Heat Transfer to Supercritical Water in Gaseous State or Affected by Mixed Convection in Vertical Tubes

2006 ◽  
Author(s):  
E. N. Pis’menny ◽  
V. G. Razumovskiy ◽  
E. M. Maevskiy ◽  
A. E. Koloskov ◽  
I. L. Pioro
Keyword(s):  
Heat Transfer ◽  
Mixed Convection ◽  
Supercritical Water ◽  
Operating Conditions ◽  
Maximum Effect ◽  
Upward Flow ◽  
Downward Flow ◽  
Gaseous State ◽  
Transfer Data ◽  
Vertical Tubes

The results on heat transfer to supercritical water heated above the pseudocritical temperature or affected by mixed convection flowing upward and downward in vertical tubes of 6.28-mm and 9.50-mm inside diameter are presented. Supercritical water heat-transfer data were obtained at a pressure of 23.5 MPa, mass flux within the range from 250 to 2200 kg/(m2s), inlet temperature from 100 to 415°C and heat flux up to 3.2 MW/m2. Temperature regimes of the tubes cooled with supercritical water in a gaseous state (i.e., supercritical water at temperatures beyond the pseudocritical temperature) were stable and easily reproducible within a wide range of mass and heat fluxes. An analysis of the heat-transfer data for upward and downward flows enabled to determine a range of Gr/Re2 values corresponding to the maximum effect of free convection on the heat transfer. It was shown that: 1) the heat transfer coefficient at the downward flow of water can be higher by about 50% compared to that of the upward flow; and 2) the deteriorated heat-transfer regime is affected with the flow direction, i.e., at the same operating conditions, the deteriorated heat transfer may be delayed at the downward flow compared to that at the upward flow. These heat-transfer data are applicable as the reference dataset for future comparison with bundle data.

Experiment of Heat Transfer to Supercritical Water Flowing in Vertical Annular Channels

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Zhendong Yang ◽  
Qincheng Bi ◽  
Han Wang ◽  
Gang Wu ◽  
Richa Hu
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Flux ◽  
Supercritical Water ◽  
Experimental Parameter ◽  
Outer Diameter ◽  
Buoyancy Effect ◽  
Upward Flow ◽  
Downward Flow ◽  
Annular Channels

An experimental study of heat transfer to supercritical water has been performed at Xi'an Jiaotong University with a vertical annular tube. The annular test sections were constructed with an annular gap of 2 mm and an internal heater of 8 mm outer diameter. Experimental parameter covered pressures of 23 and 25 MPa, mass fluxes of 700 and 1000 kg/m2s, and heat fluxes of 200–1000 kW/m2. Experimental data were acquired from downward flow and upward flow, respectively. There were differences of heat-transfer characteristics between the two flow directions. Compared to upward flow, the heat-transfer coefficient increased at downward flow. A strong effect of spacer on heat transfer is observed at locations downstream of the device in the annuli regardless of flow direction. The spacer effect impaired the buoyancy effect at low heat flux, but not for large heat flux. Complex of forced convection and mixed convection in supercritical water is due to various thermophysical properties and the gravity. The affected zone of the spacer effect depends on the flow conditions. The buoyancy effect was analyzed qualitatively in this study and the criterion Gr¯/Re2.7<10-5 for negligible heat-transfer impairment was discussed. Four correlations were compared with the experimental data; the Swenson correlation predicted nearly the experimental data but overpredicted slightly the heat-transfer coefficients.

Numerical Analysis of Thermal-Hydraulic Behavior of Supercritical Water in Vertical Upward/Downward Flow Channels

2008 ◽  
Author(s):  
Hanyang Gu ◽  
Xu Cheng ◽  
Xiaojing Liu
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Supercritical Water ◽  
Square Lattice ◽  
Bulk Temperature ◽  
Upward Flow ◽  
Downward Flow ◽  
Hydraulic Behavior ◽  
Hydraulic Behaviour ◽  
Turbulence Mixing

Investigations on the thermal-hydraulic behavior in the SCWR fuel assembly have obtained a significant attention in the international SCWR community. However, there is still a lack of understanding and ability to predict the heat transfer behavior of supercritical fluids. In this paper, the numerical analysis is carried out to study the thermal-hydraulic behaviour in vertical sub-channels cooled by supercritical water. Remarkable differences in characteristics of secondary flow are found, especially in square lattice, between the upward flow and downward flow. The turbulence mixing across sub-channel gap for downward flow is much stronger than that for upward flow in wide lattice when the bulk temperature is lower than pseudo-critical point temperature. For downward flow, heat transfer deterioration phenomenon is suppressed with respect to the case of upward flow at the same conditions.

Heat Transfer to Water at Supercritical Parameters in Vertical Tubes, Annular Channels, 3- and 7-Rod Bundles

2013 ◽  
Author(s):  
V. G. Razumovskiy ◽  
E. M. Mayevskiy ◽  
A. E. Koloskov ◽  
E. N. Pis’mennyi ◽  
I. L. Pioro
Keyword(s):  
Heat Transfer ◽  
Supercritical Water ◽  
Experimental Studies ◽  
Heat Fluxes ◽  
Bulk Temperature ◽  
Experimental Setup ◽  
Gaseous State ◽  
Annular Channels ◽  
Wide Range ◽  
Vertical Tubes

The data on deteriorated transfer to supercritical water in vertical tubes and channels simulating coolant flow in fuel assemblies obtained at the same experimental setup during more than dozen of years are considered and compared with some known results of the experimental studies performed by other authors. They involve the data for vast ranges of geometry, mass velocity, heat flux rate, and pressure, in some cases for up- and downward flow, for flow with and without thermoacoustic oscillations. For the first time the data illustrating deterioration of heat transfer in the bundles of fuel elements are presented. An attempt to explain the phenomena of “inlet” peak of wall temperature is made. It is shown that temperature regimes of the tubes cooled with supercritical water in a gaseous state (i.e., at bulk temperature above the pseudocritical temperature) are close to linear, stable and easily reproducible within a wide range of mass and heat fluxes. Some requirements to the experimental setup, coolant quality, test sections etc. that should be followed in studying thermal and hydraulic parameters of supercritical coolant are analyzed.

A New Heat Transfer Correlation for Supercritical RP-3 Flowing in Vertical Tubes

2017 ◽  
Author(s):  
Longyun Wang ◽  
Zhi Tao ◽  
Jianqin Zhu ◽  
Haiwang Li ◽  
Zeyuan Cheng
Keyword(s):  
Heat Transfer ◽  
Influence Factors ◽  
Hydrocarbon Fuel ◽  
Operating Conditions ◽  
Major Influence ◽  
Absolute Deviation ◽  
New Correlation ◽  
Vertical Tubes ◽  
Correction Terms ◽  
Good Agreement

A new empirical correlation for upward flowing supercritical aviation kerosene RP-3 in the vertical tubes is proposed. In order to obtain the database, numerical simulation with a four-component surrogate model on RP-3 and LS low Reynolds turbulence model in vertical circular tube has been performed. Tubes of diameter 2mm to 10mm are studied and operating conditions cover pressure from 3MPa to 6MPa. Heat flux is 500KW/m2, mass flow rate is 700kg/(m2·s). The numerical results on wall temperature distribution under various conditions are compared with experimental data and a good agreement is achieved. The existing correlations are summarized and classified into three categories. Three representative correlations of each category are selected out to evaluate the applicability in heat transfer of supercritical RP-3. The result shows that correlations concluded from water and carbon-dioxide do not perform well in predicting heat transfer of hydrocarbon fuel. The mean absolute deviation of them is up to 20% and predict about 80% of the entire database within 30% error bands. So a new correlation which is applicable to different working conditions for supercritical RP-3 is put forward. Gnielinski type has been adapted as the basis of the new correlation for its higher accuracy. In consideration of major influence factors of supercritical heat transfer, correction terms of density and buoyancy effect are added in. The new correlation has a MAD of 9.26%, predicting 90.6% of the entire database within ±15% error bands. The comparisons validate the applicability of the new correlation.

Supercritical water heat transfer in vertical tubes: A look-up table

2008 ◽  
Vol 50 (2-6) ◽  
pp. 532-538 ◽  
Author(s):  
Matthias F. Loewenberg ◽  
Eckart Laurien ◽  
Andreas Class ◽  
Thomas Schulenberg
Keyword(s):  
Heat Transfer ◽  
Supercritical Water ◽  
Look Up Table ◽  
Vertical Tubes

ICONE23-1163 CFD MODELING OF SUPERCRITICAL WATER HEAT TRANSFER IN A VERTICAL BARE TUBE UPWARD FLOW

2015 ◽  
Vol 2015.23 (0) ◽  
pp. _ICONE23-1-_ICONE23-1 ◽  
Author(s):  
Vladimir Agranat ◽  
Michael Malin ◽  
Igor Pioro ◽  
Rand Abdullah ◽  
Valery A. Perminov
Keyword(s):  
Heat Transfer ◽  
Supercritical Water ◽  
Cfd Modeling ◽  
Upward Flow ◽  
Bare Tube

Comparison of Three-Rod Bundle Data With Existing Heat-Transfer Correlations for Bare Vertical Tubes

2010 ◽  
Author(s):  
Krysten King ◽  
Amjad Farah ◽  
Sahil Gupta ◽  
Sarah Mokry ◽  
Igor Pioro
Keyword(s):  
Heat Transfer ◽  
Supercritical Water ◽  
Annular Channel ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Rod Bundle ◽  
Nuclear Systems ◽  
Heat Transfer Correlations ◽  
Vertical Tubes ◽  
Bare Tube

Many heat-transfer correlations exist for bare tubes cooled with SuperCritical Water (SCW). However, there is very few correlations that describe SCW heat transfer in bundles. Due to the lack of extensive data on bundles, a limited dataset on heat transfer in a SCW-cooled bundle was studied and analyzed using existing bare-tube correlations to find the best-fit correlation. This dataset was obtained by Razumovskiy et al. (National Technical University of Ukraine “KPI”) in SCW flowing upward in a vertical annular channel (1-rod channel) and tight 3-rod bundle consisting of tubes of 5.2-mm outside diameter and 485-mm heated length. The heat-transfer data were obtained at pressures of 22.5, 24.5, and 27.5 MPa, mass flux within a range from 800 to 3000 kg/m2s, inlet temperature from 125 to 352°C, outlet temperature up to 372°C and heat flux up to 4.6 MW/m2. The objective of this study is to compare bare-tube SCW heat-transfer correlations with the data on 1- and 3-rod bundles. This work is in support of SuperCritical Water-cooled Reactors (SCWRs) as one of the six concepts of Generation-IV nuclear systems. SCWRs will operate at pressures of ∼25MPa and inlet temperatures of 350°C.

Numerical Investigation of Heat and Mass Flux Effects on Heat Transfer Characteristics of Supercritical Water in an Upward Flow Vertical Tube

2014 ◽  
Vol 592-594 ◽  
pp. 1667-1671
Author(s):  
T. Vinoth ◽  
K. Karuppasamy ◽  
D. Santhosh Kumar ◽  
R. Dhanuskodi
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Flux ◽  
Supercritical Water ◽  
Mass Flux ◽  
Vertical Tube ◽  
Upward Flow ◽  
Heat Transfer Characteristics ◽  
Ansys Fluent ◽  
Transfer Characteristics

In the present work, the heat transfer characteristics of supercritical pressure water are numerically investigated in an upward flow vertical smooth tube. The numerical simulations are carried out by using Ansys-Fluent solver. The objective of the present work is to investigate the effect of heat flux and mass flux on heat transfer characteristics in supercritical water. In order to perform numerical simulation, experimental data of Mokryet al.[2] is considered. Various simulations were carried out for the inlet parameters of temperature 350°C, pressure 240bar; heat flux values ranging from 190 to 884kW/m2and mass flux values ranging from 498 to 1499kg/m2s. Based on the available parameters of heat flux and mass flux, they are segregated as groups with heat flux to mass flux ratios of 0.39 and 0.67. According to computational data, the heat transfer enhancement and heat transfer deterioration phenomenon of supercritical water were analyzed and based on the comparison with experimental data; their occurrence and mechanism were addressed.

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