scholarly journals First results of the two-phase argon avalanche detector performance with CsI photocathode

2007 ◽  
Vol 581 (1-2) ◽  
pp. 241-245 ◽  
Author(s):  
A. Bondar ◽  
A. Buzulutskov ◽  
A. Grebenuk ◽  
D. Pavlyuchenko ◽  
R. Snopkov ◽  
...  
Keyword(s):  
Two Phase ◽  
Detector Performance ◽  
First Results

Vibration of a Tube Bundle in Two-Phase Freon Cross-Flow

1995 ◽  
Vol 117 (4) ◽  
pp. 321-329 ◽  
Author(s):  
M. J. Pettigrew ◽  
C. E. Taylor ◽  
J. H. Jong ◽  
I. G. Currie
Keyword(s):  
Two Phase Flow ◽  
Tube Bundle ◽  
Density Ratio ◽  
Cross Flow ◽  
Flow Regimes ◽  
Phase Flow ◽  
Two Phase ◽  
Void Fractions ◽  
Fluidelastic Instability ◽  
First Results

Two-phase cross-flow exists in many shell-and-tube heat exchangers. The U-bend region of nuclear steam generators is a prime example. Testing in two-phase flow simulated by air-water provides useful results inexpensively. However, two-phase flow parameters, in particular surface tension and density ratio, are considerably different in air-water than in steam-water. A reasonable compromise is testing in liquid-vapor Freon, which is much closer to steam-water while much simpler experimentally. This paper presents the first results of a series of tests on the vibration behavior of tube bundles subjected to two-phase Freon cross-flow. A rotated triangular tube bundle of tube-to-diameter ratio of 1.5 was tested over a broad range of void fractions and mass fluxes. Fluidelastic instability, random turbulence excitation, and damping were investigated. Well-defined fluidelastic instabilities were observed in continuous two-phase flow regimes. However, intermittent two-phase flow regimes had a dramatic effect on fluidelastic instability. Generally, random turbulence excitation forces are much lower in Freon than in air-water. Damping is very dependent on void fraction, as expected.

The Effect of Functional Spacers on the Liquid Film Thickness and Dryout in a BWR Fuel Bundle Model

2018 ◽  
Author(s):  
Christian Bolesch ◽  
Lukas Robers ◽  
Robert Zboray ◽  
Horst-Michael Prasser
Keyword(s):  
Film Thickness ◽  
Liquid Film ◽  
Structural Integrity ◽  
Heating System ◽  
Liquid Film Thickness ◽  
Two Phase ◽  
High Resolution Data ◽  
Fuel Bundle ◽  
First Results ◽  
Key Aspects

For the BWRs, the dryout margin is one of the core design limitation factors. Today’s industry standard is to use a large margin to dryout and functional spacer grids with vanes to enhance the heat transfer and to reduce the fraction of entrained droplets. Difficulties for precise measurements under reactor conditions lead to a lack of knowledge on the exact effects of the spacers on the flow and suggest the use of scaled experiments. For this experiment, the goal is to provide high-resolution data for CFD code validation as well as visualizing the effects of functional spacers and the liquid film and potentially the dryout front. The Dryout Tomography Experiment (DoToX) facility at ETH Zürich is a closed loop experiment for two-phase flow investigations in a fuel bundle model using a modelling fluid. Key aspects are a single undisturbed subchannel and the surrounding four heating rods containing a liquid heating system. This setup allows for a steady state dryout without endangering the structural integrity of the facility and for the 3D reconstruction of the time averaged void distribution within the flow channel by means of an X-Ray and cold neutron Computer Tomography (CT). In this study we pay special attention to the annular flow in the upper half of the sub channel. We investigate the first results delivered by the facility. Prototypical spacer designs available in the open literature were used. We present the Liquid Film Thickness (LFT) distributions on the walls of the heating rods. Improvements towards the dryout performance as well as drawbacks of the specified spacer design are highlighted.

Direct Steam Generation in Parabolic Troughs: First Results of the DISS Project

2002 ◽  
Vol 124 (2) ◽  
pp. 134-139 ◽  
Author(s):  
M. Eck ◽  
W.-D. Steinmann
Keyword(s):  
Steady State ◽  
Controller Design ◽  
Experimental Results ◽  
Phase Flow ◽  
Simulation Studies ◽  
Steam Generation ◽  
Two Phase ◽  
State Tests ◽  
Direct Steam ◽  
First Results

This article presents the latest experimental results of the European DISS (DIrect Solar Steam) project. The experiments are subdivided into steady state and transient tests. The goal of the steady state tests is the investigation of the thermohydraulic phenomena of the occurring two phase flow, whereas the transient tests are needed for the controller design. The experimental results are compared to simulation studies. Implications for the plant operation will be discussed.

Diphasic transfer of oxygen in vertical flow filters: a modelling approach

2011 ◽  
Vol 64 (1) ◽  
pp. 109-116 ◽  
Author(s):  
A. Petitjean ◽  
A. Wanko ◽  
N. Forquet ◽  
R. Mosé ◽  
F. Lawniczak ◽  
...  
Keyword(s):  
Multiphase Model ◽  
Vertical Flow ◽  
Treatment Efficiency ◽  
Two Phase ◽  
Convection Diffusion ◽  
First Order ◽  
First Order Kinetics ◽  
First Results ◽  
Diffusion Phenomena ◽  
Modelling Approach

Oxygen renewal, as a prominent phenomenon for aerobic bacterial activity, deeply impacts vertical flow constructed wetland (VFCW) treatment efficiency. The authors introduce a multiphase model able to simulate oxygen transfer in VFCWs. It is based on a two-phase flow module, and a transport module. The transport module is able to deal with convection/diffusion phenomena, inter-phase (air–water) mass exchange, and first-order kinetics. The first results displayed for the air phase allow us to draw the following ideas on the design of vertical filters. The ponding phenomenon is more efficient for oxygen renewal than non-ponding batch loading: it provides a higher value, sooner, and deeper in the filter. In non-colonised filters and for standard batch loading, oxygen convection in the air phase is predominant for oxygen renewal. The seepage front limits oxygen renewal through the bottom of the filter and leads to an insufficient oxygen concentration on the lowest part of the filter.

The CLEO III SILICON MICROVERTEX DETECTOR

2001 ◽  
Vol 16 (supp01c) ◽  
pp. 1081-1083
Author(s):  
◽  
JIK LEE
Keyword(s):  
Solid Angle ◽  
Radial Distance ◽  
Silicon Detector ◽  
Silicon Detectors ◽  
Detector Performance ◽  
Radiation Length ◽  
Front End ◽  
Innermost Layer ◽  
Capacitive Load ◽  
First Results

The upgrade of the CLEO detector has finished with the installation of the new silicon detector in February 2000. The detector is a four layer barrel-style device with double-sided silicon detectors. It spans the radial distance from 2.5 cm to 10.2 cm and cover 93% of the solid angle surrounding the interaction region. The innermost layer is 16 cm, the outermost is 55 cm long. Important features of the new design are a very small radiation length of the detector material and new front-end electronics to deal with the capacitive load of the long silicon wafer chains. First results of the detector performance will be presented.

scholarly journals The CDF Experiment at the Tevatron: The First Two Years of Run II

2003 ◽  
Vol 18 (24) ◽  
pp. 1643-1660 ◽  
Author(s):  
Arnd Meyer
Keyword(s):  
Top Quark ◽  
Accelerator Complex ◽  
Detector Performance ◽  
Physics Potential ◽  
The Future ◽  
First Results ◽  
Integrated Luminosity

The 1992–1995 running of the Fermilab Tevatron (the so-called Run I) ended with many important physics goals accomplished, including the discovery of the top quark, and the anticipation of many further questions to be answered in the future. After many upgrades to the detector and to the accelerator complex, Run II began in April 2001. First results obtained by the Collider Detector at Fermilab (CDF) collaboration from the analysis of early Tevatron Run II data are reported here. They fall into two categories: a number of measurements have been performed with the primary goal of establishing detector performance and physics potential. Another set of measurements make use of completely new capabilities of the upgraded detector, thus allowing for competitive results with a modest amount of integrated luminosity.

Experimental Investigations of the Influence of Waterdroplets in Compressor Cascades

2006 ◽  
Author(s):  
Enno Ulrichs ◽  
Franz Joos
Keyword(s):  
Water Injection ◽  
Suction Side ◽  
Experimental Investigations ◽  
Compressor Cascade ◽  
Two Phase ◽  
Flow Angle ◽  
Water Load ◽  
Phase Doppler Anemometry ◽  
First Results ◽  
Droplet Sizes

This paper presents first results of experiments in a two-phase-flow cascade wind-tunnel. A Phase-Doppler-Anemometry system is used to measure velocity and water droplet-sizes in a compressor cascade. The local velocity with water injected is slower than the air flow without water injection due to droplet inertia and loss of momentum. Ligament formation and breakup caused by Rayleigh-Taylor instabilities is observed at the trailing edge resulting in particle sizes between 20 μm and 30 μm independent of flow velocity and the size of the nozzle used for water injection. Another region in the last third of the suction side is found, where a separation of droplets below 10 μm occurs. A change in flow angle at the cascade outlet is observed depending on water-load and droplet-size in the inlet.

Mechanical Behavior and Oxidation Properties of Molybdenum-Modified Cr3Si/Cr5Si3 Intermetallics

1994 ◽  
Vol 364 ◽  
Author(s):  
M. Nazmy ◽  
C. Noseda ◽  
G. Sauthoff ◽  
B. Zeumer ◽  
D. Anton
Keyword(s):  
Oxidation Resistance ◽  
Chromium Oxide ◽  
Creep Behavior ◽  
Two Phase ◽  
Good Oxidation Resistance ◽  
Intermediate Temperature Range ◽  
Chromium Silicide ◽  
Chromium Oxide Layer ◽  
First Results ◽  
Oxidation Properties

AbstractA series of two-phase chromium silicide base intermetallics have been investigated with respect to creep behavior and oxidation resistance. The first results of these investigations are reported. Good oxidation resistance has been demonstrated in one composition, which was due to the formation of the protective vitrious SiO2 layer, while the chromium oxide layer is very helpful at the intermediate temperature range.

Ultrasonic Imaging and Velocimetry in Two-Phase Pipe Flow

1993 ◽  
Vol 115 (2) ◽  
pp. 108-116 ◽  
Author(s):  
S. L. Morriss ◽  
A. D. Hill
Keyword(s):  
Pipe Flow ◽  
Petroleum Industry ◽  
Doppler Velocity ◽  
Measurement Technology ◽  
Pulsed Doppler ◽  
Rate Measurement ◽  
Flow Rate Measurement ◽  
Two Phase ◽  
Ultrasonic Measurements ◽  
First Results

This paper presents the first results of an experimental and theoretical investigation of the feasibility of using ultrasonic measurements in multiphase pipe flow. Extant downhole flow rate measurement technology used in the petroleum industry is not adequate in some multiphase flow regimes, particularly when the well is deviated from vertical. Ultrasonics offers Doppler velocity and imaging capabilities, both of which could be of great value in production logging. Some air-water measurements, both imaging and velocimetry, are presented, along with a discussion of pulsed Doppler theory.

Direct Steam Generation in Parabolic Troughs: First Results of the DISS Project

2001 ◽  
Author(s):  
M. Eck ◽  
W.-D. Steinmann
Keyword(s):  
Steady State ◽  
Controller Design ◽  
Experimental Results ◽  
Phase Flow ◽  
Simulation Studies ◽  
Steam Generation ◽  
Two Phase ◽  
State Tests ◽  
Direct Steam ◽  
First Results

Abstract This article presents the latest experimental results of the European DISS (DIrect Solar Steam) project. The experiments are subdivided into steady state and transient tests. The goal of the steady state tests is the investigation of the thermohydraulic phenomena of the occurring two phase flow, whereas the transient tests are needed for the controller design. The experimental results are compared to simulation studies. Implications for the plant operation will be discussed.

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