Optimization and Correlation of a Class 8 Truck Cooling System

Abstract

Development in engine technology to meet recent heavy vehicle emissions legislation has increased the demand on heavy vehicle cooling systems. The use of PowerFLOW®, a commercial computational fluid dynamics (CFD) software, allows a product development team to access a variety of cooling system improvements with no impact to the vehicle external appearance. This paper provides an overview of the PowerFLOW® modeling process and the results for several studies involving modifications to engine and cooling system parts. The design changes include the repositioning of the exhaust gas recirculation (EGR) cooler, changes to the fan diameter and position, and modifications to the exit shape of the shroud. Initial work focused on increasing cooling air mass flow and used a body force fan model with isothermal calculations. Results indicated only minimal changes with the EGR cooler repositioning, however, fan modifications resulted in a 13 percent cooling air massflow increase. The impact of the fan shroud exit shape on fan blade tip loss was computed with a multiple reference frame (MRF) fan model. Finally a detailed cooling system correlation study was performed involving a comparison to isothermal air mass flow rates and later thermal calculations involving heat exchangers modeled with PowerCOOL®