EFFECTS OF AXIAL TEMPERATURE-GRADIENT ON MOMENTUM AND HEAT-TRANSFER WITH OSCILLATING PRESSURE AND FLOW

Effects of axial temperature gradient on heat transfer, momentum trans fer and energy conversion mechanisms within a closed cylinder-piston a pparatus are analyzed. Assuming that the gas density change is small, the first-order and steady second-order solutions of continuity, momen tum and energy equations are obtained. The solutions show that there e xists a steady circulating flow and the magnitude of the steady axial velocity increases as the axial temperature gradient increases. There exists not only an oscillating component of heat flux between the gas and the wall, but also a steady component whose direction depends on a xial temperature gradient. It is shown that heat is pumped from the wa ll near the piston to the wall near closed-end for negative axial temp erature gradient. Heat transfer relation for both oscillating pressure and oscillating flow conditions is proposed.