The physical model of a CO2 micro-channel air cooled tube and micro-channel flat tube was established and the grid was divided. The effects of mass flow distribution were simulated when the depth f was 4

5

and 6 mm and the inlet tube was at 1/6 and 1/2 of the length of collector tube. The predicted wall temperature distribution was verified by the experimental results of CO2 micro-channel gas cooler with flat tube. The predicted results show that when f is 4 mm and the inlet pipe is at 1/6 location of the collector tube

mass flow distribution is the best with an unevenness of 0.4×10-3. The predicted heat transfer of CO2 in the flat tube shows that with the increase in mass flow of CO2

the heat exchange in the flat tube increases. When the mass flow rate is increased from 2.3 kg/h to 2.5 kg/h

the heat exchange rate is increased by 21.4%. When the mass flow is kept constant

the outlet temperature of CO2 increases with the increase in CO2 inlet temperature. Besides

under the condition of different CO2 inlet temperatures

the error range of the micro-channel flat wall surface temperature between experimental and simulation values is within 10%

which verifies the accuracy of this simulation. Therefore

the results can guide the engineering design of micro-channel cooling unit.