The grain size decreased as SiC nanoparticles were used during the conventional FSSW process because of the pinning effects. On the other hand, during the FSSW with SiC nanoparticles, continuous dynamic recrystallization was the prominent mechanism in the microstructure evolution of the stir zone. According to the results, both continuous and discontinuous dynamic recrystallizations occurred during conventional FSSW. The comparison of microstructure evolution and mechanical properties of the aluminum and copper in the weld zone of the joint has been analyzed by light microscopy, electron backscattered diffraction (EBSD), and scanning electron microscopy. The rise in the viscosity of the base liquid decreases the Brownian motion, while it increases the thermophoretic diffusion, which can participate together in making the system more sensitive.ĭue to the high application of dissimilar Al-Cu joints in different industries, pure copper and the AA2024 alloy with SiC nanoparticles were successfully welded by friction stir spot welding (FSSW).
Glycerine-titanium dioxide is found to be the least stable due to the highest viscosity of glycerine and lowest conductivity of titanium dioxide, while the lowest density of aluminum and the lowest viscosity of the kerosene make the kerosene-aluminum most stable. Numerical computations are performed for forty different nanoliquids to understand the substantial rise in their sensitivity.
Most importantly, no boundary conditions are imposed on nanoparticles’ volume fraction, which makes the situation under consideration more realistic. The variables are not combined at any stage to define new non-dimensional fluid numbers and hence the eigenvalue equation is obtained directly in terms of the physical properties of the fluid. The amount of nanoparticles in the fluid is assumed to be so small that it doesn’t vary along the vertical direction at the initial state. The present article investigates the thermal convection phenomenon in a nanofluid layer to find a practical analytic expression of Rayleigh’s number, which is extensively analyzed numerically. Nanoparticles significantly influence the convective heat transfer in fluids but little is known about the behavior of various thermophysical properties of nanofluids at the onset of convection.
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