Experimental Setup for Heat Transfer Analysis on Rectangular Plate by Natural Convection (original) (raw)
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Maǧallaẗ al-handasaẗ, 2023
An experimental investigation of natural convection heat transfer from an isothermal horizontal, vertical and inclined heated square flat plates with and without circular hole, were carried out in two cases, perforated plates without an impermeable adiabatic hole "open core" and perforated plates with an impermeable adiabatic hole "closed core" by adiabatic plug. The experiments covered the laminar region with a range of Rayleih number of (1.11x10 6 ≤Ra Lo ≤4.39x10 6), at Prandtle number (Pr=0.7). Practical experiments have been done with variable inclination angles from horizon (Ф=0 o ,45 o ,90 o ,135 o and 180 o), facing upward (0 o ≤Ф<90 o), and downward (90 o ≤Ф<180 o). The results showed that the temperature gradient increases while the thermal boundary layer thickness decreases when Grashof number and perforation ratio (m) increase. The temperature gradient for inclined position facing upward is less than facing downward, while the thermal boundary layer thickness is greater. The temperature gradient decreases while the thermal boundary layer thickness increases for perforated plates with an adiabatic core as compared with perforated plates without an adiabatic core. The value of average Nusselt number increases with increasing perforation ratio, and Grashof number for all specimens with and without an adiabatic core, also increases by increase in inclination of plates approaching the higher value at vertical position (Ф=90 o), then decreases with increasing inclination of plates till horizontal position (Ф=180 o). The average Nusselt number values for perforated plates with an adiabatic core are lower than for perforated plates without an adiabatic core for all perforation ratios. Maximum heat transfer rate occurs at perforated plate with perforation ratio of (m=0.1) without adiabatic core for vertical position (Ф=90 o), at a range of Grashof number (1.576x10 6 ≤Gr Lo ≤6.292x10 6), while the rate of heat transfer decreases with increasing perforation ratio for plates with and without adiabatic core for decrease in heat transfer rate area. The rate of heat transfer for perforated plates with circular hole is more than for perforated plates with square hole at the same perforation ratios (m=0.1,0.16,0.24 and 0.36). It found that the lack of core flow decreases the overall heat transfer rate by (6.477%). There was a good agreement for the experimental present work results compared with other pervious results .
Investigation of the effect of different materials on convective heat transfer
Journal of Mechanical Engineering and Sciences
Conventionally, the study of convection heat transfer merely focuses on the behavior of air flow without considering the conductive effect of the horizontal flat plate. However, it is expected that the conductive effect of the horizontal plate somewhat affects the air flow temperature across the flat plate. Therefore, it is motivated to study the variation of air flow temperature across different materials of flat plate in various time frame. The materials used in this study are aluminium, stainless steel and cast iron. Infrared camera and FloEFD simulation software are used to measure the upper surface temperature of the flat plate. For forced convection, the study is carried out within the range of 103 £ Re £ 104 and within the range of 1 × 107 £ Ra < 2.2 × 107 for natural convection. Flow velocity of 2.3 m/s, 4.1 m/s and 5.2 m/s are used for the forced convection. The results showed that aluminium plate cools down faster than the other two metal plates used in all scenarios. S...
HEAT TRANSFER ENHANCEMENT IN PLATES BY NATURAL CONVECTION WITH AND WITHOUT VERTICAL CONFINING WALLS
Natural Convection flow in a vertical channel with internal objects is encountered in several technological applications of particular interest of heat dissipation from electronic circuits, refrigerators, heat exchangers, nuclear reactors fuel elements, dry cooling towers, and home ventilation etc.This study deals with the study of natural convection in horizontal plate with and without vertical confining walls. The parameters varied during the experimentation are heat input, aspect ratio (the ratio of gap of horizontal plate with respect to vertical plate and gap of horizontal plate from bottom to top). The present study aims to determine the heat transfer characteristics, along the plate for the selection of optimum dimension for design purpose. Further, the influences of aspect ratio on the performance characteristics of heat transfer will be studied.
Review on Natural Convective Heat Transfer from Inclined Narrow Plates
International Journal for Research in Applied Science & Engineering Technology (IJRASET), 2019
In many engineering situations, the equipment is placed at different geographical locations which are not accessible to regular maintenance and which requires cooling of the surfaces continuously and natural/free convection heat transfer process is preferred for this applications. Natural Convection is one of the major modes of heat transfer that can be classified in terms of being natural, forced, gravitational, granular, or thermomagnetic. In the past decade, several studies on convection heat transfer in much geometry, enhancement of heat transfer by adding narrow strip (fin), effects of the magnetic field in heat transfer, heat transfer in a porous medium have been reported. The effects of Prandtl (Pr), Reynolds (Re), Grashof (Gr), and Rayleigh numbers (Ra), fin length, fin height, fin spacing, and their orientation have also been investigated. This paper reviews various researchers work on fluid flow and heat transfer behavior which is carried out by means different types of fin attachments, their orientation & angle of inclination of the base plate.
Study of natural and forced heat transfer coefficients on a vertical heated plate
INCAS Bulletin, 2015
Infrared thermography measurement technique is a methodology which detects infrared energy emitted from an object, converts it to temperature, and displays images of temperature distribution. It is a powerful non-invasive methodology for the analysis of surface temperature measurements. The infrared camera represents a truly two-dimensional transducer, allowing for considerably high accurate measurements of surface temperature maps even in the presence of relatively high spatial gradients. The infrared thermography measurement technique is used in this experimental study to estimate the heat transfer coefficient over a flat plate. The main objective of this study was to get insights about the heat transfer in solids and on solid surfaces and its quantitative measurement. An infrared camera was used to calculate the temperature distribution for the evaluation of the heat transfer coefficient. Two study cases were taken into account: a first case without any fluid jet is calculated, where natural convection over the plate emerges due to the buoyancy effect, and a second case where a circular air jet is impinged on the surface-in this case the forced convection heat transfer coefficient has been evaluated.
Natural Convective Heat Transfer from Inclined Narrow Plates
In many engineering situations, the equipment is placed at different geographical locations which are not accessible to regular maintenance and which requires cooling of the surfaces continuously and natural/free convection heat transfer process is preferred for this applications. Natural Convection is one of the major modes of heat transfer that can be classified in terms of being natural, forced, gravitational, granular, or thermomagnetic. In the past decade, several studies on convection heat transfer in much geometry, enhancement of heat transfer by adding narrow strip (fin), effects of the magnetic field in heat transfer, heat transfer in a porous medium have been reported. The effects of Prandtl (Pr), Reynolds (Re), Grashof (Gr), and Rayleigh numbers (Ra), fin length, fin height, fin spacing, and their orientation have also been investigated. This paper reviews various researchers work on fluid flow and heat transfer behavior which is carried out by means different types of fin attachments, their orientation & angle of inclination of the base plate.
Experimental Comparison of Natural Convection Heat Transfer from Various Dimpled Plates
Convection is usually the dominant form of heat transfer in liquids and gases. Although sometimes discussed as a third method of heat transfer, convection is usually used to describe the combined effects of heat conduction within the fluid (diffusion) and heat transference by bulk fluid flow streaming. Convective heat transfer is the transfer of heat from one place to another by the movement of fluids, a process that is essentially the transfer of heat via mass transfer. Bulk motion of fluid enhances heat transfer in many physical situations, such as between a solid surface and the fluid. This paper refers to the convective heat transfer from a V-Fin Array whose surface is made black and the fins are sticked to it to form horizontal fin array and in form of V-Fins to form V-Fin array.
Computational Fluid Dynamics Analysis of Horizontal Heated Plate for Natural Convection
Free or natural convection heat transfer is predominant in many engineering applications such as cooling of electronic equipment, pollution, materials processing, energy systems, and safety in thermal processes and geophysical flows. The present work discusses about the result of a computational fluid dynamics study of Steady, Laminar, Free convection heat transfer in a horizontal plate facing upwards in which two walls are adiabatic and other two ends are open to the ambient .The aim is to simulate the flow using appropriate CFD tools and compare the results with available experimental data. The CFD tool used here is ANSYS-FLUENT.
The Effect of Plate Size on the Natural Convective Heat Transfer Intensity of Horizontal Surfaces
Heat Transfer Engineering, 2005
Natural convective heat transfer from Jtat horizontal isothermal plates has been investigated for more than a century. In the present study, the infiuence ofthe size ofthe plate on the heat flux is investigated. Two ranges ofthe heat transfer intensity are proposed for this problem, for the plates with characteristic length .smaller than 0.1-0.2 m. the heat transfer coefficient is inversely proportional to the plate width: for plates wider than 0.2 m. the heat fiitx is nol infiuenced by the ptaie width. The explanation for the discrepancy between the two ranges of natural convective heat transfer based on analysis and comparison of e.xperimental data available in the literature has been proposed.