In the present study, the performance of an electronic chip cooling system based on a heat sink containing Phase Change Materials (PCMs) was simulated. A novel approach for modeling the phase change process in the energy balance equation was investigated. Various PCMs, such as lauric acid, stearic acid, an‎d n-eicosane, were employed to delay the time for the electronic chip to reach its critical temperature of 80°C.This research introduced a new approach utilizing the enthalpy-porosity method. In this approach, the latent heat was modeled using data from Differential Scanning Calorimetry (DSC) analysis of the PCM. The specific heat capacity an‎d melt fraction of the PCM, calculated from the DSC analysis, were incorporated into the governing equations.The studied parameters, in addition to the type of PCM, included different applied heat fluxes (power levels) an‎d various PCM fill ratios within the heat sink cavities. The effect of the presence an‎d absence of natural convection within the PCM region was also examined.First, the results of the numerical simulation were compared with experimental data under similar conditions. The relative error percentage between the data in identical cases did not exceed 8%. This indicates a close agreement between the numerical predictions an‎d the experimental data.As expected, increasing the applied power from 6W to 15W resulted in a reduction of the time taken to reach the critical temperature. For lauric acid at a 50% fill ratio, this time decreased from 36 minutes to 9.5 minutes. For stearic acid at a 50% fill ratio, it decreased from 33 minutes to 8.5 minutes.Furthermore, for different fill ratios (30%, 50%, an‎d 80%) of both materials, an increase in the fill ratio—due to the enhanced thermal energy storage capacity—led to an increase in the time to reach the critical temperature. At 10W power, for lauric acid, the time to reach the critical temperature increased from 13 minutes at a 30% fill ratio to 20.5 minutes at an 80% fill ratio. For stearic acid under similar conditions, these values were 14 minutes an‎d 23 minutes, respectively.When 10W power was applied to the heat sink containing lauric acid at different fill ratios, neglecting natural convection resulted in a reduction of approximately 3 minutes in the time to reach the critical temperature compared to when natural convection within the PCM region was considered.n-Eicosane was studied to eva‎luate the performance of the new simulation approach proposed in this research. The results, consistent with the physical properties of n-eicosane, confirmed the accuracy of the present simulation method in predicting PCM behavior. According to the results obtained for the three materials, in the case where the critical temperature of the board is in the low range, such as 40 degrees Celsius, the n-icosane material has a better performance than the other two materials. Also, if the system operates at low powers, using 50% filling of the materials has a good performance in delaying the time to reach the critical temperature an‎d is also economical. On the other han‎d, the method used in the present study was compared with the conventional methods used in previous studies, which in addition to being more consistent with the experimental results, also has a shorter execution time. Also, the performance of the heat sink in scenarios of 10 minutes on an‎d 80 minutes off was investigated in a single cycle an‎d three consecutive cycles. In three consecutive cycles, the numerical results were more consistent with the experimental data. The average numerical error in three cycles was equal to 8%.

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محسن نصراصفهاني , ارجمند مهرباني زين آباد