M2 Sunil Rangaswamy and Axel Larsson presents their master’s thesis

Student: Sunil Rangaswamy och Axel Larsson
Main Supervisor: Nils Basse, Volvo Cars
Examiner: Hua-Dong Yao
Opponent: Prajwal Srinivas

Abstract

This report presents the creation and evaluation of an air-cooling steady state model for a Volvo Cars powerpack. It should simulate the heat transfer and temperatures from the components of the powerpack. Especially interesting is how the NVH (Noise Vibration Harshness) encapsulation effects the cooling performance. An existing 1D model already existed that handled the internal heat generation and the liquid cooling of the powerpack. Twenty chosen operating conditions were iteratively calibrated between the 1D model and a full car 3D model to yield heat transfer coefficients (HTC) for each thermal node in the extension. They were chosen as variable sweeps from a central base case, yielding four to five data points to analyse each variable's impact from separately. The results show that the air-cooling increases as a fraction of the total cooling as the car velocity and driveshaft torque increases. It also shows that most air-cooling bypasses the encapsulation, meaning it has little impact on the performance. When compared with physical measurements the accuracy of the model is poor. This is most likely caused by the lack of calibration for operating conditions where multiple variables were changed from the base case. It is therefore recommended that future work simulates these too. This could not be done in this project due to time and computational constraints.