No abstract

The problem of controlled liquid delivery to a microelectromechanical system (MEMS) device is one that is being continuously investigated. There are many types of valves being fabricated for different applications. For single-use systems, burst valves are an ideal choice. These types of valves ensure that there is no leaking of the fluid to the rest of the system. Models have been developed using COMSOL multiphysics incorporated in an optimization routine to study and predict the behavior of valves made with metallic resistors over silicon nitride membranes, with the goal of developing a tool that can be used to design low-power valves. Power and temperature data for valves made in our MEMS facility have been used to obtain an average overall heat transfer coefficient, which in turn is used to predict the voltage, temperature and stress of the breaking point of the valves. The simulation results were found to be adequate to represent the behavior of valves for two ohmic heater designs fabricated with gold and platinum. The models can be used to compare different valve designs to minimize the energy required for actuation. Experimental data showed that the valves could be broken with between 15 and 50 mJ.