Design, Manufacturing and Testing of a Stirling Engine with Slider-Crank Mechanism

Abstract

In this study, a beta type Stirling engine with slider-crank mechanism having swept volume of 365 cm3 was designed, manufactured and performances tested. The design phase was first started by determining the operating parameters of the engine. The necessary mathematical calculations were performed by considering the operating conditions of the Stirling engine with a slider-crank mechanism to be manufactured. After determining the engine parameters, the dimensional design phase was started within the tolerance limits of the engine parts. The parts were designed by the computer-aided SolidWorks program in solid modeling and by the AutoCAD program in two-dimensional design and projecting. Each part used in the manufacturing of the Stirling engine was assembled delicately in the assembly process. A prony-type dynamometer, liquefied petroleum gas (LPG) fuel, and electronically controlled electric heater systems were developed to perform the performance tests and analyses of the manufactured engine. Experimental studies were conducted at hot end temperatures of 627 °C, 727 °C, and 827 °C and at a cold end temperature of 27 °C by utilizing an electrical heater as a heat source and air as a working fluid. According to the results obtained in experimental studies for different heater temperatures and different charge pressures, it was revealed that engine power values increased depending on the heater temperature and charge pressure increase. The maximum power values at all heater temperatures were acquired at a charge pressure of 4 bar. In this study, the maximum engine power was obtained as 69.5 W at a hot end temperature of 827 °C, at a charge pressure of 4 bar, and at an engine speed of 200 rpm when a stainless-steel displacement piston and air as a working fluid were utilized, and the maximum engine torque value was obtained as 4.21 Nm at a charge pressure of 4 bar and an engine speed of 135 rpm. The lowest engine power among the maximum engine power values obtained in all experimental studies was found as 17.09 W at a hot end temperature of 627 °C, at a pressure of 1 bar, and at an engine speed of 185 rpm. The maximum power values of the engine developed within the scope of this study at hot end temperatures of 627 °C, 727 °C, and 827 °C were determined to be 31.2 W, 48.3 W, and 69.5 W, respectively. Upon examining the results obtained from experimental studies, it is observed that the heater temperature and charge pressure have significant impacts on the performance values of Stirling engines. Within the scope of this study, a new power generation system that could use renewable energy sources was put into operation.