1. 1
UMA MAHESWARARAO GADDALA
Research Scholar
Department of Mechanical Engineering, National Institute of Technology-Warangal.
Visualization Of Melting Behaviour Of Palmitic Acid Inside A
Spherical Container (Paper ID : MERS-TE-23)
By
National Symposium of Mechanical Engineering Research Scholars
Supervisor:
Dr. D. Jaya Krishna, Asst. Professor,
Department of Mechanical Engineering,
National Institute of Technology- Warangal
3. INTRODUCTION
• The main challenge of using renewable energy sources is
development of reliable and feasible energy storage systems to
eliminate the discrepancy between energy supply and demand
• Phase Change Material (PCM) is a useful remedy when there is a
mismatch between the supply and demand of energy.
Applications
• Thermal management systems ,Solar power plants to store thermal
energy during day time and reuse it during the later part of the day
3
5. Organics Inorganic Eutectics
Merits
Availability in a large
temperature range
Compatibility with
conventional
Chemically stable
High heat of fusion
Safe and non-reactive
Recyclable
De-merits
Low thermal conductivity in
their solid state.
Volumetric latent heat storage
capacity is low
Flammable
cost
Low cost and easy
availability
Sharp melting point
High thermal
conductivity
High heat of fusion
Low volume change
Non-flammable
Change of volume is
very High
Super cooling
Nucleating agents are
needed
Eutectics have
sharp melting
point
Volumetric
storage density is
high
Only limited data
is available on
thermo physical
properties as the
use of these
materials are very
new to thermal
storage application
5
6. Challenges Associated with PCM
• Material Compatibility
• Material Properties and Thermal Performance
• Cost and Availability
• Health & Safety
• Disposal
6
7. LITERATURE REVIEW
7
Author Paper Results/Conclusion
Levent and Zafer[1] Total solidification time of a
liquid phase change material
enclosed in cylindrical spherical
containers, Applied Thermal
Engineering. 25 (2005) 1488–
1502.
This study investigates the inward
solidification problem of a phase change
material (PCM) encapsulated in a
cylindrical/spherical container.
The governing dimensionless equations of
the problem and boundary conditions are
formulated and solved numerically
Kousksou et al. [2]
Bdcarrats et al. [3]
Dynamic Modeling Of The
Storage Of An Encapsulated Ice
Tank, Applied Thermal
Engineering. 25 (2005) 1534–
1548.
Phase-Change Thermal Energy
Storage Using Spherical
Capsules: Performance Of A
Test Plant, Int J. Refrig.
19(1996) 187-196.
Presented a numerical study on the process
of crystallization of the encapsulated PCM
inside a cylindrical tank.
Performed experimental and numerical
studies on energy storage phenomena of a
PCM inside a spherical capsule.
A simulation program that considers aspects
of both the surrounding heat transfer fluid
and the phase-change material packed inside
the nodules is developed.
8. Cont.......
8
Tan [4] Constrained And
Unconstrained Melting Inside
A Sphere, International
Communications in Heat and
Mass Transfer. 35 (2008) 466–
475.
Conducted experiments on the Constrained
and unconstrained melting of PCM inside a
spherical container
The PCM used in his study was n-octane,
the results were provided in terms of the
variation of solid- liquid interface with
time.
Felix et al. [5]
Khodadadi and
Zhang [6]
Experimental and Numerical
analysis of melting of PCM
inside a spherical capsule, Join
Thermophysics and Heat
Transfer Conference (2006).
Effects Of Buoyancy-Driven
Convection On Melting Within
Spherical Containers,
International Journal of Heat
and Mass Transfer 44 (2001)
1605-1618
Carried out experimental and numerical
investigation of PCM melting behaviour
inside a spherical.
Experiments were carried out with heat
transfer fluid temperature ranging from 70
to 82 °C for a capsule of radius 49 mm.
Performed a computational study on the
effect of buoyancy-driven convection on
melting within spherical containers.
It was found that Prandtl number plays an
important role in the melting process.
9. Cont.......
9
Khot et al. [7] Experimental Investigation of
Phase Change Phenomena of
Paraffin Wax inside a Capsule,
International Journal of
Engineering Trends and
Technology. 2(2011) 2231-5381.
An experimental designed to
facilitate the visualisation of
melting phenomenon.
The visualise study confirms
that unconstrained melting is
faster than the constrained
melting. Under the
constrained melting
conditions
Sanjay Kumar and Jaya
Krishna [8]
Differential Scanning Calorimetry
(DSC) Analysis Of Latent Heat
Storage Materials For Low
Temperature (40-80oC) Solar
Heating Applications,
International Journal of
Engineering Research &
Technology. 2(2013) 2278-0181.
Have used Differential
Scanning Calorimetry to
determine the thermophysical
properties of different types of
PCM.
10. Conclusion from Literature Review
A suitable phase change temperature and a large latent heat of fusion
are the most important requirements for any PCM
Requirements
Physical requirements: suitable phase change temperature, large
latent heat of fusion, reproducible phase change or cycling stability,
little subcooling, no phase separation, and good thermal
conductivity.
Economic requirements: development of a marketable product, low
price and good recyclability are the main requirements.
The first selection of a PCM is usually done with respect to the
physical requirements
10
11. Thermophysical properties of Palmitic acid
Melting point, oC 62
Latent heat of fusion, j/kg 203400
Specific heat (Solid), J/kgK 2200
Specific heat (Liquid), J/kgK 2480
Thermal conductivity(Solid), W/mK 0.16
Thermal conductivity(Liquid), W/mK 0.162
Density (Solid), kg/m3 942
Density (Liquid), kg/m3 862
Volumetric thermal expansion coefficient of liquid, K-1 7.72×10-4
11
13. Design details of Experimental setup
• Glass window 15mm ×30 mm
• Borosil flask 500ml
• K-type thermocouples
• hot water bath
• data acquisition system
• digital camera
Schematic of Experimental setup
13
17. Conclusions
• During the initial period of the phase change process , the conduction
heat transfer plays major role, along the inner wall of the spherical
container
• Phase change process of Palmitic acid depends on many factors such as
thermal conductivity, melting temperature, specific heat and latent heat
of fusion etc
• As natural convection in the upper part of the spherical container is
strengthened. it was observed that melting rate at the bottom region is
faster than the top
• Design of the system is also important in optimizing energy storage
17
18. References
1. Levent B.,Zafer I., Total solidification time of a liquid phase change material enclosed in
cylindrical/spherical containers, Applied Thermal Engineering. 25 (2005) 1488–1502.
2. Bareiss M., Beer H., An Analytical Solution Of The Heat Transfer Process During Melting
Of An Unfixed Solid Phase Change Material Inside A Horizontal Tube, International
Journal of Heat and Mass Transfer. 27(1984) 739-746.
3. Kousksou T., Bedecarrats J. P., Dumas J. P., Mimet A., Dynamic Modelling Of The
Storage Of An Encapsulated Ice Tank, Applied Thermal Engineering. 25 (2005) 1534–1548.
4. Bdcarrats J. P., Strub F., Falcon B., Dumas J. P., Phase-Change Thermal Energy Storage
Using Spherical Capsules: Performance Of A Test Plant, Int J. Refrig. 19(1996) 187-196.
5. Tan F. L., Constrained And Unconstrained Melting Inside A Sphere, International
Communications in Heat and Mass Transfer. 35 (2008) 466–475.
6. Felix R. A., Solanki S. C., Saini J. S., Experimental and Numerical analysis of melting of
PCM inside a spherical capsule, Join Thermophysics and Heat Transfer Conference (2006).
7. Khodadadi J. M. and Zhang Y., Effects Of Buoyancy-Driven Convection On Melting Within
Spherical Containers, International Journal of Heat and Mass Transfer 44 (2001) 1605-
1618.
18
19. 8. Sanjay K. R. Subrata S., Gravity-assisted melting in a spherical enclosure:effects of natural
convection, International Journal of Heat and Mass Transfer 33(1990) 1135-1147.
9. Khot S. A., Sane N. k., Gawali B. S., Experimental Investigation of Phase Change Phenomena
of Paraffin Wax inside a Capsule, International Journal of Engineering Trends and
Technology. 2(2011) 2231-5381.
10. Sanjay Kumar R.,Jaya Krishna D., Differential Scanning Calorimetry (DSC) Analysis Of
Latent Heat Storage Materials For Low Temperature (40-80oC) Solar Heating Applications,
International Journal of Engineering Research & Technology. 2(2013) 2278-0181.
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