Simple-Mix: An Updated MATLAB Code for Thermodynamics Modeling in a Gamma-Type Stirling Engine with a Working Fluid Mixture

The Stirling engine is an external combustion engine that can be utilized in electricity generation. Existing literature indicates that air is less expensive than helium as the working fluid but has the same low power and efficiency. Hence, the present updated MATLAB code attempts to use a mixture of air and helium as working fluids or other mixtures of other gases. To this end, this software proposes an experimentally validated non-ideal thermodynamic model for a gamma-type Stirling engine. After validation, a mixing gas of air and helium was used instead of an operating fluid in the thermodynamic model. Finally, an example was run to demonstrate the software outputs for a hybrid engine.