Download or read book Filmwise Condensation Heat transfer of Steam and R 113 on Smooth and Finned Tubes with Simulated Inundation written by and published by . This book was released on 1999 with total page 396 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 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.
Download or read book Journal of Heat Transfer written by and published by . This book was released on 1992 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Further Studies in Filmwise Condensation of Steam on Horizontal Finned Tubes written by Keith Andrew Swensen and published by . This book was released on 1992 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Condensation Heat Transfer Enhancement written by V. G. Rifert and published by WIT Press (UK). This book was released on 2004 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: In processes with condensation of steam-to-gas compositions or refrigerative agents an intensification of condensation is often required because thermal resistance on the condensation side can be greater than the thermal resistance of the heat transfer wall on the cooling side. In this work, a pair of researchers from the National Technical U. of Ukraine and the State Academy of Refrigeration (Ukraine) provide information about the enhancement of condensation, including research results from the former USSR they feel deserves wider dissemination as well as discussion of different theoretical models of the condensation process. The US office of WIT Press is Computational Mechanics. Annotation : 2004 Book News, Inc., Portland, OR (booknews.com).
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 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 Enhanced Condensation of R 113 on a Small Bundle of Horizontal Tubes written by and published by . This book was released on 1991 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: Condensation of R-113 was studied using an evaporator condenser test platform. The condenser section contained four horizontal tubes (nominal outer diameter 15.9 mm) forming a vertical in line column with a pitch-to-diameter ratio of 2.25 and a condensing length of 1.2m. The condenser tubes could be operated either individually (ie. as a single tube apparatus) or as a small tube bundle. This allowed investigation of the effects of condensate inundation on different types of condenser tubes. Tubes tested were smooth copper tubes, copper/nickel KORODENSE roped tubes, KORODENSE tubes wrapped with wire, and copper/nickel finned tubes (26 fpi). The outside heat transfer coefficient was calculated by experimentally determining the overall heat transfer coefficient and then using a modified Wilson Plot procedure. Great care was taken to ensure the results were not vitiated by the presence of noncondensibles. Results obtained with the smooth copper tubes are in agreement with published data and verify satisfactory operation of the test platform. Furthermore, problems associated with the apparatus encountered by previous workers were successfully overcome. In comparison to the top smooth tubes, the copper nickel top KORODENSE tube yielded about a 22% increase.
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 Effect of Condensation on Performance and Design of Extended Surfaces written by and published by DIANE Publishing. This book was released on with total page 59 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Condensate Inundation on Steam Condensation Heat Transfer to Wire Wrapped Tubing written by Georgios Dimitriou Kanakis and published by . This book was released on 1983 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: Steam condensation heat transfer measurements were made in a 5-tube test condenser having an additional perforated tube to simulate up to 30 active tubes. Results were obtained for smooth tubes and roped tubes wrapped with wire. A Sieder-Tate equation was used to correlate the inside heat-transfer coefficient. For smooth tubes, a leading coefficient of 0.029 was found, while it was 0.061 for the roped tubes. The average condensing coefficient measured for 30 smooth tubes was 0.59 times the Nusselt coefficient calculated for the first tube. When the smooth tubes were wrapped with wire, this ratio increased up to 0.86. Further, roped tubes without wire experienced a ratio of 0.63, while roped tubes wrapped with wire resulted in a ratio of 0.86. These preliminary data show that wire-wrapped tubes may lead to a significant reduction in condenser surface area. (Author).
Download or read book The Effect of Condensate Inundation on Steam Condensation Heat Transfer in a Tube Bundle written by S. K. Brower and published by . This book was released on 1985 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: Steam-condensation heat-transfer measurements were made using a 5-tube in-line test condenser with an additional perforated tube to simulate up to 30 active tubes. Results were obtained for smooth tubes wire-wrapped tubes and dropwise-coated tubes. The average outside heat-transfer coefficient for 30 smooth tubes was 0.64 times the Nusselt coefficient fo the first tube. A total of eight wire-diameter and wire-pitch combinations were tested: 1.6-mm-diameter wire wrapped at 16 mm, 7.6 mm and 4 mm wire pitches, 1.0-mm-diameter wire wrapped at 8 mm, 4 mm and 2 mm wire pitches, and 0.5-mm-diameter wire wrapped at 4 and 2 mm wire pitches. The best bundle performance was obtained when the tubewere wrapped with 1.0-mm-diameter wire at a wire pitch of 4 mm. This combination resulted in an average outside heat-transfer coefficient for 30 tubes that was 1.15 times the value computed for the first time using the Nusselt theory. The average outside heat-transfer coefficient for 30 dropwise-coated tubes was 1.1 times the value of the heat-transfer coefficient for the first tube in the tube bundle. Using either wire-wrapped tubes or dropwise-coated tubes, it is possible to significantly reduce the condenser surface area and overall size. Keywords: Inundation, Smooth, wire-wrapped tubes. (Theses).
Download or read book The Effect of Condensate Inundation on Steam Condensation Heat Transfer to Wire Wrapped Tubing written by and published by . This book was released on 1983 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Steam condensation heat transfer measurements were made in a 5-tube test condenser having an additional perforated tube to simulate up to 30 active tubes. Results were obtained for smooth tubes and roped tubes wrapped with wire. A Sieder-Tate equation was used to correlate the inside heat-transfer coefficient. For smooth tubes, a leading coefficient of 0.029 was found, while it was 0.061 for the roped tubes. The average condensing coefficient measured for 30 smooth tubes was 0.59 times the Nusselt coefficient calculated for the first tube. When the smooth tubes were wrapped with wire, this ratio increased up to 0.86. Further, roped tubes without wire experienced a ratio of 0.63, while roped tubes wrapped with wire resulted in a ratio of 0.86. These preliminary data show that wire-wrapped tubes may lead to a significant reduction in condenser surface area. (Author).
