The document summarizes a study of the vortex tube using computational fluid dynamics (CFD) modeling. It discusses the basic workings of the Ranque-Hilsch vortex tube, which uses compressed gas to produce hot and cold air streams without moving parts. The study uses ANSYS Fluent software to build a 3D CFD model of the vortex tube and simulate the temperature separation phenomenon using the k-epsilon turbulence model. The model is meshed and boundary conditions are applied to analyze factors like temperature distribution, energy transfer, and heat dissipation within the vortex tube.

1. MAJOR
ASSIGNMENT
SUBMITTED BY :
MAHENDRA PATEL
(K10632)
SUBMITTED TO :
MR. ADITAY MISHARA
STUDY 0F VORTEX TUBE USING A CFD
MODEL

2. INTRODUCTION
The vortex tube was invented by a French physicist named Georges J.
Ranque in 1931 when he was studying processes in a dust separated
cyclone. It was highly unpopular during its conception because of its
apparent inefficiency. The patent and idea was abandoned for several years
until 1947, when a German engineer Rudolf Hilsch modifed the design of the
tube. Since then, many researchers have tried to find ways to optimize its
efficiency. Until today, there is no single theory that explains the radial
temperature separation. Hundreds of papers have been published about the
temperature separation in the vortex tube, with the greatest contribution
being to the understanding of the Ranque–Hilsch vortex tube.
Types Of Vortex Tube
 1-Uni-flow vortex tube
 2-Counterflow vortex tube

3.  The Ranque-Hilsch vortex tube is a mechanical device
operating as a refrigerating machine without any moving parts,
by separating a compressed gas stream into a low total
temperature region and a high one. Such a separation of the
flow into regions of low and high total temperature is referred to
as the temperature (or energy) separation effect
Working

5.  The vortex tube, also known as the Ranque-Hilsch vortex tube, is a
mechanical device that separates a compressed gas into hot and cold
streams. The air emerging from the "hot" end can reach temperatures
of 200 °C, and the air emerging from the "cold end" can reach -50 °C.[1]
It has no moving parts.
 Pressurized gas is injected tangentially into a swirl chamber and
accelerated to a high rate of rotation. Due to the conical nozzle at the
end of the tube, only the outer shell of the compressed gas is allowed
to escape at that end. The remainder of the gas is forced to return in an
inner vortex of reduced diameter within the outer vortex.

6.  This approach is based on first-principles physics alone
and is not limited to vortex tubes only, but applies to
moving gas in general. It shows that temperature
separation in a moving gas is due only to enthalpy
conservation in a moving frame of reference.
 The main physical phenomenon of the vortex tube is the
temperature separation between the cold vortex core and
the warm vortex periphery. The "vortex tube effect" is fully
explained with the work equation of Euler,[2] also known
as Euler's turbine equation, which can be written in its
most general vectorial form as:

7. CFD MODEL
 The ansys icem CFD is used for making the volume mesh for
the vortex tube model. the standard k-epsilon turbulence model
is used. Skye et al [6] investigate the RNG k-epsilon turbulence
model but the result is not correlated with the experimental
data, Reynolds stress equation also can’t be converge for this
simulation walls are consider as no slip boundary condition. the
3D model is meshed with tria element in icem meshing tool, the
velocity along the axial direction is the reason for creating the
forced and free vortex zone inside the tube.

8. The present work is done using ansys fluent 14.5; it is the volume based solver.
The solver used 3 dimensional steady, compressible, pressure based setup,
density based solver diverged for this vortex tube problem, energy equation is
on for capture the energy and temperature distribution. K-epsilon model is used
2equation model is used and for finding the wall friction on fluid standard wall
function is used. Finding the heat dissipation between the layers can be
captured by viscous heating function. Air is used as material body. Because the
flow is considered as compressible flow ideal gas equation is used. No
interaction between environment and computation domain.The inlet of the
vortex tube is defined as a pressure inlet and cold outlet and hot outlet is
defined as a pressure outlet and the atmospheric temperature is given as a
input in the model. Wall is assumed as a adiabatic condition. The fluent
package solved by mass, momentum and energy equation.

9. Nozzle (Generator)
 The nozzles are of converging type, diverging type are converging-diverging type as per the
design. An efficient nozzle is designed to have higher velocity, greater mass flow, and minimum
inlet losses Chamber is a portion of nozzle in the same plane of nozzle and facilitates the
tangential entry of high velocity air stream into hot side. Generally, the chambers are not of
circular form, but they are gradually converted into spiral form The main function of nozzle is to
provide tangential entry of air into chamber which (tangential velocity of air) cause vortex (swirl)
formation in vortex tube.
Diaphragm
 A Diaphragm called cold orifice, with a suitable sized hole in its center is placed immediately to
the left of the tangential inlet nozzle. The compressed air is then introduced into the tube
through this nozzle. After rebouncing of swirl air from the conical valve (hot outlet), cold air
passes through the Centre of tube and finally comes out by diaphragm.
Valve
 Valve obstructs the flow of air through hot side coming from nozzle and it also controls the
quantity of hot air through vortex tube. Conical valve at right end of the tube confines the exiting
air to regions near the outer wall and restricts it to the central portion of the tube from making a
direct exit
DETAILS OF VORTEX TUBE

10. Cold air side
 he central part of the air flows in reverse direction from valve and makes exit
from the left end of the tube with sizeable temperature drop, thus creating a
cold stream. Cold side is a cylindrical portion through which cold air is
passed.
Hot air side
Conical valve at right end of the tube confines the exiting air to regions near
the outer wall and restricts it to the central portion of the tube from making a
direct exit. The outer part of the air near the wall of the tube escapes
through the right end of the tube and is found to have temperature higher
than that of inlet air.

11. Efficiency
 Vortex tubes have lower efficiency than
traditional air conditioning equipment. They are
commonly used for inexpensive spot cooling,
when compressed air is available

12. Vortex tube applications
 Commercial vortex tubes are designed for industrial applications to
produce a temperature drop of up to 71 °C (127 °F). With no moving
parts, no electricity, and no Freon, a vortex tube can produce
refrigeration up to 6,000 BTU/h (1,800 W) using only filtered
compressed air at 100 PSI (6.9 bar). A control valve in the hot air
exhaust adjusts temperatures, flows and refrigeration over a wide
range.
 Vortex tubes are used for cooling of cutting tools (lathes and mills,
both manually-operated and CNC machines) during machining. The
vortex tube is well-matched to this application: machine shops
generally already use compressed air, and a fast jet of cold air
provides both cooling and removal of the "chips" produced by the tool.
This completely eliminates or drastically reduces the need for liquid
coolant, which is messy, expensive, and environmentally hazardous.

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