Experimental analysis on wave dynamics of pressure oscillating tube

Abstract

The 600 mm double-opening pressure oscillation tube as the core component of industrial-scale gas wave refrigerator (GWR) and its visualization investigation platform are designed and setup in this paper. The quantitative description of the density gradient field in the gas wave oscillation tube is obtained by high speed multi-schlieren splicing technology which is firstly proposed in this paper, and its accuracy is validated with two-dimensional Euler equation under different pressure ratios and rotating speeds.The experimental results show that the shockwave Mach number increases with the increasing of pressure ratio or rotating speed.When the pressure ratio increases from 1.5 to 3, the intensity of both shockwave S1 and 1st reflected expansion wave E1 increase significantly and strengthening the expansion process after HP nozzle closed.When the rotating speed is increased from 800 rpm to 2400 rpm, the movement path of the 2nd expansion waves E2 as nozzle closing gradually bend towards the LT port, which slows down the movement speed of the 1st reflected expansion wave E1 and increases the residence time of the 2nd expansion wave E2, which benefits the refrigeration. The higher pressure ratio and rotation speed mean the shorter distance of shockwave to the HP nozzle, which is an important guidance to lightweight strategy of GWR and extend the application into compact construction requirements.