Abstract:

Based on the existed experimental results， this paper applies the Computational Fluid Dynamics （CFD） to investigate the leading edge structure of the cooling tube and airflow speed on the thermal-hydraulic performance of an air-cooled charge air cooler （ACAC）. Results showed that， under the same fillet radius R₁ the Fanning friction factor f raises with the increasing airflow speed， but at the same airflow speed f decreases with the increasing of R₁， when taking R₁=0.9 mm as a baseline， the f of R₁=0 mm increased at a maximum of 12.42%， the f of R₁=3.6 mm deceased at a maximum of 5.41%； For the Nusselt number Nu， under the same fillet radius R₁ it raises with the increasing airflow speed， but at the same airflow speed it decreases with the increasing of R₁， also taking R₁=0.9 mm as a baseline， the Nu of R₁=0 mm increases at a maximum of 2.22 % and the Nu of R₁=3.6 mm decreases at a maximum of 1.49 %； For PEC， under the same fillet radius R₁ it raises with the increasing airflow speed， and at the same airflow speed， it also increases with the increasing of R₁， again taking R₁=0.9 mm as a baseline， the PEC value of R₁=0 mm decreases at a maximum of 10.13 % and increases at a maximum value of 3.4 % when R₁=3.6 mm. In summary， when R₁=3.6 mm， airflow speed equals 7.5 m/s， the ACAC achieves its best thermal-hydraulic performance， therefore， increasing R₁ and airflow speed is helpful to improve the thermal-hydraulic performance of ACAC.

Key words: mechanical engineering, air-cooled charge air cooler, leading edge structure of cooling tube, airflow speed, computational fluid dynamics, thermal-hydraulic performance