Research Proposal: Enhancing Heat Transfer with CNT Nanomaterials

This project investigates the application of carbon nanotubes (CNTs) to enhance the performance of heat exchangers and transformers. It begins with a problem statement highlighting the widespread use of heat exchangers and the potential of nanomaterials like CNTs to improve their efficiency due to their superior thermal properties. A literature review discusses existing research on CNT nanofluids and their impact on heat dissipation in transformers, noting the benefits of increased thermal conductivity. The scope of the proposed work focuses on adapting to environmental challenges and improving heat transfer techniques using CNTs in heat exchangers and transformers. Research questions address how to enhance heat exchanger performance, the impact of CNTs, the use of CFD for numerical study, and the effect of CNT particle concentration. The proposed approach involves both experimental analysis of CNT membranes in heat exchangers and CFD analysis of CNT nanofluids in transformers. The project outlines a timeline, resource needs, and a list of references. The student expresses keen interest in heat transfer and fluid flow problems, with a focus on nanomaterials and heat exchangers.

Problem statement: Heat exchangers are the devices which have application in wide
varieties of industries like power generation, oil & gas, refrigeration, chemical, food &
beverage etc. With the advancement of time and miniaturisation of the system use of heat
exchangers are increasing day by day. This can be achieved by using nanomaterial as they
possess higher thermal properties, larger surface area to volume ratio and higher density.
Present work will focus on the use of carbon nanotube (CNT) in the heat exchanger and
transformer as it possesses high thermal conductivity and high density which helps in
maintaining the required heat standard. Experimental analysis of heat exchanger based on the
CNT membrane and computational fluid dynamics (CFD) analysis of the transformer based
on the CNT nanofluids will be performed.
Literature review: Carbon nanotubes are one of the most widely utilizing fields of research
these days. There has been a current progression in the field of CNT nanofluids prompting a
relating increment in their extent of use. CNT gives higher heat dissipation and good energy
transmission compared to the conventional fluids and other nanofluids utilizing in this zone
(Esfe et al, 2014). A lot of heat is created in a transformer amid the typical task because of
different losses. This generated heat should be scattered out of the transformer to expand its
productivity and diminish its workload. Transformer oil being used has lower conductivity
but incorporation of nanoparticles with higher conductivity can enhance the general
conductivity of the transformer oil. Numerous examination papers record that expansion of
designed nanoparticles improves the warm execution of the ordinary transformer oil (Huang
et al, 2016). Studies demonstrate that mass flow rate change in vertical channels happens
because of flow in horizontal channels (Goodarzi et al, 2015). Coefficient of heat exchange
relies upon the Reynolds number and Grashof number and demonstrates that forced
convection due to liquid water gives more heat exchange compared to natural air (Huminic
and Huminic (2016).

CFD simulations were performed using a sliced model to study the thermal performance of an
(ONAN) distributor transformer. Velocity and temperature profiles were investigated at
various conditions and the pattern of fluid flow was realised to be similar in all scenarios
(Knowles et al, 2015). In another study where such parameters as temperature change
distribution, electrophoresis, and velocity distribution were examined using silicon carbide
nanofluids, it was found out that the heat performance of the transformer oil greatly and
significantly improved. This was due to the addition of the nanofluids (Ellahi et al, 2015).
Three-dimensional natural convection CFD simulations were done on two diverse nanofluids
to inspect heat exchange. Nusselt number, overall heat transfer coefficient and Rayleigh
number are approximated for different particles concentration to inspect heat transfer
performance (Wu et al, 2016).
Scope of the proposed work: Keeping in mind the end goal to adapt to the natural
difficulties and show signs of improvement and proficient techniques for heat transfer. Heat
exchangers are the devices which recover the energy and are being utilized widely in
different industries. It is important to embrace strategies that can empower us to disseminate
heat effectively. CNT add up to heat exchangers is the new concentration because of its
uncommon preferences and this will directly influences the total heat exchanger performance.
Consequently, examining heat exchange qualities of CNT offer essential information for their
use in total heat exchangers. As nanofluids reduce the weight and size of the heat exchanger
which can give higher thermal exchange efficiency. These nanofluids can be utilized in
different industries like power generation, oil & gas, refrigeration, chemical, food &
beverage, automobile, fuel cells, military radar and laser systems (Yu et al, 2018).
Research questions:
1. How to further enhance the heat exchanger performance
2. Impact of application of the carbon nanotubes in the heat exchanger field.

3. Utilization of CFD to study the CNT nanofluids based transformer problem
numerically.
4. Impact of CNT particle concentration on the overall output from the system.
Proposed approach: Experimental and numerical analysis will be conducted in the present
work. For numerical analysis CFD is utilized in the present work. In experimental process
CNT as a membrane material is introduced. Four different set of chamber made of membrane
will be analysed in the present work, each chamber will consist two layers. CNT as
nanofluids will be utilized in the transformer to enhance its performance. To conduct this
conventional transformer oil is mixed with the CNT nanofluids with weight percentage
varying from 0 to 2%. As I have great interest in problems related to heat transfer and fluid
flow, I am very keen to work and explore the file of nanomaterial and heat exchanger. I also
have basic knowledge of the heat transfer and heat exchanger.
Timeline and resources:
For the project, I will spend between 10 and 12 hours per week
List of references:
Esfe, M. H., Saedodin, S., Mahian, O., & Wongwises, S. (2014). Thermophysical properties,
heat transfer and pressure drop of COOH-functionalized multi walled carbon nanotubes/water
nanofluids. International Communications in Heat and Mass Transfer, 58, 176-183.
Huang, D., Wu, Z., & Sunden, B. (2016). Effects of hybrid nanofluid mixture in plate heat
exchangers. Experimental Thermal and Fluid Science, 72, 190-196.
Goodarzi, M., Amiri, A., Goodarzi, M. S., Safaei, M. R., Karimipour, A., Languri, E. M., &
Dahari, M. (2015). Investigation of heat transfer and pressure drop of a counter flow
corrugated plate heat exchanger using MWCNT based nanofluids. International
communications in heat and mass transfer, 66, 172-179.
Huminic, G., & Huminic, A. (2016). Heat transfer and entropy generation analyses of
nanofluids in helically coiled tube-in-tube heat exchangers. International Communications in
Heat and Mass Transfer, 71, 118-125.
Knowles, T. R., Carpenter, M. G., & Yamaki, Y. R. (2015). U.S. Patent Application No.
14/572, 761.

Ellahi, R., Hassan, M., & Zeeshan, A. (2015). Study of natural convection MHD nanofluid by
means of single and multi-walled carbon nanotubes suspended in a salt-water solution. IEEE
Transactions on Nanotechnology, 14(4), 726-734.
Wu, Z., Wang, L., Sundén, B., & Wadsö, L. (2016). Aqueous carbon nanotube nanofluids
and their thermal performance in a helical heat exchanger. Applied Thermal Engineering, 96,
364-371.
Yu, W., Duan, Z., Zhang, G., Liu, C., & Fan, S. (2018). Effect of an Auxiliary Plate on
Passive Heat Dissipation of Carbon Nanotube-Based Materials. Nano letters, 18(3), 1770-
1776.