Thin film NiTi fluidic-thermostat array

An autonomous fluidic-thermostat array was successfully designed and fabricated using thin film nickel-titanium (NiTi) shape memory alloy (SMA). Unlike existing micro-devices that require external electric sources for opening/closing, the present device relies on changes in the environmental fluid temperature. This micro-scale device was tested as an array of thermostats and produced a maximum flow rate of 722.8 ml/min with 34.5 kPa of forward pressure. The flow rate reduced as much as 60% when the temperature of water increased to 80/spl deg/C. The large energy density property (i.e. 25 MJ/m/sup 3/) of NiTi enabled the thermostat flap to reduce flow rate with dynamic liquid pressures ranging from 6.9 kPa to 34.5 kPa.