Numerical study of the effect of the turning angle on heat transfer in multilayered elements of external enclosure structures

When building low-rise buildings with a variety of structural elements, it is important to have an idea of their thermal state in extreme heat exchange conditions. Therefore, the study of heat transfer processes in heat-stressed elements of external fences is relevant and of considerable practical interest. The purpose of this work is to conduct parametric studies in typical angular fragments of inhomogeneous enclosing structures with u-turn angles from 60 to 150°. At the same time, the analysis of the thermal state is carried out for both external and internal angles. The mathematical modeling of spatial heat transfer in the fragments under consideration is based on the solution of a nonlinear system of differential equations of thermal conductivity with corresponding boundary conditions by the finite element method using the Thermal module included in the ANSYS software package. The analysis of numerical results given for three types of enclosing structures made using various technologies allowed us to clarify the influence of their geometric and thermophysical characteristics on the distribution of temperature and heat flow over the thickness of the fragments under consideration, as well as to determine the change in these parameters on both the internal and external surfaces of the structure. To establish that for all types of walling with increasing rotation angle, the temperature in the inner corner of the structure decreases, and in the outer increases, and the density of the heat flow behaves vice versa; the distance from the corner to the area stabilization with increasing angle of rotation reduces, smiling for all types of structures for temperature and heat flow; an increase in the thermal resistance leads to a temperature increase and decrease of the heat flux in the corner tend to be developed fragments; issue recommendations for creating energy-efficient structures that meet modern requirements.

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Numerical Modeling of Radiative and Convective Heat Transfer From an Irradiated Complex Window Assembly

10.1115/imece2000-1413 ◽

2000 ◽

Author(s):

M. Collins ◽

S. J. Harrison ◽

P. H. Oosthuizen ◽

D. Naylor

Keyword(s):

Heat Transfer ◽

Radiative Heat ◽

Numerical Study ◽

Two Dimensional ◽

Plate Surface ◽

The Finite Element Method ◽

Radiation Model ◽

Conjugate Conduction ◽

Plate Distance ◽

Steady Laminar

Abstract The present numerical study examines the influence of heated, horizontal, and rotateable louvers on the convective and radiative heat transfer from a hot or cold vertical isothermal surface. The system models absorption of solar energy in a Venetian blind adjacent to the indoor surface of a window. Building on previous analyses, a steady, laminar, two-dimensional, conjugate conduction / convection / radiation model of this problem has been developed, and solutions have been obtained using the finite element method. Validation of the model against existing solutions has been undertaken. Results were obtained for two window temperatures (warm and cool compared to ambient), two louver to plate spacings, and three louver angles. The results clearly demonstrate the effect of the model variables on heat transfer from the plate surface. With few exceptions, steady periodicity along the plate was clearly demonstrated. More importantly, increased independence of the results from the louver angle as louver to plate distance increased was demonstrated.

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Numerical Study of Cavitation in Cryogenic Fluids

Journal of Fluids Engineering ◽

10.1115/1.1883238 ◽

2005 ◽

Vol 127 (2) ◽

pp. 267-281 ◽

Cited By ~ 92

Author(s):

Ashvin Hosangadi ◽

Vineet Ahuja

Keyword(s):

Heat Transfer ◽

Experimental Data ◽

Critical Temperature ◽

Thermal Effects ◽

Free Stream ◽

Numerical Study ◽

Stream Velocity ◽

Transfer Model ◽

Cryogenic Fluids ◽

Parametric Studies

Numerical simulations of cavitation in liquid nitrogen and liquid hydrogen are presented; they represent a broader class of problems where the fluid is operating close to its critical temperature and thermal effects of cavitation are important. A compressible, multiphase formulation that accounts for the energy balance and variable thermodynamic properties of the fluid is described. Fundamental changes in the physical characteristics of the cavity when thermal effects become significant are identified; the cavity becomes more porous, the interface less distinct, and it shows increased spreading while getting shorter in length. The heat transfer model postulated in variants of the B-factor theory, where viscous thermal diffusion at the vapor-liquid interface governs the vaporization, is shown to be a poor approximation for cryogenic fluids. In contrast the results presented here indicate that the cavity is sustained by mass directly convecting into it and vaporization occurring as the liquid crosses the cavity interface. Parametric studies for flow over a hydrofoil are presented and compared with experimental data of Hord (1973, “Cavitation in Liquid Cryogens II—Hydrofoil,” NASA CR-2156); free-stream velocity is shown to be an independent parameter that affects the level of thermal depression.

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Numerical study of heat transport in thermally isolated flow-rate microsensors

Canadian Journal of Physics ◽

10.1139/p92-143 ◽

1992 ◽

Vol 70 (10-11) ◽

pp. 904-907

Author(s):

N. Swart ◽

A. Nathan

Keyword(s):

Heat Transfer ◽

Heat Flow ◽

Boundary Conditions ◽

Heat Transport ◽

Flow Rate ◽

Energy Equation ◽

Numerical Study ◽

Control Volume ◽

Circuit Simulator ◽

Temperature Distributions

The temperature distributions in thermally isolated cantilever based flow-rate microsensors have been numerically calculated for different gas temperatures and gas velocities. In particular, we investigate the efficiency of heat transfer to the flowing gas and corresponding directions of heat flow in the system. The above analysis is based on a solution to the energy equation under appropriate boundary conditions. The equation was discretized using a control volume procedure, based on which an equivalent circuit was devised and subsequently simulated using a circuit simulator such as SPICE.

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Numerical study on flow over a confined oscillating cylinder with a splitter plate

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-06-2018-0286 ◽

2019 ◽

Vol 29 (5) ◽

pp. 1629-1646 ◽

Cited By ~ 1

Author(s):

Arya Ghiasi ◽

Seyed Esmaeil Razavi ◽

Abel Rouboa ◽

Omid Mahian

Keyword(s):

Heat Transfer ◽

Reynolds Number ◽

Drag Reduction ◽

Oscillation Frequency ◽

Stokes Equations ◽

Numerical Study ◽

Splitter Plate ◽

Content Type ◽

Plate Length ◽

Parametric Studies

Purpose This study aims to investigate the effect of the simultaneous usage of active and passive methods (which in this case are rotational oscillation and attached splitter plate, respectively) on the flow and temperature fields to find an optimum situation which this combination results in heat transfer increment and drag reduction. Design/methodology/approach The method of the solution was based on finite volume discretization of Navier–Stokes equations. A dynamic grid is coupled with the solver by the arbitrary Lagrangian–Eulerian (ALE) formulation for modeling cylinder oscillation. Parametric studies were performed by altering oscillation frequency, splitter plate length and Reynolds number. Findings Oscillation in different frequencies was found to be complicated. Higher frequencies provide more heat transfer, but in the lock-on region, they bring remarkable increment to the drag coefficient. It was observed that simultaneous usage of oscillation and splitter plate may have both positive and negative effects on drag reduction and heat transfer increment. Finally F = 2 and L = 0.5 were chosen as an optimum combination. Originality/value In this study, the laminar incompressible flow and heat transfer from a confined rotationally oscillating circular cylinder with an attached splitter plate are investigated. Parametric studies are performed by changing oscillation frequency, splitter plate length and Reynolds number.

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The influence of different geometrical dimensions of convectors on the heat transfer from panel radiators

SN Applied Sciences ◽

10.1007/s42452-021-04276-2 ◽

2021 ◽

Vol 3 (3) ◽

Author(s):

Tamer Calisir ◽

Senol Baskaya

Keyword(s):

Heat Transfer ◽

Numerical Study ◽

Sheet Thickness ◽

Point Of View ◽

Total Heat ◽

Heat Output ◽

Simulation Data ◽

Vertical Location ◽

Parametric Studies ◽

Geometrical Dimensions

AbstractIncrease in total heat output of panel radiators could play an important role in domestic energy saving, where convectors (convection fins) play a key role. Hence, it is important to obtain the best possible design of convectors, in order to increase the heat output of panel radiators. In this sense, a numerical study has been performed to show the effects of different geometrical dimensions of convectors on the heat transfer used in domestic panel radiators, to obtain the highest possible total heat output. Firstly, simulation data were verified by analytical results, and afterwards, parametric studies were performed for a single convector mounted on a constant temperature wall, and the natural convective heat transfer has been modelled. The effects of convector height, convector sheet thickness, convector trapezoidal height, distance between opposing convectors, convector tip width, vertical location of convector and cut-off ratio have been considered. The results showed that the heat transfer increases with the increase in convector thickness and height. However, the consumed sheet metal material amount increases as well. From a manufacturing point of view, this should be considered at the same time. On the other hand, with the increase in trapezoidal height, the heat transfer increases, and above a certain value the heat transfer decreases. The heat transfer increases with the distance of opposing convectors and becomes almost constant above a certain value. The results of the present study could guide in the change of the internal design of panel radiators with convectors, in order to increase the heat transfer and reduce material costs.

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Numerical Study of Temperature Distributions and Solidification Pattern in the Weld Pool of Arc Welded Plate

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.392.218 ◽

2019 ◽

Vol 392 ◽

pp. 218-227

Author(s):

Anshul Yadav ◽

Anil Kumar ◽

Priya Gupta ◽

Devendra Kumar Sinha

Keyword(s):

Heat Transfer ◽

Numerical Model ◽

Heat Flow ◽

Weld Pool ◽

Numerical Study ◽

Welding Process ◽

Transient Temperature ◽

Transient Temperature Distribution ◽

Solidification Pattern ◽

Arc Welding Process

The study on heat flow in welding is essential as the quality of the weld depends on mainly heat flow through the welded plate. The heat input from welding source flows in a limited zone, and it subsequently flows into the workpiece by conduction. In this study, an attempt is taken to predict the transient temperature distribution and solidification pattern through a numerical model and the associated mathematical technique considering the solidification and heat transfer, of molten weld pool when it is covered with flux and without flux in arc welding process. The numerical model developed in this study solves fluid flow and heat transfer considering solidification and melting phase change the along with natural convection in the meltpool. It was found that the flux is functioning as insulation on the welded pool, hence it restricts rapid solidification and increases the mushy zone width.

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