Nodal Analysis of Stirling Cycle Devices

This paper describes a general-purpose program for the nodal analysis of Stirling-cycle devices or other cyclic regenerative machines, and presents an extensive discussion of results for an illustrative problem. The program employs finite-difference, explicit-forward solutions, and is readily adaptable to various machine topologies. The machine is divided into specifiable numbers of fluid and solid nodes. The program solves the gas-dynamic differential equations (mass, momentum and energy balances) for each fluid node and an energy balance for each solid node. Interactions between these are represented by heat transfer and fluid friction terms. The kinetic energy of the fluid and the inertial resistance to flow acceleration are accounted for. Leakages through seals and ports are included in the analysis. Special schemes for enhanced mathematical stability and for accelerated convergence to a steady-state cycle are employed. The program is applicable to both disciplined-piston and free-piston engines. It can automatically generate very detailed outputs, both tabular and graphic (Eulerian, LaGrangian, and 3-dimensional) to help provide insight and understanding. Extensive illustrations and discussions are presented. There are two copies in the file and an extra copy in the ESD files.