Transient cooling of electronic components by flat heat pipes

This paper presents a theoretical investigation of a Flat Heat Pipe (spreader) designed for the cooling of multiple electronic components in transient state. This model is a transient model, coupling 3D thermal model with a 2D hydrodynamic one through the mass flux of evaporation–condensation, which occurs in a mass conservation equation. The model makes it possible to obtain the FHP wall transient temperatures, the transient pressures, velocities and temperatures in both liquid and vapor phases. A comparison of the behaviour of the FHP and an equivalent solid plate submitted to a transient thermal cycle shows that the FHP enhanced the electronic components cooling for the long thermal cycle duration when the solid plate is more efficient for the very short transient thermal cycles. The FHP provides also a very low thermal resistance, which helps to minimise the temperature gradient and then the hot spots and overheating.