The Development and Performance Characterization of Turbine Prototypes for a MEMS Spirometer

The design, optimization, and performance characterization of turbine prototypes for the development of a Microelectromechanical Systems spirometer is reported. Four different turbines were designed based on large-scale Savonius turbine architecture. The number of turbine blades was optimized through finite-element simulations to maximize the induced moment and rotational speed at normal breathing flow rates. The turbines were manufactured and tested for their speed performance with respect to input flow rate, pressure difference, and actuation power, showing good agreement with the simulation results. The highest rotational speed was achieved with involute-bladed turbine design with eight blades, and was measured to be 10.56 kr/min at the peak 25-lpm flow rate. Real-life testing with this design was carried out on healthy subjects to demonstrate its capability of performing respiration flow rate measurements. The turbine prototypes presented in this paper allow for the development of low-cost and portable MEMS spirometers for remote- and self-monitoring of lung malfunctions in chronic obstructive pulmonary disease and asthma diseases.