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Flashing inception in flowing liquids

Description: The inception of net vaporization in flashing flows is examined. It is suggested that the flashing inception can be expressed as two additive effects. One is due to the static decompression which is a function of the initial temperature and also of the expansion rate. The other effect which is a function of Reynolds number and flashing index, is due to the turbulent fluctuations of the flowing liquid. It is shown that by taking a three standard deviation band on the turbulent velocity fluctuations, an adequate representation of the inverse mass flux effect on flashing inception for existing data is obtained. The turbulence effects are combined with the correlation of Alamgir and Lienhard to provide predictive methods recommended for the case where both static and convective decompression effects exist.
Date: April 1, 1980
Creator: Jones, O. C., Jr.
Partner: UNT Libraries Government Documents Department

Inception and development of voids in flashing liquids. [BWR; PWR]

Description: Recent work aimed at correctly describing nonequilibrium vapor generation rates in flashing liquids in decompressing flows similar to those which might be encountered in a loss of coolant accident in a nuclear reactor is summarized. Analysis is reviewed which describes the flashing inception superheat in terms of the turbulence intensity for a given expansion rate and initial temperature, and interfacial area density and interfacial heat flux, and the volumetric vapor generation rates. Comparisons with existing data are included and further experiments being undertaken are described, including typical recent results.
Date: June 1, 1979
Creator: Jones, O.C. Jr.
Partner: UNT Libraries Government Documents Department

Flashing inception in flowing liquids. [PWR]

Description: The inception of net vaporization in flashing flows is examined. It is suggested that the flashing inception can be expressed as two additive effects. One is due to the static decompression which is a function of the spinodal limit and also of the expansion rate. The other effect which is a function of Reynolds number and flashing index, is due to the turbulent fluctuations of the flowing liquid. It is shown that by taking a three standard deviation band on the turbulent velocity fluctuations, an adequate representation of the inverse mass flux effect on flashing inception for existing data is obtained.
Date: January 1, 1979
Creator: Jones, O.C. Jr.
Partner: UNT Libraries Government Documents Department

Non-equilibrium aspects of water reactor safety

Description: A critical review of the thermal non-equilibrium phase change models applicable to the water reactor safety calculations is presented. Four specific areas are discussed: (1) rapid depressurization (flashing), (2) post-dryout heat transfer, (3) direct contact condensation, and (4) sub-cooled boiling. The models have been judged from a mechanistic viewpoint, and the areas where further work is needed have been pointed out. It is suggested that when a phase change occurs due to a difference in the bulk fluid temperatures, the non-equilibrium phase change process can be viewed as a linear, non-homogeneous thermal relaxation phenomenon. Direct measurements of the actual phase change rates and the interfacial area densities are emphasized. Finally, a recommendation for the volumetric vapor generation rates applicable to the above four specific areas is given.
Date: July 1, 1977
Creator: Jones, O.C. Jr. & Saha, P.
Partner: UNT Libraries Government Documents Department

Correlation of local heat flux from inclined volume-heated pools in bubbly flow

Description: Local and average heat transfer from volume-boiling pools in the two-phase bubbly flow regime to vertical and inclined flat boundaries were measured. The experimental technique and newly developed gold electroplated microthermocouples to make the measurements are described. A modification to the Boussinesq approximation for liquids is outlined which includes the effect of the average void fraction in a modified Rayleigh number. Heat transfer to vertical and inclined surfaces is correlated in a fashion similar to natural convection in the bubbly flow regime. These new correlations agreed in general with those based on average heat transfer data obtained by Gabor et al. The data from one reference, however, were found to lie significantly below the present data on an average as well as local basis.
Date: January 1, 1980
Creator: Greene, G.A.; Abuaf, N. & Jones, O.C. Jr.
Partner: UNT Libraries Government Documents Department

Experimental measurement of local heat flux from volume-heated boiling pools to inclined boundaries

Description: The heat transfer characteristics of volume-heated boiling pools are of central importance in safety analysis of fast breeder reactors. The fluid dynamic characteristics, as well as the containability of such boiling systems depend intimately on the heat loads applied to the surrounding boundaries. Results from this work have demonstrated that local heat loads vary significantly from the average values reported in the early literature. This paper describes an experimental investigation of local boiling heat transfer from volume-heated pools to vertical and inclined boundaries, and comparison is made to heat transfer correlations available in the literature.
Date: January 1, 1979
Creator: Greene, G.A.; Abuaf, N. & Jones, O.C. Jr.
Partner: UNT Libraries Government Documents Department

Optical probe for local void fraction and interface velocity measurements. [BWR; PWR]

Description: In view of the importance of obtaining unsteady local void fraction and interface velocities in liquid-vapor two-phase flows, an optical probe with a controlled tip geometry was developed and is described. In order to minimize the disturbances caused to the flow field by the presence of the probe, its dimensions have been miniaturized. The electronic and hydrodynamic response of the probe were investigated experimentally. The probe was found to be sensitive to both the interface velocities and the phase present at the probe tip. A possible explanation for the behavior of the probe is presented. Within the velocity range checked and with proper calibration, the optical probe developed can be used to determine both local void fractions and interface velocities.
Date: March 1, 1978
Creator: Abuaf, N.; Jones, O.C. Jr. & Zimmer, G.A.
Partner: UNT Libraries Government Documents Department

LARP LHC 4.8 GHZ Schottky System Initial Commissioning with Beam

Description: The LHC Schottky system consists for four independent 4.8 GHz triple down conversion receivers with associated data acquisition systems. Each system is capable of measuring tune, chromaticity, momentum spread in either horizontal or vertical planes; two systems per beam. The hardware commissioning has taken place from spring through fall of 2010. With nominal bunch beam currents of 10{sup 11} protons, the first incoherent Schottky signals were detected and analyzed. This paper will report on these initial commissioning results. A companion paper will report on the data analysis curve fitting and remote control user interface of the system. The Schottky system for the LHC was proposed in 2004 under the auspices of the LARP collaboration. Similar systems were commissioned in 2003 in the Fermilab Tevatron and Recycler accelerators as a means of measuring tunes noninvasively. The Schottky detector is based on the stochastic cooling pickups that were developed for the Fermilab Antiproton Source Debuncher cooling upgrade completed in 2002. These slotted line waveguide pickups have the advantage of large aperture coupled with high beam coupling characteristics. For stochastic cooling, wide bandwidths are integral to cooling performance. The bandwidth of slotted waveguide pickups can be tailored by choosing the length of the pickup and slot spacing. The Debuncher project covered the 4-8 GHz band with eight bands of pickups, each with approximately 500 MHz of bandwidth. For use as a Schottky detector, bandwidths of 100-200 MHz are required for gating, resulting in higher transfer impedance than those used for stochastic cooling. Details of hardware functionality are reported previously.
Date: March 18, 2011
Creator: Pasquinelli, Ralph J.; Jansson, Andreas; Jones, O. Rhodri & Caspers, Fritz
Partner: UNT Libraries Government Documents Department

Development of an electrical impedance computed tomographic two-phase flows analyzer. Final report

Description: This report summarizes the work on the research project on this cooperative program between DOE and Hitachi, Ltd. Major advances were made in the computational reconstruction of images from electrical excitation and response data with respect to existing capabilities reported in the literature. A demonstration is provided of the imaging of one or more circular objects within the measurement plane with demonstrated linear resolution of six parts in two hundred. At this point it can be said that accurate excitation and measurement of boundary voltages and currents appears adequate to obtain reasonable images of the real conductivity distribution within a body and the outlines of insulating targets suspended within a homogeneous conducting medium. The quality of images is heavily dependent on the theoretical and numerical implementation of imaging algorithms. The overall imaging system described has the potential of being both fast and cost effective in comparison with alternative methods. The methods developed use multiple plate-electrode excitation in conjunction with finite element block decomposition, preconditioned voltage conversion, layer approximation of the third dimension and post processing of boundary measurements to obtain optimal boundary excitations. Reasonably accurate imaging of single and multiple targets of differing size, location and separation is demonstrated and the resulting images are better than any others found in the literature. Recommendations for future effort include the improvement in computational algorithms with emphasis on internal conductivity shape functions and the use of adaptive development of quadrilateral (2-D) or tetrahedral or hexahedral (3-D) elements to coincide with large discrete zone boundaries in the fields, development of a truly binary model and completion of a fast imaging system. Further, the rudimentary methods shown herein for three-dimensional imaging need improving.
Date: August 1, 1998
Creator: Ovacik, L. & Jones, O.C.
Partner: UNT Libraries Government Documents Department

Heat removal characteristics of volume-heated boiling pools with inclined boundaries in bubbly flow regime

Description: The heat transfer characteristics of volume-heated boiling pools are of importance in the safety analysis of hypothetical core disruptive accidents in liquid metal fast breeder reactors. Investigations into the heat transfer and hydrodynamic behavior of such volume-heated boiling pools have been few. The existing work in boiling pool heat transfer is reviewed, and current modeling efforts are described. The current experiment is discussed in detail, and significant improvements in experimental techniques are described. The data for local convective boundary heat transfer coefficient and pool-averaged void fraction are presented for the bubbly flow regime over a range of dimensionless power, j/sub g/sup 00//U/sub 00/, up to unity, and wall angles of 90/sup 0/ (vertical), 75/sup 0/, and 60/sup 0/. The data are compared to existing correlations for local heat transfer and to a one-dimensional drift flux model for local and average void fraction. It is shown that the drift flux model predicted the experimental data for average void fraction in the bubbly flow regime well when based upon the net boiling power. However, it was demonstrated that the existing correlations for local and average boundary heat flux (based on Gustavson's data) underpredicted the present data by as much as a factor of 2 or more.
Date: January 1, 1979
Creator: Greene, G.A.; Jones, O.C. Jr.; Abuaf, N. & Schwarz, C.E.
Partner: UNT Libraries Government Documents Department

One-dimensional model of vapor generation in steady flashing flow

Description: In order to predict the critical flow rates of a vapor-liquid two-phase mixture through pipes discharging into a low pressure environment, it is necessary to understand the characteristics of a flashing two-phase mixture. Of particular importance is the transition from single-phase (liquid) to two-phase flow as a result of rapid depressurization of the liquid in the flow causing the liquid to vaporize or flash. Results of a series of flashing experiments performed by Reocreux (1974) are available in the literature. The nonequilibrium vapor generation model developed at BNL is discussed, and the application of this model to the evaluation of Reocreux's experiments is presented.
Date: January 1, 1979
Creator: Wu, B.J.C.; Saha, P.; Abuaf, N. & Jones, O.C. Jr.
Partner: UNT Libraries Government Documents Department

Condensation induced water hammer in steam generators

Description: The case of condensation induced water hammer in nuclear steam generators is summarized, including both feed ring-type and economizer-type geometries. A slug impact model is described and used to demonstrate the parametric dependence of the impact pressures on heat transfer rates, initial pressures, and relative initial slug and void lengths. The results of the parametric study are related also to the economizer geometry and a suggested alternative model is presented. The importance of concerns regarding attenuation of shocks in two-phase media is delineated, and a simple experiment is described which was used to determine negligible attenuation within the accuracy of the experiment for void fractions up to over 30% in bubbly and slug flows.
Date: June 1, 1979
Creator: Jones, O.C. Jr.; Saha, P.; Wu, B.J.C. & Ginsberg, T.
Partner: UNT Libraries Government Documents Department

Comparison of measured and calculated average void fraction in volume-boiling pools with inclined boundaries. [LMFBR]

Description: Accident analysis of an HCDA in an LMFBR often involves consideration and calculation of thermal hydraulic events related to boiling pools of fuel and steel mixtures in the disrupted core, as well as the subsequent motion of these two-phase mixtures out of the core. In many cases, the thermal-hydraulic state of the boiling fuel-steel or fuel pool may determine the initial or boundary conditions for subsequent calculations. Calculations of boundary heat losses are directly dependent on knowledge of the local and pool-average void fraction, and assessment of models to predict the average void fraction depends on the availability of these experimental data. Experiments have been performed to determine the distribution of boundary heat losses from volume-heated boiling pools and the pool-averaged void fraction.
Date: January 1, 1979
Creator: Greene, G.A.; Jones, O.C. Jr.; Abuaf, N. & Schwarz, C.E.
Partner: UNT Libraries Government Documents Department

Evaluation of condensation-induced water hammer in preheat steam generators

Description: A review of Westinghouse 1/8-scale water hammer tests and data analysis was carried out. BNL has concluded that water hammers occurred in the feedwater line during many of the 1/8-scale tests. These events were probably caused by steam bubble entrapment and collapse in the partially-filled feedwater line. Recorded vessel pressure pulse activity under two-phase operating conditions was rare and, in those cases where pulses were recorded, the pressure pulse amplitudes were small. Either void collapse water hammers are unlikely events under these two-phase conditions, or events that did occur were attenuated in magnitude by the two-phase medium and internal structures before the pulse reached the pressure transducer. Pressure pulse attenuation in two-phase air-water media was studied experimentally at BNL. It was found that no significant attenuation could be detected in two-phase flows over distances of approximately 1 to 2 ft. The effects of internals, however, were not considered. The Westinghouse scaling laws have also been critically reviewed. An independent BNL analysis was carried out to verify the Westinghouse scaling laws. It has been found that the present state-of-the-art on the condensation heat transfer and the mechanism of vapor cavity formation precludes us from deriving any credible scaling criteria. However, it was found that under certain operating conditions the condensation-induced void collapse could be an oscillatory process. This may partially explain the apparent randomness of the water hammer phenomenon seen in most experimental studies.
Date: September 1, 1980
Creator: Saha, P.; Ginsberg, T.; Wu, B.J.C. & Jones, O.C. Jr.
Partner: UNT Libraries Government Documents Department

Void fluctuation dynamics and measurement techniques

Description: The current state of the art of void fluctuation dynamics and measurement techniques is briefly reviewed. New and improved measurement techniques which have been developed are described including two local probes which both have the capability of being responsive to phase presence and interfacial velocity. It is shown that the dynamics of a thin liquid film on optical probes have strong effects on the response not heretofore recognized.
Date: June 1, 1979
Creator: Jones, O.C. Jr; Abuaf, N.; Zimmer, G.A. & Feierabend, T.
Partner: UNT Libraries Government Documents Department

Development of BNL Heat Transfer Facility 1: flashing experiments

Description: A major area of interest to reactor safety technology is the prediction of actual vapor generation rates under conditions of thermal nonequilibrium as would be encountered during a loss-of-coolant accident (LOCA) in a light water reactor. In support of the development of advanced codes dealing with LOCA induced flashing, analytical models of the nonequilibrium vapor generation processes of interest have been formulated, and an experimental facility has been constructed to provide data to verify these models. This facility is known as BNL Heat Transfer Facility. The experimental facility consists of a flow loop, test section and the data acquisition and analysis system. The main portion of the flow loop is constructed from three inch nominal (7.6 cm) stainless steel pipe. High purity water is circulated through the loop using a centrifugal pump rated 1500 l/min at 600 kPa. Very close and stable control of all loop parameters is required since flashing is sensitive to very small changes in such parameters as flow rate, subcooling, and pressure.
Date: January 1, 1979
Creator: Leonhardt, W.J.; Klein, J.H.; Zimmer, G.A.; Abuaf, N. & Jones, O.C. Jr.
Partner: UNT Libraries Government Documents Department

Hard X-ray Imaging for Measuring Laser Absorption Spatial Profiles on the National Ignition Facility

Description: Hard x-ray (''Thin wall'') imaging will be employed on the National Ignition Facility (NIF) to spatially locate laser beam energy deposition regions on the hohlraum walls in indirect drive Inertial Confinement Fusion (ICF) experiments, relevant for ICF symmetry tuning. Based on time resolved imaging of the hard x-ray emission of the laser spots, this method will be used to infer hohlraum wall motion due to x-ray and laser ablation and any beam refraction caused by plasma density gradients. In optimizing this measurement, issues that have to be addressed are hard x-ray visibility during the entire ignition laser pulse with intensities ranging from 10{sup 13} to 10{sup 15} W/cm{sup 2}, as well as simultaneous visibility of the inner and the outer laser drive cones. In this work we will compare the hard x-ray emission calculated by LASNEX and analytical modeling with thin wall imaging data recorded previously on Omega and during the first hohlraum experiments on NIF. Based on these calculations and comparisons the thin wall imaging will be optimized for ICF/NIF experiments.
Date: April 25, 2006
Creator: Dewald, E L; Jones, O S; Landen, O L; Suter, L; Amendt, P; Turner, R E et al.
Partner: UNT Libraries Government Documents Department

Laser-beam propagation in high temperature hohlraum plasmas

Description: The authors have developed a new target platform to study propagation and backscatter of a frequency-doubled (2{omega}) laser beam through large-scale length plasmas at ignition-design densities, intensities and temperatures above 3 keV. The plasma is created by heating a gas filled hohlraum target with 37 heater beams that deliver a total energy of up to 15 kJ in a 1 ns square pulse. They measure a factor of two higher temperatures than in open geometry gasbag targets investigated earlier. This new temperature regime with a measured beam transmission of up to 80% suggests we can expect good laser coupling into ignition hohlraums at the National Ignition Facility (NIF) using 2{omega} light.
Date: September 15, 2005
Creator: Niemann, C.; Froula, D.; Divol, L.; Meezan, N.; Jones, O.; Ross, R. et al.
Partner: UNT Libraries Government Documents Department

Debris and Shrapnel Mitigation Procedure for NIF Experiments

Description: All experiments at the National Ignition Facility (NIF) will produce debris and shrapnel from vaporized, melted, or fragmented target/diagnostics components. For some experiments mitigation is needed to reduce the impact of debris and shrapnel on optics and diagnostics. The final optics, e.g., wedge focus lens, are protected by two layers of debris shields. There are 192 relatively thin (1-3 mm) disposable debris shields (DDS's) located in front of an equal number of thicker (10 mm) main debris shields (MDS's). The rate of deposition of debris on DDS's affects their replacement rate and hence has an impact on operations. Shrapnel (molten and solid) can have an impact on both types of debris shields. There is a benefit to better understanding these impacts and appropriate mitigation. Our experiments on the Omega laser showed that shrapnel from Ta pinhole foils could be redirected by tilting the foils. Other mitigation steps include changing location or material of the component identified as the shrapnel source. Decisions on the best method to reduce the impact of debris and shrapnel are based on results from a number of advanced simulation codes. These codes are validated by a series of dedicated experiments. One of the 3D codes, NIF's ALE-AMR, is being developed with the primary focus being a predictive capability for debris/shrapnel generation. Target experiments are planned next year on NIF using 96 beams. Evaluations of debris and shrapnel for hohlraum and capsule campaigns are presented.
Date: September 4, 2007
Creator: Eder, D; Koniges, A; Landen, O; Masters, N; Fisher, A; Jones, O et al.
Partner: UNT Libraries Government Documents Department

NIF-Scale Hohlraum Asymmetry Studies Using Point-Projection Radiograph of Thin Shells

Description: Our current OMEGA experimental campaign is developing the thin shell diagnostic for use on NIF with the needed accuracy. The thin shell diagnostic has the advantage of linearity over alternative measurement techniques, so that low-order modes will not corrupt the measurement of high-order modes. Although our random measurement errors are adequate, we need to monitor beam balance and ensure that the thin shells have a uniform thickness.
Date: October 6, 2000
Creator: Pollaine, S.; Bradley, D.; Landen, O.; Wallace, R. & Jones, O.
Partner: UNT Libraries Government Documents Department

Engineering Study of Water Injection in 14 Oil Reservoirs of North Louisiana

Description: Report issued by the Bureau of Mines over engineering studies of water injections in Louisiana oil reservoirs. As stated in the introduction, "this Bureau of Mines report presents operating practices and results of pressure maintenance and secondary recovery by water injection or by water injection supplemented by gas injection" (p. 1). This report includes tables, and maps.
Date: 1962
Creator: Meadows, Paul; Hawkins, Murphy E.; Weaver, L. K. & Jones, O. W.
Partner: UNT Libraries Government Documents Department

Green (2(omega)) Laser Beam propagation in high-temperature Hohlraum Plasmas

Description: We demonstrate propagation and small backscatter losses of a frequency-doubled (2{omega}) laser beam interacting with inertial confinement fusion hohlraum plasmas. The electron temperature of 3.3 keV, approximately a factor of two higher than achieved in previous experiments with open geometry targets, approaches plasma conditions of high-fusion yield hohlraums. In this new temperature regime, we measure 2{omega} laser beam transmission approaching 80% with simultaneous backscattering losses of less than 10%. These findings suggests that good laser coupling into fusion hohlraums using 2{omega} light is possible.
Date: October 26, 2007
Creator: Niemann, C; Berger, R; Divol, L; Froula, D H; Jones, O S; Kirkwood, R K et al.
Partner: UNT Libraries Government Documents Department

Enchanced hohlraum radiation drive through reduction of wall losses with high-Z mixture "cocktail" wall materials

Description: We present results from experiments, numerical simulations and analytic modeling, demonstrating enhanced hohlraum performance. Care in the fabrication and handling of hohlraums with walls consisting of high-Z mixtures (cocktails) has led to our demonstration, for the first time, of a significant increase in radiation temperature (up to +7eV at 300 eV) compared to a pure Au hohlraum, in agreement with predictions and ascribable to reduced wall losses. The data extrapolated to full NIF suggest we can expect an 18% reduction in wall loss for the current ignition design by switching to cocktail hohlraums, consistent with requirements for ignition with 1MJ laser energy.
Date: May 17, 2006
Creator: Schein, J; Jones, O; Rosen, M; Dewald, E; Glenzer, S; Gunther, J et al.
Partner: UNT Libraries Government Documents Department

Demonstration of Enhanced Radiation Drive in Hohlraums Made with High-Z Mixture "Cocktail" Wall Material

Description: We present results from experiments, numerical simulations and analytic modeling, demonstrating enhanced hohlraum performance. Care in the fabrication and handling of hohlraums with walls consisting of high-Z mixtures (cocktails) has led to our demonstration, for the first time, of a significant increase in radiation temperature compared to a pure Au hohlraum that is in agreement with predictions and is ascribable to reduced wall losses. This data suggests that a NIF ignition hohlraum made of a U:Au:Dy cocktail should have {approx}17% reduction in wall losses compared to a similar gold hohlraum.
Date: February 6, 2007
Creator: Schein, J; Jones, O; Rosen, M; Dewald, E; Glenzer, S; Gunther, J et al.
Partner: UNT Libraries Government Documents Department