Exploratory Design and Development of Compact Naval Condensers

Prepared for: Naval Sea Systems Command, Code 0331http://archive.org/details/exploratorydesig17martN000247WR9G078N

An analytical and experimental investigation of rotating, non-capillary heat pipes

An approximate theoretical model is derived for laminar film condensation on the inside of a rotating, truncated cone, and is used to predict the heat transfer performance of rotating, non-capillary heat pipes for a wide variety of parametric conditions. Experimental results are presented for water, ethyl alcohol, and freon-113 in a stainless steel heat pipe rotating to speeds of 2800 rpm. Results show that these devices can be used effectively to transfer large quantities of heat in rotating systems. Predicted results agree to within + or - 20 percent of the experimental data. Dropwise condensation, instead of film condensation, improves heat pipe performance while the presence of non-condensible gases impairs performance.NASA ORDER W-13007Approved for public release; distribution is unlimited

Heat pipe cooling of large electric motors

The U.S. Navy has a continued interest in using components having greater performance-to-weight ratios than those in current use. Such efficient components would provide more space for other components that have a direct bearing on the mission capabilities of naval vessels. This is especially the case for submarines as there are severe restrictions on the size and weight of any components on board these vessels.Prepared in conjunction with research conducted for the David Taylor Research Center and funded by the Naval Postgraduate School.http://archive.org/details/heatpipecoolingo00martN

Effects of Surface Conditions on Nucleate Pool Boiling of Sodium

Commercial grade sodium was boiled from a horizontal disk at pressures of 65 mm, 200 mm, and 400 mm Hg absolute, with sodium temperatures ranging from 1200 F to 1500 deg F. Heat fluxes as high as 236,000 Btu/hr sqft were attained. Boiler surface finishes ranged from highly polished mirror finishes to coarse, porous coatings. By following a prescribed cleaning and filling procedure, nucleate-boiling results were generally reproducible for a given-type surface. The effect of roughness as well as any aging and hysteresis effects were experimentally determined. Incipient nucleate boiling results are discussed as well as the effect of pressure and pool depth on the nucleateboiling curve.This work was supported jointly by the National Science Foundation, National Aeronautics and Space Administration, and the U. S. Atomic Energy Commission

An evaluation of liquid and two-phase cooling techniques for use in electrical machinery

The advantages that can be achieved through the use of advanced techniques for cooling of electric machinery are discussed. A brief literature survey is presented on liquid cooling of rotating machinery, where the liquid is in off-axis rotation. The lack of models to adequately predict pressure drop and heat -transfer performance in this situation has been noted.David W. Taylor Naval Ship R&D Center, Annapolis, MDhttp://archive.org/details/evaluationofliqu00wannPrepared for: David W. Taylor Naval Ship Research and Development Center Annapolis, MarylandN

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http://archive.org/details/feasibilitystudy00searNAN

Performance Rating of Enhanced Marine Condensers

Prepared for: David Taylor Naval Ship R&D Center Annapolis, MD 2140 2http://archive.org/details/performanceratin18nunnN00167-82-WR-011

A critical review of heat transfer enhancement techniques for use in marine condensers

A variety of heat transfer enhancement techniques are reviewed and evaluated for use in marine condensers. This review includes tube-side enhancement, as well as shell-side enhancement techniques. At present, the most promising technique to enhance heat transfer on the tube side is with one of the commercially available, mildly indented, corrugated tubes. With this type of tube, the shell-side heat transfer enhancement is not as large and is uncertain due to the, as yet determined, complex effects of vapor shear and condensate inundation. Large bundle tests with enhanced tubing are therefore required before the details of tube-to-tube interaction will be fully understood. (Author)supported by the David W, Taylor Naval Ship Research and Development Center under Work Request No, N00167-82-WR2-0114,http://archive.org/details/criticalreviewof00martN0167-82-WR2-0114N

A predictive method to describe the boiling behavior of refrigerant-oil mixtures

The need for efficient and environmentally safe refrigerants is of great concern to the Navy, and is driving them to explore the performance of alternate refrigerants for use in shipboard evaporators. Each time a new refrigerant is considered, one must also consider how oil contamination will affect its performance. The present study surveys the literature for a predictive technique to calculate the nucleate boiling heat transfer behavior of refrigerant-oil mixtures that is fundamental to the operation of refrigerant systems. There were three expressions found that could be considered for use. These expressions for the nucleate boiling heat transfer were empirically based formulations, which means that a new series of experiments must be conducted every time a different refrigerant-oil combination is considered for use. An expression that is currently under development for mixtures in general was found that is based only upon the thermophysical properties of the fluids and their mixtures. No empirical constants are necessary. The mass diffusion coefficient of the oil in the refrigerant is found to be the key property to be measured in order to evaluate the predictive capability of this expression. Experiments are proposed to obtain this key property and then to this expression will be developed as the experiments indicate are necessaryDavid Taylor Research Center, Annapolis, Maryland, Naval Sea Systems Commandhttp://archive.org/details/predictivemethod00lloyN0002490WR02886NAApproved for public release; distribution is unlimited

Heat transfer and two-phase flow during shell-side condensation

The article of record as published may be found at http://dx.doi.org/10.1080/01457638408962767This paper surveys the evolution of power condenser tube bundle arrangements and examines present-day designs. Condensation heat transfer during shell-side flow is reviewed, including the effects of vapor shear, condensate inundation, noncondensable gases, and enhancement techniques. The difficulties experienced in calculating vapor pressure drop through tube bundles are described as well as recent attempts to obtain more reliable correlations. The modeling of these phenomena to predict shell-side condenser performance is reviewed, as well as the use of one- and two-dimensional computer codes. Appropriate topics for future research are identified