Journal of Advanced Research in Numerical Heat Transfer

CFD Simulation of Solar Dish Concentrator with Different Cavity Receivers

Wed, 06 Nov 2024 00:00:00 +0700

The use of solar dish concentrators for harnessing solar energy is an established technology in the Realm of renewable energy solutions. This study presents a comprehensive Computational Fluid Dynamics (CFD) simulation to analyze the performance of a solar dish concentrator equipped with different cavity receivers. The aim is to optimize the thermal efficiency and energy absorption capabilities of the system. Various geometries of cavity receivers, including cylindrical, cubical, and hemispherical shapes, are evaluated under identical operational conditions. The simulations consider factors such as incident solar radiation, heat losses, temperature distribution, and fluid flow dynamics within the cavity. Results indicate significant variations in thermal performance based on the cavity design, with certain geometries exhibiting superior heat retention and minimal thermal losses. This research provides critical insights into the design and optimization of cavity receivers, contributing to the advancement of high-efficiency solar dish concentrator systems. The findings are expected to aid in the development of more efficient solar energy harvesting technologies, promoting sustainable energy solutions.

Analysis of Heat Distribution Processes and Casting Defects Supports 2D Direct Pouring using CFDs

Wed, 06 Nov 2024 00:00:00 +0700

Bolster and bogie frame of a train constitute a unified wheel system in both locomotives and non-locomotive cars. The bolster serves as the support for the bogie against the car body. Generally, both the bolster and bogie frame are made of steel construction with AAR Grade B+ cast material, which is categorized as medium carbon steel. In the casting of the bolster, despite hollow molds being made to the exact shape of the final product, often there are occurrences of hollow spots or imperfect shapes due to the challenging control of the cooling and solidification processes. This is caused by improper placement of mold venting channels. This study investigates the process of filling molten metal into the mold, the flow of molten metal, and the solidification process. The research utilizes ANSYS simulation software. The casting simulation method using ANSYS includes the following processes: Pre-Processing, Processing Stage, and Post-Processing. Pre-processing involves the creation of geometries, meshing, determination of parameters, and fluid property determination. The geometry model used is 2D. The Processing Stage includes setting general parameters, model determination, and defining material properties. Post-processing involves presenting and analyzing the obtained results. It can be concluded that the temperature distribution during the casting process to cooling generates a pattern where thicker sections have the highest temperature. Direct pouring gating systems tend to be vulnerable to porosity or hole defects in products because the molten metal comes into direct contact with the mold and it's difficult to control the solidification process.

MHD Natural Convection Flow of Casson Ferrofluid at Lower Stagnation Point on a Horizontal Circular Cylinder

Wed, 06 Nov 2024 00:00:00 +0700

This study considers the mathematical model of MHD free convection flow on horizontal circular cylinder immersed in Casson ferrofluid, specific to stagnation region. The set of non-linear partial differential equations that governed the model is first transformed to a simpler set of equations using the non-similar transformation. This set of equations then reduced to ordinary partial equations which reflects to the case of stagnation region and solved numerically using the implicit finite difference method known as the Keller-box method. Blood and magnetite are taken as the based-fluid and the ferroparticles for the Casson ferrofluid, respectively. From the numerical study, it was found that the Newtonian ferrofluid with the same Prandtl values had lower thermal and velocity boundary layer thicknesses compared to a Casson ferrofluid. The increase of Casson parameter reduced the thermal boundary layer thickness which physically enhanced the Nusselt number.

Simulation of Dissimilar (Al1100-Cu) Friction Stir Welding using Convection Coefficient Between Workpiece and Backing Plate Based on Its Deformation

Wed, 06 Nov 2024 00:00:00 +0700

Friction stir welding is considered a solution to conventional welding issues, particularly when dissimilar materials are involved. The implication of complex phenomena encourages researchers to utilize numerical simulations in their research. Despite the backing plate being the most significant cause of heat loss, researchers tend to simplify the heat transfer coefficient to the backing plate without considering the deformation pattern of the workpiece. The pressure applied by the tool increases the contact conductance between the workpiece and the backing plate, influencing heat transfer coefficient distribution. This paper aims to model the FSW process involving the deformation of the workpiece. A backing plate in the form of asbestos is employed to capture the deformation of the workpiece on an experimental test. Quadratic polynomial equations are used as an approach to measuring deformation patterns. Based on the results of this study, the coefficient convection distribution based on the deformation pattern produced a temperature history close to the experimental results. Validation of material flow in the model was also carried out.

Nonlinear Mixed Convective Flow of Darcy-Forchheimer Maxwell Tri-Hybrid Nanofluid Past a Riga Plate

Abhilash Anand Kumar, Sreedhar Sobhanapuram, Mangali Veera Krishna — Wed, 06 Nov 2024 00:00:00 +0700

This contribution aims to explain the nonlinear thermal flow for Darcy-Forchheimer Maxwell tri-hybrid nanofluid flow over a Riga wedge in the context of boundary slip. Three types of nanomaterials, alumina, Copper and Titania have been mixed into the base fluid known as engine oil. Thermal properties with the effects of porous surface and nonlinear mixed convection have been established for the particular combination. Applying a set of appropriate variables, the couple of equations that evaluated the energy and flow equations was transferred to the non-dimensional form. For numerical computing, the MATLAB software's bvp4c function is used. This article looks at how distinct dimensionless parameters affect the velocity field, temperature distribution, drag force, and Nusselt number. It has been detected that flow rate decay with expansion in porosity parameter and nanoparticles volumetric fractions whereas it rises with wedge angle, Grashof numbers, Darcy-Forchheimer, nonlinear Grashof number and Maxwell fluid parameter. Thermal profiles increase with progress in the heat source, nanoparticles volumetric fractions, viscus dissipation and nonlinear thermal radiation. The percentage increase in skin friction factor is 18.3 and 15.0 when Mh and m take input in the ranges of 0.1 ≤ Mh ≤ 0.3 and 0.1 ≤ m ≤ 0.3.

Water Inlet Behavior in Engine Colling Piping on Indonesian Traditional Wooden Vessel using CFD Simulation

Wed, 06 Nov 2024 00:00:00 +0700

Traditional wooden boat builders in East Kalimantan make the main engine seawater cooling system by using the water currents created by the movement of the ship without the use of suction pumps. This system has been applied to several wooden ships of various sizes. However, the size of the water flow in the pipe is not known by the builders at each ship's speed. Thus, in this paper, an investigation is carried out on seawater cooling pipes on the behavior of fluids moving in the pipes. This study aims to determine the effect of ship speed on the flow of water that occurs in the cooling pipe (inlet and outlet water). The approach taken in this paper is a computer simulation based on Computational Fluid Dynamics (CFD) by analyzing the current flow (Va) of the water discharge in the cooling pipes at speeds of 1 - 9 knots. CFD can show very detailed results in analyzing fluid flow parameters in pipes. Based on the simulations performed, the average flow velocity has increased by around 14.73% for every 1 knot increase in speed. Meanwhile, the average flow rate will increase on the pipe by 14.78% for every 1 knot increase in speed. For the average pressure obtained, the vertical pipe will increase 25% for every 1 knot increase and the horizontal pipe shell will increase 19.86% for every 1 knot increase. Meanwhile, the recommended minimum ship speed is 2.5 knots to get the required cooling seawater flow rate.

Optimizing Solar Dish Concentrator Efficiency with Nanofluids and Diverse Cavity Design

Wed, 06 Nov 2024 00:00:00 +0700

The quest for enhanced efficiency in solar energy systems has directed significant attention towards optimizing solar dish concentrators. This study investigates the performance enhancement of solar dish concentrators through the use of advanced nanofluid solutions and innovative cavity designs. The experimental setup includes various nanofluid concentrations and different cavity geometries to evaluate their impact on the overall efficiency of the system. Experimental and numerical results demonstrate a marked improvement in thermal performance, with nanofluid and cavity designs achieving up to 12% increase in efficiency compared to conventional systems. The results revealed that the hemispherical and the cubical cavities are the most effective designs, while the cylindrical cavity presents lower performance. The findings provide valuable insights into the potential of nanofluid-based solar dish concentrators and underline the importance of cavity design in optimizing solar energy harnessing. This study lays the groundwork for future research and development in high-efficiency solar energy systems, contributing to the advancement of suitable and renewable energy technologies.

Numerical Solutions of Stiff Chemical Reaction Problems using Hybrid Block Backward Differentiation Formula

Wed, 06 Nov 2024 00:00:00 +0700

This research paper introduces an advanced approach to address the numerical challenges associated with stiff chemical reaction problems. We propose employing a Hybrid Diagonally Implicit Block Backward Differentiation Formula coupled with strategically placed off-step points to improve the accuracy and efficiency of numerical solutions. Stiff chemical reactions, commonly encountered in various industrial processes, require advanced numerical techniques to precisely capture rapid changes in concentrations. Our hybrid formulation enhances stability and computational efficiency by building on the diagonally implicit structure of block backward differentiation formulas, offering improved performance for solving stiff chemical reaction problems. Under a specific selection of a free parameter, the method is found to possess both zero-stability and A−stability properties. Convergence analysis demonstrates its ability to accurately approximate exact solutions. Through rigorous experimentation and comparative analysis, this research will illustrate the effectiveness of the developed method in solving stiff ordinary differential equations. The expected outcomes include the development of the new numerical method, its validation through comprehensive numerical experiments and insights into its performance and applicability in diverse science and engineering domains.