The heat transfer characteristics of supercritical CO_2 in non-uniform heated vertical upward flow were studied by numerical simulations

under conditions with mass flow rate of 100 kg/(m~2·s)

heat flux of 28～50 kW/m~2 and inlet pressure of 7.6～8.6 MPa. The differences between uniform and non-uniform heating were compared. In terms of non-uniform heating

the effects of heat flux and inlet pressure on convective heat transfer coefficient

buoyancy effect and acceleration effect were discussed. Based on the numerical results

a new heat transfer correlation was developed and compared with the present simulation data. The results show that

compared with uniform heating

the local convective heat transfer coefficient is lower and the wall temperature is higher under nonuniform heating. With the increase of heat flux

the convective heat transfer coefficient decreases

while the buoyancy and acceleration effects are more pronounced. Under high heat flux condition

with the increase of inlet pressure

the convective heat transfer coefficient increases

while the buoyancy and acceleration effects decrease. The new heat transfer correlation can predict the heat transfer mechanisms of supercritical CO_2 in this study well.