The effect of buoyancy force on natural convection heat transfer of nanofluid flow in triangular cavity with different barriers.

This article aims to investigate the thermophysical properties of viscous nanofluid in the two-dimensional geometry of a triangular cavity containing inverted triangle, square, and rhombus obstacles with different boundary conditions. The boundary conditions of the triangular cavity are investigated in two mechanisms: 1) uniform temperature at the base of the cavity and 2) non-uniform temperature (sinusoidal function) at the base of the cavity. The finite element method was used to solve the governing equations of the viscous nanofluid flow. The effect of flow control parameters on velocity and temperature profile is considered in a wide range of Rayleigh and Prandtl numbers. The innovation of this study is to use different obstacles in the two-dimensional geometry of the triangular cavity and compare their velocity profiles and temperature distribution in different boundary conditions. The results show that in the obstacles used in the triangular cavity, with the increase of buoyancy force and Rayleigh number, the values of velocities increased and caused the formation of vortex flow, and the pattern of velocity vectors in the cavity with the rule of uniform temperature has given a distinctive feature. Also, the application of trigonometric temperature functions in general and sinusoidal temperature functions in particular with high frequency can effectively create a vortex flow and increase the heat transfer rate.

Free convection in a square wavy porous cavity with partly magnetic field: a numerical investigation.

Natural convection in a square porous cavity with a partial magnetic field is investigated in this work. The magnetic field enters a part of the left wall horizontally. The horizontal walls of the cavity are thermally insulated. The wave vertical wall on the right side is at a low temperature, while the left wall is at a high temperature. The Brinkman-Forchheimer-extended Darcy equation of motion is utilized in the construction of the fluid flow model for the porous media. The Finite Element Method (FEM) was used to solve the problem's governing equations, and the current study was validated by comparing it to earlier research. On streamlines, isotherms, and Nusselt numbers, changes in the partial magnetic field length, Hartmann number, Rayleigh number, Darcy number, and number of wall waves have been examined. This paper will show that the magnetic field negatively impacts heat transmission. This suggests that the magnetic field can control heat transfer and fluid movement. Additionally, it was shown that heat transfer improved when the number of wall waves increased.

A comprehensive review of microbial fuel cells considering materials, methods, structures, and microorganisms.

Microbial fuel cells (MFCs) are promising for generating renewable energy from organic matter and efficient wastewater treatment. Ensuring their practical viability requires meticulous optimization and precise design. Among the critical components of MFCs, the membrane separator plays a pivotal role in segregating the anode and cathode chambers. Recent investigations have shed light on the potential benefits of membrane-less MFCs in enhancing power generation. However, it is crucial to recognize that such configurations can adversely impact the electrocatalytic activity of anode microorganisms due to increased substrate and oxygen penetration, leading to decreased coulombic efficiency. Therefore, when selecting a membrane for MFCs, it is essential to consider key factors such as internal resistance, substrate loss, biofouling, and oxygen diffusion. Addressing these considerations carefully allows researchers to advance the performance and efficiency of MFCs, facilitating their practical application in sustainable energy production and wastewater treatment. Accelerated substrate penetration could also lead to cathode clogging and bacterial inactivation, reducing the MFC's efficiency. Overall, the design and optimization of MFCs, including the selection and use of membranes, are vital for their practical application in renewable energy generation and wastewater treatment. Further research is necessary to overcome the challenges of MFCs without a membrane and to develop improved membrane materials for MFCs. This review article aims to compile comprehensive information about all constituents of the microbial fuel cell, providing practical insights for researchers examining various variables in microbial fuel cell research.

An investigation into a semi-porous channel's forced convection of nano fluid in the presence of a magnetic field as a result of heat radiation.

This study investigates the impact of heat radiation on magnetically-induced forced convection of nanofluid in a semi-porous channel. The research employs Akbari-Ganji's and Homotopy perturbation methods to analyze the effects of multiple parameters, including Hartmann number, Reynolds number, Eckert number, radiation parameter, and suction parameter, on the flow and heat transfer characteristics. The results demonstrate that increasing Reynolds number, suction, and radiation parameters increases temperature gradient, providing valuable insights into improving heat transfer in semi-porous channels. The study validates the proposed methods by comparing the results with those obtained from other established methods in the literature. The main focus of this work is to understand the behavior of nanofluids in semi-porous channels under the influence of magnetic fields and heat radiation, which is essential for various industrial and engineering applications. The future direction of this research includes exploring the effects of different nanoparticle shapes and materials on heat transfer performance and investigating the influence of other parameters, such as buoyancy forces and variable properties, on the flow and heat transfer characteristics. The findings of this study are expected to contribute to the development of more efficient thermal management systems in the future.

The HAN method for a thermal analysis of forced non-Newtonian MHD Reiner-Rivlin viscoelastic fluid motion between two disks.

In this article, the semi-analytical technique of the Hybrid Analytical and Numerical Method (the HAN Method) is used to study the non-transient forced non-Newtonian MHD Reiner-Rivlin viscoelastic fluid motion that is constrained between two plates. The magnetic field is also present in this model. The governing equations are in the PDE form and by using the Von Kármán similarity variables, they transformed into a set of ODEs. The HAN-method is applied to solve the ODEs and their associated boundary conditions, analytically. In addition, for the validation, the HAN solution results were compared with the HPM and numerical technique of Runge-Kutta results. And finally, new results were extracted from the HAN solutions in a quantitative form.