Due to the advantages of small power equipment and high efficiency

the supercritical CO_2 Brayton cycle power generation system has great potential for application. The heat transfer characteristics of supercritical CO_2 is one of the critical parameters for design of relative devices of the power generation system

and it is experimentally studied in a horizontal straight circular tube where the maximum pressure of supercritical CO_2 reaches 15 MPa and the maximum temperature reaches 500 ℃. The results show that: the higher the pressure of the supercritical CO_2

the lower the peak value of the heat transfer coefficient at the pseudo-critical temperature and the flatter the change of the heat transfer coefficient with the temperature; while at high temperatures

the heat transfer coefficient mainly depended on the mass flux. A heat transfer correlation of supercritical CO_2 at temperatures ranging from 30 ℃ to 500 ℃ was proposed

it can not only predict the heat transfer characteristics of supercritical CO_2 well in the vicinity of the pseudo-critical temperature

but also accurately predict the heat transfer characteristics at high temperatures.