Positioning Effect on Free Convection with an Elliptical Plate Placed in a Circular Enclosure

2020 ◽  
Vol 12 (8) ◽  
pp. 1054-1062
Author(s):  
Parth Patpatiya ◽  
Soumya ◽  
Bhavya Shaan ◽  
Bhavana Yadav
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
The Body ◽  
Elliptical Plate ◽  
Numerical Studies ◽  
First Case ◽  
Varied Temperature ◽  
Laminar Natural Convection ◽  
The Given ◽  
Plate System

In this analysis we have examined the process of the steady state laminar natural convection around heated elliptical plate with Rayleigh number 10^6 positioned inside a circular enclosure. The purpose of the numerical analysis is to analyze the behavior of isotherms, streamlines and heat transfer rate in enclosure plate system due to the variation in the position of elliptical plate (r/D =0.00, 0.05, and 0.2) and aspect ratio, where the given diameter of the enclosure is D and r is the distance between the centre of elliptical plate and centre of circle. Elliptical plate is inclined at different angles and results are summed up in relative manner. There are two cases, in first case aspect ratio a/D and b/D is varied and D is kept constant, whereas in second case aspect ratio a/D and b/D is kept constant and D is varied. Temperature difference between the enclosure and the inner body (i.e., temperature of inner body is kept high as compared to the enclosure) is maintained. Two dimensional study is followed by considering air as a fluid in enclosure. The effects of the Heat Transfer and Flow of Fluid are analyzed by the streamlines and isotherms plotted for the body placed inside enclosure. Value of local Nusselt number (Nu) is also plotted along the wall of elliptical plate and along the surface of the circular enclosure. For every aspect ratio isotherms and streamlines had been plotted. This work has been validated with various other numerical studies and was in good conciliation.

Flow over a heated block in a vertical channel

2014 ◽  
Vol 24 (5) ◽  
pp. 1044-1056
Author(s):  
Shahzada Zaman Shuja ◽  
Bekir Yilbas
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Aspect Ratio ◽  
Thermal Boundary Layer ◽  
The Body ◽  
Channel Inlet ◽  
Content Type ◽  
Transfer Rates ◽  
Aspect Ratios ◽  
Tilting Angle

Purpose – The heat transfer rates from the body to the working fluid can be improved through altering geometric configurations of the body and its arrangement in the flow system. One of the arrangements for this purpose is to locate the body at the channel inlet while the convection current opposes it. Since the flow field in the channel inlet influences the heat transfer rates, changing the aspect ratio and inclination of the body is expected to modify the flow field while enhancing the heat transfer rates. Consequently, investigation into the influence of the aspect ratios and tilting angles of the body on the heat transfer rates in the channel flow becomes essential. The paper aims to discuss these issues. Design/methodology/approach – Numerical simulation of flow in a channel with the presence of solid block is carried out. The block aspect ratio is changed while keeping the area of the block constant for all aspect ratios. The tilting angle is also incorporated analysis to examine its effect on the Nusselt number. Findings – The throttling effect of the block at channel inlet accelerates the flow between the channel wall and the block faces. This, in turn modifies the thermal boundary layer around the block. In this case, heat transfer rates increase considerably at the block faces where the flow acceleration suppresses the thermal boundary layer thickness. This is more pronounced for large block tilting angles. The Nusselt number attains low values for the block face opposing to the flow at the channel inlet and the back face of the block. This is attributed to the mixing of the thermal current emanating from the side faces of the block in the region close to the back surface. In this case, thermal boundary layer thickens and the heat transfer rates from the block reduce significantly. The Nusselt number improves with reducing the block aspect ratio, which is particularly true along the side faces of the block. In addition, the influence of the block tilting angle on the Nusselt number is considerable for the low block aspect ratios. Research limitations/implications – The model study is validated with the previous studies for the drag coefficient. The study covers all the aspects of the flow situations and discusses the resulting fluid field and the heat transfer rates from the block. Practical implications – It is an interesting work for cooling applications. The block aspect ratio and its tilting angle in the channel influence considerably the flow field and the Nusselt number variation around the block faces. Social implications – The cooling technology may be improved through implementing the findings of the current work. Originality/value – It is an original work and it has never been submitted to other journals.

Dimensionless Correlating-Equations for Predicting the Optimal Tilting Angle of Water-Filled Square and Shallow Enclosures Differentially Heated at Sides

2013 ◽  
Vol 394 ◽  
pp. 163-172
Author(s):  
Marta Cianfrini ◽  
Roberto de Lieto Vollaro ◽  
Alessandro Quintino ◽  
Massimo Corcione
Keyword(s):  
Heat Transfer ◽  
Rayleigh Number ◽  
Aspect Ratio ◽  
Convection Heat Transfer ◽  
Heated Wall ◽  
Tilting Angle ◽  
Shallow Cavities ◽  
Correlating Equations ◽  
Laminar Natural Convection ◽  
Dimensionless Correlations

Laminar natural convection heat transfer inside water-filled, tilted square and shallow cavities heated at one side and cooled at the opposite side, is studied numerically. A computational code based on the SIMPLE-C algorithm is used to solve the system of the mass, momentum and energy transfer governing equations. Simulations are performed using the Rayleigh number based on the length of the heated and cooled sides, the height-to-width aspect ratio of the enclosure, and the positive tilting angle with respect to the gravity vector (which corresponds to configurations with the heated wall facing upwards), as independent variables. It is found that the heat transfer performance has a peak at an optimal tilting angle which increases as the Rayleigh number is decreased and the aspect ratio is increased. On the basis of the results obtained, a set of dimensionless correlations is developed.

scholarly journals Simulating a convectional heat transfer in buildings with radiant gas heating

2018 ◽  
Vol 194 ◽  
pp. 01025 ◽  
Author(s):  
Anton N. Ermolaev ◽  
Olga V. Khaustova ◽  
Ilya A. Turaev
Keyword(s):  
Heat Transfer ◽  
Heat Output ◽  
Heated Zone ◽  
Software Products ◽  
Thermal Output ◽  
Numerical Studies ◽  
Gas Heating ◽  
Room Volume ◽  
Experimental Researches ◽  
The Given

The paper presents the results of the simulation of convectional heat transfer in buildings with radiant gas heating. The study is provided by numerical researches based on existing buildings and numerical studies with the use of modern software ANSYS Multiphysics Fluent, Autodesk Inventor. The data reliability is ensured by the use of fundamental laws in regards to numerical researches and approved mathematic models application; certificated measuring equipment; licensed software products; matching of numerical and experimental researches; matching of the simulation with other works. The simulation of luminous infrared gas emitters of all thermal powers (5, 10, 15, 20, 30, 40 kW) in pre-wall and central placements at heights of 4, 5, 6, 7, 8, 9, 10 m was conducted. Gas-fired infrared heat emitters with heat output of 5, 10, 15, 20, 30, 40 kW were studied. Obtained function of IR-heated zone diameter is close to logarithmic function of thermal output. Effective emitter placement heights and least horizontal pitch for the given room volume were determined.

Skeleton-Section Template Parameterization for Shape Optimization

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Ping Hu ◽  
Lei Yang ◽  
Baojun Li
Keyword(s):  
Shape Optimization ◽  
Design Parameters ◽  
Deformation Method ◽  
Cross Sectional ◽  
Numerical Studies ◽  
First Case ◽  
Crushing Force ◽  
Crashworthiness Design ◽  
The Cross ◽  
The Given

A technique based on a skeleton-section template for parameterizing finite element (FE) models is reported and applied to shape optimization of thin-walled beam components. The template consists of a skeletal curve and a set of cross-sectional profiles. The skeletal curve can be used to derive global model variations, while the cross section is designed to obtain local deformations of the given shape. A mesh deformation method based on the radial basis functions (RBF) interpolation is employed to derive the shape variations. Specifically, the skeleton-embedding space and an anisotropic distance metric are introduced to improve the RBF deformation method. To validate the applicability of the proposed template-based parameterization technique to general shape optimization frameworks, two proof-of-concept numerical studies pertaining to crashworthiness design of an S-shaped frame were implemented. The first case study focused on global deformations with the skeletal curve, and the second treated the cross-sectional profiles as design parameters to derive local reinforcements on the model. Both studies showed the efficiency of the proposed method in generation of quality shape variants for optimization. From the numerical results, considerable amount of improvements in crashworthiness performances of the S-shaped frame were observed as measured by the peak crushing force (PCF) and the energy absorption. We conclude that the proposed template-based parameterization technique is suitable for shape optimization tasks.

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