Performance evaluation of PEMC liquid level detection sensors subjected to temperature variation

In this study, a Resonant Piezoelectric-excited Millimeter-sized Cantilever (PEMC) is used for liquid level sensing. The effect of environmental temperature variation on the performance of a piezoelectric liquid level sensor is investigated via Finite Element Modeling (FEM). In order to validate this model, the results obtained by FEM are compared with the theoretical and experimental results for a sensor operating at constant room temperature. The results show that the FEM developed in this study can predict accurately the dynamic behavior of sensor subjected to temperature variation of environment. The results of the simulation show that although the natural frequencies of sensor change due to temperature variation, the resulted shift remains almost the same regardless specific immersion depths. The results demonstrate that temperature variation of about 50°C affects the liquid level measurements accuracy up to 100μm which is significant comparing to a minimum detectable liquid level change of about 8μm by this sensor reported previously in literature.