The influence of the shuttle effect on the intensification of heat losses in a Stirling engine

The paper presents a methodology of calculating negative heat flows in the cylinder-piston group of the Stirling engine. Some of the most important of them are the shuttle effect and the pumping losses. The introductory part of the article describes the physical side of the phenomena under investigation. The main relationships recommended by the researchers for the calculation of the shuttle effect and pumping losses are presented in the paper. A mathematical model is developed for the purpose of calculating the heat losses mentioned. The model is based on representing the phenomenon as quasistationary radial heat transfer by means of convection and radiation. A system of algebraic differential equations of heat exchange between single elements of arrays is presented. The system of the main equations is solved by a numerical method of integration (a variety of Euler method - the method of limiting overrelaxation). Algorithms of controlling the accuracy of the calculations performed are incorporated in the program of calculation. The algorithm is used for defining the level of shuttle conduction and pumping loss in the1R30/6 Stirling engine designed at Saint-Petersburg State Marine Technical University. In addition a methodology of finding the heat dissipation factor in the gap between the displacer and the cylinder wall was developed. The extent of influence of the engine design data on the phenomena under consideration is analyzed. Rank diagrams are constructed that visualize the results obtained.