Experimental study on the thermodynamic

Dissertant

Ibrahim, Ramez Aofail

University

University of Technology

Faculty

-

Department

Department of Electromechanical Engineering

University Country

Iraq

Degree

Ph.D.

Degree Date

2004

English Abstract

In this thesis try was done to find an optimum design and arrangement of a vortex tube with a divergent chamber which can be used as a cooling device of maximum efficiency that would supply air at large temperature drop, by changing the tube parameter.

The experimental investigation was carried out on a divergent vortex tube rig especially designed for the present study covering all tests.

Experimental work was carried out on the divergent vortex tube by changing the angle of divergence, with the ranges (0°= 1.72, 2.29, and 4.01) with diameters (20 mm, 30 mm) and changing the ratio (L / D) with ranges (10, 15, 19.33, and 23).

Consequently the study of energy separation performance of seventh vortex tubes was carried out.

The effect of different cold outlet diameters (de=10 : mm, 4 =12 mm, and dc=14 mm) and different outlet nozzle diameters (= 4 mm, d = 5 mm, and d = 6.5 mm) on the performance of the vortex tube is described by using one nozzle or two nozzles by varying the pressure of the inlet air and cold air mass ratio (fm within the ranges (Pies=2 - 7 bar) and (fie = 0–1) Experimental study the effect of insulation on the performance is described, the cold air temperature increase for well insulated vortex tube especially in the region of the minimum cold air mass ratio.

Experimental data obtained in these vortex chambers were compared with those on straight vortex chambers.

Observation indicates that a divergent tube with a small angle of divergence (0°= 1.72) is effective in obtaining a higher temperature separation and makes possible a shortening of the chamber length.

The experimental results show that optimum design of divergent vortex chamber that gives a high-energy separation is: 0° = 1.72, dn = 6.5 mm, a z=l4 mm, number of nozzles = 2, angle of cone value = 30° D=20 mm, and <£ =23), D The results show a pronounced influence of divergent vortex tube No.2 (0° = 1.72 L~ 460 mm), on the energy separation performance, Le the highest temperature of the hot air stream and the lowest temperature of the cold air stream reach (88 °C) at (ftc = 0.812) and (-41.3 °C) at (ue = 0.303) respectively.

The experimental study predicts three empirical results between the outlet nozzle diameter (d), cold outlet diameter (dj, number of nozzles (N), inside vortex tube diameter (D), length of vortex tube (L) as : Ndn2/D2=0.0105 N=1 …(A) Ndn2/D2=0.211 N=2 dc2/Ndn=2.3 (N=1,N=2) …(B) L = 23 D (N = 1, N = 2) …(C) The above equations give the optimum design divergent vortex tube and high separation energy.

Two new empirical relations for the prediction of the temperatures of the cold and hot air of different divergent vortex tubes being geometrically similar to each other are presented.

The correlations are in good agreement with experimental results.

Moreover, similarity relation of geometrical similar divergent vortex tubes obtained from the dimensional analysis and confirmed by experimental work is presented.

Main Subjects

Mechanical Engineering

Topics

• Physics
• Mechanics
• Thermodynamics
• Dynamics
• Quantum theory

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-305809