Further studies in filmwise condensation of steam on horizontal finned tubes by Keith Andrew Swensen

Cover of: Further studies in filmwise condensation of steam on horizontal finned tubes | Keith Andrew Swensen

Published by Naval Postgraduate School, Available from the National Technical Information Service in Monterey, Calif, Springfield, Va .

Written in English

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Book details

ContributionsMarto, P. J., Memory, Stephen B.
The Physical Object
Pagination127 p. ;
Number of Pages127
ID Numbers
Open LibraryOL25523199M

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Calhoun: The NPS Institutional Archive Theses and Dissertations Thesis Collection Further studies in filmwise condensation of steam on horizontal finned tubes.

Over the years, there has been significant variation in the filmwise steam condensation data at NPS on horizontal low-integral finned tubes. With a view to increasing the accuracy of the data, inserts were used inside the tubes to reduce inside thermal resistance; however, significant discrepancies then occurred in the calculated outside heat-transfer coefficient when compared to data taken.

Thesis advisors, P.J. Marto and Stephen Memory. Film condensation occurs when the temperature of a vertical, impermeable, and wettable wall next to a porous medium saturated with vapor falls below saturation temperature (Fig.

).In addition to gravity-driven downward liquid flow, the liquid also infiltrates the vapor region due to capillary force. The latter will create a two-phase region between the liquid film and the vapor region.

Further studies in filmwise condensation of steam on horizontal finned tubes. there has been significant variation in the filmwise steam condensation data at NOS on horizontal low0integral finned tubes. With a view to increasing the accuracy of the data, inserts were used inside the tubes to reduce inside thermal resistance; however Author: Keith Andrew Swensen.

The film condensation heat transfer performance of six externally finned copper tubes has been evaluated. All tubes had rectangular-shaped fins with a height and thickness of 1 mm. The spacing between fins was,and mm.

Data were also obtained for a smooth tube whose outside diameter of mm was equal to the. Recently, in order to improve the steam condensation heat transfer performance in the presence of air, Tong et al [15] conducted experiments on vertical longitudinal finned tubes.

However, the. Over the years, there has been significant variation in the filmwise steam condensation data at NPS on horizontal low-integral finned tubes. With a view to increasing the accuracy of the data, inserts were used inside the tubes to reduce.

Filmwise condensation measurements of steam were made on horizontal finned tubes under vacuum and near-atmospheric conditions. Data were obtained for copper tubes with fins of rectangular, triangular, trapezoidal, and parabolic cross sections, and for a commercially-available finned tube.

The geometrical parameters of all the specimens investigated are summarized in Table surfaces with longitudinal fins are named R1 and R1 fin has a rectangular cross-section of width (d b) and height (l) of mm and mm, respectively whereas the T1 fin has a triangular cross-section with the base width (d b) of mm and the same height as the R1 fin of mm.

Augmentation of horizontal in-tube condensation of steam John Henri Royal Iowa State University Follow this and additional works at: THE FINNED TUBES 99 Introduction 99 Background 99 Dropwise Condensation Studies Filmwise Condensation Studies Filmwise condensation is expected to occur in most instances because the formation of dropwise condensation IS greatly influenced by the presence of non-condensable gases, the nature and composition of surfaces and the velocity of vapour past the surface.

Filmwise Condensation Mechanism on a Vertical Plane Surface-- Assumption. same temperature difference between the steam & the sur-face, dropwise condensation is much more effective then filmwise condensation & for this reason the former is desirable although in practical plants it rarely occurs for prolonged periods.

In filmwise condensation a laminar film of vapour is created upon a surface. Experiments have been performed to study the effects of air on filmwise condensation from steam-air mixtures undergoing forced flow over a 3/4 in.

OD horizontal tube. Local condensation rates at the stagnation point are reported for saturation temperatures of – deg F, bulk to wall temperature differences of 3–30 deg F, bulk air mass. This paper presents a few salient features of an investigation carried out to study the heat transfer augmentation during condensation of water and Ra vapor on horizontal integral-fin tubes.

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Experimental Heat Transfer: Vol. 16, No. 4, pp. An experimental study on the role of non-condensable gases in the condensation of steam inside slightly inclined tubes was presented by Caruso et al. The experiments were carried out under the following conditions: inner diameter of the tube and mm, inclination of the tube 7°, mass fraction of the non-condensable gas between 5 and.

On the other hand, the sinusoidal fin geometry of Specimen S 1 promoted the draining of the condensate film from the fin tip to the fin base which significantly improved heat transfer near the fin tip.

In comparison with the plain surface, enhancement factors (η) of and were achieved with Specimens C 1 and S 1, respectively. EXPERIMENTAL STUDIES ON STEAM CONDENSATION IN HORIZONTAL AND VERTICAL MICROTUBES.

Sadaghiani AK. Motezakker.A Ko. şar. with different twisted ratios of 6, 9, 12 and 15 [9] and micro-fin tubes [10] have been used due to their high condensation heat on condensation heat transfer in inclined tubes for Ra was investigated by Meyer et al.

Film wise condensation. In film wise condensation, the surface over which the steam condenses is wet-able and hence, as the steam condenses, a film of condensate is formed.

Generally, film wise condensation results in low heat transfer rates as the film of condensate impedes the heat transfer.

Steam and steam-air mixtures were condensed on bundles of in-line, titanium tubes. The row-by-row heat transfer coefficients are presented against bundle position. They show the expected behavior for filmwise condensation but demonstrate a different one for dropwise.

Honda, H., Nozu, S. and Mitsumori, K. () Augmentation of Condensation on Horizontal Finned Tubes by Attaching a Porous Drainage Plate. Proc. ASME-JSME Thermal Engng. Joint Conf., 3, Honda, H. and Nozu, S. () A Prediction Method for Heat Transfer during Film Condensation on Horizontal Integral Fin Tubes.

Heat Transfer,   Tubes are smooth. And for smooth surface the condensation will be of film condensation type i.e. it will form a film over the surface during condensation. The film thus formed will act as an insulation and therefore will decrease the effective hea.

Filmwise steam condensation in the highly instrumented containment Thermal-Hydraulics facility TOSQAN J. Malet, E. Porcheron, P. Cornet, J. Vendel Institut de Radioprotection et de Sûreté Nucléaire (IRSN) DPEA/SERAC, Laboratoire de Physique et de Métrologie des Aérosols et du Confinement.

BP 68, Gif-sur-Yvette cedex, France. pressure drop in horizontal tube 34 chapter 3 theory introduction 35 heat transfer 35 mass transfer 37 basic aspects of two phase flow and heat transfer in horizontal tubes 42 properties of mixtures 46 development of an equation forheat transfer 51 development of formulae used inevaluating.

Transport Phenomena in Multiphase Systems by A. Faghri & Y. Zhang 13 Chapter 8: Condensation Heat flux across the film thickness () Heat transfer rate per unit width for the control volume () where.

Latent heat effects of condensation dominate the process () dΓ is found by differentiating the expression for mass flow rate per. CONDENSATION OF STEAM ON MULTIPLE HORIZONTAL TUBES Makas, Aytaç M.S., Department of Mechanical Engineering Supervisor: Assoc.

Prof. Cemil Yamalı Aprilpages The problem of condensation of steam on a vertical tier of horizontal tubes is investigated by both analytical and experimental methods in this study. A computer. Film wise and Drop wise condensation are nothing but two different results of condensation of vapor/steam when gets into contact of cooled surface.

In film wise condensation, the cooled surface is smooth and friction-less which results in quick. exchange of heat during dropwise and filmwise condensation.

This unit contained with an integrated steam generator boiler and steam extraction through control valve to the chamber tubes. Condensation of steam on the surface of tubes causes heat transferred from steam to tubes. Due to this placement of the suction pipe in the center of the tube nest, the exhaust steam flows radially inward over the tubes towards the suction pipe.

The condensate is collected at the bottom of the condenser and pumped to the hot well. We can say that it is the improved form of the down flow surface condenser. @article{osti_, title = {Condensation heat transfer of steam on a single horizontal tube.

Master's thesis}, author = {Graber, K A}, abstractNote = {An experimental apparatus was designed, constructed and instrumented in an effort to systematically and carefully study the condensation heat-transfer coefficient on a single, horizontal tube.

The lower plate carries an electric heating element which converts water to steam at a rate which is determined by the electrical power input. This steam flows upwards to the Dropwise and Filmwise condensers where it is condensed by transferring heat to the cooling water, and the condensate returns to the lower end of the vessel for re-evaporation.

The condensation in horizontal tubes plays an important role for the prediction of the operation mode of horizontal steam generators of VVER reactors or passive safety systems for the next generation of nuclear power plants.

is based on Huhn's general film flow theory [7] with respect to filmwise con-densation. Here the field equations. In Figure 4, the results for downward, horizontal and upward flow of low pressure steam condensing in 5 × 15 (width × depth) in-line and staggered banks of horizontal plain tubes are plotted on the coordinates of versus F, where Nu = αD/λ L, Re L =, F =, α is the mean heat transfer coefficient for a tube row perpendicular to the vapor.

@article{osti_, title = {A prediction method for heat transfer during film condensation on horizontal low integral-fin tubes}, author = {Honda, H and Nozu, S}, abstractNote = {A method for predicting the average heat transfer coefficient is presented for film condensation on horizontal low integral-fin tubes.

Approximate equations based on the numerical analysis of surface tension. Heat-transfer measurements were made for condensation of R and steam on a smooth tube and on three finned tubes with rectangular shape fins. These tubes had a fin height and width of mm and spacings of, and mm (tubes A, B, and C respectively).

Data were taken by increasing the vapor velocity from to m/s for R Nusselt not studied wave of water steam on condensate surface. Flow of water steam in tubes side form waves on condensate surface and wave effect increase condensation heat transfer coefficient.

Key Words: Condensation, vertical tube, water steam, heat exchanger, condensation heat transfer coefficient, wave effect. An experimental investigation of the use of pin fin arrays to enhance filmwise condensation of steam on vertical plates was carried out.

New fin geometries of cylindrical, conical and sinusoidal profiles were produced and investigated in a condensation chamber. Condensation on Horizontal Tubes Gravity controlled condensation on a single horizontal tube is examined The analysis is then extended to industrial situation of multiple tubes in a bundle considering inundation effects Single Horizontal Tube () () 3 1/ 4 0.

η − λ ρ ρ −ρ ∆ α = sat w o l l l g v T T D g h In alternate form (). Condensation on the outside of a horizontal tube in crossflow. The correlations that we discussed thus far have been limited to cases in which the flow of the condensate is driven by gravity. When the vapor is forced to flow over the cooler surface, the vapor interacts with the condensate and drags liquid in the vapor flow direction.In the same study referenced above, an times improvement in heat transfer coefficient was measured with dropwise condensation over filmwise condensation.

It is suspected that the degradation of the surface around the perimeter may have contributed to .Rifert, V. G., Heat transfer and flow modes of phases in laminar film vapour condensation inside a horizontal tube, Int. J. Heat Mass Transfer, 31 (), 3, pp.

; Cavallini, A., et al., Condensation inside and outside smooth and enhanced tubes - a review of recent research. International Journal of Refrigeration, 26 (), pp.

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