Assessment & optimization of Front End Cooling module of a
Commercial Vehicle by CFD based simulation & prototype
Overall cycle time and prototype testing are significantly decreased by assessment of cooling module performance in the design stage itself. Hence, Front End Cooling and Thermal Management are essential components of the vehicle design process. Performance of the cooling module depends upon a variety of factors like frontal opening, air flow, under-hood sub-systems, module positioning, front grill design, fan operation.
Effects of design modifications on the engine cooling performance are quantified by utilizing computational fluid dynamics (CFD) tool FluentTM. Vehicle frontal configuration is captured in the CFD model considering cabin, cargo and underbody components. Heat Exchanger module is modelled as a porous medium to simulate the fluid flow. Performance data for the Heat Exchanger module is generated using the 1D KuliTM software.
In this paper, CFD simulation of Front End Cooling is performed for maximum torque and maximum power operating conditions. Analysis results predict and plot the air flow patterns in the under-body region by obtaining velocity streamlines in the wind tunnel volume. Hot and cold air recirculation zones are identified and rectified by design changes. Temperature and velocity data for the inlet surfaces of Heat Exchanger are obtained to better describe the air flow impact. Limiting Ambient Temperature (LAT) and Intake Manifold Temperature Difference (IMTD), two important parameters which signify the cooling performance of radiator and intercooler respectively are calculated and set within the acceptance criteria.
Reduction of hot air recirculation over Heat Exchanger module leads to significantly improved cooling performance. Design modifications of the front end geometry and use of different heat exchangers and fans produce better results by means of an iterative process. The methodology is validated by conducting cooling trials in the vehicle for both the operating conditions. Overall correlation between CFD predictions and test results is excellent.