冷却システム内で迂回する流れにより生じる圧力損失とその最適化

抄録

One solution to reduce the cooling system noise generated by construction machinery is to drive the fan at low speed while ensuring the flow rate required for the cooling system. An approach to achieve this is to reduce the pressure drop that occurs in the flow path in the cooling system. Using CFD is effective for estimating the three-dimensional spatial pressure drop characteristics of the system, but the mechanism of pressure drop that occurs in the three-dimensional flow field has not been clarified. In this study, the flow field around the axial flow fan placed in the cooling system enclosure is visualized, and the mechanism of pressure drop that occurs in the three-dimensional flow field considering the actual configuration is clarified. With the default exhaust port, we found that portions of the fan outlet flow divert significantly inside the enclosure and are exhausted at exhaust port outlets located some distance away from the fan. With the optimized exhaust port, there are few diverting flow and the flow in the enclosure is discharged in a shorter route than the default exhaust port, so the pressure drop is reduced and the flow rate is increased. Hence, by expelling the flow at the exhaust port via the shortest path without allowing it to mix chaotically inside the enclosure, the flow rate can be increased using the same fan speed.