TES chairman, Dr. Ben Zandi, recently gave a keynote presentation at the SAE World Congress on “Advances in Modeling and Simulation of Vehicle Thermal Management Systems”. Below is the description of the presentiation:
Speed and accuracy are of paramount importance in the modeling and simulation of vehicle systems and components. Today’s commercially available thermal/flow analysis software packages either offer speed or sacrifice speed for accuracy: 1) approximate modeling using one-dimensional (1D) simplistic network solvers (flow and thermal) for quick prediction of flow and thermal fields, or 2) detailed modeling using complex and sophisticated three-dimensional (3D) heat transfer and computational fluid dynamics. The first approach provides the simulation speed, sacrificing accuracy and can possibly lead to oversimplification, while the second approach offers accuracy at the cost of speed. Therefore, the analyst is often forced to make a choice between the two approaches, or find a way to link or couple the two methods. The linking between one-dimensional and three-dimensional models using separate software packages has been attempted and accomplished for a number of years with some frustration. This coupling procedure involves a very tedious and time-consuming task of interfacing between the two packages made more difficult by the lack of access to the source code. Furthermore, there may be issues relating to overall convergence, as well as the convergence of each solver, which can lead to compromised accuracy. For a truly coupled approach, modifications to the source code of the solvers would be required if the analysts had access to it.
This presentation discusses the advantages and shortcomings of each methodology and offers a hybrid approach to bridge the gap between “speed” and “accuracy”. A complete thermal modeling and simulation methodology is introduced offering a variety of approaches for modeling complex systems and components. This avoids any of the unnecessary “overhead” associated with a single modeling approach type. As an example, by allowing the combination of a full three-dimensional analysis in the radiator and the use of a network-based approach for pipes and pumps, the analyst can study the effects of orientation, fouling and related environmental conditions within the radiator and its effect on the complete system. The ability to combine these modeling approaches within a single system model allows one to employ the right tool for the job. This greatly reduces the model development / analysis time allowing for the timely generation of results from which informed design decisions can be inferred. This modeling approach is demonstrated though 1D/3D examples analyzed using the ADFlo software package.