Download or read book Film Condensation of Steam on Externally Enhanced Horizontal Tubes written by Evagelos S. Mitrou and published by . This book was released on 1986 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heat-transfer measurements were made for filmwise condensation of steam on externally enhanced horizontal tubes under vacuum and at atmospheric pressure. Data were obtained for copper tubes with circular fins of rectangular, triangular, trapezoidal, and parabolic cross sections for spiral fins of triangular cross section, for commercially available finned tubes and for wire-wrapped tubes. Four spirally finned tubes from each of Cu, Cu-ni, A1 and stainless steel and two tubes with fins of rectangular cross section from each of Cu-Ni and A1 were manufactured and tested to investigate the effect of thermal conductivity. Among sprially finned tubes, the optimum fin pitch was found to be 1.6 mm. The tubes with a parabolic fin shape showed the best performance with steam-side enhancements of 4.1 and 6.2 under vacuum and at the atmospheric pressure respectively. Enhancement ratios as high as 3.5 and 2.1 were obtained under vacuum and at atmospheric pressure, respectively, for the commercially available finned tubes. The heat-transfer performance decreased with decreasing tube metal thermal conductivity. For the wire-wrapped tubes, an optimum pitch to wire diameter ratio of about 5.1 was found, with steam-side enhancements of about 1.9 and 2.2 under vacuum and at atmospheric pressure, respectively. A recent theoretical analysis of laminar film of low-surface-tension fluids on wire-wrapped tubes was modified to include the condensate retention of the tube due to the high surface tension of water. Agreement between this modified analysis and the experimental data was favorable. Keywords: Heat transfer coefficient.
Download or read book Film Condensation of Steam on Externally Finned Horizontal Tubes written by Frederick A. Flook and published by . This book was released on 1985 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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. A stainless steel finned tube was also tested to investigate the effect of thermal conductivity. Maximum enhancements of about 4.8 were obtained under vacuum conditions, and about 6.9 at atmospheric pressure, compared to a smooth tube having an outside diameter equal to the root diameter of the finned tubes. The optimum fin spacing was found to be about 2.0 mm for rectangularly shaped-fins with a fin-thickness of 1.0 mm, and fin height of 0.5 and 1.5 mm. Fins with a parabolic shape were shown to perform better than fins of rectangular shape, and fins were shown to degrade the performance of stainless steel tubes. The effects of vapor shear were also shown to have only a small influence on the steam-side heat transfer coefficient. A theoretical model proposed by Webb et al. was found to underpredict the experimental data. Several suggestions to modify this model are described. Keywords: External fin; Heat transfer coefficient; Enhancement, Condenser tubes (Theses).
Download or read book Film Condensation of Steam on Externally Finned Horizontal Tubes written by and published by . This book was released on 1985 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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. A stainless steel finned tube was also tested to investigate the effect of thermal conductivity. Maximum enhancements of about 4.8 were obtained under vacuum conditions, and about 6.9 at atmospheric pressure, compared to a smooth tube having an outside diameter equal to the root diameter of the finned tubes. The optimum fin spacing was found to be about 2.0 mm for rectangularly shaped-fins with a fin-thickness of 1.0 mm, and fin height of 0.5 and 1.5 mm. Fins with a parabolic shape were shown to perform better than fins of rectangular shape, and fins were shown to degrade the performance of stainless steel tubes. The effects of vapor shear were also shown to have only a small influence on the steam-side heat transfer coefficient. A theoretical model proposed by Webb et al. was found to underpredict the experimental data. Several suggestions to modify this model are described. Keywords: External fin; Heat transfer coefficient; Enhancement, Condenser tubes (Theses).
Download or read book Filmwise Condensation of Steam on Externally Finned Horizontal Tubes written by William M. Poole and published by . This book was released on 1983 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: The film-condensation characteristics of a smooth tube and six externally-finned tubes having fins 1 mm high and 1 mm thick, and ptiches of 1.5, 2.0, 2.5, 3.0, 5.0, and 10.0 mm, were experimentally tested. A smooth copper tube with an active length of 133.5 mm, an outside diameter of 19.05 mm, and an inside diameter of 12.7 mm was first tested to correlate the inside heat-transfer coefficient using the Sieder-Tate equation. The leading coefficient for this equation was found to be 0.034 + or - 0.001, and was used to derive the external condensing coefficient for all of the tubes by subtracting the inside and wall resistances from the measured overall resistance. The condensing coefficient was measured, both at atmospheric pressure and vacuum (84 mm hg), with the heat flux as a variable. Condensation data taken for the smooth tube were compared with data in the literature to check the reliability of the apparatus and the data-reduction procedures. The data for the finned tubes showed an optimum pitch of 2.5 mm. (Author).
Download or read book CONDENSATION OF STEAM ON MULTIPLE HORIZONTAL TUBES written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 program is written to perform the analysis of laminar film condensation on the horizontal tubes. The program is capable to calculate condensate film thickness and velocity distribution, as well as the heat transfer coefficient within the condensate. An experimental setup was also manufactured to observe the condensation phenomenon. Effects of tube diameter and temperature difference between steam and the tube wall on condensation heat transfer have been analytically investigated with the computer program. Experiments were carried out at different inclinations of the tier of horizontal tubes. Effects of the steam velocity and the distance between the horizontal tubes are also experimentally investigated. Results of the experiments are compared to those of the studies of Abdullah et al., Kumar et al. and Nusselt as well as to the analytical results of the present study.
Download or read book An Experimental Study of Filmwise Condensation on Horizontal Enhanced Condenser Tubing written by and published by . This book was released on 1979 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heat transfer and hydrodynamic performance of eight different geometrically enhanced tubes of different metals was determined. Results were compared to a 25.4 mm (1.0 in.) OD, smooth stainless steel tube. Steam at about 21 kPa (3 psia) was condensed on the outside surface of each enhanced tube, horizontally mounted in the center of a dummy tube Bank. Each tube was cooled on the inside by water. The overall heat transfer coefficient was determined directly from experimental data. The inside and outside heat transfer coefficients were determined using the Wilson plot technique. The cooling water pressure drop was measured inside the tube and converted to the friction factor in the enhanced section. The overall heat transfer coefficients of the enhanced tubes were increased as much as 1.9 times, and the corrected pressure drops of the enhanced tubes were as large as 4 times the corresponding smooth tube value for the same cooling water velocity. The helix angle should be 45 deg to 60 deg on the inside surface and 90 deg on the outside surface of the tube to obtain maximum inside and outside heat transfer coefficients. (Author).
Download or read book An Experimental Study of Filmwise Condensation on Horizontal Enhanced Condenser Tubing written by Huseyin Ciftci and published by . This book was released on 1979 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heat transfer and hydrodynamic performance of eight different geometrically enhanced tubes of different metals was determined. Results were compared to a 25.4 mm (1.0 in.) OD, smooth stainless steel tube. Steam at about 21 kPa (3 psia) was condensed on the outside surface of each enhanced tube, horizontally mounted in the center of a dummy tube Bank. Each tube was cooled on the inside by water. The overall heat transfer coefficient was determined directly from experimental data. The inside and outside heat transfer coefficients were determined using the Wilson plot technique. The cooling water pressure drop was measured inside the tube and converted to the friction factor in the enhanced section. The overall heat transfer coefficients of the enhanced tubes were increased as much as 1.9 times, and the corrected pressure drops of the enhanced tubes were as large as 4 times the corresponding smooth tube value for the same cooling water velocity. The helix angle should be 45 deg to 60 deg on the inside surface and 90 deg on the outside surface of the tube to obtain maximum inside and outside heat transfer coefficients. (Author).
Download or read book Energy Research Abstracts written by and published by . This book was released on 1986 with total page 936 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Some Aspects of Film Condensation of Steam on Finned Tubes written by James M. Coumes and published by . This book was released on 1989 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heat-transfer measurements were made for filmwise condensation of steam on smooth tubes and finned tubes with rectangular-shaped fins. The influence of fin root diameter on a single horizontal finned tube was examined by taking data for two families of tubes whose fin root diameters were 12.7 and 19.05 mm. Each family of tubes had fins that were 1 mm thick and 1 mm high, but with fin spacings of 0.25, 0.50, 1.0, 1.5, 2.0, and 4.0 mm. To compare results being obtained in a concurrent research project with Queen Mary College (University of London), data were collected on two tubes whose fin root diameters were 12.7 mm, and which had fin thickness of 0.5 mm, fin heights of 1.59 mm, and fin spacings of 1.0 mm. A comparison of the enhancement ratios (based on constant vapor-side temperature drop) with past Naval Postgraduate School (nps) studies showed good agreement. The apparatus was then modified in order to study the effects of condensate inundation.
Download or read book An Experimental Apparatus to Study Enhanced Condensation Heat Transfer of Steam on Horizontal Tubes written by and published by . This book was released on 1982 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In an effort to explore the possibility of building compact naval steam condensers, an experimental apparatus was designed and constructed to study enhanced condensation heat transfer of steam on horizontal tubes. Special care was taken to ensure a leak-tight apparatus so that the non-condensable gas content of the steam can be kept to a few parts-per-million. The boiler and steam piping is made of glass and stainless steel with rubber gaskets. Copper is used for the condensing tubes. The completed system has been tested satisfactorily at full power. (Author).
Download or read book Masters Theses in the Pure and Applied Sciences written by Wade H. Shafer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thougtit that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna tional publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 31 (thesis year 1986) a total of 11 ,480 theses titles trom 24 Canadian and 182 United States universities. We are sure that this broader base tor these titles reported will greatly enhance the value ot this important annual reterence work. While Volume 31 reports theses submitted in 1986, on occasion, certain univer sities do re port theses submitted in previousyears but not reported at the time.
Download or read book Filmwise Condensation of Steam on Horizontal Wire wrapped Smooth and Roped Titanium Tubes written by Thomas Joseph O'Keefe and published by . This book was released on 1992 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Apparatus to Study Enhanced Condensation Heat Transfer of Steam on Horizontal Tubes written by Raymond Lynn Krohn and published by . This book was released on 1982 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: In an effort to explore the possibility of building compact naval steam condensers, an experimental apparatus was designed and constructed to study enhanced condensation heat transfer of steam on horizontal tubes. Special care was taken to ensure a leak-tight apparatus so that the non-condensable gas content of the steam can be kept to a few parts-per-million. The boiler and steam piping is made of glass and stainless steel with rubber gaskets. Copper is used for the condensing tubes. The completed system has been tested satisfactorily at full power. (Author).
Download or read book An Experimental Study of Steam Condensation on a Single Horizontal Tube written by Derry Thomas Pence and published by . This book was released on 1978 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental test facility capable of investigating plain and enhanced horizontal tubes was built. The test facility consists of an electric boiler, test condenser and associated piping for steam, condensate and cooling water. Performance of the test condenser was checked at a steam pressure of 3 psia with cooling water velocities ranging from 5 to 25 ft/sec. Condensation data was obtained for a single, 0.625 inch outside diameter, 90-10 copper-nickel tube in a simualted tube bundle to determine the overall, inside and outside heat transfer coefficients. The overall heat transfer coefficient was determined directly from experimental data, and the Wilson Plot technique was used to determine the inside and outside heat transfer coefficients. The experimentally obtained values for the inside heat transfer coefficient are within 5 percent of the theoretical values predicted by the Sieder-Tate equation. The experimental values obtained for the outside heat transfer coefficient are within 8 percent of the theoretical values predicted by the Nusselt equation. (Author).
Download or read book Enhanced Heat Transfer written by M. B. Pate and published by . This book was released on 1992 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Heat Transfer in Condensation and Boiling written by Karl Stephan and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: I welcome the opportunity to have my book translated, because of the great emphasis on two-phase flow and heat transfer in the English-speaking world, as related to research, university education, and industrial practice. The 1988 Springer-Verlag edition of "Warmeiibergang beim Kondensieren und beim Sieden" has been enlarged to include additional material on falling film evaporation (Chapter 12) and pressure drop in two-phase flow (Chapter 13). Minor errors in the original text have also been corrected. I would like to express my sincere appreciation to Professor Green, Asso ciate Professor of German at Rensselaer, for his excellent translation and co operation. My thanks go also to Professor Bergles for his close attention to technical and linguistic details. He carefully read the typescript and made many comments and suggestions that helped to improve the manuscript. I hope that the English edition will meet with' a favorable reception and contribute to better understanding and to progress in the field of heat transfer in condensation and boiling. February 1992 K. Stephan Preface to the German-Language Edition This book is a continuation of the series "Heat and Mass Transfer" edited by U. Grigull, in which three volumes have already been published. Its aim is to acquaint students and practicing engineers with heat transfer during condensa tion and boiling, and is intended primarily for students and engineers in mechanical, chemical, electrical, and industrial processing engineering.
Download or read book Filmwise Condensation of Steam on Low Integral Finned Tubes written by Ioannis V. Georgiadis and published by . This book was released on 1984 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: Filmwise condensation heat-transfer measurements of steam were made on horizontal tubes under vacuum and near-atmospheric pressures. Data were taken for smooth tube and for 21 tubes which contained rectangularly-shaped, low integral fins. The fin geometry was systematically varied in order to investigate the dependence of the steam-side heat-transfer coefficient on fin spacing, thickness and height. The condensation process was found to be most sensitive to fin spacing and to be weakly dependent on fin thickness. When the fin height was increased from 1.0 to 2.0 mm, the increase in the heat-transfer coefficient was about 20 percent, while the increase in condensing area was 51 percent. The best performing finned tube had a fin height of 1.5 mm, a fin thickness of 1.0 mm and a fin height of 2.0 mm. It showed an enhancement over the smooth tube of between 4 to 5 under vacuum conditions and around 6 at atmospheric conditions. Thus, the use of finned tubes may result in a significant reduction in size and weight of present-day steam condensers. Originator-supplied key words include: Steam, Condensation, Filmwise, Tube, Low Integral Fin, Heat-Transfer Coefficient, Enhancement.
