Numerical investigation of the energy separation effect and flow mechanism inside convergent, straight, and divergent double‐sleeve RHVT

Abstract

This study provides analysis of a cooled Ranque-Hilsch vortex tube (RHVT) with various specifications. It shows how cooling influences energy conversion inside the RHVT and improves performance of the device in separation of hot gas from the cold stream within the fluid by presenting the temperature detachment (the temperature diminution of cold air (ΔT c = T i − T c ), isentropic efficiency (η is ), and coefficient of performance (COP) of divergent, convergent, and straight VTs. Two key parameters including hot tube length and number of nozzles for cooling and insulated cases are investigated to find out how the performance of the VT is affected by different geometry configurations under cooling conditions. These influences were researched for straight, convergent, and divergent VT separators under different flow characteristics. The optimum geometrical conditions for the cooling cases were identified. Results are indicative of positive influence of cooling for energy separation inside a VT. The quantities of ΔT c , η is , and COP for the cooled RHVT are greater than uncooled RHVT for various types of VTs. Cooling the VTs leads to an increase of 12.5% in ΔT c , 14.4% in η is , and 15.1% in COP when the base case was an uncooled VT.Thermal design and management of vortex tube (VT) has emerged as one of the most efficient cooling strategies for refrigeration and air conditioning systems. VTs are simple stationary devices for separation of the gaseous components of a pressurized mixture without consuming any specific works or energy. 1 Figure 1 is a schematic of energy separation within a VT. Due to its low cost, compactness, mobility, quietness, environmentally friendly operation, and the fact that they do no need any input work, VTs are beginning to replace the inefficient, energy consuming, useless machines in a variety of industrial applications where cooling, separation, and depressurizing issues are desired. 2 A desirable application for VTs for the purpose of depressurizing can be continued in the natural gas transmission industry. The pressure of gas pipelines near the customers need to be reduced to a working level, which is devoid of any danger and hazards. Conventional throttling valves for this aim would reduce pressure and the temperature of gas simultaneously resulting in exergy destruction and entropy generation. A VT can successfully play the role of a depressurizer in a more energy-efficient manner. 3 The energy separation through the VT, namely Ranque-Hilsch effect, is an important subject of matter in the archival literature. Many different numerical and experimental techniques were used to analyze the performance of VTs with different geometries under various flow conditions. The summary of main experimental works pointing at designing VTs is reported by Behera et al 4 and Yilmaz et al. 5 Sharma et al 6 presented a review on computational methods used by various literature to comprehend the energy separation and optimize the device and brought suggestions for improving the performance of the dev...

CFD simulation on optimum material to fabricate the counter flow of Ranque–Hilsch vortex tube

“…This study suggests that the operation of the commercial vortex tube used resulted in mixing, introducing other processes that reduce separation compared to equilibrium ignition. Bazgir et al 22 proposed the analysis to enhance the performance of RHVT with a reduction in the temperature of cold air, isentropic efficiency, and COP of converging and diverging hot tube-were recorded. Two important parameters namely the length of the hot pipe, and the number of nozzles were considered for the applications of cooling and insulation, further they examined to determine how the VT process was affected by the various geometric configurations on the cooled tube.…”