Use of MADM Techniques for Optimization of Thermal Performance of Ranque Hilsch Vortex Tube

In the present study MADM methods are used for optimization of geometrical combinations. The vortex tube is very simple thermo-fluidic apparatus which generates low temperature and high temperature air streams. The inlet fluid is tangentially compressed into the inlet nozzles of vortex tube. Thermal performance of vortex tube is noticeably influenced by its geometrical and operational parameters. In this study effect of various geometrical (L/D ratio: 15, 16, 17, 18; exit valve angle; ; cold end orifice diameter: 5,6 and , tube divergence angle: ) and operational parameters (inlet pressure: 2 to 6 bars) on the performance of vortex tube have been investigated experimentally. The best configuration of the vortex tube is chosen using Multiple Attribute Decision Making (MADM) techniques. COP for cooling and the ideal temperature difference on the cold end were used to analyse the vortex tube's performance. The WSM (Weighted Sum Method), WPM (Weighted Power Method), TOPSIS (Technique for Order Preference by Similarity to Ideal Solution), and AHP (Analytical Hierarchy Process) MADM (Multiple Attribute Decision Making) methods are used. Experimental best performing combinations are obtained for Length to Diameter ratios with exit valve angle as and at orifice diameter for inlet pressure of 5 and 6 bar pressure. Best COP, efficiency and cold end temperature difference are and respectively for the combination of 15 valve angle, orifice diameter and 2 bar pressure by MADM techniques.