Impact of centerline no-slip on vortex tube performance.

摘要

The Ranque-Hilsch vortex tube or simply the vortex tube is a device that separates a high pressure gas into a low pressure hot stream and a low pressure cold stream simultaneously without the need for a power supply. Although this device is largely applied for cooling, especially spot cooling of electronic controls, machining operations and such, there has been certain interest in exploring its phase separation ability.;This thesis presents results of an innovative method that is aimed towards improving the phase separation and condensate collection application of the vortex tube. In this study a centerline no-slip condition is introduced in the vortex tube by suspending different inserts (rods and tubes) through it. The effects on the cooling capacity of the vortex tube along with the effects on inlet, cold and hot mass flow rates are observed. The experimental results indicate that even though the inserts negatively impact the refrigeration effect at higher cold fractions, for lower cold ratios the method works satisfactorily. There is a definite increase in cold mass flow rate due to centerline no-slip with corresponding decrease in hot mass flow rates. The reasons for this phenomenon are explored in the thesis. It was also concluded that as the outer diameter of the insert increases, the refrigeration effect decreases. A stainless steel rod of outer diameter 1/8" turned out to be the optimum insert for the current study.;This study also aims at locating the centerline axial stagnation point by analyzing the temperature profile along the centerline of the vortex tube.