Study on Condensation Heat Transfer Under High-Temperature, High-Pressure Conditions

2008 ◽  
Author(s):  
H. Yuasa ◽  
N. Abe ◽  
H. Ono ◽  
K. Shirakawa ◽  
S. Morooka
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
High Temperature ◽  
Vapor Condensation ◽  
Condensation Heat Transfer ◽  
Vapor Flow ◽  
Test Results ◽  
New Correlation ◽  
High Pressure High Temperature ◽  
Condensation Effect

Knowing the predicted overpressure rate under anticipated operational occurrences (AOOs) is very important when evaluating the integrity of a BWR reactor pressure vessel. One of the factors that influence the overpressure rate is the wall condensing performance. Many condensing studies have been done under low-pressure conditions without vapor flow, but few condensing test results under BWR conditions have been reported. Therefore, the purposes of this study were to extend the vapor condensing data base for high-pressure, high-temperature conditions, to improve the heat transfer correlation and to evaluate the condensing effect on the overpressure rate. Condensation heat transfer tests have been performed with the pressure range from 0.5 to 8 MPa under upward and downward vapor flow. The test section consisted of a condensing tube and a water-cooling jacket. The condensing tube was a circular tube. The test results showed that the condensation heat transfer coefficient increased with the velocity of vapor flow due to enhancement of heat transfer caused by turbulence of the liquid film. We obtained a new correlation for condensation heat transfer that considered vapor shear force and condensate film Reynolds number. This new correlation agreed well with experimental data over a wide range of pressure. New correlation was incorporated into TRACG02modT1 code. When the condensation heat transfer tests were analyzed using this modified TRACG02modT1 code, the calculated condensation heat transfer coefficients were found to be in considerable agreement with the measured data. Furthermore, when the main steam isolation valve AOO (safety relief valve capacity design) of the BWR plant was evaluated by this modified TRACG02modT1 code, we found that the vapor condensation effect appeared under relatively high-pressure conditions and the pressure with improved condensation model was lower than that without vapor condensation. In summary, the condensation heat transfer model of TRACG02modT1 code has been improved based on high-pressure, high-temperature condensation test data with vapor flow. The vapor condensation effect was found to be strong, especially in the pressure increase AOO of the actual plant.

Experimental investigation of wall heat transfer due to spray combustion in a high-pressure/high-temperature vessel

2021 ◽  
pp. 146808742110072
Author(s):  
Karri Keskinen ◽  
Walter Vera-Tudela ◽  
Yuri M Wright ◽  
Konstantinos Boulouchos
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
High Pressure ◽  
High Temperature ◽  
High Speed ◽  
Transfer Problem ◽  
Wall Heat Transfer ◽  
Gas Temperature ◽  
Reference Case ◽  
High Pressure High Temperature

Combustion chamber wall heat transfer is a major contributor to efficiency losses in diesel engines. In this context, thermal swing materials (adapting to the surrounding gas temperature) have been pinpointed as a promising mitigative solution. In this study, experiments are carried out in a high-pressure/high-temperature vessel to (a) characterise the wall heat transfer process ensuing from wall impingement of a combusting fuel spray, and (b) evaluate insulative improvements provided by a coating that promotes thermal swing. The baseline experimental condition resembles that of Spray A from the Engine Combustion Network, while additional variations are generated by modifying the ambient temperature as well as the injection pressure and duration. Wall heat transfer and wall temperature measurements are time-resolved and accompanied by concurrent high-speed imaging of natural luminosity. An investigation with an uncoated wall is carried out with several sensor locations around the stagnation point, elucidating sensor-to-sensor variability and setup symmetry. Surface heat flux follows three phases: (i) an initial peak, (ii) a slightly lower plateau dependent on the injection duration, and (iii) a slow decline. In addition to the uncoated reference case, the investigation involves a coating made of porous zirconia, an established thermal swing material. With a coated setup, the projection of surface quantities (heat flux and temperature) from the immersed measurement location requires additional numerical analysis of conjugate heat transfer. Starting from the traces measured beneath the coating, the surface quantities are obtained by solving a one-dimensional inverse heat transfer problem. The present measurements are complemented by CFD simulations supplemented with recent rough-wall models. The surface roughness of the coated specimen is indicated to have a significant impact on the wall heat flux, offsetting the expected benefit from the thermal swing material.

scholarly journals High-pressure synthesis and crystal structure of the mixed-cation borate Ga4In4B15O33(OH)3

2019 ◽  
Vol 74 (4) ◽  
pp. 357-363
Author(s):  
Daniela Vitzthum ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
Diffraction Data ◽  
X Ray Diffraction ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Mixed Cation ◽  
High Pressure High Temperature ◽  
Pressure Synthesis

AbstractThe mixed cation triel borate Ga4In4B15O33(OH)3 was synthesized in a Walker-type multianvil apparatus at high-pressure/high-temperature conditions of 12.5 GPa and 1300°C. Although the product could not be reproduced in further experiments, its crystal structure could be reliably determined via single-crystal X-ray diffraction data. Ga4In4B15O33(OH)3 crystallizes in the tetragonal space group I41/a (origin choice 2) with the lattice parameters a = 11.382(2), c = 15.244(2) Å, and V = 1974.9(4) Å3. The structure of the quaternary triel borate consists of a complex network of BO4 tetrahedra, edge-sharing InO6 octahedra in dinuclear units, and very dense edge-sharing GaO6 octahedra in tetranuclear units.

Iodine-mediated high-pressure high-temperature carbonization of hydrocarbons and synthesis of nanodiamonds

2021 ◽  
Vol 137 ◽  
pp. 111189
Author(s):  
E.A. Ekimov ◽  
K.M. Kondrina ◽  
I.P. Zibrov ◽  
S.G. Lyapin ◽  
M.V. Lovygin ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
High Pressure High Temperature

scholarly journals Multianvil High-Pressure/High-Temperature Synthesis and Characterization of multiferroic HP-Co3TeO6

2021 ◽  
Author(s):  
Gunter Heymann ◽  
Elisabeth Selb ◽  
Toni Buttlar ◽  
Oliver Janka ◽  
Martina Tribus ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Type Structure ◽  
Synthesis And Characterization ◽  
Temperature Synthesis ◽  
Space Group ◽  
Crystal System ◽  
High Temperature Synthesis ◽  
High Pressure High Temperature

By high-pressure/high-temperature multianvil synthesis a new high-pressure (HP) phase of Co3TeO6 was obtained. The compound crystallizes in the acentric trigonal crystal system of the Ni3TeO6-type structure with space group R3...

Method to reduce the oil pressure during HPHT diamond synthesis: FEM simulations and experiments

CrystEngComm ◽  
2020 ◽  
Vol 22 (44) ◽  
pp. 7601-7606
Author(s):  
Chunxiao Wang ◽  
Hong-an Ma ◽  
Liangchao Chen ◽  
Xinyuan Miao ◽  
Liang Zhao ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Cell Assembly ◽  
Diamond Synthesis ◽  
Fem Simulations ◽  
High Pressure High Temperature ◽  
New Type

Here, a new type of supercharged cell assembly is proposed that can effectively reduce the oil pressure during high-pressure, high-temperature (HPHT) diamond synthesis.

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