Simulation of Single Bubble Dynamics in Nucleate Pool Boiling Using a Conservative Level Set Method

Most energy conversion systems and cooling devices employ nucleate pool boiling because of its high efficiency of heat exchange. It is a liquid-vapor phase change process associated with ebullition, characterized by cyclic growth and departure of vapor bubbles from heated wall and greatly influenced by the bubble growth mechanism. Bubble dynamics is difficult to simulate due to the difficulty of tracking the liquid vapor interface without smearing it, the discontinuity in material properties due to high density ratio and the need to take surface tension into account that introduces a jump in the pressure field. This paper focuses on the accurate representation of surface tension effects on bubble dynamics in nucleate pool boiling. The complete Navier-Stokes equations are solved and liquid-vapor interface is captured using a conservative level-set technique, curvature of interface is computed using the level set function and surface tension forces are evaluated as a body force according to the continuum surface force method. This enables us to simulate flows with large density and viscosity differences, to capture the shape of the deforming interface of the bubble while maintaining good mass conservation. The ability of the model is demonstrated with the numerical example of a growing bubble.