Effect of orifice flow and heat transfer on gas spring hysteresis

Abstract

The combined effect of orifice flow and heat transfer on piston power dissipation within a gas spring has been evaluated within the framework of a small perturbation theory. The relationship between piston displacement and gas spring pressure perturbation has been deduced. Numerical results are presented for the effect of orifice flow and heat transfer on piston power, normalized with respect to piston displacement. The variation of normalized piston power P with orifice flow parameter K, at a fixed heat transfer, has a local maximum. When operating at the value of K corresponding to the local maximum in P, the effect of heat transfer is to decrease P. The variation of P with heat transfer, at fixed K, has been evaluated for a parallel-plate geometry and specific heat equal to y = 7/5 and 5/3. In the absence of an orifice (K = 0), the optimum heat transfer provides, for y = 7/5 and 5/3, a peak power equal to 22 and 30%, respectively, of peak power associated with optimum K and no heat transfer.