A review of heat transfer deterioration of supercritical carbon dioxide flowing in vertical tubes: Heat transfer behaviors, identification methods, critical heat fluxes, and heat transfer correlations

Author(s):  
Jingzhe Xie ◽  
Dechao Liu ◽  
Hongbin Yan ◽  
Gongnan Xie ◽  
Sandra K.S. Boetcher
Author(s):  
Prabu Surendran ◽  
Sahil Gupta ◽  
Tiberiu Preda ◽  
Igor Pioro

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.


Author(s):  
Sahil Gupta ◽  
Donald McGillivray ◽  
Prabu Surendran ◽  
Liliana Trevani ◽  
Igor Pioro

This paper presents an analysis of three new heat-transfer correlations developed for supercritical carbon dioxide (CO2) flowing in vertical bare tubes. A large set of experimental data was obtained at Chalk River Laboratories (CRL) AECL. Heat-transfer tests were performed in upward flow of CO2 inside 8-mm ID vertical Inconel-600 tube with a 2.208-m heated length. Data points were collected at outlet pressures ranging from 7.4 to 8.8 MPa, mass fluxes from 900 to 3000 kg/m2s, inlet fluid temperatures from 20 to 40°C, and heat fluxes from 15 to 615 kW/m2; and for several combinations of wall and bulk-fluid temperatures that were below, at, or above the pseudocritical temperature. The objective of the present experimental research is to obtain reference dataset on heat transfer in supercritical CO2 and improve our fundamental knowledge of the heat-transfer processes and handling of supercritical fluids. In general, heat-transfer process to a supercritical fluid is difficult to model, especially, when a fluid passes through the pseudocritical region, as there are very rapid variations in thermophysical properties of the fluid. Thus, it is important to investigate supercritical-fluid behaviour within these conditions. In general, supercritical carbon dioxide was and is used as a modelling fluid instead of supercritical water due to its lower critical parameters compared to those of water. Also, supercritical carbon dioxide is proposed to be used as a working fluid in the Brayton gas-turbine cycle as a secondary power cycle for some of the Generation-IV nuclear-reactor concepts such as a Sodium-cooled Fast Reactor (SFR), Lead-cooled Fast Reactor (LFR) and Molten-Salt-cooled Reactor (MSR). In addition, supercritical carbon dioxide was proposed to be used in advanced air-conditioning and geothermal systems. Previous studies have shown that existing correlations deviate significantly from experimental Heat Transfer Coefficient (HTC) values, especially, within the pseudocritical range. Moreover, the majority of correlations were mainly developed for supercritical water, and our latest results indicate that they cannot be directly applied to supercritical CO2 with the same accuracy as for water. Therefore, new empirical correlations to predict HTC values were developed based on the supercritical CO2 dataset. These correlations calculate HTC values with an accuracy of ±30% (wall temperatures with accuracy of ±20%) for the analyzed dataset.


2012 ◽  
Vol 134 (8) ◽  
Author(s):  
Alan Kruizenga ◽  
Hongzhi Li ◽  
Mark Anderson ◽  
Michael Corradini

Competitive cycles must have a minimal initial cost and be inherently efficient. Currently, the supercritical carbon dioxide (S-CO2) Brayton cycle is under consideration for these very reasons. This paper examines one major challenge of the S-CO2 Brayton cycle: the complexity of heat exchanger design due to the vast change in thermophysical properties near a fluid’s critical point. Turbulent heat transfer experiments using carbon dioxide, with Reynolds numbers up to 100 K, were performed at pressures of 7.5–10.1 MPa, at temperatures spanning the pseudocritical temperature. The geometry employed nine semicircular, parallel channels to aide in the understanding of current printed circuit heat exchanger designs. Computational fluid dynamics was performed using FLUENT and compared to the experimental results. Existing correlations were compared, and predicted the data within 20% for pressures of 8.1 MPa and 10.2 MPa. However, near the critical pressure and temperature, heat transfer correlations tended to over predict the heat transfer behavior. It was found that FLUENT gave the best prediction of heat transfer results, provided meshing was at a y+ ∼ 1.


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