Numerical study on Flow Characteristics of Microchannel Shell-and-Tube Heat Exchanger with Supercritical CO2
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DOI: 10.23977/meimie.2019.43025
Author(s)
Jiang Xinying, Fang Yufeng and Liu Meng
Corresponding Author
Jiang Xinying
ABSTRACT
The microchannel shell-and-tube heat exchangers with supercritical CO2 have the characteristics of small volume and high operating temperature. Based on the heat transfer formula and heat balance equation, the practical conditions, such as the variable properties of supercritical fluid, heat dissipation in high temperature conditions and uneven mass flow distribution in microchannels, are considered to establish a thermal calculation model suitable for supercritical fluid and microscale heat transfer, and uses MATLAB programming for numerical calculation. The research found that the heat dissipation cannot be ignored under the high temperature conditions even microchannel heat exchanger volume is small. The heat dissipation rate decreases with the increasing heat transfer power per unit volume. Affected by heat dissipation, the flow distribution between the outermost and middle layer has a large gap. The mass flow rate in columns of tubes decreases along the direction of high-temperature airflow affected by the order of contact with the high temperature flow. The results show that increasing the unit heat power can reduce the heat dissipation, and reducing the diameter of microchannel can reduce the uneven flow distribution.
KEYWORDS
Microchannel tube, supercutical fluid, Microscale fluids