Numerical simulation of thermo-pneumatic effects for gas-liquid flows in microchannels
Résumé
Numerical simulations of an air bubble flowing in a microchannel
filled with liquid water and heated on the walls are presented.
Due to the small channel size, pressure changes may be
induced by a heat supply on the walls. The aim is to quantify
these pressure changes. A specific model is developed in order
to describe the bubble pressure. Air in the bubble is modeled
as a perfect gas, under the low Mach approximation while the
liquid is modeled as an incompressible fluid. The Navier Stokes
equations and the energy equation are solved. The interface description
is performed combining front tracking techniques and a
Heaviside step function. A first validation test-case is presented.
Then, various heating conditions are examined including uniform
and non uniform heating conditions, constant and time dependent
heating conditions. It is shown that pressure oscillations
in the bubble may be induced by an appropriate thermal actuation.