THE IMPACT OF UNCERTAINTIES ASSOCIATED WITH REGENERATOR HYDRODYNAMIC CLOSURE PARAMETERS ON THE PERFORMANCE OF INERTANCE TUBE PULSE TUBE CRYOCOOLERS

Recent investigations have shown that CFD techniques can be applied for modeling the entire pulse tube (PTC) cryocooler systems. However, the results of CFD simulations can be trusted only if they are based on correct closure relations. The hydrodynamic and heat transfer parameters associated with regenerators are among the most important closure relations for these cryocooler systems. In this investigation the impact of uncertainties associated with oscillatory and steady flow resistance parameters on the performance of Inertance Tube Pulse Tube Cryocoolers (ITPTC) is examined using CFD simulations. This objective is achieved by simulations where reference or baseline ITPTCs systems operating in near steady-periodic conditions are modeled in their entirety. Ten transient simulations is performed using oscillatory and steady flow hydrodynamic closure relations corresponding to some of the most widely used regenerator fillers. The effects of uncertainties in the regenerator closure parameters on the cryocoolers performance parameters, as well as their key local hydrodynamic transport processes, are thus quantified.