You think the fan is working inefficiently? The air flow is behaving suspiciously? Consumes too much energy? Perhaps the reason in the form of blades... or mode of operation... or operating conditions… Computer experiment will help to give the answer!

CALCULATION OF FLOW RATE CHARACTERISTICS OF THE FAN

Computer simulation of air flow resulting from rotation of the rotor fan has been carried out. The geometric model of the rotor and the rotational speed (4000 rpm), consistent with the design and operating conditions of a standard PC cooling system fan. Virtual experiment allowed us to determine the airflow through the fan (average velocity at the inlet and outlet of the system, mass flow), to see a picture of traffic flows, and calculate the loads on the blades.

The problem was solved in the nonstationary setting, but to initiate the decision the results were used of a preliminary steady-state solution.

Fig. 1. – The distribution of the vector velocity field in the cross section of the model

Figures 2 and 3 show graphs of mass flow and mean flow velocity at the inlet and outlet of the design. It is noticeable that although the magnitude of the average velocity oscillates around its mean value (Fig. 2), these variations can be considered negligible due to their small influence on the mass airflow (Fig. 3). This allows when calculating the cooled space to replace the rotating fan by fixed boundary, which defines the input flow rate equal to the average velocity at the outlet fan.

Fig. 2. – Average velocity at the inlet and outlet of the model

Fig. 3. – Mass flow of air through the inlet and outlet boundary