Studies on Flow Resistance and Heat Transfer of Regenerator Wire Meshes of Stirling Engine in Oscillatory Flow

This paper describes in detail experimental results on flow resistance and heat transfer of regenerator wire meshes of a Stirling engine in oscillatory flow. The results show that for Re>300, the friction factor of wire mesh became lower than that in previous studies. It has been clarified that the friction factor in a decelerating period becomes higher than that in an accelerating period under the condition that both Valensi number and maximum Reynolds number exceed Certain values. A new experimental method for estimating Nusselt number of wire mesh in oscillatory flow is proposed. This method employs a cylindrical probe having two thermocouples attached on opposite sides of the cylinder facing the direction of oscillatory flow. It has been clarified that the Nusselt number of wire mesh becomes a function of Reynolds number and open area ratio when aperture size of wire mesh is used as the representative length. Also, experiments on so-called "spring mesh" were carried out.