Thin film NiTi microthermostat array

An autonomous flow restricting microthermostat array was successfully designed and fabricated using thin film nickel–titanium (NiTi) shape memory alloy (SMA). The device relies on changes in the environmental fluid temperature for closing without external electric sources. The array of 88 microthermostats was tested at pressures ranging from 6.9 to 34.5 kPa and water temperatures of room temperature and 80 °C. At 34.5 kPa and room temperature, the flow rate was 722.8 ml/min. As the temperature of the water increased to 80 °C, the flow rate was reduced by 90% depending on the pressure. Finite element predictions are in relatively good agreement with the measured flow rates.