## 1 Introduction
T-WorkFlow not only automatically generates the computational grid and the set-up for the flow simulation but also produces dedicated output to monitor, for example, the solution evolution at run-time. In fact, the tool can \"capture\" a cross-sectional control surface for each radiant channel, regardless of the CAD reference system, and monitor the volumetric flow rate distribution in each of them, along with the corresponding standard deviation value. The main post-processing operations are also fully automated, and the tool provides quantitative results to help the designer identify the radiator configuration that meets the desired performance. This includes achieving an almost uniform distribution of flow across channels for a given flow rate value at the inlet. This condition is of utmost importance as it enhances the overall efficiency of the heat transfer. The radiator case study presented in this paper mainly serves as an example of the potential applications of similar automation tools in a real industrial design process. In fact, the main goal of this work is to gain and share experience in developing a, possibly open-source, complete CFD workflow that is as general as possible and that can be easily \"extended\" to the simulation of other car details, e.g., external aerodynamics, in the near future. It is important to note that this work focuses on process optimization; thus, assessing the accuracy of the numerical results is not the primary objective, as the company has previously established a correlation with the experimental data. This prior knowledge undoubtedly allowed for the confident selection of physical models and numerical strategies used in this research. In developing T-WorkFlow, we intentionally limited the number of user inputs as much as possible, e.g., by automating the choice of the parameters needed for mesh generation, to make the tool more user-friendly and suitable for the \"repetitive application\" in batch simulations and/or optimization cycles. Together with the few numerical user inputs to be set through a graphical interface (cf. Section 3.1), T-WorkFlow requires the CAD model of the radiator to be simulated in.stp format, along with the triangulations of the inlet, outlet, and wall surfaces in.stl format, as shown in Figure 1. These files are essential for both mesh generation and automatically setting the boundary conditions in the OpenFOAM [5] dictionaries. In this paper, we evaluate the performance of T-WorkFlow by simulating two radiator models. These are completely identical from the geometrical point of view, with the exception of the junction area between the channels and the inlet and outlet tanks. Configuration A exhibits radiant channels smoothly connected to the external surface of the tanks, while Configuration B is characterized by channels \"partially immersed\" in the water tanks. These differences are illustrated in Figure 2 through a cross-sectional detail near the tanks of the flow domain. Actually, each radiator mounted on Tatuus cars has a tank-channel junction similar to that of Configuration B. Configuration A, on the other hand, is a possible geometric simplification that leads to a reduction in the number of mesh elements and thus to computational savings; see Section 4. Therefore, the specific objective of the comparison presented in this paper is to understand whether the simplified Configuration A can be effectively used to study the performance of this radiator model without deviating significantly from the numerical results obtainable from the \"real\" Configuration B. Computational savings ensured by the use of Configuration A in place of Configuration B represent an aspect of foremost importance considering the high number of simulations and the tight deadlines characteristic of the design phase. To this purpose, in Section 4, performance indicators for these two configurations are presented and compared. Figure 1: Boundary surfaces for a generic radiator model. Figure 2: Cross-sectional detail near the tanks of the flow domain.