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In this article, we are focusing on heat and mass transfer through a Multicomponent tubular reactor containing a cooling jacket by thermal decomposition of propylene oxide in water. The chemical reaction is an irreversible, 1st order reaction and an exothermic reaction that yields propylene glycol with enthalpy = −84,666 J/mol. The constant rate of the reaction is followed by the Arrhenius equation in which the activation energy is taken on a trial basis in the range from 75,000 to 80,000 J/mol with a fixed frequency factor. For the fluid to flow, the Reynolds number is kept in the range from 100 to 1000. The three partial differential equations of mass, momentum, and energy are coupled to study heat and mass transfer in a tubular reactor by using the chemistry interface in COMSOL Multiphysics 5.4. The initial concentration of propylene oxide is tested in the range from 2 to 3% and the thermal conductivity of the mixture is tested in the range 0.599–0.799. It was found that the amount deactivated of the compound decreases with an increase in Reynolds number. Propylene oxide is decomposed at about 99.8% at Re = 100 at lower activation energy and gives the total maximum enthalpy change in the tubular reactor. Observing the relationship between Sherwood numbers to Nusselt numbers, it was deducted that the convective heat transfer is opposite to convective mass transfer for high Reynolds numbers. [ABSTRACT FROM AUTHOR]

In this study, we have used Lie group analysis procedure to propose a novel model for transforming the governing equations of double diffusive MHD hyperbolic tangent fluid flow model into a system of nonlinear ordinary differential equations (ODEs). The solution of these equations is then investigated numerically by employing Shooting method. We also reported and presented our results graphically illustrating the results and analysis of physical parameters on concentration, velocity, and temperature profiles and on other physical quantities present in the flow model. The results show that fluid temperature increases with rise in the modified Dufour and velocity slip parameters whereas opposite behavior is observed for thermal slip parameter. Moreover, the Nusselt number declines with enhanced values of modified Dufour parameter whereas its opposite effect has been observed for Dufour-solutal Lewis number and Prandtl number. [ABSTRACT FROM AUTHOR]

This research examines the thin-film nanomaterial movement in three dimensions over a stretchable rotating inclined surface. Similarity variables are used to transform fundamental systems of equations into a set of first-order differential equations. The Runge–Kutta Fourth Order approach is utilized for numerical computations. The impact of embedded parameters (variable thickness, unsteadiness, Prandtl number, Schmidt number, Brownian-motion, and thermophoretic) is examined carefully. Physically and statistically, the indispensable terms namely Nusselt and Sherwood numbers are also investigated. Results indicated that, as the dimensionless parameter S raises, the temperature field decreases. In reality, as the values of S increases, heat transmission rate from the disc to the flowing fluid reduces. Internal collisions of liquid particles are physically hampered at a low rate. The momentum boundary layer is cooled when the parameter S is increased, as a consequence local Nusselt number rises. Sherwood number decreases as the parameter S increases because of inter collision of the microscopic fluid particles. Enhancing in the apparent viscosity and concentrations of the chemical reactions, a higher Schmidt number, Sc, lowers the Sherwood number. With increasing values of Prandtl number the Nusselt number decreases. For validation purpose, the RK4 method is also compared with homotopy analysis method (HAM). The results are further verified by establishing an excellent agreement with published data. [ABSTRACT FROM AUTHOR]

This research article deals with the nonlinear thermally radiated influences on non-Newtonian nanofluid considering Jeffrey fluid in a rotating system. The governing equations of the nanofluid have been transformed to a set of differential nonlinear equations, using suitable similarity variables. The Homotopy Analysis Method (HAM) and Runge–Kutta Method of order 4 (RK Method of order 4) are used for the solution of the modeled problem. The variation of the skin friction, Nusselt number, Sherwood number, and their impacts on the velocity distribution, temperature distribution, and concentration distribution have been examined. The influence of the Hall effect, rotation, Brownian motion, porosity, and thermophoresis analysis are also investigated. Moreover, for comprehension of the physical presentation of the embedded parameters, Deborah number β , viscosity parameter R , rotation parameter Kr , Brownian motion parameter Nb , porosity parameter γ , magnetic parameter M , Prandtl number Pr , thermophoretic parameter Nt , and Schmidt number Sc have been plotted and deliberated graphically. For large values of Brownian parameter, the kinetic energy increases, which in turn increases the temperature distribution, while the thermal boundary layer thickness decreases by increasing the radiation parameter, and the Hall parameter increases the motion of the fluid in horizontal direction. Also, the mass flux has been observed as a decreasing function at the lower stretching plate. [ABSTRACT FROM AUTHOR]

The objectives of this study involve the optimization of longitudinal porous fins of square cross-section using metaheuristic algorithms. A generalized nonlinear ordinary differential equation is derived using Darcy and Fourier’s laws in the energy balance around a control volume and is solved numerically using RFK 45 method. The temperature of the base surface is higher than the fin surface, and the fin tip is kept adiabatic or cooled by convection heat transfer. The other pertinent parameters include Rayleigh number (100 ≤ Ra ≤ 104), Darcy number, (10−4 ≤ Da ≤ 10−2), relative thermal conductivity ratio of solid phase to fluid (1000 ≤ kr ≤ 8000), Nusselt number (10 ≤ Nu ≤ 100), porosity (0.1 ≤ φ ≤ 0.9). The impacts of these parameters on the entropy generation rate are investigated and optimized using metaheuristic algorithms. In computer science, metaheuristic algorithms are one of the most widely used techniques for optimization problems. In this research, three metaheuristic algorithms, including the firefly algorithm (FFA), particle swarm algorithm (PSO), and hybrid algorithm (FFA-PSO) are employed to examine the performance of square fins. It is demonstrated that FFA-PSO takes fewer iterations and less computational time to converge compared to other algorithms. [ABSTRACT FROM AUTHOR]

In this study, pressure-driven flow in the slip regime is investigated in rectangular microducts. In this regime, the Knudsen number lies between 0.001 and 0.1. The duct aspect ratio is taken as 0 ≤ ε ≤ 1 . Rarefaction effects are introduced through the boundary conditions. The dimensionless governing equations are solved numerically using MAPLE and MATLAB is used for artificial neural network modeling. Using a MAPLE numerical solution, the shear stress and heat transfer rate are obtained. The numerical solution can be validated for the special cases when there is no slip (continuum flow), ε = 0 (parallel plates) and ε = 1 (square microducts). An artificial neural network is used to develop separate models for the shear stress and heat transfer rate. Both physical quantities are optimized using a particle swarm optimization algorithm. Using these results, the optimum values of both physical quantities are obtained in the slip regime. It is shown that the optimal values ensue for the square microducts at the beginning of the slip regime. [ABSTRACT FROM AUTHOR]