Shape Characteristics and Condensation Heat Transfer of Supersonic Steam Jet in Subcooled Water

2017 ◽  
Author(s):  
Wang Fangnian ◽  
Qin Huan ◽  
Chen Yaodong ◽  
Bai Ning ◽  
Xing Mian ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Expansion Ratio ◽  
Penetration Length ◽  
Shape Identification ◽  
Maximum Expansion ◽  
Heat Transfer Correlations ◽  
The Look ◽  
Experimental Values ◽  
Regime Map ◽  
Shape Characteristics

The shape characteristics and direct contact condensation (DCC) heat transfer of submerged supersonic steam jet were investigated. One of the shape identification methods is the DCC shape regime map as a function of nozzle exit pressure, mass flux and pool water temperature, another one is the Look Up Table. Then based on the theoretical analysis, the new basic expressions of supersonic steam jet dimensionless penetration length, maximum expansion ratio, and heat transfer correlations were given, which were in terms of Ma number and Ja number. The correlations were nonlinearly fitted and validated well against the experimental data form open literatures. The discrepancies of penetration length and maximum expansion ratio between predicted and experimental values were within ±25% and ±12% respectively. Supersonic steam jet DCC heat transfer is feasible to be calculated via the identification of steam jet shape and selection of the corresponding shape and heat transfer correlations.

Integration of Genetic Programing With Genetic Algorithm for Correlating Heat Transfer Problems

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Yan Liu ◽  
Jian Yang ◽  
Jing Xu ◽  
Zhi-long Cheng ◽  
Qiu-wang Wang
Keyword(s):  
Heat Transfer ◽  
Genetic Algorithm ◽  
Heat Exchanger ◽  
Tube Heat Exchanger ◽  
Finned Tubes ◽  
Performance Of Heat Transfer ◽  
Heat Transfer Correlations ◽  
Predicted Values ◽  
Experimental Values ◽  
Transfer Problems

In the present paper, the genetic programing (GP) is integrated with the genetic algorithm (GA) for deriving heat transfer correlations. In the process of developing heat transfer correlations with the approach (GP with GA (GPA)), the GP is first employed to obtain some potential optimal forms. After that, the forms are further optimized with the global GA to reach minimum errors between the predicted values and experimental values. With the proposed approach, three typical different heat transfer problems are applied to the data reduction processes from published experimental data, which are heat transfer in a shell-and-tube heat exchanger (STHE) with continuous helical baffles, a single row heat exchanger with helically finned tubes and a finned oval-tube heat exchanger with double rows of tubes, respectively. The results indicate that the GPA approach could improve the performance of heat transfer correlations obtained with the GP. Compared with the power-law-based correlations, the heat transfer correlations obtained with the approach have higher predicted accuracies and more excellent robustness.

Theoretical Post-Dryout Heat Transfer Model

2018 ◽  
Vol 1 (1) ◽  
pp. 142-150
Author(s):  
Murat Tunc ◽  
Ayse Nur Esen ◽  
Doruk Sen ◽  
Ahmet Karakas
Keyword(s):  
Heat Transfer ◽  
Droplet Diameter ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Operating Pressure ◽  
Vertical Pipe ◽  
Two Phase ◽  
Experimental Values ◽  
Reactor Operating ◽  
Coolant System

A theoretical post-dryout heat transfer model is developed for two-phase dispersed flow, one-dimensional vertical pipe in a post-CHF regime. Because of the presence of average droplet diameter lower bound in a two-phase sparse flow. Droplet diameter is also calculated. Obtained results are compared with experimental values. Experimental data is used two-phase flow steam-water in VVER-1200, reactor coolant system, reactor operating pressure is 16.2 MPa. On heater rod surface, dryout was detected as a result of jumping increase of the heater rod surface temperature. Results obtained display lower droplet dimensions than the experimentally obtained values.

Comparison of Existing Supercritical Carbon Dioxide Heat Transfer Correlations for Horizontal and Vertical Bare Tubes

2012 ◽  
Author(s):  
Prabu Surendran ◽  
Sahil Gupta ◽  
Tiberiu Preda ◽  
Igor Pioro
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Wall Temperature ◽  
Statistical Error ◽  
Heat Fluxes ◽  
Transfer Coefficients ◽  
Bulk Fluid ◽  
Heat Transfer Correlations ◽  
Supercritical Carbon

This paper presents a thorough analysis of ability of various heat transfer correlations to predict wall temperatures and Heat Transfer Coefficients (HTCs) against experiments on internal forced-convective heat transfer to supercritical carbon dioxide conducted by Koppel [1], He [2], Kim [3] and Bae [4]. It should be noted the Koppel dataset was taken from a paper which used the Koppel data but was not written by Koppel. All experiments were completed in bare tubes with diameters from 0.948 mm to 9 mm for horizontal and vertical configurations. The datasets contain a total of 1573 wall temperature points with pressures ranging from 7.58 to 9.59 MPa, mass fluxes of 400 to 1641 kg/m2s and heat fluxes from 20 to 225 kW/m2. The main objective of the study was to compare several correlations and select the best of them in predicting HTC and wall temperature values for supercritical carbon dioxide. This study will be beneficial for analyzing heat exchangers involving supercritical carbon dioxide, and for verifying scaling parameters between CO2 and other fluids. In addition, supercritical carbon dioxide’s use as a modeling fluid is necessary as the costs of experiments are lower than supercritical water. The datasets were compiled and calculations were performed to find HTCs and wall and bulk-fluid temperatures using existing correlations. Calculated results were compared with the experimental ones. The correlations used were Mokry et al. [5], Swenson et al. [6] and a set of new correlations presented in Gutpa et al. [7]. Statistical error calculations were performed are presented in the paper.

scholarly journals Computational examination of two-phase microchannel heat transfer correlations with conjugate heat spreading

2019 ◽  
Vol 132 ◽  
pp. 68-79 ◽  
Author(s):  
Bryan E. Burk ◽  
Torben P. Grumstrup ◽  
Taylor A. Bevis ◽  
Jack Kotovsky ◽  
Todd M. Bandhauer
Keyword(s):  
Heat Transfer ◽  
Two Phase ◽  
Heat Transfer Correlations ◽  
Heat Spreading

LES of Turbulent Separated Flow and Heat Transfer in a Symmetric Expansion Plane Channel

2005 ◽  
Vol 127 (5) ◽  
pp. 865-871 ◽  
Author(s):  
Kazuaki Sugawara ◽  
Hiroyuki Yoshikawa ◽  
Terukazu Ota
Keyword(s):  
Heat Transfer ◽  
Finite Difference ◽  
Plane Channel ◽  
Separated Flow ◽  
Expansion Ratio ◽  
Vortical Flow ◽  
Flow And Heat Transfer ◽  
Finite Difference Equations ◽  
Separated And Reattached Flow ◽  
Fundamental Equations

The LES method was applied to analyze numerically an unsteady turbulent separated and reattached flow and heat transfer in a symmetric expansion plane channel of expansion ratio 2.0. The Smagorinsky model was used in the analysis and fundamental equations were discretized by means of the finite difference method, and their resulting finite difference equations were solved using the SMAC method. The calculations were conducted for Re=15,000. It is found that the present numerical results, in general, agree well with the previous experimental ones. The complicated vortical flow structures in the channel and their correlations with heat transfer characteristics are visualized through various fields of flow quantities.

Influence of Radial Rotation on Heat Transfer in a Rectangular Channel With Two Opposite Walls Roughened by Hemispherical Protrusions at High Rotation Numbers

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Shyy Woei Chang ◽  
Tong-Miin. Liou ◽  
Wei-Chun Chen
Keyword(s):  
Heat Transfer ◽  
Infrared Thermography ◽  
Rotation Number ◽  
Rectangular Channel ◽  
Flow Region ◽  
Transfer Data ◽  
Nusselt Numbers ◽  
Rotation Numbers ◽  
Heat Transfer Correlations ◽  
Rotating Channel

Detailed heat transfer distributions over two opposite leading and trailing walls roughened by hemispherical protrusions were measured from a rotating rectangular channel at rotation number up to 0.6 to examine the effects of Reynolds (Re), rotation (Ro), and buoyancy (Bu) numbers on local and area-averaged Nusselt numbers (Nu and Nu¯) using the infrared thermography. A set of selected heat transfer data illustrates the Coriolis and rotating buoyancy effects on the detailed Nu distributions and the area-averaged heat transfer performances of the rotating channel. The Nu¯ for the developed flow region on the leading and trailing walls are parametrically analyzed to devise the empirical heat transfer correlations that permit the evaluation of the interdependent and individual Re, Ro, and Bu effect on Nu¯.

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