COOLING HEAT TRANSFER ENHANCEMENT MECHANISM OF SUPERCRITICAL PRESSURE CO2 IN DIVERGING VARIABLE CROSSSECTION CIRCULAR TUBE IN SOLAR THERMAL POWER GENERATION

被引：0
|
作者：
He J. [1 ]
Zhu B. [1 ]
Peng B. [1 ]
Dang X. [1 ]
机构：
[1] School of Mechanical & Electronical Engineering, Lanzhou University of Technology, Lanzhou
来源：
Taiyangneng Xuebao/Acta Energiae Solaris Sinica | 2023年 / 44卷 / 09期
关键词：
Brayton cycle; diverging tube; heat transfer enhancement; numerical simulation; solar thermal power generation; supercritical pressure CO2;
D O I：
10.19912/j.0254-0096.tynxb.2022-0672
中图分类号：
学科分类号：
摘要：
The SST k-ω turbulence model was used to numerically simulate the heat transfer characteristics of supercritical pressure CO2（S- CO2）in constant-section circular tube，horizontal diverging tube and diverging tubes with different inclination angles under cooling conditions. The computational results indicate that compared with that of the uniform cross-section tube，the total heat transfer coefficient of the horizontal diverging tube and the 30° inclined diverging tube are increased by 32.33% and 33.12% respectively under same heat transfer area，and the pressure drop are decreased by 53.87% and 9.86%，respectively. Using comprehensive Performance Evaluation Criteria（PEC），it is found that the comprehensive performance of the horizontal diverging tube is the best. Based on the assumption that S-CO2 has“phase- transition-like”at pseudo-critical temperature Tpc ，the distribution of the liquid-like film along the length of the tube is obtained，and it is found that at the same section，the thickness of the liquid-like film of the 30° diverging tube is the smallest，the liquid- like film thickness of the constant- section circular tube is the biggest. The mechanism of heat transfer enhancement is explained from the point of view of supercritical two-phase-like. © 2023 Science Press. All rights reserved.
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页码：249 / 256
页数：7
相关论文
共 27 条
  • [1] YANG L., A novel and efficient cogeneration system of waste heat recovery integrated carbon capture and dehumidification for coal-fired power plants［J］, Energy conversion and management, 255, (2022)
  • [2] OKASHA A, DEB K., Bi-objective optimization of transcritical CO2 heat pump systems［J］, Energy, 247, (2022)
  • [3] MA Y J，, PAN L S，, WEI X L，, Et al., Theoretical investigation on performance of supercritical CO2 Brayton cycle for solar thermal power generation system［J］, Acta energiae solaris sinica, 39, 5, pp. 1255-1262, (2018)
  • [4] KHATOON S，, KIM M H., Preliminary design and assessment of concentrated solar power plant using supercritical carbon dioxide Brayton cycles［J］, Energy conversion and management, 252, (2022)
  • [5] YING Z Z, YANG T F，, CHEN D, Et al., Experiment and simulation of fluidizing-particle heat exchanger for supercritical CO2 Brayton cycle of CSP［J］, Acta energiae solaris sinica, 43, 3, pp. 274-281, (2022)
  • [6] YANG Y Y，, LI M X，, WANG K Y，, Et al., Study of multi-twisted-tube gas cooler for CO2 heat pump water heaters ［J］, Applied thermal engineering, 102, pp. 204-212, (2016)
  • [7] HUANG C Y, WANG Y，, Et al., Review on the characteristics of flow and heat transfer in printed circuit heat exchangers［J］, Applied thermal engineering, 153, pp. 190-205, (2019)
  • [8] WANG J H., Flow and heat transfer characteristics of supercritical fluids for tower solar thermal power generation ［D］, (2019)
  • [9] YOON S H，, KIM J H，, HWANG Y W，, Et al., Heat transfer and pressure drop characteristics during the in- tube cooling process of carbon dioxide in the supercritical region ［J］, International journal of refrigeration, 26, 8, pp. 857-864, (2003)
  • [10] LIU Z B, YANG Y F，, Et al., Experimental study on heat transfer and pressure drop of supercritical CO2 cooled in a large tube［J］, Applied thermal engineering, 70, 1, pp. 307-315, (2014)
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