Micro Newcomen steam engine using two-phase working fluid

A micro steam engine is developed based on Newcomen steam engine. In the micro engine, a flexible ripple tube takes the place of piston and cylinder, to overcome the serious problems of friction and leakage in micro scale. We use two-phase octane as working fluid of the micro engine, because two-phase octane has higher power density than gaseous one. The micro engine is tested under different operational conditions to investigate its performance. It produces a maximum net mechanical work of 0.405 J per cycle with an efficiency of 2.58%. This experiment proves the feasibility of the micro steam engine.

Research highlights
► Micro engine is difficult to manufacture. Moreover, the problems of abrasion and leakage in micro scale cannot be overcome based on the available technology. To solve the problems, we developed a micro Newcomen steam engine, but take the place of the piston and cylinder with a flexible ripple tube. It works as one monolithic part, thus solves the problems of friction and leakage. Moreover, we use two-phase octane as working fluid of the micro engine, because two-phase octane has higher power density than gaseous one. The experiment proves feasibility of micro steam engine.