Experimental and numerical investigations on the intermittent heat transfer performance of rectangular cavity plate fin phase change material based heat sink

Thermal management of equipment in confined spaces is of great importance for the safe operation of equip-ment. Solid-liquid phase change materials (PCM) can be applied to the thermal management of intermittent electronic equipment because of their large isothermal latent heat absorption capacity. In this paper, experi-mental and numerical research on the thermal performance of an intermittent rectangular cavity plate fin PCM-based heat sink is carried out, which can be applied to heat dissipation in narrow spaces with high heat flow. The optimal PCM-based heat sink structure is obtained by numerical simulation based on the Taguchi method, and the enthalpy method is used to model the phase change process. Temperature testing and visualization experi-ments are used to visually present the PCM-based heat sink's internal temperature distribution and validate the numerical model. The effects of fin structure parameters, heating power, cooling air speed and number of intermittent cycles on thermal performance (base temperature, liquid fraction and operating time) are analyzed for different structured PCM-based heat sinks. The results show that the PCM-based heat sink with 8 fins, 15 mm fin height and 2 mm fin thickness has the longest stage C at the critical base temperature of 348 K and reaches the maximum operating time of 1193 s during the charging cycle. The natural convection in stage C of the charging cycle plays a crucial role in prolonging the operating time. Meanwhile, increasing the number of intermittent cycles can result in longer operating time and lower critical base temperature. As the number of intermittent cycles increases from 1 to 8, the temperature difference between the maximum and minimum temperature of the base during the whole cycle is reduced from 48 K to 25 K, and the temperature fluctuations gradually decrease.