Abstract: With the improvement of people requirements for a healthy indoor environment, the current indoor fresh air exchange cannot effectively improve the indoor air quality. In order to ensure effective indoor ventilation, provide sufficient fresh air volume and improve product competitiveness, wall-mounted air conditioner is taken as the research object, by optimizing the aerodynamic resistance of various components in its internal multi-blade centrifugal fan module, the low impedance air flow improvement design is carried out from the aspects of air inlet pipe, air cavity, fresh air filter and so on. By verifying the hand model, the fresh air volume is increased by about 33% at the same speed; At the same time, under the condition of sufficient fresh air rate, the internal air flow uniformity is improved and the noise quality at the same speed is guaranteed.

Key words: Air conditioner, Multi-blade centrifugal fan, Fresh air rate, Aerodynamic optimization