Experimental and CFD analysis on thermal performance of Double-Circuit vortex tube (DCVT)-geometrical optimization, energy transfer and flow structural analysis

摘要

Three arrangements of hot and cold exhaust locations determine the types of vortex tubes; Parallel vortex tube (PVT, cold and hot are in the same place), Ranque-Hilsch vortex tube (RHVT, cold and hot are in two opposite places) and Double-Circuit vortex tube (DCVT, just like the RI-IVT but an additional low pressure line is added to the hot valve side). This research focuses on a parametric study (experiments and numerical simulations) on Double-Circuit vortex tubes (DCVT). In this study the impact of valve diameter (15-30 mm) and the pressure ratio (extra injection pressure/inlet pressure) on the separation quality is investigated. Also, the flow behavior inside the DCVT with different nondimensional valve diameters is reported and the effect of flow structural patterns on the DCVT performance is discussed. Based on the experimental results, there is an optimum value for each of the nondimensional control valve diameter (D-n, = Dth/D) and the nondimensional pressure (P-ex/P-in) equal to 0.77 and 0.2, respectively. In this research the effects of turbulent flow field, trailing vortices, cooled region volume and turbulent viscosity on thermal capability of the DCVT are reported using an accurate 3D CFD model made based on the experiments. (C) 2017 Elsevier Ltd. All rights reserved.