Study on Heat Transfer of Heat Exchangers in the Stirling Engine : Heat Transfer in a Heated Tube under the Periodically Reversing Flow Condition

Heat transfer characteristics in heated tubes under periodically reversing flow conditions have been experimentally investigated, using a test apparatus that simulates heat exchangers for an actual Stirling engine. It is shown that the heat transfer characteristics under these conditions are greatly affected by the piston phase difference that generates the reversing flow of working fluid, and this phenomenon is peculiar to heat transfer under periodically reversing flow, which is different from the conventional convective heat transfer under steady flow. The experimental correlation for the heat transfer coefficient under these conditions is induced through the use of the working gas velocity evaluated from the Schmidt cycle model, which is one of the ideal Stirling cycles concerning the influence of the piston phase difference.