Heat transfer to a single particle exposed to a thermal plasma

1982 ◽  
Vol 2 (2) ◽  
pp. 185-212 ◽  
Author(s):  
Xi Chen ◽  
E. Pfender
Keyword(s):  
Heat Transfer ◽  
Single Particle ◽  
Thermal Plasma

Kinetic Theory Treatment for Heat Transfer in Plasma Spraying

2002 ◽  
Author(s):  
Q. Zhang ◽  
M. A. Jog
Keyword(s):  
Heat Transfer ◽  
Kinetic Theory ◽  
Plasma Spraying ◽  
Thermal Plasma ◽  
Particle Surface ◽  
High Plasma ◽  
Transport Equations ◽  
Electron Velocity ◽  
Theory Approach ◽  
Charged Species

In plasma spraying process thermal plasma is used as a heat source to heat and melt metallic or ceramic particles. In this paper, heat transfer from a thermal plasma to a solid spherical particle has been analyzed using a kinetic theory approach. We have considered a solid particle introduced in an ionized gas made up of electrons, ions, and neutrals. Two-sided electron velocity and temperature distributions and two-sided ion velocity distributions are used. Maxwell’s transport equations are obtained by taking moments of the Boltzmann equation. The transport equations are solved with the Poisson’s equation for the self-consistent electric field. The ion and the electron number density distributions, temperature distribution, and the electric potential variation are obtained. The charged species flux to the particle surface is evaluated. Heat transport to the surface is calculated by accounting for all the modes of energy transfer including the energy deposited during electron and ion recombination at the surface. Results indicate that contribution to heat transfer from charged species recombination is substantial at high plasma temperatures.

scholarly journals First and Second Law Thermodynamic Analyses of Hybrid Nanofluid with Different Particle Shapes in a Microplate Heat Exchanger

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1466
Author(s):  
Kunal Sandip Garud ◽  
Seong-Guk Hwang ◽  
Taek-Kyu Lim ◽  
Namwon Kim ◽  
Moo-Yeon Lee
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Single Particle ◽  
Performance Index ◽  
Second Law ◽  
Hybrid Nanofluid ◽  
Bejan Number ◽  
Fluid Temperature ◽  
Shaped Nanoparticles ◽  
Hybrid Nanofluids

The improvement in the quantitative and qualitative heat transfer performances of working fluids is trending research in the present time for heat transfer applications. In the present work, the first and second law analyses of a microplate heat exchanger with single-particle and hybrid nanofluids are conducted. The microplate heat exchanger with single-particle and hybrid nanofluids is analyzed using the computational fluid dynamics approach with symmetrical heat transfer and fluid flow analyses. The single-particle Al2O3 nanofluid and the hybrid Al2O3/Cu nanofluid are investigated for different nanoparticles shapes of sphere (Sp), oblate spheroid (OS), prolate spheroid (PS), blade (BL), platelet (PL), cylinder (CY) and brick (BR). The first law characteristics of NTU, effectiveness and performance index and the second characteristics of thermal, friction and total entropy generation rates and Bejan number are compared for Al2O3 and Al2O3/Cu nanofluids with considered different-shaped nanoparticles. The OS- and PL-shaped nanoparticles show superior and worse first and second law characteristics, respectively, for Al2O3 and Al2O3/Cu nanofluids. The hybrid nanofluid presents better first and second law characteristics compared to single-particle nanofluid for all nanoparticle shapes. The Al2O3/Cu nanofluid with OS-shaped nanoparticles depicts maximum values of performance index and Bejan number as 4.07 and 0.913, respectively. The first and second law characteristics of the best combination of the Al2O3/Cu nanofluid with OS-shaped nanoparticles are investigated for various volume fractions, different temperature and mass flow rate conditions of hot and cold fluids. The first and second law characteristics are optimum at higher hot fluid temperature, lower cold fluid temperature, lower hot and cold fluid mass flow rates. In addition, the first and second law characteristics have improved with increase in volume fraction.

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