A New Scroll-type Air Motor with Magnetic Spirals

The scroll-type air motor, also named the scroll expander, has been widely used for different applications due to its characteristics of compact structure and high energy conversion efficiency. However, the leakage and the friction result in non-negligible energy losses. This paper presents the recent work on developing a new scroll-type air motor with mounted permanent magnetic spirals and investigates its potential in leakage reduction and efficiency improvement, especially at low-pressure air supply conditions. A method for the implementation of the magnetic scroll air motor is proposed. A prototype is manufactured and initial experimental tests are conducted to study the generalized torque distribution. A mathematical model for the magnetic scroll air motor is developed and a corresponding simulation study is presented. The study shows that the proposed magnetic scroll air motor structure is feasible in terms of manufacturing and has the potential to reduce the air leakage and thus to improve the energy efficiency by a maximum of around 15% at a supply pressure of Pa with a flank leakage clearance reference of 0.06mm.