scholarly journals Design Optimization of Plate-Fin Heat Exchanger in a Gas Turbine and Supercritical Carbon Dioxide Combined Cycle with Thermal Oil Loop

2021 ◽  
Vol 12 (1) ◽  
pp. 42
Author(s):  
Yue Cao ◽  
Jun Zhan ◽  
Jianxin Zhou ◽  
Fengqi Si
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Genetic Algorithm ◽  
Heat Flux ◽  
Supercritical Carbon Dioxide ◽  
Pareto Frontier ◽  
Combined Cycle ◽  
Nsga Ii ◽  
Thermal Oil ◽  
Supercritical Carbon

This paper presents an investigation on the optimum design for a plate-fin heat exchanger (PFHE) of a gas and supercritical carbon dioxide combined cycle which uses thermal oil as intermediate heat-transfer fluid. This may promote the heat transfer from low heat-flux exhaust to a high heat-flux supercritical carbon dioxide stream. The number of fin layers, plate width and geometrical parameters of fins on both sides of PFHE are selected as variables to be optimized by a non-dominated sorting genetic algorithm-II (NSGA-II), which is a multi-objective genetic algorithm. For the confliction of heat transfer area and pressure drop on the exhaust side, which are the objective indexes, the result of NSGA-II is a Pareto frontier. The technique for order of preference by similarity to ideal solution (TOPSIS) approach is applied to choose the optimum solution from the Pareto frontier. Finally, further simulation is performed to analyze the effect of each parameter to objective indexes and confirm the rationality of optimization results.

High Flux Microscale Solar Thermal Receiver for Supercritical Carbon Dioxide Cycles

2015 ◽  
Author(s):  
Thomas L’Estrange ◽  
Eric Truong ◽  
Charles Rymal ◽  
Erfan Rasouli ◽  
Vinod Narayanan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Heat Flux ◽  
Supercritical Carbon Dioxide ◽  
Surface Temperature ◽  
Thermal Efficiency ◽  
Solar Thermal ◽  
Fluid Temperature ◽  
Thermal Receiver ◽  
Supercritical Carbon

Characterization of a microchannel solar thermal receiver for a supercritical carbon dioxide (sCO2) is presented. The receiver design is based on conjugate computational fluid dynamics and heat transfer simulations as well as thermo-mechanical stress analysis. Two receivers are fabricated and experimentally characterized — a parallel microchannel design and a microscale pin fin array design. Lab-scale experiments have been used to demonstrate the receiver integrity at the design pressure of 125 bar at 750°C surface temperature. A concentrated solar simulator was designed and assembled to characterize the thermal performance of the lab scale receiver test articles. Results indicate that, for a fixed exit fluid temperature of 650°C, increase in incident heat flux results in an increase in receiver and thermal efficiency. At a fixed heat flux, efficiency decreased with an increase in receiver surface temperature. The ability to absorb flux of up to 100 W/cm2 at thermal efficiency in excess of 90 percent and exit fluid temperature of 650°C using the microchannel receiver is demonstrated. Pressure drop for the pin array at the maximum flow rate for heat transfer experiments is less than 0.64 percent of line pressure.

scholarly journals Experimental study on forced convective heat transfer of supercritical carbon dioxide in a horizontal circular tube under high heat flux and low mass flux conditions

2019 ◽  
Vol 11 (3) ◽  
pp. 168781401983080 ◽  
Author(s):  
Junhui Wang ◽  
Pengcheng Guo ◽  
Jianguo Yan ◽  
Fengling Zhu ◽  
Xingqi Luo
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Heat Flux ◽  
Supercritical Carbon Dioxide ◽  
Mass Flux ◽  
High Heat ◽  
High Heat Flux ◽  
Buoyancy Effect ◽  
Low Mass ◽  
Supercritical Carbon

This study focuses on the convective heat transfer characteristics of supercritical carbon dioxide flowing in a horizontal circular tube under high heat flux and low mass flux conditions. The influences of thermophysical property, buoyancy effect, and thermal acceleration on the heat transfer characteristics are discussed. The parameters are as follows: system pressure is 7.6–8.4 MPa, mass flux is 400–500 kg/m2 s, heat flux is 30–200 kW/m2, fluid temperature is 20°C −62°C, and Reynolds number is 1.23 × 104 to 4.3 × 104. The wall temperature and heat transfer coefficient of supercritical carbon dioxide are obtained. The results show that, under the condition of high heat flux and low mass flux, heat transfer deterioration would happen, in which thermophysical property and buoyancy effect are the main factors. When the pressure is 7.6 MPa, the buoyancy factor is greater than 10−3 in the whole heat transfer area, and the buoyancy effect cannot be ignored, while the thermal acceleration factor is 9.5 × 10−8 to 4 × 10−6 and the effect of thermal acceleration can be negligible. The experimental data are compared with the predictions using seven empirical correlations, in which the Liao–Zhao correlation shows the best performance.

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.

Supercritical Carbon Dioxide Heat Transfer in Horizontal Semicircular Channels

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
Alan Kruizenga ◽  
Hongzhi Li ◽  
Mark Anderson ◽  
Michael Corradini
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Heat Exchanger ◽  
Supercritical Carbon Dioxide ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Brayton Cycle ◽  
Heat Exchanger Design ◽  
Transfer Behavior ◽  
Supercritical Carbon

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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