Thermodynamic analysis of Stirling engines.

An analysis is made of the heat-transfer and energy transformation processes in a closedcycle regenerative heat-energy converter, e.g., a Stirling engine, by treating this as a distributed-parameter system, where variations in space occur simultaneously with transients. A system of partial and ordinary differential equations is derived for the cyclic variation with time and position of the temperature and pressure of the working fluid. This is the first time that variable regenerator matrix and wall temperatures, leakage, aerodynamic, thermodynamic, and mechanical losses are all accounted for. An integration of the Variables results in angular speed, torque, cyclic heat transfer, work output or input, and losses, from which a complete energy balance can be made. It is shown that the basic heat-transfer equations in the heat exchangers are identical with those for the regenerator. A simple nondimensional parameter ^ (mean effective pressure ratio) is defined which permits one to assess the advantage of changing any one of the many individual interdependent variables in a design for machine optimization.