Existing solutions of the problem of axisymmetric stagnation-point flow and heat transfer on either a cylinder or a flat plate are for incompressible fluid. Here, fluid with viscosity proportional to a linear function of temperature is considered in the problem of an unaxisymmetric stagnation-point flow and heat transfer of an infinite stationary cylinder with non-uniform normal transpiration U0(φ) and constant heat flux. The impinging free-stream is steady and with a constant strain rate k¯. A reduction of Navier–Stokes and energy equations is obtained by use of appropriate similarity transformations. The semi-similar solution of the Navier–Stokes equations and energy equation has been obtained numerically using an implicit finite-difference scheme. All the solutions aforesaid are presented for Reynolds numbers, Re=k¯a2/2υ∞, ranging from 0.01 to 100 for different values of Prandtl number and viscosity-variation parameter and for selected values of transpiration rate function, S(φ)=U0(φ)/k¯a, where a is cylinder radius and υ∞ is the reference kinematic viscosity of the fluid. Dimensionless shear-stresses corresponding to all the cases increase with the increase in Reynolds number and transpiration rate function while dimensionless shear stresses decrease with the increase in viscosity-variation parameter. The local coefficient of heat transfer (Nusselt number) increases with increasing the transpiration rate function and Prandtl number

In the current article, the effect of nanofluid blast on the forced convection heat transfer in the intra-channel turbulent flow with a sudden expansion is investigated. The different cases of Newtonian, non-Newtonian, and incompressible fluids have been studied. The effects of non-Newtonian fluid index, magnetic field, nanoparticle volume fraction and nanofluid blowing frequency parameters on the pressure drop and heat transfer in the intra-channel flow have been reviewed. The simulation was performed using finite volume method as the solution strategy. The results revealed that higher values of Re and nanoparticles volume fraction resulted in the Nusselt number increasement. Also, increasing the magnetic field and decreasing the non-Newtonian fluid index increased the forced heat transfer coefficient and subsequently the Nusselt number. The results showed that the sinus velocity caused to increase the rate of the heat transfer and slightly lower friction coefficient. However, higher frequencies caused increasing of heat transfer and friction coefficient. Finally, it was founded that higher values of the Re had the most influence on the performance of the system and the magnetic field and sinus velocity were in the next step.

The importance of exchangers in the competitive ambiance of different industries has been proven. One of the most widely used exchangers in the industry, especially in the oil and gas industry, is plate heat exchangers. The aim of this study was to enhance the heat transfer coefficient in plate heat exchangers using nanofluids. Al₂O₃/water nanofluid with different Reynolds number and nanoparticle volume fractions was applied. The problem geometry was produced using Solidworks and Gambit softwares and numerically solved using Fluent software. The plate heat exchanger consists of 10 plates with specified distances which arranged on top of each other. A single-phase and homogeneous nanofluid was considered. In the present work, the effects of volume fraction of nanoparticle, Reynolds number, Chevron angle, horizontal distance, and pitch length on the flow and heat transfer parameters have been investigated. The results revealed that the optimum conditions for heat transfer, pressure drop and the pumping power were obtained at 60°/60° Chevron angle, the volume fraction of 2% and the horizontal distance of 60 mm.