Calculation of fan efficiency, pressure ratio, and flow rate after changing the medium

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For a fan, the experimental data are as follows: the inlet conditions involve air at 98 Kpa and 60°C (with a specific heat ratio of 1.4 and composed of 79% N2 and 21% O2), the flow rate is 100 m3/min, the pressure ratio is 1.5, and the motor power is x KW. So for this fan, when the medium is changed to pure CO2 (assuming a specific heat ratio of 1.3), the inlet parameters are 1 atm (one atmosphere) and 0℃ ； At this time, what are the fan’s flow rate, pressure ratio, and motor power? What assumptions are needed to obtain such a result? My current idea is: first, assume that the velocity at the fan inlet, the volumetric flow rate, as well as the rotor speed of the fan and its efficiency are all equal ； Second, if the velocity triangles are identical, various losses (friction, leakage, secondary flow, etc.) are approximately proportional, and the Mach number of the impeller is less than 0.3 (without considering density changes), then the principles of geometric similarity in similarity theory, equal Beckley numbers, equal inlet Mach numbers, and the effect of Reynolds number can be neglected (RE > 2×10^5). However, the adiabatic indices k of the two gases are not equal; what should be done in such a case to calculate the flow rate, pressure ratio, and motor power of the fan for different media? Help, please! Thank you all, guys!