The pulse tube engine: A numerical and experimental approach on its design, performance, and operating conditions

The pulse tube engine is a simple heat engine based on the pulse tube process. Due to its simplicity it has a high potential to be applicable in waste heat usage and energy harvesting purposes. In this work, mathematical and experimental design tools are developed to study a pressurized laboratory scale pulse tube engine. The mathematical model is based on the transient numerical solution of the governing differential equations for mass, momentum and energy. The Modelica environment of SimulationX is used to solve the equations numerically and the model is employed to design the experimental test engine with helium as working fluid. The transient behavior of the pulse tube engine's underlying thermodynamic properties is studied numerically and experimentally under different design parameters as well as for different heat input temperatures, filling pressures and operating frequencies. The measured engine characteristics are compared with the calculated predictions. Internal and external power losses are quantified. Design studies for a further development of the pulse tube engine are performed experimentally. The developed numerical tool provides a rational framework for up-scaling the current laboratory model to industrial scale.