Computational fluid dynamics simulations of a realistic mini-truck engine cooling fan with comparison to experimental design conditions.

In general, the thermodynamic power cycle of a mini-truck diesel engine has a thermal efficiency of less than 40%. During operation, its cooling system needs to transfer around 60% of the generated heat to air at the radiator. Nowadays, diesel engines have high performance, producing a large amount of mechanical power, which inevitably leads to a large amount of heat being rejected. Thus, the radiator demands a higher air flow rate. Additionally, fan efficiency is also important since the fan itself draws the power from the engine. Therefore, both performance and efficiency are critical parameters to be considered for the cooling fan. In Thailand, there is another consideration concerning the country's hot and humid environment with its frequent traffic jams in urban areas. This paper presents computational fluid dynamics (CFD) simulations of a mini-truck engine cooling fan operating at two rotational speeds. The resulting fan static pressures and flow rates are compared with (limited) experimental data. The pressure values are roughly 11% different from the experimental data due to the pressure measuring locations. For the flow rates, the difference between the simulations and the experimental data are about 48%. The large differences are due to differences between the experimental method from the fan testing standard and the simplified simulation setup as well as possibly deviations in the 3D model of the fan geometry from the actual piece. Nevertheless, the performance trends from the simulations are consistent. For example, the ratio of the flow rates at the two operating conditions is close to that from the experimental data. Thus, the simulation methods as set up in this work have potential to be used in the design process of engine cooling fans. [ABSTRACT FROM AUTHOR]