Heat Transfer on a Small Stirling Engine

—Heat Transfer on Expansion Chamber Wall—

Abstract

It is very important to research the heat transfer of stirling engine for improvement of thermal efficiency. Therefore, the authors investigated the heat transfer coefficient between cylinder wall and working gas by measuring a heat flux at expansion cylinder wall. Then, the heat transfer coefficient of this stirling engine were calculated by dividing the generalized equation for determination of heat transfer coefficient between heating-expansion and cooling-compression stroke. It was found that the arrangements of experimental values roughly coincide with instantaneous and mean heat transfer coefficient. The above-mentioned equations for this stirling engine are as follows:
α_g=0.042D^-0.42v^0.58p^0.58T_g^-0.19 Heating-expansion stroke (1)
α_g=0.0236D^-0.47v^0.53p^0.53T_g^-0.11 Cooling-compression stroke (2)
where, α_g; heat transfer coefficient, D; cylinder bore, v; piston speed, p; gas pressur in cylinder, T_g; gas temperature in cylinder.