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

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 degrees to 25 degrees. 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/m(2) 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.