THERMOPHYSICAL PROPERTIES OF NANOFLUIDS CONTAINING MULTI-WALLED CARBON NANOTUBES (MWCNT)

Author(s):  
Alexandre Oliveira ◽  
Letícia Oliveira ◽  
Amir Zacarias Mesquita ◽  
ENIO BANDARRA FILHO
Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2300
Author(s):  
Salah Almurtaji ◽  
Naser Ali ◽  
Joao A. Teixeira ◽  
Abdulmajid Addali

Coolants play a major role in the performance of heat exchanging systems. In a marine gas turbine engine, an intercooler is used to reduce the compressed gas temperature between the compressor stages. The thermophysical properties of the coolant running within the intercooler directly influence the level of enhancement in the performance of the unit. Therefore, employing working fluids of exceptional thermal properties is beneficial for improving performance in such applications, compared to conventional fluids. This paper investigates the effect of utilizing nanofluids for enhancing the performance of a marine gas turbine intercooler. Multi-walled carbon nanotubes (MWCNTs)-water with nanofluids at 0.01–0.10 vol % concentration were produced using a two-step controlled-temperature approach ranging from 10 °C to 50 °C. Next, the thermophysical properties of the as-prepared suspensions, such as density, thermal conductivity, specific heat capacity, and viscosity, were characterized. The intercooler performance was then determined by employing the measured data of the MWCNTs-based nanofluids thermophysical properties in theoretical formulae. This includes determining the intercooler effectiveness, heat transfer rate, gas outlet temperature, coolant outlet temperature, and pumping power. Finally, a comparison between a copper-based nanofluid from the literature with the as-prepared MWCNTs-based nanofluid was performed to determine the influence of each of these suspensions on the intercooler performance.


2021 ◽  
Vol 2119 (1) ◽  
pp. 012117
Author(s):  
V Ya Rudyak ◽  
G R Dashapilov ◽  
A A Shupik

Abstract This article is devoted to the study of the thermophysical properties of nanofluids with single-walled and multi-walled carbon nanotubes (CNT). Their weight concentration varied from 0.05 to 0.2%. Nanofluids, based on ethylene glycol and water, were studied. Dispersants were also used. The diffusion of CNT had been systematically investigated by the method of dynamic light scattering and their effective hydrodynamic dimensions were determined. The rheology and viscosity of all nanofluids were studied. It is shown that nanofluids are either pseu-doplastic or viscoplastic. Their rheology changes with increasing CNT concentration and temperature. However, in all cases, the viscosity of nanofluids with single-walled CNTs is signifi-cantly higher than that of nanofluids with multi-walled CNTs. In the last part, the electrical conductivity of all these nanofluids and the dispersants effect on it are investigated.


2020 ◽  
Vol 31 (23) ◽  
pp. 235402 ◽  
Author(s):  
Balaji Bakthavatchalam ◽  
Khairul Habib ◽  
R Saidur ◽  
Syed Shahabuddin ◽  
Bidyut Baran Saha

2021 ◽  
Vol 66 (4) ◽  
pp. 1717-1729 ◽  
Author(s):  
Carlos Alberto Nieto de Castro ◽  
Ana Paula da Costa Ribeiro ◽  
Andreia Oliveira Figueiras ◽  
Elisa Langa ◽  
Salomé Inês Cardoso Vieira ◽  
...  

2021 ◽  
Vol 8 (3A) ◽  
Author(s):  
Alexandre Melo Oliveira ◽  
Amir Zacarias Mesquita ◽  
Enio Pedone Bandarra ◽  
Daniel Flórez Morales

To evaluate the synthesis and characterization of MWCNT (Multi-walled Carbon Nanotubes) with different degrees of functionalization in distilled water. The thermophysical properties (thermal conductivity and viscosity) of these nanofluids were measured at a temperature range (20-60°C) and concentrations (0.005-0.05%) by volume. Increases in thermal conductivity and viscosity were found 9.3% and 4.7%, respectively, at a volumetric concentration of 0.01% at a temperature of 30°C. The study of new fluids that improve the rate of removal of heat is fundamental to obtain greater efficiency of energy systems. Among the several factors that compromise the efficiency of the energy systems, we can highlight the thermophysical limitations of the conventional fluids, inhibiting in a very significant way some industrial applications. In this work we intend to improve the heat transfer characteristics of fluids commonly used by the addition of nanoparticles, made up of carbon nanotubes, in water which is the most used fluid for the cooling of nuclear reactors in operation today. It is intended to improve the heat transfer characteristics of fluids commonly used by the addition of nanoparticles, made of carbon nanotubes, through the addition of nanoparticles, made up of carbon nanotubes, in water which is the most used fluid for refrigeration of nuclear reactors currently in operation. In order to assess its benefits for the applicability and nuclear systems, ie primary coolant, safety systems, major accident mitigation strategies.


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