Numerical simulation of pool boiling heat transfer on rib surfaces under non-uniform electric field

Boiling heat transfer has become the primary method for dissipating heat from high-power electronic devices. However, the heat dissipation mechanism of boiling in high-voltage environments urgently needs improvement. In this study, a numerical calculation model coupling electrical, thermal, and fluid fields was established. By customizing the electric field force equation and employing the vapor-liquid phase change Lee model, four different electrode configurations were designed on the rib surface, each generating a distinct electric field structure. Numerical simulations of boiling on rib surfaces with the four electrode arrangements under various voltage differences revealed that non-uniform electric fields are generated at the rib corners. Bubbles were observed to deviate from the strong field region and escape to the weak field region under the influence of the electric field. This effect can disrupt the vapor film covering layer during the transition boiling or film boiling stages, thereby enhancing the boiling heat transfer capability and increasing the critical heat flux. Within the voltage difference range of U = 25 similar to 75 kV, designing non-uniform electric fields could uniformly increase the heat flux density on the rib surface, while also enhancing the critical heat flux by 10.9 % to 35 %. This study provides theoretical support for the design of novel cooling systems and heat dissipation structures for highvoltage, high thermal power electronic devices.