Development of CFD method to model thermal properties of laminates in a truck cab : Modeling solids and HVAC performance

Sammanfattning: The study of Heating, Ventilation and Air Conditioning (HVAC) system performance is important to understand its energy consumption, especially for electric vehicles. The purpose of this thesis is to develop a methodology to simulate the flow within the Scania S20H cab while also capturing the thermal properties of the fluid and solids within the cab. This is done by setting up a heat-up simulation of a stationary cab in STAR-CCM+ (Siemens Industry Software Inc, Plano TX,USA). The thesis speaks about the limitations with the current methodologies and delves into the theoretical aspects of such a scenario. The new method is a complete Computational Fluid Dynamics (CFD) method that involves conjugate heat transfer, shell modeling and temperature dependent Heat Transfer Coefficient (HTC). A benchmark case is run to understand the uncertainties introduced by virtue of the shell model. When its effects are understood and deemed minimal in the context of thesis, a steady state case for the full truck model is simulated. After it was found that the physics is well captured, a fully transient case is run to validate the model against the experimental data. The simulations best capture the behaviour of low insulation and low thickness areas such as the windshield. The gap between the simulation and experiment increases with increasing thickness and insulation. The model is found to perform mostly well with some variations between regions in the cab. The thesis satisfied its objectives in developing a methodology to better ease the conceptual design process. Additionally, guidelines for the workflow of the methodology are presented along with the limitations and scope for improvement.