Numerical Study on Heat Transfer and Flow Characteristics of Supercritical CO₂ in Printed Circuit Heat Exchangers with Zigzag Channels

Abstract

The heat transfer and flow characteristics of supercritical CO₂ in zigzag printed circuit heat exchangers (PCHEs) with different arcuate-sectional channels are numerically analyzed in this paper. The influences of channel width and bending angle of PCHE channels were discussed in detail. The upper side length of the arcuate channel ranges from 1.6 to 4.0 mm, and the bending angle varies from 15° to 25°. The inlet temperatures and pressures in cold side and hot side of PCHE are 373 K, 21 MPa and 493 K, 9 MPa, respectively. The mass flux in both sides of PCHE is equal, which ranging from 200 to 600 kg/m² s. The results show that the characteristics of heat transfer and flow in zigzag PCHEs are extremely complex, which are mainly related to the flow impact and separation in channels. In general, increasing channel width can enhance the heat transfer. In a certain mass flux and bending angle range, increasing the channel width appropriately can reduce the friction factor effectively. However, when the limit is exceeded, increasing the channel width will increase friction factor. Therefore, appropriate channel width and bending angle can simultaneously enhance heat transfer and reduce resistance, which has significance for the design optimization of PCHE structure.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (Grant Nos. U20B2035 & 11675128).

Notes on contributors

Qingqing Wang

Qingqing Wang is a Ph.D. candidate in State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, China. His current research fields are supercritical heat transfer experiment and numerical calculation, compact heat exchanger design and nuclear reactor safety.

Xin Huang

Xin Huang is a Ph.D. candidate in State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, China. His current research fields are supercritical heat transfer experiment and numerical calculation, and flow field analysis of air-cooling power plant.

Bo Xu

Bo Xu is a Ph.D. candidate in State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, China. His current research fields are air-liquid two-phase flow in nuclear piping, and flow noise analysis.

Qiuxiang Chen

Qiuxiang Chen is a Ph.D. candidate in State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, China. Her current major research field is nuclear reactor safety, including analysis of nuclear reactor water-loss accident, and nuclear reactor direct safety injection.

Haijun Wang

Haijun Wang is a full professor in State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, China. He obtained his Ph.D. in power engineering and engineering thermophysics in 2001 from Xi’an Jiaotong University. His research interests include multiphase heat transfer, supercritical heat transfer, nuclear reactor safety and air-cooling system.