IJRI-TE-03-010 CFD ANALYSIS ON EJECTOR COOLING SYSTEM WITH VARIABLE THROAT GEOMETRY

International Journal of Research and Innovation on Science, Engineering and Technology (IJRISET)
Need for development
Designing of Ejector
• Due to raise in global warming need for development of
highly efficient eco-friendly systems is increased
• Ejector Cooling system is one of the eco-friendly system
developed to reuse waste gases
• But ejector cooling system is rarely used because of high
set up cost and low efficiency
• Improvement of ejector efficiency will boost up the use of
ejector cooling systems
Literature review
As we know that ejector principle is known from 100
years. Since, ejector has the capacity of generating low
pressure and then lifting pressure, it can be relegated the
refrigeration purposes to applications where waste heat is
easily available from sources such as automobiles, industrial
processes and solar, etc.
The first steam ejector refrigeration system was developed
by Maurice Leblanc in 1910 and gained in popularity
for air conditioning applications until the development
of chlorofluorocarbon refrigerants in the 1930’s
and their use in the vapour compression cycle which was
much more efficient than alternative thermally driven cycles.
Research and development continued however and
the ejector technology found applications in many engineering
fields particularly in the chemical and process
industries. Systems have been developed with cooling
capacities ranging from a few KW to 60,000 kW but despite
extensive development effort the COP of the system,
which can be defined as the ratio of the refrigeration effect
to the heat input to the boiler, if one neglects the pump
work which is relatively small, is still relatively low, less
than 0.2. Ejector refrigeration systems are not presently
commercially available off the shelf but a number of companies
specialise in the design and application of bespoke
steam ejector systems that use water as a refrigerant for
cooling applications above 0° C. To improve the efficiency
of the simple ejector cycle more complex cycles have been
investigated as well as the integration of ejectors with vapour
compression and absorption systems. An example of
this is the Denso transport refrigeration system. Significant
effort has also been devoted to the development of
solar driven ejector refrigeration systems.
Depending on the application, injector is synonymously
used for ejector. The main difference in this case is the
discharge pressure at the diffuser exit. While the diffuser
exit pressure of the ejector is closer to that of the suction
flow than that of the motive fluid, the term injector
is sometimes used for applications in which the diffuser
discharge pressure can actually reach the pressure
of the driving fluid. Other synonyms encountered in the
literature are eductor, diffusion pump, aspirator, and jet
pump. In case the total flow exiting the diffuser consists
of only a single component.
DESIGNING
CATIA - which stands for Computer Aided Three-dimensional
Interactive Application - is the most powerful and
widely used CAD (computer aided design) software of its
kind in the world. CATIA is owned/developed by Dassault
Systems of France and until 2010, was marketed worldwide
by IBM.
Wire mesh model of ejector body with dimensions
Isometric view of ejector body
Wire mesh model of motive nozzle
Isometric view of motive nozzle solid model
CFD ANALYSIS ON EJECTOR ORIGINAL MODEL
(Working fluid R134a)
IMPORT CATIA MODEL
• Open Ansys Workbench and then Fluid Flow (Fluent) →
double click
• Select geometry and then right click, import geometry
by choosing the → select browse →open part → ok
73