Comparison of an analytical and computational fluid-dynamics models of a commercial Ranque-Hilsch vortex tube operating with Air and Methane

Abstract

This paper presents a comparison between the behavior predicted by a computational fluid-dynamic model (CFD) and an analytical model for a commercial vortex tube using air and methane as working fluids, in addition to a three-dimensional mesh for this purpose. The numerical simulation of the turbulent, compressible and high vorticity flow was carried out using RANS equations, the Realizable k-e turbulence model and STAR-CCM+ as software for the equations solution. The variables measured in this work were temperature, pressure and velocity at the exit nozzles of the vortex generator and the tube discharges, resulting in errors of less than 16% between CFD and the analytical model. This numerical study represents a first approximation of the vorticityphenomenon and has been developed in order to establish a prototype simulation model that provides, under certain inlet conditions to the process, preliminary information on the vortex tube industrial implementation for obtaining liquefied natural gas.

Reducing Energy Consumption and CO2 Emissions in Natural Gas Preheating Stations Using Vortex Tubes

“…All the relevant variables take lower values than those from nitrogen. As mentioned in the introduction, reference [32] also obtained a lower value of temperature separation when comparing air (mostly nitrogen) and methane. The hot temperature separation is a 30% lower than that obtained without heating, but cold temperature separation is very near to zero, significantly differing from the 4 • C obtained with nitrogen.…”

“…Ref. [34] also performed a 3D CFD simulation of a six nozzle VT, with methane and air as working fluids, arriving at the same conclusion as [32]: methane simulations result in a slightly lower temperature separation for both hot and cold ends.…”

“…Ref. [32] performed a 3D CFD simulation, together with an analytical model, comparing the performance of a VT with air and methane as working fluids. They found that both hot and cold temperature separation were lower for methane.…”