Author: George M. BertschPublisher:
ISBN:
Category :
Languages : en
Pages : 147
Book Description
Nucleate Pool Boiling Characteristics of R-124
Author: George M. BertschThe Effect of Oil on the Onset of Nucleate Pool Boiling of R-124 from a Single Horizontal Tube
Author: George D. PerryPublisher:
ISBN:
Category :
Languages : en
Pages : 147
Book Description
An investigation on the effect of oil on the onset of nucleate pool boiling of R-124 from a single horizontal tube was conducted at saturation temperature of 2.2 deg C. Pure R-124 and R-124/oil mixtures of 3% and 10% (by weight) miscible alkylbenzene oil were used. The tubes tested were: (1) smooth tube, (2) 19 fins per inch and (3) 26 fins per inch low-integral finned (GEWA-K) tubes, and (4) porous-coated (HIGH FLUX) tube. The effect of dissolved gases, subcooling and pressure on the onset of nucleate boiling were also investigated. An oil concentration of 3% tends to delay the onset of nucleate pool boiling (compared to pure R-124) on the smooth tube and GEWA-K 19 fins per inch tube, but not on the GEWA-K 26 fins per inch and HIGH FLUX tubes. The reason for this is not known precisely but is very repeatable. A 10% oil concentration tends to delay the onset of nucleate pool boiling on all tubes tested. This is due mainly to the increase of surface tension, and saturation temperature with increase in oil concentration. The presence of dissolved gases in the pool tends to lower the onset of nucleate pool boiling by increasing the number of entrapped vapor nuclei. Pressurization and subcooling tend to increase the onset of nucleate pool boiling by deactivating potential nucleation sites.
The Effect of Oil on the Onset of Nucleate Pool Boiling of R-124 from a Single Horizontal Tube
Author: George D. PerryPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
An investigation on the effect of oil on the onset of nucleate pool boiling of R-124 from a single horizontal tube was conducted at saturation temperature of 2.2 deg C. Pure R-124 and R-124/oil mixtures of 3% and 10% (by weight) miscible alkylbenzene oil were used. The tubes tested were: (1) smooth tube, (2) 19 fins per inch and (3) 26 fins per inch low-integral finned (GEWA-K) tubes, and (4) porous-coated (HIGH FLUX) tube. The effect of dissolved gases, subcooling and pressure on the onset of nucleate boiling were also investigated. An oil concentration of 3% tends to delay the onset of nucleate pool boiling (compared to pure R-124) on the smooth tube and GEWA-K 19 fins per inch tube, but not on the GEWA-K 26 fins per inch and HIGH FLUX tubes. The reason for this is not known precisely but is very repeatable. A 10% oil concentration tends to delay the onset of nucleate pool boiling on all tubes tested. This is due mainly to the increase of surface tension, and saturation temperature with increase in oil concentration. The presence of dissolved gases in the pool tends to lower the onset of nucleate pool boiling by increasing the number of entrapped vapor nuclei. Pressurization and subcooling tend to increase the onset of nucleate pool boiling by deactivating potential nucleation sites.
Nucleate Pool Boiling Characteristics of Gewa-T Finned Surfaces in Freon-113
Author: R. J. PulidoPublisher:
ISBN:
Category :
Languages : en
Pages : 101
Book Description
Pool boiling heat-transfer measurements were made using seven Gewa-T copper tubes in R-113. The first tube (18-mm OD x 0.75 fins/mm x 0.25 mm gap) was tested under three conditions: (a) plain, (b) with four shrouds and (c) with up to 5 wires (0.13 mm diameter) wrapped in the inter-fin trough area. Verifying prior data, the shroud with longitudinal openings of 60 deg at the top and 8.5 deg at at the bottom gave the best performance among the four shrouds tested. This shroud increased the boiling heat-transfer coefficient by 253 percent (over the smooth tube case) at a heat flux of 10,000 W/sq m while it showed only a 18 percent increase at 100,000 W/sq m. When wire wraps were provided, in all cases, the heat-transfer coefficient was improved at all heat fluxes. The use of three wires gave the best performance with 341-percent increase in heat-transfer coefficient at 10,000 W/sq m and a 130 percent increase at 100,000 W/sq m. The next three Fewa-T tubes had dimensions of 25 mm OD x 0.75 fins/mm with fin-tip gaps of 0.15, 0.25, and 0.35 mm, respectively. The last three Gewa-T tubes had the same dimensions except that the fin density was 1.02 fins/mm. For each of these fin densities, the 0.25 mm fin-tip gap produced the best boiling performance at all heat fluxes. Originator supplied keywords include: Nucleate pool boiling; Gewa-T finned surfaces.
Masters Theses in the Pure and Applied Sciences
Author: Wade H. ShaferPublisher: Springer Science & Business Media
ISBN: 1461303931
Category : Science
Languages : en
Pages : 427
Book Description
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 dis semination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought 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 concerned if the printing and distribution of the volumes were handled by an international 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 Corporation 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 39 (thesis year 1994) a total of 13,953 thesis titles from 21 Canadian and 159 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this impor tant annual reference work. While Volume 39 reports theses submitted in 1994, on occasion, certain uni versities do report theses submitted in previous years but not reported at the time.
Convective Flow Boiling
Author: John C. ChenPublisher: CRC Press
ISBN: 1000723852
Category : Science
Languages : en
Pages : 776
Book Description
This book comprises selected papers from the First International Conference on Convective Flow Boiling. The purpose of the conference is to examine state-of-science and recent developments in technology of flow boiling, i.e., boiling systems which are affected by convective flows.
Nucleate Pool Boiling Characteristics of Gewa-T Finned Surfaces in Freon-113
Author: Ricardo J. Pulido O.Publisher:
ISBN:
Category : Mechanical engineering
Languages : en
Pages : 100
Book Description
Nucleate Boiling Characteristics and the Critical Heat Flux Occurrence in Subcooled Axial-flow Water Systems
Author: R. J. WeatherheadPublisher:
ISBN:
Category : Cooling
Languages : en
Pages : 40
Book Description
Experimental data obtained at CISE on two-phase adiabatic flow are presented. The measured quantities are pressure drop and liquid film thickness on the inner and the outer wall of the conduit. The pressure loss and film flow rate are evaluated. The experimental data are discussed and the effects of various physical and geometrical parameters are investigated. A simple relation for the pressure loss in adiabatic dispersed regime is given.
A Review and Assessment of Boiling Heat Transfer and the Departure from Nucleate Boiling
Author: Gerhard O. MuellerPublisher:
ISBN:
Category : Nucleate boiling
Languages : en
Pages : 196
Book Description
Author: