Research Interests
Simulation of temperature gradient effects in MEMS acceleration sensors
Micro-electromechanical systems (MEMS), especially acceleration sensors, are crucial in automotive and consumer electronic devices like smartphones or airbag control units. However, in these densely packed electronic devices distances between neighboring components are very small. Thus, power intensive components like microprocessors can heat up and create temperature gradients in their vicinity. As a result, new failure mechanisms for offset drifts are introduced, which are caused by temperature driven non-equilibrium flows. Since these rarefaction effects cannot be simulated by standard Navier-Stokes solvers, an alternative Lattice Boltzmann solver is used to predict offset drifts and optimize MEMS structures.
To simulate the fluid flow inside the MEMS accelerometer, we use a Lattice Boltzmann Method (LBM) and the open source code OpenLB. The work can be split in two steps: In the first step we implement suitable boundary conditions for microflows (also called slip boundary conditions) and we evaluate different models on an isothermal flow using the Knudsen minimum paradox. In the second step we implement a thermal flow and incorporate the thermal creep effect, which describes the fluid moving only due to temperature gradients and study the influence of different parameters on the force the fluid exerts on an obstacle inside it.