Arul Prakash Raji

In recent years, researchers have shown considerable interest in supercritical carbon dioxide (sCO₂) Brayton cycle-based power plants due to their unique characteristics and higher efficiency compared with conventional Rankine cycle systems. The printed circuit heat exchanger (PCHE) is a key component that significantly influences the performance of the sCO₂ cycle, owing to its compact structure and high surface area-to-volume ratio. However, designing efficient and compact PCHEs continues to be a significant challenge, mainly because it requires balancing heat transfer effectiveness with pressure drop, a task made more complex by the intricate configuration of micro-channels. This study aims to investigate the impact of airfoil fin geometry modifications on heat transfer enhancement in PCHEs using the ANSYS Fluent computational tool. Ten novel stepped airfoil fin models were introduced and analysed. The results demonstrate that airfoil fin model 9, characterised by a double-stepped profile and a flattened trailing edge, achieves a 28% increase in heat transfer rate and a 27.37% improvement in the Nusselt number compared with the baseline airfoil fin design under various operating conditions. These improvements are attributed to enhanced turbulence generated by the stepped profile, which promotes more effective convective heat transfer.

Small gas turbine (SGT) engines power the latest generation of unmanned aerial vehicles (UAVs). This study investigates the axial flow–natured rotor blades of an SGT compressor. Rotor structures in axial flow compressors have failed due to complex stress scenarios. Lightweight, high‐resistance material can reduce the failure rate of axial flow compressors in fixed‐wing UAVs. Compressor blade designs are completed in 3DEXPERIENCE after extensive material investigation, in which the design data are evaluated through standard analytical procedures. First, an axial flow compressor blade for a long‐range UAV is analyzed using computational fluid dynamics, in which imposed the complicated rotodynamic conditions in a single moving reference frame to the axial flow compressor rotor blade. Curvature and proximity discretization are employed in conjunction with ANSYS Mesh in this study. The edges and faces are scaled by a local mesh facility. Because of the intricate nature of the flow, an enhanced wall treatment turbulence model based on the k ‐epsilon parameter was employed. The computational method based on fluid‐structure interaction (FSI) uses aerodynamic pressure distributions on the compressor blade as a basis for structural analyses. For this structural investigation, FSI has been used with a single‐coupling direction. Composite compressor blades are put through an FSI inspection to ensure they are perfect. Epoxy has been used to analyze the structural integrity of a variety of modern composites, including those made from carbon fiber–reinforced polymers, glass fiber–reinforced polymers, and Kevlar fiber–reinforced polymers. Researchers used ANSYS Workbench to conduct in‐depth analyses of over 25 lightweight materials. The blades are free to move in reaction to a shift in position at low, medium, and high rotational speeds, while the main hub remains stationary. This study lays the door for the development of axial flow compressors using nontraditional lightweight high‐resistance materials.

The use of energy resources has been critical to the advancement of human civilisation. Finding a reliable energy source is one of the most difficult tasks of the twenty-first century. Natural gas, coal, and other conventional energy sources have hastened the industrialization and modernisation of several countries. However, there is widespread concern that the release of carbon dioxide into the atmosphere from these traditional sources is the leading cause of climate change. Increased pollution, flooding, drought, rising sea levels, high temperatures, and other effects of climate change have a significant impact on the environment. As a result, current research is focusing on renewable and sustainable energy sources. Hydro energy is a low-cost and environmentally friendly way to generate electricity. Even still, the vast majority of hydroelectric energy remains underutilised. Hydrostatic and hydrodynamic methods are the two most common approaches for extracting energy from water. The Gravitational Vortex Hydropower (GVHP) with Hydro-Rotor is one such renewable turbine. By routing the water into a GVHP basin, which generates a water vortex on its inside surface while it runs, the mechanical energy of free-flowing water is converted to kinetic energy in this GVHP. The major goal of this study is to investigate the flow field characteristics of a GVHP numerically for various geometrical variables such as basin diameter, cone angle, and notch angle. CATIA is used to create several geometric models, which are then simulated using a commercial (computational fluid dynamics) CFD application. Different geometric factors of conical basin design were studied using computational hydrodynamic analysis, and their impacts on vortex generation and tangential velocity in the study region are recorded. The maximum tangential velocity derived from different basin geometry can be used to forecast the performance of the GVHP. Finally the optimized GVHP along with its dimensions such as cone angle of 14^O, a notch angle of 13^O, and a basin diameter of 1000 mm are found out and suggested for real-time applications.

The impacts of conflicting aerodynamic forces and side drifting forces are the primary unstable elements in automobiles. The action of an unstable environment in automobile vehicles increases the chance of an accident occurring. As a result, much study is required to determine how opposing aerodynamic forces and side drifting force affects function, as well as how to deal with them for safe and smooth navigation. In this work, an intercity bus is chosen as a main object, and computational fluid dynamics (CFD) analysis is used to estimate aerodynamic forces on the bus in all major directions. Experimentation is also carried out for validation reasons. CFD findings for a scaled base model and a dimple-loaded model based on experimental results from a subsonic wind tunnel are demonstrated to be correct. The drag forces generated by CFD simulations on test models are carefully compared to the experimental drag findings of same-dimensioned models. The error percentages between the results of these two methods are acquired and the percentages are determined to be within an acceptable range of significant limitations. Following these validations, CATIA is used to create a total of nine distinct models, the first of which is a standard intercity bus, whereas the other eight models are fitted with drag reduction techniques such as dimples, riblets, and fins on the surface of their upper cumulus side. A sophisticated computational tool, ANSYS Fluent 17.2, is used to estimate the comparative assessments of the predictions of aerodynamic force fluctuations on bus models. Finally, dimples on the top and side surfaces of the bus model (DESIGN–I) are proposed as a more efficient model than other models because dimples are a vital component that may lower pressure drag on the bus by 18% in the main flow direction and up to 43% in the sideslip direction. Furthermore, by minimizing the different aerodynamic force sources without impacting the preparatory needs, the proposed model may provide comfortable travel. The real-time bus is created, and the finalized drag reduction is applied to the optimized places over the whole bus model. In addition, five distinct size-based bus models are developed and studied in terms of aerodynamic forces, necessary energy to resist aerodynamic drag, required forward force for successful movement, instantaneous demand for particular power, and fuel consumption rate. Finally, the formation of aeroacoustic noise owing to turbulence is estimated using sophisticated computer simulation. Last, for real-time applications, multi-parametric studies based on appropriate intercity buses are established.

Hydropower is a superior energy extraction approach, which has been made to work based on renewable energy sources. In the generation of hydropower, Gravitational Vortex Hydropower (GVHP) plays a predominant contributor role because of its free turbulence-relayed energy utilization concept and flexible as well as compact size. Owing to the huge contribution of GVHP in the hydropower sector, multi-objective-based investigations have emerged. However, there is still insufficient literature available for the technology to precede optimum turbine blade design. Two important categories are involved in these multidisciplinary investigations, in which the first phase, a numerical investigation has been done using ANSYS to identify the location of maximum tangential velocity in a conical basin with different notch angles, conical angles, basin shapes, anddiameters. In this second phase, the focal aim is to carry out the numerical investigation on Gravitation Vortex Turbine Blades (GVTB) for the different geometry in order to get the optimum power output with a high structural lifetime through HSI (Hydro–Structural Interaction) computation. The entire conceptual designs of this SGVHP and its hydro-rotors are modeled with the help of CATIA. ANSYS Fluent is a CFD (Computational Fluid Dynamics) numerical tool, which is primarily used in this paper for all the hydrodynamic analyses. Finally, the standard analytical approaches are used for the comparative determinations of thrust production by hydro-rotors, power extraction by hydro-rotors, and propulsive efficiency for the selection process of best hydro-rotors. HSI analyses are additionally carried out and thereby the suitable lightweight material is picked.

The present work examines the oxygen enrichment on diesel engine at the fuel side and air side. Oxygenation at the fuel side is done by blending the Dimethyl carbonate (DMC) additive with a maximum percentage of oxygen whereas that of air side is done by coupling a blower to the inlet manifold. The experiment was conducted with four different blends of oxygenated additives with diesel, and then the effects of supercharging in these blends were analyzed. The performance and emission characteristics of DMC blend with diesel fuel were examined and compared with the base engine characteristics. The results show that for 5% of DMC there is an increase in the thermal efficiency of the engine and decrease the CO emissions.

The modern world needs an innovative solution in the non-renewable energy field, because of its excessive usage. Due to rapid reduction of non-renewable energy sources, along with rising demand for energy is a matter of serious concern. This paper provides a better solution for this non-renewable energy problem. It is a hybrid technique in the energy field with good quality by decreasing the pure content and increase the subordinate content which must have the similar property of pure content. Biodiesel generally derived from the biological source and it can be used as an alternative fuel for diesel engines, because it has certain unique property like diesel. Biodiesel can be used as a direct replacement of diesel fuel or it also can be used as a blending element for diesel fuel in a compression ignition engines. In this paper, the biofuel called Calophyllum Inophyllum oil can be effectively blended with diesel through transesterification process. The Calophyllum Inophyllum blended with diesel at various proportions such as 20%, 40%, 60%, and 80% are tested for performance and emissions in a single cylinder variable compression ratio four stroke diesel engine test rig. The experimental results show that for 80% blend with a compression ratio of 18:1 has increased the performance of the engine, particularly the brake thermal efficiency and the CO and smoke emission levels are also found to be reduced considerably when compared to existing diesel fuel.