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Research on Vapor Reheat And Liquid-Liquid Heat Exchange

Description: From Forward and From Introductory- Summary : "This is the seventy-eighth of a series of reports designed to present accounts of progress in saline water conversion with the expectation that the exchange of such data will contribute to the long-range development of economical processes applicable to large-scale, low-cost dimineralization of sea or other saline water. The distillation system has operated with only minor difficulties. Mass transfer coefficients are in the range predicted from previous experiments. It is emphasized that the data reported above are not the best values obtained, but rather those upon which there is statistical justification based upon analysis of all the data."
Date: September 1963
Creator: FMC Corporation
Partner: UNT Libraries Government Documents Department

Analytical method for determining performance of turbojet-engine tail-pipe heat exchangers

Description: From Introduction: "The NACA Lewis laboratory has undertaken a program of analytical study to evaluate the effect on turbojet-engine performance of extracting energy from several points in the cycle. The program included an investigation of the effects of air bleed from the compressor outlet, hot gas bleed from the turbine inlet, hot gas bleed from the turbine outlet, and shaft power extraction (references 1 to 4). "
Date: September 1951
Creator: Behun, Michael & Chandler, Harrison C., Jr.
Partner: UNT Libraries Government Documents Department

Use of stagnation temperature in calculating rate of heat transfer in aircraft heat exchangers

Description: From Summary: "Theoretical and experimental investigations of the effect of frictional heat on the rate of heat transmission at high fluid velocities are briefly reviewed. On the basis of these investigations, calculations are made which show that the use of the stagnation temperature of the cooling air as the effective temperature for heat transfer in an aircraft heat exchanger is sufficiently accurate."
Date: October 1943
Creator: Wood, George P.
Partner: UNT Libraries Government Documents Department

Effect of the performance of a turbosupercharged engine of an exhaust-gas-to-air heat exchanger for thermal ice prevention

Description: From Summary: "This report presents the results of a flight investigation to determine the effect on the performance of a turbosupercharged engine of an exhaust-gas-to-air heat exchanger installed between the engine-exhaust collector ring and the turbosupercharger." The background, results, and discussion of the investigation are described.
Date: August 23, 1945
Creator: Look, Bonne C.
Partner: UNT Libraries Government Documents Department

Plastic Heat Exchangers : A State-of-the-Art Review

Description: Significant increases in energy utilization efficiency can be achieved through the recovery of low-temperature rejected heat. This energy conserving possibility provides incentive for the development of heat exchangers which could be employed in applications where conventional units cannot be used. Some unique anticorrosion and nonstick characteristics of plastics make this material very attractive for heat recovery where condensation, especially sulfuric acid, and fouling occur. Some of the unique characteristics of plastics led to the commercial success of DuPont's heat exchangers utilizing polytetrafluoroethylene (trade name Teflon) tubes. Attributes which were exploited in this application were the extreme chemical inertness of the material and its flexibility, which enabled utilization in odd-shaped spaces. The wide variety of polymeric materials available ensures chemical inertness for almost any application. Lower cost, compoundability with fillers to improve thermal/mechanical properties, and versatile fabrication methods are incentives for many uses. Also, since many plastics resist corrosion, they can be employed in lower temperature applications (< 436 K), where condensation can occur and metal units have been unable to function. It is clear that if application and design can be merged to produce a cost-effective alternate to present methods of handling low-temperature rejected heat, then there is significant incentive for plastic heat exchangers, to replace traditional metallic heat exchangers or to be used in services where metals are totally unsuited.
Date: July 1979
Creator: Miller, David; Holtz, Robert E.; Koopman, R. Nelson; Marciniak, Thomas J. & MacFarlane, Donald R.
Partner: UNT Libraries Government Documents Department

Tube Vibration in Industrial-Size Test Heat Exchanger (90° Square Layout)

Description: Tube vibrations in heat exchangers are being systematically investigated in a series of tests performed with an industrial-size test exchanger. Results from water-flow tests of eleven different tube bundles, in six- and eight-cross-pass configurations on a 90 degree square layout with a pitch-to-diameter ratio of 1.25 are reported. The test cases include full tube bundles, no-tubes-in-window bundles, finned tube bundles, and proposed field and design fixes. The testing focused on identification of the lowest critical flow-rate to initiate fluid-elastic instability (large amplitude tube motion) and the location within the bundle of the tubes which first experience instability. The test results are tabulated to permit comparison with results obtained from previous tests with a 30 degree triangular layout tube bundle. Instability criteria are evaluated preliminarily. Pressure drop data are also generated and reported.
Date: February 1983
Creator: Halle, Henry & Wambsganss, M. W.
Partner: UNT Libraries Government Documents Department

Sodium Reactor Experiment Power Expansion Program: Heat Transfer Systems Modifications

Description: Abstract: Under the Power Expansion Program (PEP), modifications have been made to the Sodium Reactor Experiment (SRE) facility to improve plant reliability and permit an increase in power to 30 Mwt, with a reactor coolant outlet temperature up to 1200°F.
Date: October 9, 1964
Creator: Freede, W. J. & Roberts, J. K.
Partner: UNT Libraries Government Documents Department

Fluidelastic Instability in Shell and Tube Heat Exchangers: A Framework for a Prediction Method

Description: A framework for a method to predict fluid-elastic instability in heat exchanger tube bundles is presented. The method relies on a three-dimensional, cylindrical coordinate, thermal-hydraulic analysis code to obtain a representation of the three-dimensional flow distribution within the heat exchanger. With this information, local cross-flow velocities corresponding to each tube in the exchanger are obtained by interpolation and resultant cross-flow velocity distributions are computed. With a knowledge of the vibration mode shapes and frequencies, reduced effective cross-flow velocities are then computed for each tube. A comparison with experimental results shows excellent agreement: the tubes with high values of predicted reduced effective cross-flow velocity are the same tubes that first experience fluid-elastic instability in the flow tests and vibrate most violently; also, the simulation correctly predicts that the tubes directly exposed to the flow from the inlet nozzle have a low potential for fluid-elastic instability. Very good agreement is also shown in the comparison of the predicted reduced effective cross-flow velocities with the critical value obtained from a design guide. In summary, the feasibility of developing a heat exchanger tube vibration prediction method, based on a computer simulation of flow distribution, is demonstrated. Such a method would have immediate application in design optimization. However, further development and evaluation are required.
Date: December 1982
Creator: Wambsganss, M. W.; Yang, C. I. & Halle, J.
Partner: UNT Libraries Government Documents Department

Shellside Waterflow Pressure Drop and Distribution in Industrial-Size Test Heat Exchanger

Description: The shellside pressure drop between the inlet and outlet nozzles as well as the pressure drops through individual sections of different shell-and-tube test-exchanger configurations are measured under water flow. The segmentally baffled test exchanger is nominally 0.6 m (2 ft) in diameter, 3.7 m (12 ft) long and contains a tube bundle of 19 mm (0.75 in.) outside-diameter tubes. Results are reported of 24 test cases obtained from various combinations of parameters: 30 degrees triangular or 90 degrees square tube layout patterns (all on a 1.25 pitch-to-diameter ratio), numbers of cross-passes, sizes of nozzles, plain or finned tubes, and full or special fix tube bundles. The exponential change of pressure drop as a function of flow-rate is also investigated and an attempt is made to calculate nozzle losses.
Date: January 1983
Creator: Halle, Henry & Wambsganss, M. W.
Partner: UNT Libraries Government Documents Department

How the Performance of a Superconducting Magnet is affected by theConnection between a small cooler and the Magnet

Description: As low temperature cryocoolers become more frequently used to cool superconducting magnets, it becomes increasingly apparent that the connection between the cooler and the magnet has an effect on the design and performance of the magnet. In general, the use of small coolers can be considered in two different temperature ranges; (1) from 3.8 to 4.8 K for magnet fabricated with LTS conductor and (2) from 18 to 35 K for magnets fabricated using HTS conductor. In general, both temperature ranges call for the use of a two-stage cooler. The best method for connecting a cooler to the magnet depends on a number of factors. The factors include: (1) whether the cooler must be used to cool down the magnet from room temperature, (2) whether the magnet must have one or more reservoirs of liquid cryogen to keep the magnet cold during a loss of cooling, and (3) constraints on the distance from the cooler cold heads and the magnet and its shield. Two methods for connecting low temperature coolers to superconducting magnets have been studied. The first method uses a cold strap to connect the cold heads directly to the loads. This method is commonly used for cryogen-free magnets. The second method uses a thermal siphon and liquid cryogens to make the connection between the load being cooled and the cold head. The two methods of transferring heat from the magnet to the cooler low temperature cold head are compared for the two temperature ranges given above.
Date: September 8, 2005
Creator: Green, Michael A.
Partner: UNT Libraries Government Documents Department

The Results of Recent MICE Superconducting Spectrometer Solenoid Test

Description: The MICE spectrometer solenoid magnets will be the first magnets to be installed within the MICE cooling channel. The MICE spectrometer solenoids may be the largest magnets that have been cooled using small two stage coolers. During the previous test of this magnet, the cooler first stage temperatures were too high. The causes of some of the extra first stage heat load has been identified and corrected. The rebuilt magnet had a single stage GM cooler in addition to the three pulse tube coolers. The added cooler reduces the temperature of the top of the HTS leads, the shield and of the first stage of the pulse tube coolers.
Date: October 15, 2010
Creator: Green, Michael A.; Virostek, Steve P. & Zisman, Michael S.
Partner: UNT Libraries Government Documents Department

The Effect of Circuiting Arrangement on the Thermal Performance of Refrigeration Mixtures in Tube-and-Fin Condensing Heat Exchangers

Description: For the pure or azeotropic refrigerants typically used in present air conditioning and refrigeration applications, the refrigerant changes phase at a constant temperature. Thus, the refrigerant circuiting arrangement such as crossfiow, counterfiow, or cross-counterflow, has no effect on the thermal performance. For zeotropic refrigerant mixtures, however, the phase-change occurs over a temperature range, or "glide", and the refrigerant circuiting arrangement, or flow path through the heat exchanger, can affect the thermal performance of both the heat exchangers as well as the overall efficiency of the vapor compression cooling cycle. The effects of tsvo diflerent circuiting arrangements on the thermal performance of a zeotropic retligerant mixture and an almost azeotropic refrigerant mixture in a four-row cross-countertlow heat exchanger arrangement are reported here. The two condensers differ only in the manner of circuiting the refrigerant tubes, where one has refrigerant always flowing downward in the active heat transfer region ("identical order") and the other has refrigerant alternating flow direction in the active heat transfer region ("inverted order"). All other geometric parameters, such as bce are% fin louver geometry, refrigerant tube size and enhancement etc., are the same for both heat exchangers. One refrigerant mixture (R-41OA) un&rgoes a small temperature change ("low glide") during phase change, and the other retligerant mixture (a multi- component proprietary mixture) has a substantial temperature change ("high glide") of approximately 10"C during the phase change process. The overall thermal conductance, two-phase conductance, and pressure drop are presented. For the flow conditions of these tests, which are representative of resi&ntial cooling conditions, inverted order circuiting is more desirable than identical order. The potential thermal advantages of the i&ntical order arrangement for high-glide zeotropic refrigerant mixtures are negated by the increased parasitic refrigerant-side pressure drop utiortunately resulting from tkbrication requirements of the identical order circuiting.
Date: March 15, 1999
Creator: Chen, D.T. & Conklin, J.C.
Partner: UNT Libraries Government Documents Department