Heat transfer and pressure drop in turbulent nanofluid flow in a pin-fin heat sink : fin and nanoparticles shape effects

In this paper, the turbulent flow of a nanofluid in a channel is simulated in the presence of a pinfin heatsink. Pin fins have different shapes, including hexagonal, circular, square, and triangular that are considered in two different arrangements. Constant heat flux is applied to the heatsink from its bottom due to the operation of an electronic chip. The nanoparticles suspended in water are alumina, which are in different shapes such as blades, bricks, cylinders, and plates. Their shape effect is investigated. The nanofluid enters the channel at a constant velocity in the range of 1–3 m/s and a constant volume percentage of 2%, and exits after cooling the pin-fin heatsink. The standard k-ε turbulence model is used to model turbulent flow, and the SIMPLEC method is employed to linearize the equations. The variables include fin type, fin arrangement, nanoparticle shape, and nanofluid velocity. Their effect on the maximum and average heatsink temperature and pressure drop (ΔP) is studied. The results show that increasing the velocity leads to a reduction in heatsink temperature, and the use of brick-shaped nanoparticles and circular fin results in the best cooling performance. Also, the use of circular fin and brick nanoparticles requires less ΔP than other cases.The Deanship of Scientific Research (DSR) at King Abdulaziz University, Jeddah.https://http//www.elsevier.com/locate/csiteam2022Mechanical and Aeronautical Engineerin

Applying artificial neural network and response surface method to forecast the rheological behavior of hybrid nano‐antifreeze containing graphene oxide and copper oxide nanomaterials

In this study, the efficacy of loading graphene oxide and copper oxide nanoparticles into ethylene glycol-water on viscosity was assessed by applying two numerical techniques. The first technique employed the response surface methodology based on the design of experiments, while in the second technique, artificial intelligence algorithms were implemented to estimate the GO-CuO/water-EG hybrid nanofluid viscosity. The nanofluid sample’s behavior at 0.1, 0.2, and 0.4 vol.% is in agreement with the Newtonian behavior of the base fluid, but loading more nanoparticles conforms with the behavior of the fluid with non-Newtonian classification. Considering the possibility of non-Newtonian behavior of nanofluid temperature, shear rate and volume fraction were effective on the target variable and were defined in the implementation of both techniques. Considering two constraints (i.e., the maximum R-square value and the minimum mean square error), the best neural network and suitable polynomial were selected. Finally, a comparison was made between the two techniques to evaluate their potential in viscosity estimation. Statistical considerations proved that the R-squared for ANN and RSM techniques could reach 0.995 and 0.944, respectively, which is an indication of the superiority of the ANN technique to the RSM one.https://www.mdpi.com/journal/sustainabilitydm2022Mechanical and Aeronautical Engineerin

Dynamic Analysis of Sigmoid Bidirectional FG Microbeams under Moving Load and Thermal Load: Analytical Laplace Solution

This paper presents for the first time a closed-form solution of the dynamic response of sigmoid bidirectional functionally graded (SBDFG) microbeams under moving harmonic load and thermal environmental conditions. The formulation is established in the context of the modified couple stress theory to integrate the effects of microstructure. On the basis of the elasticity theory, nonclassical governing equations are derived by using Hamilton’s principle in combination with the parabolic higher-order shear deformation theory considering the physical neutral plane concept. Sigmoid distribution functions are used to describe the temperature-dependent thermomechanical material of bulk continuums of the beam in both the axial and thickness directions, and the gradation of the material length scale parameter is also considered. Linear and nonlinear temperature profiles are considered to present the environmental thermal loads. The Laplace transform is exploited for the first time to evaluate the closed-form solution of the proposed model for a simply supported (SS) boundary condition. The solution is verified by comparing the predicted fundamental frequency and dynamic response with the previously published results. A parametric study is conducted to explore the impacts of gradient indices in both directions, graded material length scale parameters, thermal loads, and moving speed of the acted load on the dynamic response of microbeams. The results can serve as a principle for evaluating the multi-functional and optimal design of microbeams acted upon by a moving load

Dynamic Analysis of Sigmoid Bidirectional FG Microbeams under Moving Load and Thermal Load: Analytical Laplace Solution

This paper presents for the first time a closed-form solution of the dynamic response of sigmoid bidirectional functionally graded (SBDFG) microbeams under moving harmonic load and thermal environmental conditions. The formulation is established in the context of the modified couple stress theory to integrate the effects of microstructure. On the basis of the elasticity theory, nonclassical governing equations are derived by using Hamilton’s principle in combination with the parabolic higher-order shear deformation theory considering the physical neutral plane concept. Sigmoid distribution functions are used to describe the temperature-dependent thermomechanical material of bulk continuums of the beam in both the axial and thickness directions, and the gradation of the material length scale parameter is also considered. Linear and nonlinear temperature profiles are considered to present the environmental thermal loads. The Laplace transform is exploited for the first time to evaluate the closed-form solution of the proposed model for a simply supported (SS) boundary condition. The solution is verified by comparing the predicted fundamental frequency and dynamic response with the previously published results. A parametric study is conducted to explore the impacts of gradient indices in both directions, graded material length scale parameters, thermal loads, and moving speed of the acted load on the dynamic response of microbeams. The results can serve as a principle for evaluating the multi-functional and optimal design of microbeams acted upon by a moving load

Design and Optimization of a Backup Renewable Energy Station for Photovoltaic Hybrid System in the New Jeddah Industrial City

This study aims to design and optimize a backup renewable energy station and possibility of the grid-connected hybrid photovoltaic (PV) power system for firms in 2nd Jeddah industrial city workshops. Wind and solar energy potentials were examined, and data from a variety of sources were obtained as part of the study process. It is important to utilize the application hybrid optimization model for electric renewables (HOMER) to evaluate relevant data as well as the suggested hybrid power system’s economic feasibility. The system’s payback is solely based on monthly grid bill savings and increased profits due to the absence of a power shortage. The most cost-effective system design is measured in terms of the original cost, ongoing cost, cost per unit, and total system net present value. As a result, fulfilling the load demand with 220 kW wind turbines and 500 kW solar PV is both cost-effective and efficient. The simulation results for the second scenario with a wind turbine show that a combination of a 500 kW PV, 300 kWh battery capacity, 22 kW wind turbine, and 315 kW converter is the most feasible solution for this case study, with SAR 4,433,658 net present cost (NPC) and SAR 0.1741 LCOE

A Novel Green Ocean Strategy for Financial Sustainability (GOSFS) in Higher Education Institutions: King Abdulaziz University as a Case Study

Financing education has recently been a big concern since educational expenditure continues to rise. As a result, there will be a gradual shift away from the “unilateral approach” to funding and toward the “diversification of financing resources”. The aim of this paper is to propose an innovative strategy plan to optimize universities’ investment sources and maintain their financial sustainability. This approach was known as the Green Ocean Strategy for Financial Sustainability (GOSFS). To effectively implement GOSFS in higher education institutions, a roadmap of 18 steps is constructed around three primary key performance areas (resource development, good governance, and regulations and legislation). The GOSFS was applied within four successive stages at King Abdulaziz University as a case study. With 18 pillars found under these three key performance areas, a long-term target for 2045 and an overall goal for 2025 were defined. In addition, the paper created novel versions of the Business Model Canvas to meet the GOSFS plan concept. To effectively employ GOSFS, four recommendations are offered to accelerate business growth and engage the university investment ecosystem, including whether to invest in highly qualified human capital, expand financial resources, or leverage technical resources. Future directions are also provided

Dynamic Analysis of a Piezoelectrically Layered Perforated Nonlocal Strain Gradient Nanobeam with Flexoelectricity

This study presents a mathematical size-dependent model capable of investigating the dynamic behavior of a sandwich perforated nanobeam incorporating the flexoelectricity effect. The nonlocal strain gradient elasticity theory is developed for both continuum mechanics and flexoelectricity. Closed forms of the equivalent perforated geometrical variables are developed. The Hamiltonian principle is exploited to derive the governing equation of motion of the sandwich beam including the flexoelectric effect. Closed forms for the eigen values are derived for different boundary conditions. The accuracy of the developed model is verified by comparing the obtained results with the available published results. Parametric studies are conducted to explore the effects of the perforation parameters, geometric dimensions, nonclassical parameters, flexoelectric parameters, as well as the piezoelectric parameters on the vibration behavior of a piezoelectric perforated sandwich nanobeam. The obtained results demonstrate that both the flexoelectric and piezoelectric parameters increased the vibration frequency of the nanobeam. The nonlocal parameter reduced the natural vibration frequency due to a decrease in the stiffness of the structures. However, the strain gradient parameter increased the stiffness of the structures and hence increased the natural vibration frequency. The natural vibration frequency based on the NSGT can be increased or decreased, depending on the ration of the value of the nonlocal parameter to the strain gradient parameter. This model can be employed in the analysis and design of NEMS, nanosensors, and nanoactuators

Mathematical and Physical Analyses of Middle/Neutral Surfaces Formulations for Static Response of Bi-Directional FG Plates with Movable/Immovable Boundary Conditions

This article is prompted by the existing confusion about correctness of responses of beams and plates produced by middle surface (MS) and neutral surface (NS) formulations. This study mathematically analyzes both formulations in the context of the bending of bi-directional functionally graded (BDFG) plates and discusses where the misconceptions are. The relation between in-plane displacement field variables on NS and on MS are derived. These relations are utilized to define a modified set of boundary conditions (BCs) for immovable simply supported plates that enables either formulation to apply fixation conditions on the refence plane of the other formulation. A four-variable higher order shear deformation theory is adopted to present the displacement fields of BDFG plates. A 2D plane stress constitution is used to govern stress–strain relations. Based on MS and NS, Hamilton’s principles are exploited to derive the equilibrium equations which are described by variable coefficient partial differential equations. The governing equations in terms of stress resultants are discretized by the differential quadrature method (DQM). In addition, analytical expressions that relate rigidity terms and stress resultants associated with the two formulations are proved. Both the theoretical analysis and the numerical results demonstrate that the responses of BDFG plates based on MS and NS formulations are identical in the cases of clamped BCs and movable simply supported BCs. However, the difference in responses of immovable simply supported BCs is expected since each formulation assumes plate fixation at different planes. Further, numerical results show that the responses of immovable simply supported BDFG plates obtained using the NS formulation are identical to those obtained by the MS formulation if the transferred boundary condition (from NS- to MS-planes) are applied. Theoretical and numerical results demonstrate also that both MS and NS formulations are correct even for immovable simply supported BCs if fixation constraints at different planes are treated properly

Static Response of 2D FG Porous Plates Resting on Elastic Foundation Using Midplane and Neutral Surfaces with Movable Constraints

The current manuscript develops a novel mathematical formulation to portray the static deflection of a bi-directional functionally graded (BDFG) porous plate resting on an elastic foundation. The correctness of the static response produced by middle surface (MS) vs. neutral surface (NS) formulations, and the position of the boundary conditions, are derived in detail. The relation between in-plane displacement field variables on NS and on MS are derived. Bi-directional gradation through the thickness and axial direction are described by the power function; however, the porosity is depicted by cosine function. The displacement field of a plate is controlled by four variables higher order shear deformation theory to satisfy the zero shear at upper and lower surfaces. Elastic foundation is described by the Winkler–Pasternak model. The equilibrium equations are derived by Hamilton’s principles and then solved numerically by being discretized by the differential quadrature method (DQM). The proposed model is confirmed with former published analyses. The numerical parametric studies discuss the effects of porosity type, porosity coefficient, elastic foundations variables, axial and transverse gradation indices, formulation with respect to MS and NS, and position of boundary conditions (BCs) on the static deflection and stresses