For example, the heat flux in ICs is usually conducted to the heat sink through interconnects and thermal vias, then dissipated to the air through convective heat transfer between the air and the surface of the heat sink. Among them the first two cooling ways have been widely studied and applied. Since the heat transfer mechanisms can be categorized into three different modes: conduction, convection and radiation, the corresponding cooling techniques also include conduction cooling, convection cooling and radiation cooling 7. Countless examples can be provided to prove the necessity of developing cooling techniques. Each increase in temperature of 1вЂ‰вЊ results in a relative efficiency drop of about 0.45% for crystalline silicon solar cells 6. Moreover, in the field of photovoltaics, the increased temperature of the solar cells induced by the sunlight shows a great influence on its reliability and efficiency. Therefore, the effective dissipation of the high heat flux is indispensable for the normal operation of these components. Driven by the modern military requirements, the power level of the RF/microwave components becomes higher and higher, leading to extremely high operating temperature 5. Research indicates that more than 50% of ICs failure is associated with the thermal issues 4. But meanwhile it also jeopardizes the performance and reliability of ICs due to the increased power densities and high on-chip temperature 1, 2, 3. For instance, with the broad applications of three-dimensional (3-D) packaging and interconnection technologies, the integrated circuits (ICs) possess great benefits including high density, reduced signal delay, low power consumption, capable of heterogeneous integration, etc. The proposed numerical model can provide a powerful tool to gain deep physical insight and optimize the physical design of radiation cooling.Д¬ooling techniques have become increasingly important in many areas.

Numerical results are given to demonstrate the accuracy, flexibilities and potential applications of the proposed method.

In this paper, we combine the heat conduction equation with a rigorous radiation boundary condition discretized by the finite-element time-domain method to simulate the radiation cooling accurately and flexibly.

The traditional way to simulate the radiation cooling is to solve the thermal conduction equation with an approximate radiation boundary condition, which neglects the wavelength and angular dependence of the emissivity of the object surface. Thus the simulation method for radiation cooling was also seldom noticed. There are three cooling routes for thermal management, namely thermal conduction, thermal convection and thermal radiation, among which the first two approaches have been widely studied and applied, while the radiation cooling has not yet attracted much attention in terrestrial environment because it usually contributes less to the total amount of thermal dissipation. Thermal management and simulation are becoming increasingly important in many areas of engineering applications.

Comsol 5.3 documentation view 2017