International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 11 Issue: 04 | Apr 2024
p-ISSN: 2395-0072
www.irjet.net
Thermohydraulic performance of Curved Trapezoidal Winglet Vortex Generator using Sudden Expansion Channel Aakash B1, Aakash Roopan P1, Abinesh A1, Sivakumar S2 1Student, Department of Mechanical Engineering, Kumaraguru College of Technology, Tamil Nadu, India.
2Assistant Professor II, Department of Mechanical Engineering, Kumaraguru College of Technology, Tamil Nadu,
India. ---------------------------------------------------------------------***--------------------------------------------------------------------1.1 Sudden expansion channel Abstract – The goal of this study is to improve heat transfer in sudden expansion channels (SECs) at various angles of attack. The SEC's expansion ratio (ER) is given the value of 2:1. In every example, the angle of attack (β) of VG is adjusted by 15 degrees, ranging from 30 to 90 degrees. This study's findings are contrasted with those of a basic rectangular channel (SRC) using a vector gauge (VG). It is assumed that the flow in the range of Reynolds (Re) numbers under investigation is laminar, stable, and incompressible. The analysis reveals that VGs are more successful in boosting heat transfer against pressure decrease at all angles of attack in SEC than in SRC. In contrast to the friction factor, which remains unchanged at SEC aspect ratios except at higher angles of attack, the rate of heat transfer increases as SEC aspect ratios rise. On the other hand, the friction factor decreases when the VG angle of attack increases. The findings show that the combined influence of longitudinal vortex flow and flow separation is responsible for the increased heat transfer rate.
Separated flows are unpredictable, which makes them difficult to comprehend. Different geometries, such as ribs, fences, bluff bodies with splitter plates, abruptly expanding pipelines, and cavities, have been used by researchers to better understand these instabilities and, to some extent, reduce the unpredictability. Because of its one fixed separation point, the sudden expansion ramped duct proved to be the most popular of all. The flow wake can be divided into three primary regions: the shear layer region, the separation bubble or recirculation zone, and the reattachment zone. These divisions are based on significant flow properties that have been examined by earlier researchers in rapid expansion geometries. The general characteristics of a sudden expansion flow result in the development of a thin boundary layer and an adverse pressure gradient, which cause an angular momentum in the flow. The turbulent structures inside the boundary layer merge as the flow continues downstream, increasing the size of the boundary layer. The layer region is the area where the border layer grows and evolves. Low-velocity recirculation is produced in the space between the shear layer and the nearby wall as a result of this flow. In the recirculation zone, a primary vortex is formed in the centre of the ramped shape, while a secondary vortex is formed next to the corner. The reattachment point is the point at which the shear layer eventually bends downward and impinges at a defined location due to the fluid's advantageous pressure gradient. The horizontal distance between the step and the reattachment point is known as the reattachment length. Together, these three areas make up the key components of a rapid expansion flow, which can be changed or manipulated to provide desired results including improved mixing qualities and decreased vibration, noise, and drag.
Key Words: Heat transfer, vortex generator, ramped expansion channel, ramp angle.
1.INTRODUCTION Transferring thermal energy from one location to another is known as heat transfer. This is important in modern engineering because devices like gas turbine blades, heat exchangers, microelectronic circuit boards, axial and centrifugal compressor blades, combustors, and heat exchangers are used to change the flow of energy wherever it is needed. Every piece of machinery has a unique heat transfer procedure, so we must comprehend how each one operates. Vortex generators have been the subject of successful recent inventions, studies, and testing to improve the effect of heat transfer; these devices are currently in use, even in real-time. Vortex generators aid in delaying the fluid's divided laminar and turbulent flows. To reduce the impact of the pressure penalty caused by the vortex generator, experiments with sudden expansion channel flow have been conducted. When compared to constant area duct flow, the pressure penalty is lessened due to the vortex generators' minimization of the boundary layer.
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1.2 Vortex Generator Vortex generators are basic structures resembling the fin's structure. The fundamental purpose of these aerodynamic gadgets is to keep the overflow over the surface to which they are attached. It is a tool that aids in lowering an aircraft's stall speed in aerodynamic terms. The lowest constant flying speed at which an aircraft can be controlled is known as the stall speed. In order to attain a safety margin
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