A MEMS Turbopump for High-Temperature Rankine Micro Heat Engines—Part II: Experimental Demonstration

This paper presents the experimental demonstration and characterization of a MEMS turbopump with thermal insulation for high temperature operation. The fabrication and design were presented in the first part of this two-part paper. The device consists of a five-wafer stack enclosing a hybrid silicon-glass rotor supported by fluid film bearings, manufactured using MEMS fabrication methods. The rotor consists of a 4-mm diameter disk with microturbine blades on one side and a spiral groove viscous pump on the other side. First, the bearings, turbine and pump operation are characterised, up to a rotational speed of 100 kRPM. The turbine provided 0.16 W of mechanical power and the pump flow rate was above 2.55 mg/s. Then, the first demonstration of a MEMS turbopump operating at elevated temperatures was accomplished. Comparison was made with a non-insulated rotor to prove the effectiveness of the thermal insulation strategies. The insulated MEMS turbopump was demonstrated at 160°C on the turbine side without boiling water on the pump side. This work therefore enables the implementation of efficient and high-power density power plants-on-a-chip for a wide range of waste heat recovery applications. [2020-0051].