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The Effect of Sink Temperature on a Capillary Pumped Loop Employing a Flat Evaporator and Shell and Tube Condenser

Description: An experimental facility for conducting research on capillary pumped loop (CPL) systems was developed. In order to simulate shipboard cooling water encountered at various locations of the ocean, the heat sink temperature of the facility could be varied. A flat plate, CPL evaporator was designed and tested under various heat sink temperatures. The sink temperature ranged from 274.3 to 305.2 K and the heat input varied from 250 to 800 W which corresponds to heat fluxes up to 1.8 W/cm{sup 2}. The CPL flat plate evaporator performed very well under this range of heat input and sink temperatures. The main result obtained showed that a large degree of subcooling developed between the evaporator vapor outlet line and liquid return line. This condensate depression increased with increasing heat input.
Date: June 24, 2002
Creator: Cerza, M.; Herron, R.C. & Harper, J.J.
Partner: UNT Libraries Government Documents Department

A STUDY OF THE VARIATION OF STEAM VELOCITY IN VERTICAL BOILING CHANNELS

Description: An analysis was made to correlate experimental boiling heat-transfer data with the variable relative velocity (C/sub s/ C/sub L/). The correlation was based on a boiling model or mechanism. The range of variables encountered included pressure, water velocity, power density, subcooling, steamvolume fraction, steam quality, and channel distance. Forced and natural circulation tests were investigated. Results are reported. (W.L.H.)
Date: November 1, 1960
Partner: UNT Libraries Government Documents Department

Analysis and Measurement of Bubble Dynamics and Associated Flow Field in Subcooled Nucleate Boiling Flows

Description: In recent years, subooled nucleate boiling (SNB) has attrcted expanding research interest owing to the emergence of axial offset anomaly (AOA) or crud-induced power shigt (CIPS) in many operating US PWRs, which is an unexpected deviation in the core axial power distribution from the predicted power curves. Research indicates that the formation of the crud, which directly leads to AOA phenomena, results from the presence of the subcooled nucleate boiling, and is especially realted to bubble motion occurring in the core region.
Date: October 1, 2008
Creator: Jones, Barclay G.
Partner: UNT Libraries Government Documents Department

Summary Results of the Neptun Boil-Off Experiments to Investigate the Accuracy and Cooling Influence of LOFT Cladding-Surface Thermocouples (System 00)

Description: Nine boil-off experiments were conducted in the Swiss NEPTUN Facility primarily to obtain experimental data for assessing the perturbation effects of LOFT thermocouples during simulated small-break core uncovery conditions. The data will also be useful in assessing computer model capability to predict thermal hydraulic response data for this type of experiment. System parameters that were varied for these experiments included heater rod power, system pressure, and initial coolant subcooling. The experiments showed that the LOFT thermocouples do not cause a significant cooling influence in the rods to which they are attached. Furthermore, the accuracy of the LOFT thermocouples is within 20 K at the peak cladding temperature zone.
Date: October 1, 1981
Creator: Tolman, E. L. & Aksan, S. N.
Partner: UNT Libraries Government Documents Department

Investigation of Spray Cooling Schemes for Dynamic Thermal Management

Description: This study aims to investigate variable flow and intermittent flow spray cooling characteristics for efficiency improvement in active two-phase thermal management systems. Variable flow spray cooling scheme requires control of pump input voltage (or speed), while intermittent flow spray cooling scheme requires control of solenoid valve duty cycle and frequency. Several testing scenarios representing dynamic heat load conditions are implemented to characterize the overall performance of variable flow and intermittent flow spray cooling cases in comparison with the reference, steady flow spray cooling case with constant flowrate, continuous spray cooling. Tests are conducted on a small-scale, closed loop spray cooling system featuring a pressure atomized spray nozzle. HFE-7100 dielectric liquid is selected as the working fluid. Two types of test samples are prepared on 10 mm x 10 mm x 2 mm copper substrates with matching size thick film resistors attached onto the opposite side, to generate heat and simulate high heat flux electronic devices. The test samples include: (i) plain, smooth surface, and (ii) microporous surface featuring 100 μm thick copper-based coating prepared by dual stage electroplating technique. Experimental conditions involve HFE-7100 at atmospheric pressure and 30°C and ~10°C subcooling. Steady flow spray cooling tests are conducted at flow rates of 2 - 5 ml/cm².s, by controlling the heat flux in increasing steps, and recording the corresponding steady-state temperatures to obtain cooling curves in the form of surface superheat vs. heat flux. Variable flow and intermittent flow spray cooling tests are done at selected flowrate and subcooling conditions to investigate the effects of dynamic flow conditions on maintaining the target surface temperatures defined based on reference steady flow spray cooling performance.
Date: May 2017
Creator: Yata, Vishnu Vardhan Reddy
Partner: UNT Libraries

A Study of the Flow of Saturated Freon-11 Through Apertures and Short Tubes

Description: An experimental study on the discharge rates of saturated and subcooled Freon-11 through apertures and short tubes is reported. The experiment covered a range of modified cavitation numbers between 0 and 500, length-to-diameter ratios of small-diameter tubes between 2 and 55, and sharp-edge apertures of nine different geometric configurations. It was found that below the modified cavitation number of 10, the iluid exhibits completely metastable singlephase ilow. When the modified cavitation number exceeds 14, two-phase critical flow may exist. In the range of modified cavitation numbers between 10 and 14, unstable transitional flow occurs (alternating single- and twophase flow). Euler numbers for the apertures of various configurations, including square, rectangular, and eyeshaped, were found to be in the same order of magnitude as those for circular shapes. The trianguiar orifices were found to possess higher Euler numbers and the Wshaped orifices lower than the circular ones. (auth)
Date: January 1, 1963
Creator: Fauske, H. K. & Min, T. C.
Partner: UNT Libraries Government Documents Department

Evaluation of riser 14 temperature response

Description: The initial sluicing activities of Project WRSS resulted in a two month increase in temperatures as measured by the Riser 14 thermocouple tree of tank 241-C-106. While this increase was anticipated, the maximum temperature was higher than expected. An evaluation was performed to determine if adequate subcooling exists in the waste to continue sluicing activities. It was determined that a minimum of 10 F subcooling exists in the waste and that the higher Riser 14 temperatures were the result of higher than assumed waste saturation temperature.
Date: March 8, 1999
Creator: OGDEN, D.M.
Partner: UNT Libraries Government Documents Department

Subcooled Boiling Near a Heated Wall

Description: Experimental measurements of void fraction, bubble frequency, and velocity are obtained in subcooled R-134a flowing over a heated flat plate near an unheated wall and compared to analytical predictions. The measurements were obtained for a fixed system pressure and mass flow rate (P = 2.4 MPa and w = 106 kg/hr) at various inlet liquid temperatures. During the experiments, electrical power was applied at a constant rate to one side of the test section. The local void fraction data, acquired with a hot-film anemometer probe, showed the existence of a significant peak near the heated wall and a smaller secondary peak near the unheated wall for the larger inlet subcoolings. Local vapor velocity data, taken with the hot-film probe and a laser Doppler velocimeter, showed broad maxima near the centerline between the heated and unheated plates. Significant temperature gradients near the heated wall were observed for large inlet subcooling. Bubble size data, inferred from measurements of void fraction, bubble frequency and vapor velocity, when combined with the measured bubble chord length distributions illustrate the transition from pure three dimensional spherical to two-dimensional planar bubble flow, the latter being initiated when the bubbles fill the gap between the plates. These various two-phase flow measurements were used for development of a multidimensional, four-field calculational method; comparisons of the data to the calculations show reasonable agreement.
Date: October 27, 2000
Creator: Trabold, T.A.; Maneri, C.C.; Vassallo, P.F. & Considine, D.M.
Partner: UNT Libraries Government Documents Department

Development of Refrigerant Change Indicator and Dirty Air Filter Sensor

Description: The most common problems affecting residential and light commercial heating, ventilation, and air-conditioning (HVAC) systems are slow refrigerant leaks and dirty air filters. Equipment users are usually not aware of a problem until most of the refrigerant has escaped or the air filter is clogged with dirt. While a dirty air filter can be detected with a technology based on the air pressure differential across the filter, such as a ''whistling'' indicator, it is not easy to incorporate this technology into existing HVAC diagnostic equipment. Oak Ridge National Laboratory is developing a low-cost, nonintrusive refrigerant charge indicator and dirty air filter detection sensor. The sensors, based on temperature measurements, will be inexpensive and easy to incorporate into existing heat pumps and air conditioners. The refrigerant charge indicator is based on the fact that when refrigerant starts to leak, the evaporator coil temperature starts to drop and the level of liquid subcooling drops. When the coil temperature or liquid subcooling drops below a preset reading, a signal, such as a yellow warning light, can be activated to warn the equipment user that the system is undercharged. A further drop of coil temperature or liquid subcooling below another preset reading would trigger a second warning signal, such as a red warning light, to warn the equipment user that the unit now detects a leak and immediate action should be taken. The warning light cannot be turned off until it is re-set by a refrigeration repairman. To detect clogged air filters, two additional temperature sensors can be applied, one each across the evaporator. When the air filter is accumulating buildup, the temperature differential across the evaporator will increase because of the reduced airflow. When the temperature differential reaches a pre-set reading, a signal will be sent to the equipment user that the air ...
Date: June 24, 2003
Creator: Mei, V.
Partner: UNT Libraries Government Documents Department

Liquid Nitrogen Subcooler ofr Calorimeters LN2 Supply

Description: This note provides calculations of heat load and coil sizing for a LN2 subcooler which will be installed in the liquid nitrogen line going from Dewar 42 to the. Liquid argon calorimeters. This subcooler must improve LN2 quality and facilitate LAr pressure regulation. The system is described in Engineering note 3740.510-EN-382. This note contains the calculations of heat loads/pressure drops of the liquid Nitrogen supply line going from the Dewar 42 to the liquid Argon calorimeters, and also the sizing of existing LN2 subcooler located in the V-tube. The note is used as a reference. The state of Nitrogen {at} point 6 - ECS entrance (according to 3740.510-EN-382) is used in the calculations. The quality of liquid x = 0.0066 with the use of existing 75 W LN2 subcooler. It has been determined that we need 29.3 W of additional subcooling in order to obtain. 100% liquid at this point with the mass flow of 25 g/s. Keeping in mind the possible error in heat transfer calculations, a 300W subcooler will be installed to replace the old 75 W subcooler. In order to achieve an acceptable conclusion, an assumption of a fully developed boundary layer was made. The hot fluid or the fluid condensing on the inside surface will determine the rate of heat transfer because A{sub o} = A{sub i} and h{sub o}A{sub o} >> h{sub i}A{sub i}. The conclusion drawn is to use a 1/2-inch copper tube wound approximately 8 times about a 9-inch diameter circle. The pressure drop in this coil will be 0.05 psi (0.0034 atm) and can be neglected.
Date: September 16, 2002
Creator: Sarychev, Michael
Partner: UNT Libraries Government Documents Department

Critical heat flux experiments in a heated rod bundle with upward crossflow of Freon 114

Description: Critical heat flux (CHF) data were obtained for upward crossflow of R-114 in a heated staggered rod bundle. Data were obtained over a broad range of mass fluxes (135 to 1,221 kg/m{sup 2} sec), inlet subcooling (0 to 55 C), and qualities ({minus}0.42 to 0.92). The present work extends the available database to higher quality, inlet subcooling, and mass flux. The test section is 3.43 cm x 15.24 cm (1.35 in. x 6 in.) in cross section with a total length of 55.88 cm (22 inches) from the top of the inlet flow straightener to the perforated plate at the test section exit. The rod bundle has a triangular pitch with a diameter (D) of 0.635 cm (0.25 in), and a pitch to diameter (P/D) ratio of 1.5. The rod bundle has 165 rods with a 15.24 cm (6 in.) heated length arranged in 55 rows of three rods each. Unheated half rods were positioned on the walls of the test section to maintain the regular rod arrangement and prevent flow bypass along the gaps between the window and the first column of heated rods. A single instrumented heater was positioned five rows upstream from the bundle exit to determine CHF. The last three rows of rods in the bundle were unheated to prevent undetected dryout downstream of the CHF position. Temperature excursions due to CHF were sensed using four imbedded thermocouples (TC) in the heater rod. The four TC temperatures were continuously monitored on a strip chart recorder. The rod heat was gradually increased until CHF was detected. Overall, the data are in good agreement with the Jensen and Tang correlation in the range of application of this correlation. The local minima in CHF which occurs near zero quality is slightly lower in the present experiment than for the ...
Date: February 1, 1997
Creator: Symolon, P.D.; Moore, W.E. & Wolf, D.F.
Partner: UNT Libraries Government Documents Department

Film boiling on spheres in single- and two-phase flows.

Description: Film boiling on spheres in single- and two-phase flows was studied experimentally and theoretically with an emphasis on establishing the film boiling heat transfer closure law, which is useful in the analysis of nuclear reactor core melt accidents. Systematic experimentation of film boiling on spheres in single-phase water flows was carried out to investigate the effects of liquid subcooling (from 0 to 40 C), liquid velocity (from 0 to 2 m/s), sphere superheat (from 200 to 900 C), sphere diameter (from 6 to 19 mm), and sphere material (stainless steel and brass) on film boiling heat transfer. Based on the experimental data a general film boiling heat transfer correlation is developed. Utilizing a two-phase laminar boundary-layer model for the unseparated front film region and a turbulent eddy model for the separated rear region, a theoretical model was developed to predict the film boiling heat transfer in all single-phase regimes. The film boiling from a sphere in two-phase flows was investigated both in upward two-phase flows (with void fraction from 0.2 to 0.65, water velocity from 0.6 to 3.2 m/s, and steam velocity from 3.0 to 9.0 m/s) and in downward two-phase flows (with void fraction from 0.7 to 0.95, water velocity from 1.9 to 6.5 m/s, and steam velocity from 1.1 to 9.0 m/s). The saturated single-phase heat transfer correlation was found to be applicable to the two-phase film boiling data by making use of the actual water velocity (water phase velocity), and an adjustment factor of (1 - {alpha}){sup 1/4} (with a being the void fraction) for downward flow case only. Slight adjustments of the Reynolds number exponents in the correlation provided an even better interpretation of the two-phase data. Preliminary experiments were also conducted to address the influences of multi-sphere structure on the film boiling heat transfer in ...
Date: August 29, 2000
Creator: Liu, C. & Theofanous, T. G.
Partner: UNT Libraries Government Documents Department

FY 1995 progress report on the ANS thermal-hydraulic test loop operation and results

Description: The Thermal-Hydraulic Test Loop (THTL) is an experimental facility constructed to support the development of the Advanced Neutron Source Reactor (ANSR) at Oak Ridge National Laboratory (ORNL). The THTL facility was designed and built to provide known thermal-hydraulic (T/H) conditions for a simulated full-length coolant subchannel of the ANS reactor core, thus facilitating experimental determination of FE and CHF thermal limits under expected ANSR T/H conditions. Special consideration was given to allow operation of the system in a stiff mode (constant flow) and in a soft mode (constant pressure drop) for proper implementation of true FE and DNB experiments. The facility is also designed to examine other T/H phenomena, including onset of incipient boiling (IB), single-phase heat transfer coefficients and friction factors, and two-phase heat transfer and pressure drop characteristics. Tests will also be conducted that are representative of decay heat levels at both high pressure and low pressure as well as other quasi-equilibrium conditions encountered during transient scenarios. A total of 22 FE tests and 2 CHF tests were performed during FY 1994 and FY 1995 with water flowing vertically upward. Comparison of these data as well as extensive data from other investigators led to a proposed modification to the Saha and Zuber correlation for onset of significant void (OSV), applied to FE prediction. The modification takes into account a demonstrated dependence of the OSV or FE thermal limits on subcooling levels, especially in the low subcooling regime.
Date: July 1, 1997
Creator: Siman-Tov, M.; Felde, D.K.; Farquharson, G.; McDuffee, J.L.; McFee, M.T.; Ruggles, A.E. et al.
Partner: UNT Libraries Government Documents Department

IDENTIFICATION AND EXPERIMENTAL DATABASE FOR BINARY AND MULTICOMPONENT MIXTURES WITH POTENTIAL FOR INCREASING OVERALL CYCLE EFFICIENCY

Description: This report describes an experimental investigation designed to identify binary and multicomponent mixture systems that may be for increasing the overall efficiency of a coal fired unit by extracting heat from flue gases. While ammonia-water mixtures have shown promise for increasing cycle efficiencies in a Kalina cycle, the costs and associated range of thermal conditions involved in a heat recovery system may prohibit its use in a relatively low temperature heat recovery system. This investigation considered commercially available non-azeotropic binary mixtures with a boiling range applicable to a flue gas initially at 477.6 K (400 F) and developed an experimental database of boiling heat transfer coefficients for those mixtures. In addition to their potential as working fluids for increasing cycle efficiency, cost, ease of handling, toxicity, and environmental concerns were considered in selection of the mixture systems to be examined experimentally. Based on this review, water-glycol systems were identified as good candidates. However, previous investigations of mixture boiling have focused on aqueous hydrocarbon mixtures, where water is the heaviest component. There have been few studies of water-glycol systems, and those that do exist have investigated boiling on plain surfaces only. In water-glycol systems, water is the light component, which makes these systems unique compared to those that have been previously examined. This report examines several water-glycol systems, and documents a database of experimental heat transfer coefficients for these systems. In addition, this investigation also examines the effect of an enhanced surface on pool boiling in water-glycol mixtures, by comparing boiling on a smooth surface to boiling on a Turbo IIIB. The experimental apparatus, test sections, and the experimental procedures are described. The mixture systems tested included water-propylene glycol, water-ethylene glycol, and water-diethylene glycol. All experimental data were obtained at atmospheric pressure with the test section oriented horizontally. The effect of ...
Date: May 1, 2002
Creator: Bajorek, Stephen M & Schnelle, J.
Partner: UNT Libraries Government Documents Department

EXPERIMENTAL INVESTIGATION OF THE EFFECTS OF ULTRASONIC VIBRATION ON BURNOUT HEAT FLUX WITH BOILING WATER. Final Summary Report, October 3, 1960-July 31, 1961

Description: Experimental results were obtained on the effect of an ultrasonic field on the burnout heat flux for water flowing at atmospheric pressure, through an annular flow channel formed by a 1/4-in.-diameter electrically heated tube and a concentric glass tube of 3/4-in. ID. The active length of the central heating element was 5 1/2 in. The ultrasonic transducer, which was operated at 25,000 cps and a maximum electrical input of 300 watts, was located at the inlet end of the flow channel. The ultrasonic waves were propagated in the water in the direction of flow and thus parallel to the surface of the heating element. Burnout conditions covered channel inlet flows from 1.61 to 6.25 ft/sec and subcooling from 16 to 28 deg F. No effect of the ultrasonic field on the burnout heat flux or on the visible boiling phenomena at burnout conditions was detectable. During boiling at heat fluxes well below burnout, the effect of the ultrasonic field was a reduction in the diameter of the envelope of bubble activity surrounding the heating element. Visual inspectibn appeared to show that this reduction was associated with a smaller average bubble size and a greater frequency of bubble formation. However, all evidence of the presence of the ultrasonic field vanished as the flow velocity increased or as the heat flux increased to the burnout level. (auth)
Date: July 31, 1961
Creator: Romie, F.E. & Aronson, C.A.
Partner: UNT Libraries Government Documents Department

BURNOUT HEAT FLUXES FOR LOW-PRESSURE WATER IN NATURAL CIRCULATION

Description: Twenty-nine experimental determinations of burn-out heat flux were made with water flowing by natural circulaion through electrically heated vertical tubes with and without internal twisted tapes and through rectangular cross sections of three aspect ratios. Heated lengths varied from 10 to 33 in., system pressure at the testsection flow exit from 14.7 to 26.3 psia, inlet subcooling from 36 to 170 deg F, and burn-out heat flux from 13,000 to 218,500 Btu/hr/sq ft. Tests were made with both unrestricted and restricted return flow paths. Three correlations were developed for predicting natural-circulation burn-out heat fluxes for such conditions. Two are useful for rapid estimation but the third involves a more fundamental assessment of the coolant mass velocity at burn-out by a graphical matching of the heat flux that a given flow rate can sustain to the heat flux that will produce that flow rate. For all the data, this approach gave average and maximum deviations of 15 and 38%, respectively. It was found that use of a slip ratio of unity is adequate for burnout prediction, and the reasons for this are discussed in detail. The small burn-out penalty incurred by a substantial restriction of return flow path, experimentally observed, is in complete accord with the theoretical model. (auth)
Date: December 20, 1960
Creator: Gambill, W.R. & Bundy, R.D.
Partner: UNT Libraries Government Documents Department

BURNOUT CONDITIONS FOR NONUNIFORMLY HEATED ROD IN ANNULAR GEOMETRY. WATER AT 1000 PSIA

Description: Tests were run to determine the burnout conditions for a nonuniformly heated rod in an annular geometry. Two special electrically heated rods were used; the cosine rod, which gave an approximate cosine axial heat flux distribution; and the truncated cosine rod, identical to the cosine, except for one end cut short. The rod to be tested was placed in a circular tube test section to form the annular flow path for the water coolant. Only the rod was heated; the outer surface (tube) was essentially adiabatic. Orientation was vertical, with flow upward. The tests were run at the following conditions: rod OD, C.540 inch; tube ID, 0.875 inch; hydraulic diameter, 0.335 inch; heated length of cosine rod, 108 inches; heated length of truncated cosine, 91 inches; pressure, 1000 psia; flow rate, 0.84 x 10/sup 6/ to 1.40 x 10/sup 6/ lb/hr-ft/sup 2/; and steam quality at exit, 12 to 35%. For each flow and iniet subcooling, the electrical power was increased until burnout was reached, thus establishing a burnout condition. Each nonuniform rod was instrumented with thermocouples in the region of anticipated burnout. The local heat flux and local quality at each position at which a thermocouple indicated a temperature rise, were determined for each burnout run. The local heat flux at burnout was plotted versus the local quality at burnout, for the two nonuniform rods. The uniform rod burnout correlation was superposed for comparison. The nonuniform rod data points averaged from 9 to 20% low. The magnitude of this deviation is considered small, and of the same order as that for the uniform rod data upon which the correlation was originally based. It was concluded that the uniform rod burnout correlation can be used to predict burnout for cosine heat flux distribution. It is tacit in this conclusion that ...
Date: June 1, 1963
Creator: Janssen, E. & Kervinen, J.A.
Partner: UNT Libraries Government Documents Department

CRITICAL HEAT FLUX AND FLOW PATTERN CHARACTERISTICS OF HIGH PRESSURE BOILING WATER IN FORCED CONVECTION

Description: High-speed motion pictures of boiling water flow patterns in conditions of forced flow at 1000 psia pressure in a vertical heated rectangular channel were taken at mass velocities from 50 to 400 lbs/sec-ft/sup 2/, fluid states from 170 Btu/lb buik enthalpy of subcooling to 0.68 bulk steam quality, and heat tluxes up to and including the critical heat flux level. An objective of the work was to make the results available for continued experimental and theoretical investigation of the critical heat flux phenomenon in forced-flow bulk-boiling systems. The results are intended to be applicable to design and development of nuclear power reactors employing high-pressure boiling water as a working fluid. Motion pictures show substantial, but not indisputable, evidence that the general arrangement of the flow, in conditions of bulk boiling, at heat fluxes near and including the critical heat flux level is characteristically a wavy turbulent liquid film, in which there is vapor formation, flowing along the channel walls with the balance of the liquid being carried as either dispersed droplets or as an emulsion with the vapor in an adjacent more rapidly and steadily moving core. (auth)
Date: April 1, 1962
Creator: Tippets, F.E.
Partner: UNT Libraries Government Documents Department

Control Dewar Subcooler Heat Exchanger Calculations

Description: The calculations done to size the control dewar subcooler were done to obtain a sufficient subcooler size based on some conservative assumptions. The final subcooler design proposed in the design report will work even better because (1) It has more tubing length, and (2) will have already subcooled liquid at the inlet due to the transfer line design. The subcooler design described in the 'Design Report of the 2 Tesla Superconducting Solenoid for the Fermilab D0 Detector Upgrade' is the final design proposed. A short description of this design follows. The subcooler is constructed of 0.50-inch OD copper tubing with 1.0-inch diameter fins. It has ten and one half spirals at a 11.375-inch centerline diameter to provide 31 feet of tubing length. The liquid helium supply for the solenoid flows through the subcooler and then is expanded through a J-T valve. The subcooler spirals are immersed in the return two phase helium process stream. The return stream is directed over the finned tubing by an annulus created by a 10-inch pipe inside a 12-inch pipe. The transfer line from the refrigerator to the control dewar is constructed such that the liquid helium supply tube is in the refrigerator return stream, thereby subcooling the liquid up to the point where the u-tubes connect the transfer line to the control dewar. The subcooler within the control dewar will remove the heat picked up in the helium supply u-tube/bayonets. The attached subcooler/heat exchanger calculations were done neglecting any subcooling in the transfer line. All heat picked up in the transfer line from the refrigerator storage dewar to the control dewar is absorbed by the supply stream. The subcooler was sized such that the two phase supply fluid is subcooled at 1.7 atm pressure and when expanded through a JT valve to 1.45 atm ...
Date: October 4, 1993
Creator: Rucinski, R.
Partner: UNT Libraries Government Documents Department

Screening reactor steam/water piping systems for water hammer

Description: A steam/water system possessing a certain combination of thermal, hydraulic and operational states, can, in certain geometries, lead to a steam bubble collapse induced water hammer. These states, operations, and geometries are identified. A procedure that can be used for identifying whether an unbuilt reactor system is prone to water hammer is proposed. For the most common water hammer, steam bubble collapse induced water hammer, six conditions must be met in order for one to occur. These are: (1) the pipe must be almost horizontal; (2) the subcooling must be greater than 20 C; (3) the L/D must be greater than 24; (4) the velocity must be low enough so that the pipe does not run full, i.e., the Froude number must be less than one; (5) there should be void nearby; (6) the pressure must be high enough so that significant damage occurs, that is the pressure should be above 10 atmospheres. Recommendations on how to avoid this kind of water hammer in both the design and the operation of the reactor system are made.
Date: September 1, 1997
Creator: Griffith, P.
Partner: UNT Libraries Government Documents Department

TWO-PHASE PRESSURE DROP IN A NATURAL CIRCULATION BOILING CHANNEL

Description: Experimental two-phase pressure drop data were obtained from a 1/4 x 2 x 60-in. vertical, uniformly heated, test section. The local volume fraction of steam was measured simultaneously with the pressure drop, thus allowing separation of the terms for hydrostatic and acceleration pressure drops from the over-all static pressure drop. The results are expressed in terms of an averge two-phase friction factor multiplier, R = DELTA P/sub TPF// DELTA P/sub L/O/sub ,/ and are co mpared with the Martinelli-Nelson correlation, the LottesFlinn correlation, and a correlation combining that of Martinelli-Nelson and a flowrate parameter. The ranges of variables include: pressure from 150 to 600 pstg; power density from 17.2 to 94.5 kw/liter of coolant; sub-cooling from 4.8 to 25.7 deg F; exit qualities from 0.009 to 0.065; exit steam volume fraction from 0.19 to 0.77; and velocities from 2.56 to 3.43 fps. (auth)
Date: August 1, 1961
Creator: Hoglund, B.M.; Weatherhead, R.J. & Epperson, T.R.
Partner: UNT Libraries Government Documents Department

Subcooler assembly for SSC single magnet test program

Description: A subcooler assembly has been designed, constructed and installed in the MAGCOOL magnet test area at Brookhaven National Laboratory. Since July 1989, it has been used for testing SSC magnets. This subcooler assembly and cryogenic system are the first of its kind ever built. Today, with more than 5000 hours of operating time, the subcooler has proved to be a reliable unit with individual components meeting design expectations. The lowest temperatures achieved with one SSC dipole are 3.0 K at the suction of the cold vacuum pump and 3.2 K at the return of the magnet. The system performs well in both steady state operation and during magnet quench, subcooling, cooldown and warmup. 4 refs., 7 figs.
Date: January 1, 1991
Creator: Wu, K.C.; Brown, D.P.; Sondericker, J.H.; Farah, Y.; Zantopp, D. & Nicoletti, A.
Partner: UNT Libraries Government Documents Department

High flux film and transition boiling

Description: An investigation was conducted on the potential for altering the boiling curve through effects of high velocity and high subcooling. Experiments using water and Freon-113 flowing over cylindrical electrical heaters in crossflow were made to see how velocity and subcooling affect the boiling curve, especially the film and transition boiling regions. We sought subcooling levels down to near the freezing points of these two liquids to prove the concept that the critical heat flux and the minimum heat flux could be brought together, thereby averting the transition region altogether. Another emphasis was to gain insight into how the various boiling regions could be represented mathematically on various parts of heating surface. Motivation for the research grew out of a realization that the effects of very high subcooling and velocity might be to avert the transition boiling altogether so that the unstable part of the boiling curve would not limit the application of high flux devices to temperatures less than the burnout temperatures. Summaries of results from the study are described. It shows that the potential for averting, the transition region is good, and points the way to further research that is needed to demonstrate the potential.
Date: February 1, 1993
Creator: Witte, L.C.
Partner: UNT Libraries Government Documents Department