A Model of In-Cylinder Heat Transfer with Inflow-Produced Turbulence

Models have been developed and tested for in-cylinder heat transfer without inflow or outflow, but there is no experimentally verified model for in-cylinder heat transfer with inflow-produced turbulence. This model extends the work of Pfriem, in which the cylinder space is divided into a central turbulent region and a laminar wall layer. The laminar wall layer thickness is made a function of inflowing gas velocity, with the functional relationship based on a cylinder wake turbulent heat transfer correlation.

The model predicts larger heat transfer magnitude and smaller heat transfer phase shift than the non-turbulent model. It predicts smaller heat transfer magnitude and larger phase shift than another inflow-produced turbulence model.

For typical Stirling machine in-cylinder conditions, the model predicts Nusselt number magnitudes ranging roughly from 100 to 2000. It predicts heat transfer phase shifts ranging from near 0 to roughly 10 degrees.