management of advanced microelectronic systems by eliminating the sequential conductive and interfacial thermal resistances which dominate the present 'remote cooling' paradigm. Single-phase interchip microfluidic flow with high thermal conductivity chips and substrates has been used successfully to cool single transistors dissipating more than 40kW/sq cm, but efficient heat removal from transistor arrays, larger chips, and chip stacks operating at these prodigious heat fluxes would require the use of high vapor fraction (quality), two-phase cooling in intra- and inter-chip microgap channels. The motivation, as well as the challenges and opportunities associated with evaporative embedded cooling in realistic form factors, is the focus of this paper. The paper will begin with a brief review of the history of thermal packaging, reflecting the 70-year 'inward migration' of cooling technology from the computer-room, to the rack, and then to the single chip and multichip module with 'remote' or attached air- and liquid-cooled coldplates. Discussion of the limitations of this approach and recent results from single-phase embedded cooling will follow. This will set the stage for discussion of the development challenges associated with application of this Gen3 thermal management paradigm to commercial semiconductor hardware, including dealing with the effects of channel length, orientation, and manifold-driven centrifugal acceleration on the governing behavior.

Development of an emergency core cooling system for the converted IEA-R1m research reactor

Energy Technology Data Exchange (ETDEWEB)

Torres, Walmir Maximo; Baptista Filho, Benedito Dias; Ting, Daniel Kao Sun [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Dept. de Tecnologia de Reatores]. E-mail: wmtorres@net.ipen.br; bdbfilho@net.ipen.br; dksting@net.ipen.br

1998-07-01

This present work describes the development program carried out in the design and construction of the Emergency Core Cooling System for the IEA-R1m Research Reactor, including the system design, the experiments performed to validate the design, manufacturing, installation and commissioning. The experiments were performed in two phases. In the first phase, the spray flow rate and distribution were measured, using a full scale mock-up of the entire core, to establish the spray header geometry and specifications. In the second phase, a test section was fitted with electrically heated plates to simulate the fuel plates. Temperature measurements were carried out to demonstrate the effectiveness of the system to keep the temperatures below the limiting value. The experimental results were shown to the licensing authorities during the certification process. The main difficulties during the system assembly are also described. (author)

Real evaporative cooling efficiency of one-layer tight-fitting sportswear in a hot environment.

Science.gov (United States)

Wang, F; Annaheim, S; Morrissey, M; Rossi, R M

2014-06-01

Real evaporative cooling efficiency, the ratio of real evaporative heat loss to evaporative cooling potential, is an important parameter to characterize the real cooling benefit for the human body. Previous studies on protective clothing showed that the cooling efficiency decreases with increasing distance between the evaporation locations and the human skin. However, it is still unclear how evaporative cooling efficiency decreases as the moisture is transported from the skin to the clothing layer. In this study, we performed experiments with a sweating torso manikin to mimic three different phases of moisture absorption in one-layer tight-fitting sportswear. Clothing materials Coolmax(®) (CM; INVISTA, Wichita, Kansas, USA; 100%, profiled cross-section polyester fiber), merino wool (MW; 100%), sports wool (SW; 50% wool, 50% polyester), and cotton (CO; 100%) were selected for the study. The results demonstrated that, for the sportswear materials tested, the real evaporative cooling efficiency linearly decreases with the increasing ratio of moisture being transported away from skin surface to clothing layer (adjusted R(2) >0.97). In addition, clothing fabric thickness has a negative effect on the real evaporative cooling efficiency. Clothing CM and SW showed a good ability in maintaining evaporative cooling efficiency. In contrast, clothing MW made from thicker fabric had the worst performance in maintaining evaporative cooling efficiency. It is thus suggested that thin fabric materials such as CM and SW should be used to manufacture one-layer tight-fitting sportswear. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Design and operation of hybrid cooling towers

International Nuclear Information System (INIS)

Alt, W.

1987-01-01

The first hybrid cooling tower at a coal-fired power station with a waste heat output of 550 MW has been in operation since the middle of 1985. Experience during the construction stage and the initial period of operation has confirmed the correctness of the design standards and of the design itself and, of course, also offers a wealth of knowledge to be observed on future construction projects. A second cooling tower of similar design is being erected at the present time. This cooling tower serves a power station unit with 2500 MW of waste heat output. The programme for this cooling tower offers the possibility for all the accumulated and evaluated experience to be of influence both on the design and also on the method of operation. This paper reports on the details. (orig.) [de

Solar Heating and Cooling of Buildings (Phase O). Volume 1: Executive Summary.

Science.gov (United States)

TRW Systems Group, Redondo Beach, CA.

The purpose of this study was to establish the technical and economic feasibility of using solar energy for the heating and cooling of buildings. Five selected building types in 14 selected cities were used to determine loads for space heating, space cooling and dehumidification, and domestic service hot water heating. Relying on existing and…

Experimental investigation of a solar adsorption chiller used for grain depot cooling

International Nuclear Information System (INIS)

Luo, H.L.; Dai, Y.J.; Wang, R.Z.; Wu, J.Y.; Xu, Y.X.; Shen, J.M.

2006-01-01

The solar cooling technology is attractive since cooling load of building is roughly in phase with solar energy availability. In this study, a solar adsorption chiller was built and tested with aim of developing an alternative refrigeration system used for grain cooling storage. This solar adsorption chiller consists of four subsystems, namely, a solar water heating unit with 49.4 m 2 solar collecting area, a silica gel-water adsorption chiller, a cooling tower and a fan coil unit. In order to achieve continuous refrigeration, two adsorption units are operated out-of-phase with mass recovery cycle in the adsorption chiller. Field test results show that, under the climatic conditions of daily solar radiation being about 16-21 MJ/m 2 , this solar adsorption chiller can furnish 14-22 deg. C chilled air with an average cooling output ranging from about 3.2-4.4 kW, its daily solar cooling COP (coefficient of performance) is about 0.1-0.13

Time-resolved crystallization of deeply cooled liquid hydrogen isotopes

Energy Technology Data Exchange (ETDEWEB)

Kuehnel, Matthias

2014-02-15

This thesis serves two main purposes: 1. The introduction of a novel experimental method to investigate phase change dynamics of supercooled liquids 2. First-time measurements for the crystallization behaviour for hydrogen isotopes under various conditions (1) The new method is established by the synergy of a liquid microjet of ∼ 5 μm diameter and a scattering technique with high spatial resolution, here linear Raman spectroscopy. Due to the high directional stability and the known velocity of the liquid filament, its traveling axis corresponds to a time axis static in space. Utilizing evaporative cooling in a vacuum environment, the propagating liquid cools down rapidly and eventually experiences a phase transition to the crystalline state. This temporal evolution is probed along the filament axis, ultimately resulting in a time resolution of 10 ns. The feasibility of this approach is proven successfully within the following experiments. (2) A main object of study are para-hydrogen liquid filaments. Raman spectra reveal a temperature gradient of the liquid across the filament. This behaviour can quantitatively be reconstructed by numerical simulations using a layered model and is rooted in the effectiveness of evaporative cooling on the surface and a finite thermal conductivity. The deepest supercoolings achieved are ∼ 30% below the melting point, at which the filament starts to solidify from the surface towards the core. With a crystal growth velocity extracted from the data the appropriate growth mechanism is identified. The crystal structure that initially forms is metastable and probably the result of Ostwald's rule of stages. Indications for a transition within the solid towards the stable equilibrium phase support this interpretation. The analog isotope ortho-deuterium is evidenced to behave qualitatively similar with quantitative differences being mass related. In further measurements, isotopic mixtures of para-hydrogen and ortho-deuterium are

Time-resolved crystallization of deeply cooled liquid hydrogen isotopes

International Nuclear Information System (INIS)

Kuehnel, Matthias

2014-02-01

This thesis serves two main purposes: 1. The introduction of a novel experimental method to investigate phase change dynamics of supercooled liquids 2. First-time measurements for the crystallization behaviour for hydrogen isotopes under various conditions (1) The new method is established by the synergy of a liquid microjet of ∼ 5 μm diameter and a scattering technique with high spatial resolution, here linear Raman spectroscopy. Due to the high directional stability and the known velocity of the liquid filament, its traveling axis corresponds to a time axis static in space. Utilizing evaporative cooling in a vacuum environment, the propagating liquid cools down rapidly and eventually experiences a phase transition to the crystalline state. This temporal evolution is probed along the filament axis, ultimately resulting in a time resolution of 10 ns. The feasibility of this approach is proven successfully within the following experiments. (2) A main object of study are para-hydrogen liquid filaments. Raman spectra reveal a temperature gradient of the liquid across the filament. This behaviour can quantitatively be reconstructed by numerical simulations using a layered model and is rooted in the effectiveness of evaporative cooling on the surface and a finite thermal conductivity. The deepest supercoolings achieved are ∼ 30% below the melting point, at which the filament starts to solidify from the surface towards the core. With a crystal growth velocity extracted from the data the appropriate growth mechanism is identified. The crystal structure that initially forms is metastable and probably the result of Ostwald's rule of stages. Indications for a transition within the solid towards the stable equilibrium phase support this interpretation. The analog isotope ortho-deuterium is evidenced to behave qualitatively similar with quantitative differences being mass related. In further measurements, isotopic mixtures of para-hydrogen and ortho-deuterium are

Time-resolved crystallization of deeply cooled liquid hydrogen isotopes

Energy Technology Data Exchange (ETDEWEB)

Kuehnel, Matthias

2014-02-15

This thesis serves two main purposes: 1. The introduction of a novel experimental method to investigate phase change dynamics of supercooled liquids 2. First-time measurements for the crystallization behaviour for hydrogen isotopes under various conditions (1) The new method is established by the synergy of a liquid microjet of ∼ 5 μm diameter and a scattering technique with high spatial resolution, here linear Raman spectroscopy. Due to the high directional stability and the known velocity of the liquid filament, its traveling axis corresponds to a time axis static in space. Utilizing evaporative cooling in a vacuum environment, the propagating liquid cools down rapidly and eventually experiences a phase transition to the crystalline state. This temporal evolution is probed along the filament axis, ultimately resulting in a time resolution of 10 ns. The feasibility of this approach is proven successfully within the following experiments. (2) A main object of study are para-hydrogen liquid filaments. Raman spectra reveal a temperature gradient of the liquid across the filament. This behaviour can quantitatively be reconstructed by numerical simulations using a layered model and is rooted in the effectiveness of evaporative cooling on the surface and a finite thermal conductivity. The deepest supercoolings achieved are ∼ 30% below the melting point, at which the filament starts to solidify from the surface towards the core. With a crystal growth velocity extracted from the data the appropriate growth mechanism is identified. The crystal structure that initially forms is metastable and probably the result of Ostwald's rule of stages. Indications for a transition within the solid towards the stable equilibrium phase support this interpretation. The analog isotope ortho-deuterium is evidenced to behave qualitatively similar with quantitative differences being mass related. In further measurements, isotopic mixtures of para-hydrogen and ortho-deuterium are

Solar sorptive cooling. Technologies, user requirements, practical experience, future prospects

Energy Technology Data Exchange (ETDEWEB)

Treffinger, P. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Hardthausen (Germany); Hertlein, H.P. [eds.] [Forschungsverbund Sonnenenergie, Koeln (Germany)

1998-09-01

Sorptive cooling techniques permit the use of low-temperature solar heat, i.e. a renewable energy of low cost and world-wide availability. The Forschungsverbund Sonnenenergie intends to develop solar sorptive cooling technologies to the prototype stage and, in cooperation with the solar industry and its end users, to promote practical application in air conditioning of buildings and cold storage of food. The workshop presents an outline of the state of development of solar sorptive cooling from the view of users and developers. Exemplary solar cooling systems are described, and the potential of open and closed sorptive processes is assessed. Future central activities will be defined in an intensive discussion between planners, producers, users and developers. [German] Der Einsatz von Sorptionstechniken zur Kaelteerzeugung erlaubt es, als treibende Solarenergie Niedertemperatur-Solarwaerme einzusetzen, also eine regenerative Energie mit sehr geringen Kosten und weltweiter Verfuegbarkeit. Der Forschungsverbund Sonnenenergie hat sich als Aufgabe gestellt, die Techniken der solaren Sorptionskuehlung bis zum Prototyp zu entwickeln und mit Industrie und Nutzern die praktische Anwendung voranzubringen. Die Anwendungsfelder sind die Klimatisierung von Gebaeuden und die Kaltlagerung von Lebensmitteln. Der Workshop gibt einen Ueberblick zum Entwicklungsstand der solaren Sorptionskuehlung aus der Sicht der Anwender und Entwickler. Bereits ausgefuehrte Beispiele zur solaren Kuehlung werden vorgestellt und das Potential geschlossener und offener Sorptionsverfahren angegeben. In intensiver Diskussion zwischen Planern, Herstellern, Nutzern und Entwicklern sollen kuenftige Arbeitsschwerpunkte herausgearbeitet werden. (orig.)

The design of aircraft brake systems, employing cooling to increase brake life

Science.gov (United States)

Scaringe, R. P.; Ho, T. L.; Peterson, M. B.

1975-01-01

A research program was initiated to determine the feasibility of using cooling to increase brake life. An air cooling scheme was proposed, constructed and tested with various designs. Straight and curved slotting of the friction material was tested. A water cooling technique, similar to the air cooling procedure, was evaluated on a curved slotted rotor. Also investigated was the possibility of using a phase-change material within the rotor to absorb heat during braking. Various phase-changing materials were tabulated and a 50%, (by weight) LiF - BeF2 mixing was chosen. It was shown that corrosion was not a problem with this mixture. A preliminary design was evaluated on an actual brake. Results showed that significant improvements in lowering the surface temperature of the brake occurred when air or water cooling was used in conjunction with curved slotted rotors.

Laser cooling and ion beam diagnosis of relativistic ions in a storage ring

International Nuclear Information System (INIS)

Schroeder, S.

1990-08-01

Particle accelerator and storage ring technology has reached an advanced state, so that different heavy ion storage rings are coming into operation by now, capable of storing even fully stripped ions up to U 92+ . The main purpose of these machines are the accumulation of ions and the ability of improving the beam quality, that is the phase space density of the stored beams. This beam cooling is done successfully by the well established stochastic and electron cooling techniques. A new cooling method, the laser cooling, is taken over from atomic beam and ion trap experiments, where it has yielded extremely low temperatures of atomic samples. As a canditate at storage rings 7 Li + ions are stored in the Heidelberg TSR at 13.3 MeV. The ion beam properties of the metastable fraction like momentum spread, storage time and the influence of residual gas scattering are investigated by colinear laser spectroscopy in the experimental section of the TSR. An optical pumping experiment using two dye laser systems yields information about ion kinematics and velocity mixing processes in the ring. Lifetimes in the order of 100 ms for velocity classes marked in this way show that laser cooling can be applied to the stored 7 Li + beam. In an experimental situation of two strong counterpropagating laser beams, both tuned near resonance, a dramatic reduction of the ion beam momentum spread is observed. With a special geometrical control of laser and ion beam the longitudinal beam temperature is reduced from 260 K to at least 3 K with very high collection efficiency. (orig./HSI) [de

Radiative cooling and broadband phenomenon in low-frequency waves

Institute of Scientific and Technical Information of China (English)

无

2000-01-01

In this paper, we analyze the effects of radiative cooling on the pure baroclinic low-frequency waves under the approximation of equatorial -plane and semi-geostrophic condition. The results show that radiative cooling does not, exclusively, provide the damping effects on the development of low-frequency waves. Under the delicate radiative-convective equilibrium, radiative effects will alter the phase speed and wave period, and bring about the broadband of phase velocity and wave period by adjusting the vertical profiles of diabatic heating. when the intensity of diabatic heating is moderate and appropriate, it is conductive to the development and sustaining of the low-frequency waves and their broadband phenomena, not the larger, the better. The radiative cooling cannot be neglected in order to reach the moderate and appropriate intensity of diabatic heating.

An extended analytical model for solid-state phase transformation upon continuous heating and cooling processes: Application in γ/α transformation

International Nuclear Information System (INIS)

Jiang, Y.-H.; Liu, F.; Song, S.-J.

2012-01-01

An extended analytical model is derived for non-isothermal solid-state phase transformation assuming interface-controlled growth mode, e.g. polymorphic or allotropic transformation. In the modeling, incorporation of thermodynamic factor into kinetics of nucleation and growth is performed, so that the model can be used to describe the transformation occurring either near or far from the equilibrium state. Furthermore, the effect of the initial transformation temperature is included through a special treatment for the “temperature integral”, so that the model can be used to depict the transformation during either continuous heating or continuous cooling. Numerical calculations demonstrate that the extended analytical model is accurate enough for practical use. On this basis, a general rate equation for non-isothermal (isochronal heating and cooling) transformation is derived. Applying the present model, the overall kinetic behavior of γ/α transformation in binary substitutional Fe-based alloys (e.g. Fe–Mn and Fe–Cu) upon cooling, measured by dilatometry, is described successfully. Compared with previous work, where a site saturation assumption is generally made, the prevalence of continuous nucleation deduced using the present model prediction seems more reasonable.

Operating experience feedback report: Assessment of spent fuel cooling. Volume 12

International Nuclear Information System (INIS)

Ibarra, J.G.; Jones, W.R.; Lanik, G.F.; Ornstein, H.L.; Pullani, S.V.

1997-02-01

This report documents the results of an independent assessment by a team from the Office of Analysis and Evaluation of Operational Data of spent-fuel-pool (SFP) cooling in operating nuclear power plants. The team assessed the likelihood and consequences of an extended loss of SFP cooling and suggested corrective actions, based on their findings

Influence of detergents on water drift in cooling towers

Science.gov (United States)

Vitkovicova, Rut

An influence of detergents on the water drift from the cooling tower was experimentally investigated. For this experimental measurements was used a model cooling tower, especially an experimental aerodynamic line, which is specially designed for the measurement and monitoring of processes taking place around the eliminators of the liquid phase. The effect of different concentrations of detergent in the cooling water on the drift of water droplets from a commonly used type eliminator was observed with visualization methods.

Effect Of Cooling Rate On Thermal And Mechanical Properties Of Cu-%24.2Mn Alloy

International Nuclear Information System (INIS)

Celik, H.

2010-01-01

In this research, different heat and mechanical treatments have been applied to the Cu-%24.2Mn and some samples have been obtained from this alloy. On these samples, phase transformations have been formed by thermal and mechanical effect. Morphological, mechanical and crystallographic properties of the phase transformations have been examined by using different physical methods. Austenite phase has been obtained in the samples which have been applied slow and rapid cooling according to the SEM analysis. It has been observed that the grain size obtained by the rapid cooling is smaller than the grain size obtained by the slow cooling. Therefore, it has been concluded that the cooling process differences, changes the grain size of the alloy. Compression stress has been applied to the alloy in order to search the deformation effect on the austenite phase transformation. The structural features of the phase transformations have been examined. Slip lines and martensite structural were observed on the surface of the alloys after the deformation. Changes in phase structure of the alloy are also examined by means of XRD technique.

An Individualized, Perception-Based Protocol to Investigate Human Physiological Responses to Cooling

Science.gov (United States)

Coolbaugh, Crystal L.; Bush, Emily C.; Galenti, Elizabeth S.; Welch, E. Brian; Towse, Theodore F.

2018-01-01

Cold exposure, a known stimulant of the thermogenic effects of brown adipose tissue (BAT), is the most widely used method to study BAT physiology in adult humans. Recently, individualized cooling has been recommended to standardize the physiological cold stress applied across participants, but critical experimental details remain unclear. The purpose of this work was to develop a detailed methodology for an individualized, perception-based protocol to investigate human physiological responses to cooling. Participants were wrapped in two water-circulating blankets and fitted with skin temperature probes to estimate BAT activity and peripheral vasoconstriction. We created a thermoesthesia graphical user interface (tGUI) to continuously record the subject's perception of cooling and shivering status during the cooling protocol. The protocol began with a 15 min thermoneutral phase followed by a series of 10 min cooling phases and concluded when sustained shivering (>1 min duration) occurred. Researchers used perception of cooling feedback (tGUI ratings) to manually adjust and personalize the water temperature at each cooling phase. Blanket water temperatures were recorded continuously during the protocol. Twelve volunteers (ages: 26.2 ± 1.4 years; 25% female) completed a feasibility study to evaluate the proposed protocol. Water temperature, perception of cooling, and shivering varied considerably across participants in response to cooling. Mean clavicle skin temperature, a surrogate measure of BAT activity, decreased (−0.99°C, 95% CI: −1.7 to −0.25°C, P = 0.16) after the cooling protocol, but an increase in supraclavicular skin temperature was observed in 4 participants. A strong positive correlation was also found between thermoesthesia and peripheral vasoconstriction (ρ = 0.84, P < 0.001). The proposed individualized, perception-based protocol therefore has potential to investigate the physiological responses to cold stress applied across populations with

Proposal of experimental setup on boiling two-phase flow on-orbit experiments onboard Japanese experiment module "KIBO"

Science.gov (United States)

Baba, S.; Sakai, T.; Sawada, K.; Kubota, C.; Wada, Y.; Shinmoto, Y.; Ohta, H.; Asano, H.; Kawanami, O.; Suzuki, K.; Imai, R.; Kawasaki, H.; Fujii, K.; Takayanagi, M.; Yoda, S.

2011-12-01

Boiling is one of the efficient modes of heat transfer due to phase change, and is regarded as promising means to be applied for the thermal management systems handling a large amount of waste heat under high heat flux. However, gravity effects on the two-phase flow phenomena and corresponding heat transfer characteristics have not been clarified in detail. The experiments onboard Japanese Experiment Module "KIBO" in International Space Station on boiling two-phase flow under microgravity conditions are proposed to clarify both of heat transfer and flow characteristics under microgravity conditions. To verify the feasibility of ISS experiments on boiling two-phase flow, the Bread Board Model is assembled and its performance and the function of components installed in a test loop are examined.

The active phasing experiment: Part I. Concept and objectives

Science.gov (United States)

Yaitskova, Natalia; Gonte, Frederic; Derie, Frederic; Noethe, Lothar; Surdej, Isabelle; Karban, Robert; Dohlen, Kjetil; Langlois, Maud; Esposito, Simone; Pinna, Enrico; Reyes, Marcos; Montoya, Lusma; Terrett, David

2006-06-01

In a framework of ELT design study our group is building an Active Phasing Experiment (APE), the main goals of which is to demonstrate the non-adaptive wavefront control scheme and technology for Extremely Large Telescope (ELT). The experiment includes verification and test of different phasing sensors and integration of a phasing wavefront sensor into a global scheme of segmented telescope active control. After a sufficient number of tests in the laboratory APE will be mounted and tested on sky at a Nasmyth focus of a VLT unit telescope. The paper presents APE as a demonstrator of particular aspects of ELT and provides a general understanding concerning the strategy of segmented mirrors active control.

Dual-scale phase-field simulation of Mg-Al alloy solidification

International Nuclear Information System (INIS)

Monas, A; Shchyglo, O; Tegeler, M; Steinbach, I; Höche, D

2015-01-01

Phase-field simulations of the nucleation and growth of primary α-Mg phase as well as secondary, β-phase of a Mg-Al alloy are presented. The nucleation model for α- and β-Mg phases is based on the “free growth model” by Greer et al.. After the α-Mg phase solidification we study a divorced eutectic growth of α- and β-Mg phases in a zoomed in melt channel between α-phase dendrites. The simulated cooling curves and final microstructures of α-grains are compared with experiments. In order to further enhance the resolution of the interdendritic region a high-performance computing approach has been used allowing significant simulation speed gain when using supercomputing facilities. (paper)

Structural optimization of a microjet based cooling system for high power LEDs

Energy Technology Data Exchange (ETDEWEB)

Sheng Liu; Zhiyin Gan [Institute for Microsystems, School of Mechanical Engineering, Huazhong University of Science and Technology, Wuhan (China); Wuhan National Lab of Optoelectronics, Huazhong University of Science and Technology, Wuhan (China); Jianghui Yang [School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan (China); Xiaobing Luo [Wuhan National Lab of Optoelectronics, Huazhong University of Science and Technology, Wuhan (China); School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan (China)

2008-08-15

Based on the previous experiments and simulations reported by the present authors, it was found the cooling system could be optimized to obtain better performance. In this paper, the microjet cooling systems with three different microjet structures were numerically investigated. The numerical model was proven by the experiments. The optimization results demonstrate that the microjet structure with one single inlet but two outlets can achieve better cooling performance. The simulation results show that the maximum temperature of the LED substrate cooled by the optimized microjet cooling device was 23 K lower than that of the LED substrate cooled by the present experimental cooling system. (author)

Piers cooling towers. From first idess to realizations

International Nuclear Information System (INIS)

Bozetto, P.; Tzincoca, A.

1988-01-01

After a first part consecrated at the historical aspect of vertical piers cooling towers the second part indicates the experience pulled of the Chooz and Golfech cooling towers conception and realization [fr

Compendium of Phase-I Mini-SHINE Experiments

Energy Technology Data Exchange (ETDEWEB)

Youker, Amanda J. [Argonne National Lab. (ANL), Argonne, IL (United States); Chemerisov, Sergey D. [Argonne National Lab. (ANL), Argonne, IL (United States); Tkac, Peter [Argonne National Lab. (ANL), Argonne, IL (United States); Kalensky, Michael [Argonne National Lab. (ANL), Argonne, IL (United States); Heltemes, Thad A. [Argonne National Lab. (ANL), Argonne, IL (United States); Rotsch, David A [Argonne National Lab. (ANL), Argonne, IL (United States); Krebs, John F. [Argonne National Lab. (ANL), Argonne, IL (United States); Makarashvili, Vakhtang [Argonne National Lab. (ANL), Argonne, IL (United States); Stepinski, Dominique C. [Argonne National Lab. (ANL), Argonne, IL (United States); Alford, Kurt [Argonne National Lab. (ANL), Argonne, IL (United States); Bailey, James [Argonne National Lab. (ANL), Argonne, IL (United States); Byrnes, James [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, Roman [Argonne National Lab. (ANL), Argonne, IL (United States); Hafenrichter, Lohman [Argonne National Lab. (ANL), Argonne, IL (United States); Hebden, Andrew [Argonne National Lab. (ANL), Argonne, IL (United States); Jerden, James [Argonne National Lab. (ANL), Argonne, IL (United States); Jonah, Charles [Argonne National Lab. (ANL), Argonne, IL (United States); Micklich, Brad [Argonne National Lab. (ANL), Argonne, IL (United States); Quigley, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States); Schneider, John [Argonne National Lab. (ANL), Argonne, IL (United States); Wesolowski, Kenneth [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States); Sun, Zaijing [Argonne National Lab. (ANL), Argonne, IL (United States)

2016-10-01

Argonne National Laboratory is assisting SHINE Medical Technologies in their efforts to develop the technology to become a domestic Mo-99 producer using low-enriched uranium (LEU). Mini-SHINE experiments are being performed with the high-current electron linear accelerator (linac) at Argonne. The target solution is a 90-150 g-U/L LEU uranyl sulfate at pH 1. In Phase 1, the convertor was tantalum with a maximum beam power on the convertor of 10 kW, and the target solution was limited to 5 L. This configuration generated a peak fission power density of 0.05 W/mL. Nine experiments were performed between February and October 2015. Results are reported and discussed for each experiment regarding the off-gas analysis system, the sampling and Mo-recovery operation, and the Mo-product concentration and purification system. In Phase 2, the convertor will be depleted uranium; beam power will increase to 20 kW; and the solution volume will be 18 L. This configuration will generate a fission power density of up to 1 W/mL.

Noise emissions of cooling towers; Geraeuschemissionen von Kuehltuermen

Energy Technology Data Exchange (ETDEWEB)

Hinkelmann, Dirk [Mueller-BBM GmbH, Gelsenkirchen (Germany)

2013-09-01

Cooling towers are often large structures with high sound emission. The impact of water drops on the water surface in the collecting basin leads to the generation of middle- and high-frequency noise that is emitted via the air intake opening and the outlet. In forced-draft cooling towers, additional noise is generated by drives and fans. The sound emissions can be predicted by means of empirical calculation models. In this way, noise control measures can be taken into account already at an early phase of planning. Different, proven measures for reduction of sound emissions are taken depending on cooling tower design. Regulations on noise acceptance testing for cooling towers are given in various standards. (orig.)

Cooling clothing utilizing water evaporation

DEFF Research Database (Denmark)

Sakoi, Tomonori; Tominaga, Naoto; Melikov, Arsen Krikor

2014-01-01

. To prevent wet discomfort, the T-shirt was made of a polyester material having a water-repellent silicon coating on the inner surface. The chest, front upper arms, and nape of the neck were adopted as the cooling areas of the human body. We conducted human subject experiments in an office with air......We developed cooling clothing that utilizes water evaporation to cool the human body and has a mechanism to control the cooling intensity. Clean water was supplied to the outer surface of the T-shirt of the cooling clothing, and a small fan was used to enhance evaporation on this outer surface...... temperature ranging from 27.4 to 30.7 °C to establish a suitable water supply control method. A water supply control method that prevents water accumulation in the T-shirt and water dribbling was validated; this method is established based on the concept of the water evaporation capacity under the applied...

Influence of detergents on water drift in cooling towers

Directory of Open Access Journals (Sweden)

Vitkovicova Rut

2017-01-01

Full Text Available An influence of detergents on the water drift from the cooling tower was experimentally investigated. For this experimental measurements was used a model cooling tower, especially an experimental aerodynamic line, which is specially designed for the measurement and monitoring of processes taking place around the eliminators of the liquid phase. The effect of different concentrations of detergent in the cooling water on the drift of water droplets from a commonly used type eliminator was observed with visualization methods.

Experimental study on the proton stochastic cooling in the NAP-M

International Nuclear Information System (INIS)

Dement'ev, E.N.; Zinevich, N.I.; Medvedko, A.S.; Parkhomchuk, V.V.; Pestrikov, D.V.

1982-01-01

Results of experiments on stochastic cooling of proton beam energy spread at NAP-M storage ring are given. Dependences of dampling decrements on beam phase density, numbers of working harmonics and values of amplification factor of feedback circuit have been studied. A differential sensor made in the form of two end-disengaged strip lines is used as a signal source for the feedback circuit. Two cooling systems were investigated: a wide-band system consisting of a sensor and correcting element and a system with a resonance filter at the input. The correcting element is made in the form of four 50 Ohm consistent strip lines. Coaxial cable sections forming with sensor strip lines two resonance lines end-closed with low input resistances of amplifiers were used as a filter. Stable spread in the beam was determined with electronics hums. Coherent beam stability related to its shift in measuring pick up electrode is detected. Method limitations due to electronics noise and collective effects in intense beams are discussed. Cooling time of low-intense particle beam equal to 150 s when decreasing spread from 3x10 - 4 to 2x10 - 4 has been determined

Improvement of thermal comfort by cooling clothing in warm climate

DEFF Research Database (Denmark)

Sakoi, Tomonori; Melikov, Arsen Krikor; Kolencíková, Sona

2014-01-01

on the inner surface. We conducted experiments with human subjects in climate chambers maintained at 30 °C and RH 50% to compare the effectiveness of the cooling clothing with that of other convective cooling devices. The use of cooling clothing with a convective cooling device improved the subjects’ thermal...... comfort compared to convective cooling alone. The supply of a small amount of water allowed the cooling clothing to provide a continuous cooling effect, whereas the effect of convective cooling alone decreased as sweat dried. However, the controllability of the cooling clothing needs to be improved....

Laser cooling of atoms and ions

International Nuclear Information System (INIS)

Morigi, G.

1999-02-01

This thesis covers my work in the field of theoretical quantum optics, focusing on laser cooling of trapped atoms and ions. Laser cooling has been extensively investigated in the last twenty years, opening the possibility in experiments to move well into the quantum regime, where quantum statistical or quantum motional effects become pronounced. The successful preparation of cold atoms by means of laser cooling has recently raised the interest in the preparation of several or even many particles in a pure quantum state of the whole system. This goal imposes certain experimental circumstances, in particular the interaction between the atoms may play a significant role and affect the conditions for laser cooling considerably. Hence, there is great interest in developing cooling schemes which are compatible with such experimental conditions and in studying theoretically laser cooling of interacting particles. The work contained in this thesis contributes to this rapidly developing field, and it can be divided in two parts. In the first part, it presents an investigation of new schemes of laser cooling of single atoms or ions in traps where the amplitude of the particle's motion is comparable with the laser wavelength. This regime is typical of experiments with ultracold, weakly interacting atomic gases, and equally relevant to quantum information processing with trapped ions. In the second part, laser cooling of strongly interacting ions in a trap is investigated, with particular attention to the effect of the Coulomb interaction on the cooling process. This system is a paradigm for the experimental implementation of a quantum computer and is currently intensively studied. The thesis is divided into five chapters, of which the first one constitutes an introduction to laser cooling and to a series of concepts which are recurrent throughout this work. The other four chapters present my personal contributions to the field. Each of them contains first a general

Horonobe underground research laboratory project. The plan for the in-situ experiments in Phase 2 and Phase 3 in/around URL

International Nuclear Information System (INIS)

Matsui, Hiroya

2005-09-01

This report describes for preliminary research plan in Phase 2 and Phase 3 taken into consideration of expected geological environment at location of URL based on the results of the investigations until FY 2003/2004. Duration of construction phase and total cost are considered as important factors for planning as well. The below items are planned for in-situ experiments in Phase 2 and Phase 3 in/around URL are planning. Phase 2. (In-situ experiments for understanding of geological environment) Geological survey at tunnel. Inflow measurement in shafts. Water pressure monitoring and groundwater sampling around shafts during excavation of URL. Investigation for EDZ around shafts. Stress measurement on support. Detail investigations for geological environment around drifts. Excavation disturbance experiment in a drift. Investigation for desaturation zone and REDOX condition around drifts. (Engineered barrier system) In-situ experiment on low-alkali concrete. In-situ experiment for gas migration in engineering barrier system. Phase 3. (In-situ experiments for understanding of geological environment) EDZ experiment for stress interference. Investigation of long-term behavior of EDZ around drifts. Detail investigation on fault/fault zone. Monitoring for the change of geological environment at earthquake. Backfill test in boreholes. (Engineered barrier system) T-H-M-C experiment. In-situ experiment for corrosion of overpack. Investigation of the influence of a concrete to engineering barrier system and geological environment. In-situ experiment for interference between backfill material and geological environment. Backfill test in a drift. (Safety assessment) Tracer tests in engineering barrier system, natural barrier and fault/fault zone. (author)

Corrosion induced clogging and plugging in water-cooled generator cooling circuit

International Nuclear Information System (INIS)

Park, B.G.; Hwang, I.S.; Rhee, I.H.; Kim, K.T.; Chung, H.S.

2002-01-01

Water-cooled electrical generators have been experienced corrosion-related problems that are restriction of flow through water strainers caused by collection of excessive amounts of copper corrosion products (''clogging''), and restriction of flow through the copper strands in the stator bars caused by growth or deposition of corrosion products on the walls of the hollow strands (''plugging''). These phenomena result in unscheduled shutdowns that would be a major concern because of the associated loss in generating capacity. Water-cooled generators are operated in one of two modes. They are cooled either with aerated water (dissolved oxygen >2 ppm) or with deaerated water (dissolved oxygen <50 ppb). Both modes maintain corrosion rates at satisfactorily low levels as long as the correct oxygen concentrations are maintained. However, it is generally believed that very much higher copper corrosion rates result at the intermediate oxygen concentrations of 100-1000 ppb. Clogging and plugging are thought to be associated with these intermediate concentrations, and many operators have suggested that the period of change from high-to-low or from low-to-high oxygen concentration is particularly damaging. In order to understand the detailed mechanism(s) of the copper oxide formation, release and deposition and to identify susceptible conditions in the domain of operating variables, a large-scale experiments are conducted using six hollow strands of full length connected with physico-chemically scaled generator cooling water circuit. To ensure a close simulation of thermal-hydraulic conditions in a generator stator, strands of the loop will be ohmically heated using AC power supply. Experiments is conducted to cover oxygen excursions in both high dissolved oxygen and low dissolved oxygen conditions that correspond to two representative operating condition at fields. A thermal upset condition is also simulated to examine the impact of thermal stress. During experiments

Car body welding with micro-jet cooling

OpenAIRE

T. Węgrzyn; J. Piwnik; D. Hadryś; R. Wieszała

2011-01-01

Purpose: of that paper was analysing welding process with device to micro-jet cooling of weld joint during welding. The main reason of it was investigate possibilities of getting higher amount of desired phase acicular ferrite. High amount of acicular ferrite influences positively on high value of impact toughness. Increasing the value of impact toughness is particular importance when making repairs car body parts. It is necessary to determine the parameters of the micro-jet cooling so that y...

Post-exercise cooling techniques in hot, humid conditions.

Science.gov (United States)