Pressure Drop Mechanisms Generated in a Cooling System Enclosure of Construction Machinery

A potential way to reduce cooling system noises generated by heavy construction machines is to generate the required cooling airflow with a low fan speed, and one way to accomplish this is to optimize the ventilation path through which the airflow generated by the cooling fan must travel. However, while the computational fluid dynamics (CFD) approach would be effective for modeling the three-dimensional (3D) pressure drop characteristic of such systems, there have been few reports aimed at clarifying the loss generation mechanisms or suggesting minimization methods based on flow field viewpoints. Accordingly, in this study, we visualize the 3D flow field characteristics of an electric cooling fan system installed within the cooling enclosure of a heavy construction machine and investigate the details of the system’s pressure drop mechanisms. Our results confirm that airflow pressure declines in areas other than the radiator account for more than half of the reduced pressure experienced by the whole system. Additionally, we found that, in the exhaust side enclosure, pressure drops increased because the exhaust port outlet shapes were not optimized to the annular airflow of the cooling fan. Most notably, we found that in the region before reaching the exhaust port outlets, the airflow from the fan repeatedly collides with obstacles within the enclosure, thus producing stagnation and turbulence that exacerbates pressure drops before being expelled into the outside environment.