## 2 Materials and Methods
### Experimental Study  
In this section, an experimental approach was used to evaluate the performance of different heatsink designs used in the cooling systems of induction hobs. The cooling system consists of a radial fan and a customized heatsink to dissipate the heat generated by electronic components. The experimental setup, as shown in Figure 4, includes a bottom plastic casing, a radial fan, and a metal heatsink. A radial-type fan was positioned in front of the metal heatsink to ensure temperature control between the heatsink and electronic components. A Design of Experiments (DOE) study was first conducted to optimize the measurement method for the Type 1 heatsink. Three factors were considered: heatsink position, measurement location, and probe freedom. Table 2 shows the full factorial design, which included three factors at various levels and a total of 12 measurements. During assembly, it is essential that the heatsink fins are aligned with the fan airflow to ensure efficient heat transfer. Misalignment during production or testing can distort airflow and lead to incorrect conclusions about cooling performance. To investigate this effect, heatsink position was defined as the first factor, with three levels. While angular misalignment was randomized, the same angle was kept constant across all tests to avoid additional variation. In the \"in fan\" configuration, the heatsink was placed directly inside the fan outlet channel. In addition, two more factors were introduced to assess their influence on airflow measurement accuracy. One is measurement type (two levels: fixed hand position vs. free hand position while holding the probe), and other is probe freedom (two levels: probe tip fixed vs. probe tip free). \begin{table}
\begin{tabular}{c c c c c} \hline
**Component** & **Component** & **Density** & **Specific Heat** & **Conduction Coef.** \\
**Name** & **Material** & **[kg/m\({}^{3}\)]** & **[J/kgK]** & **[W/mK]** \\ \hline IGBT & Silicon & 2330 & 750 & 125 \\ Bottom Tray & PA66 & 1140 & 1670 & 0.25 \\ Electronic Board & FR4 & 1850 & 1100 & 0.35 \\ Heatsink & AI 6061 & 2700 & 896 & 167 \\ Other Electronics & Silicon & 2330 & 750 & 125 \\ \hline \end{tabular}
\end{table} 
Table 1: CFD model—material properties. Figure 4: Experimental setup. After completing the DOE study, air velocity measurements were taken at specific points located (middle of the red circles) at the outlets of Type 1, Type 2, and Type 3 heatsinks, each positioned in front of the radial fan. These points highlighted as red circles are illustrated in Figure 5. For consistency, the Testo anemometer probe was carefully placed in the center of the fin spacing, and positioned between the fins rather than on their surfaces to avoid influencing the airflow or surface temperature. To further reduce variability in the measurements, an additional DOE study was conducted focusing on two experimental factors: the steadiness of the operator's hand and the freedom of the probe tip. These factors were systematically analyzed to understand their effect on measurement accuracy. As a result, an optimized methodology with reduced error margins was established, ensuring greater reliability and repeatability in airflow measurements for all heatsink types. The determined heatsink position, measurement type, and factors are shown in Figure 6. The probe freedom factor is defined based on whether the probe is fixed with a fixture or left unfixed. Air velocity measurements were taken at several predefined points in the outlet region of each heatsink, as shown in Figure 5. To ensure measurement reliability, each point was tested three times. Two different operators (ASM and MHR) performed the measurements to evaluate operator-related effects. The collected data were analyzed using One-Way Analysis of Variance (ANOVA) to examine the influence of the operator, measurement point, and timing on airflow results. ANOVA helps determine whether differences in group means are statistically significant.