This study analyses the hydrodynamic and thermal behaviours of a fully developed natural convection flow in a vertical parallel-plate microchannel with suction/injection. The velocity slip and temperature jump at the walls are taken into account. The fully developed solutions of the velocity, temperature, volume flow rate, rate of heat transfer which is expressed as the Nusselt number and skin friction are derived analytically. The influence of each governing parameter on the microchannel hydrodynamic and thermal behaviours is discussed with the aid of graphs. Results show that as suction/ injection on the channel surfaces increases, the volume flow rate increases and the rate of heat transfer decreases. In addition, it is observed that increase in the effects of rarefaction and fluid-wall interaction results in the increase in the volume flow rate and decrease in the heat transfer rate.

A numerical study is reported to investigate the transient free-convective flow through a vertical porous annulus. A closed-form solution is also presented for temperature, velocity, skin friction, and rate of heat transfer for the steady fully developed flow. During the course of numerical computation, an excellent agreement was found between steady state solutions with transient solutions at large values of time. It is also seen that steady state temperature and velocity are independent of Prandtl number in the absence of suction/injection, while dependent on Prandtl number in the presence of suction/injection.

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A semi-analytical investigation of the effect of a chemical reaction and thermal diffusion on transient natural convection flow of a viscous incompressible binary fluid with heat source/sink in a vertical and infinite tube is presented. The equations for the model are simplified with the help of the Laplace transform, solved analytically to obtain solutions whose expressions are given in modified Bessel functions. These solutions are then inverted numerically using the Riemann sum approximation method. An exhaustive model analysis is achieved by exhibiting the temperature, concentration, and velocity profiles graphically.Also, numerical values are displayed in tabular form for the Nusselt number, Sherwood number, and the shear stress. Furthermore, a version of the governing equations which are independent of time is solved analytically. The obtained results are found to coincide with the results of the time-dependent problem at an appreciable value of time. A close examination of the results reveals that raising the generative chemical reaction parameter strengthens both the concentration and momentum of the flow while they are weakened with a surge of the destructive chemical reaction. As the heat source intensifies, both fluid temperature and velocity are elevated while the species concentration is abated with the reversed phenomenon occurring as the

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