scholarly journals Determination of temperature gradient of slender structure

2021 ◽  
Vol 1209 (1) ◽  
pp. 012066
Author(s):  
M Velešík ◽  
M Požár ◽  
R Nečas
Keyword(s):  
Heat Transfer ◽  
Temperature Gradient ◽  
Cross Section ◽  
Computational Models ◽  
Temperature Sensors ◽  
Heat Transfer Analysis ◽  
Bridge Structures ◽  
Correct Determination ◽  
As Stress

Abstract This study investigates convenient methods of determination of temperature gradient of slender structures in time. Correct determination of temperature along the height of the cross-section takes a key role in defining the temperature loading of slender bridge structures. A proper definition of temperature loading is crucial for structures such as stress ribbon because of their sensitivity to temperature change in terms of geometrical changes of the structure. Correct determination of the temperature gradient is important during long-term geodetic monitoring, which might be used to prove the correctness of computational models of bridge structures. To approximate heat transfer in cross-section, a test specimen with temperature sensors installed along the height was formed and continuously monitored. The accuracy of the retrofitted temperature sensors was also investigated. The temperature at the surface of the specimen, solar radiation and wind velocity were used as input data for heat transfer analysis. The measured values from sensors situated along the height were subsequently used for verification of performed heat transfer analysis on volume computational model in the software Ansys Mechanical.

scholarly journals Passive Biaxial Tensile Dataset of Three Main Rat Heart Myocardia: Left Ventricle, Mid-Wall and Right Ventricle

2021 ◽  
Author(s):  
Fulufhelo Nemavhola ◽  
Harry Ngwangwa ◽  
Neil Davies ◽  
Thoams Franz
Keyword(s):  
Left Ventricle ◽  
Right Ventricle ◽  
Rat Heart ◽  
Computational Models ◽  
Heart Diseases ◽  
Tissue Mechanics ◽  
Soft Tissue Mechanics ◽  
Biaxial Tensile ◽  
As Stress

This article presents raw data of biaxial tensile measurements of rat heart passive myocardium conducted in lab scale environment. The passive myocardium of the rat was divided into three regions, namely: left ventricle, mid-wall and right ventricle. The biaxial dataset of passive rat myocardia is presented as stress vs strain of the passive rat myocardium in various regions. The determination of valid material properties of the heart plays an important role in the development computational models. These computational models are useful in studying various scenarios and mechanisms of heart diseases. In addition, valid and accurate materials are critical in the development of new therapies. The dataset presented here is useful in the area of soft tissue mechanics including studying the mechanisms of heart diseases such as myocardial infarction. Accordingly, the evaluation of stress and strain in left ventricle, mid-wall and right ventricle was performed.

Determination of the Nusselt versus Graetz correlation for heat transfer in channels of sinusoidal cross-section

2003 ◽  
Vol 20 (6) ◽  
pp. 1012-1016 ◽  
Author(s):  
Cu Phan ◽  
Daniel L. Holgate ◽  
Gregory J. Griffin
Keyword(s):  
Heat Transfer ◽  
Cross Section

Conjugate Heat Transfer Analysis for Film Cooling Configurations With Different Hole Geometries

2003 ◽  
Author(s):  
Dieter Bohn ◽  
Jing Ren ◽  
Karsten Kusterer
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Conjugate Heat Transfer ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Secondary Flows ◽  
Heat Transfer Analysis ◽  
Transfer Condition ◽  
Film Cooling Effectiveness

Secondary flows in the cooling jets are the main reason for the degradation of the cooling performance of a film-cooled blade. The formation of kidney vortices can significantly be reduced for shaped holes instead of cylindrical holes. For the determination of the film cooling heat transfer, the design of a turbine blade relies on the conventional determination of the adiabatic film cooling effectiveness and heat transfer conditions for test configurations. Thus, additional influences by the interaction of fluid flow and heat transfer and influences by additional convective heat transfer cannot be taken into account with sufficient accuracy. Within this paper, calculations of a film-cooled duct wall with application of the adiabatic and a conjugate heat transfer condition have been performed for different configurations with cylindrical and shaped holes. It can be shown that the application of the conjugate calculation method comprises the influence of heat transfer on the velocity field within the cooling film. In particular, the secondary flow velocities are affected by the local heat transfer, which varies significantly depending on the local position.

Fire Assessment of Steel Beam Members With Partial Passive Fire Protection Coverage

2012 ◽  
Author(s):  
Hunter Smith ◽  
Yavuz Ayhan ◽  
Ali Sari
Keyword(s):  
Heat Transfer ◽  
Cross Section ◽  
Fire Protection ◽  
Mechanical Response ◽  
Local Buckling ◽  
Offshore Structures ◽  
Heat Transfer Analysis ◽  
Passive Fire Protection ◽  
Non Linear ◽  
The Cross

In offshore structures there are instances where the application of passive fire protection (PFP) is not possible or desired on certain portions of a structural member’s surface area. The most common cases are those where the top surface is left unprotected due to the presence of deck grating or plating. Current code and standard provisions on heat transfer and strength assessment of restrained flexural members are not directly applicable to these cases. Thus, a case study is presented for performing a fire assessment of a restrained plate girder subjected to jet fire impingement with the top flange surface left unprotected. To assess residual strength and perform non-linear analyses under combined thermal and static loading, a heat transfer analysis was first performed to obtain the time histories of the two dimensional heat distributions throughout the studied cross-section. The results showed that the top flange heats up rapidly and the heat conducts very slowly down the web to the rest of the cross-section, with a very large thermal gradient occurring over the height of the section. Approximate screening calculations for the cross-section, based on AISC capacity equations, indicated that the member will quickly exceed its elastic capacity and that local buckling may occur prior to yielding. Advanced non-linear finite element analysis of the mechanical response confirmed large amounts of plasticity and local buckling occur, but showed that global integrity of the member is maintained for the duration of the fire due to redundancy and catenary action. Recommendations and conclusions on analysis methods for partially protected deck members are made based on the results of this study.

Heat-Transfer Analysis of Visco-Elastic Giesekus Fluid in a Duct Between Parallel Plates and in a Straight Pipe of a Circular Cross-Section

2015 ◽  
Author(s):  
Sara N. AlMelhi ◽  
Lyes Khezzar ◽  
Mohamed Alshehhi ◽  
Abdelkader Filali
Keyword(s):  
Heat Transfer ◽  
Cross Section ◽  
Numerical Solutions ◽  
Numerical Technique ◽  
Circular Cross Section ◽  
Heat Transfer Analysis ◽  
Rheological Parameters ◽  
Parallel Plates ◽  
Straight Pipe ◽  
Finite Element Software

This work aims to conduct numerical simulation to investigate the convective heat transfer of viscoelastic fluids obeying Giesekus model flowing either along straight pipe of circular cross-section or within the space between parallel plates with constant heat flux thermal boundary condition and neglected viscous dissipation. The numerical technique used is based on finite element software (ANSYS Polyflow 14.0) and the obtained numerical solutions are compared against the analytical solution available in literature. The effect of the rheological parameters on the heat transfer enhancement is discussed.

scholarly journals Application of lattice Boltzmann method and field synergy principle to the heat transfer analysis of channel flow with obstacles inside

2011 ◽  
Vol 15 (suppl. 1) ◽  
pp. 75-80
Author(s):  
Cheng-Chi Wang ◽  
Her-Terng Yau ◽  
Chien-Nan Lin ◽  
Po-Jen Cheng ◽  
Wei-Min Hung
Keyword(s):  
Heat Transfer ◽  
Velocity Field ◽  
Temperature Gradient ◽  
Lattice Boltzmann Method ◽  
Channel Flow ◽  
Lattice Boltzmann ◽  
Heat Transfer Analysis ◽  
Field Synergy ◽  
Field Synergy Principle ◽  
Boltzmann Method

In this paper the lattice Boltzmann method and field synergy principle are applied to simulate two-dimensional incompressible steady channel flow under low Reynolds number, and analyze the local influence on velocity field and temperature field caused by inserting cylinder obstacles of different cross-section. Furthermore, field synergy principle of elliptic flow type is applied to demonstrate that the increased interruption within the fluid increases the synergistic level between the velocity field and temperature gradient field. As the intersection angle between the velocity vector and the temperature gradient vector decreases by inserting cylinder obstacles to fluid field, the results of heat transfer will improve significantly.

Effective Permeability of a Layered Porous Cavity

2000 ◽  
Vol 123 (3) ◽  
pp. 512-519 ◽  
Author(s):  
J. C. Leong ◽  
F. C. Lai
Keyword(s):  
Heat Transfer ◽  
Temperature Gradient ◽  
System Approach ◽  
Effective Permeability ◽  
Flow Direction ◽  
The Other ◽  
Heat Transfer Analysis ◽  
Arithmetic Average ◽  
Porous Cavity ◽  
Wide Range

The feasibility of using a lumped system approach in the heat transfer analysis of a layered porous cavity is numerically investigated in this paper. Two layered cavities are considered; in one case the sublayers are perpendicular to the imposed temperature gradient while in the other case they are parallel to the imposed temperature gradient. Numerical calculations have covered a wide range of parameters (i.e., 10⩽Ra1⩽1000,0.01⩽K1/K2⩽100, and L1/LH1/H=0.25, 0.5 and 0.75). The results are presented in term of the effective Rayleigh number which is defined based on the effective permeability. Two averaging techniques are used for the evaluation of the effective permeability; one is arithmetic average and the other is harmonic average. The results show that the lumped system approach can provide a fairly accurate prediction in heat transfer if the permeability is correctly characterized. Also found is that the effective permeability of a layered porous cavity is strongly dependent on the orientation of sublayers and the primary heat flow direction.

A Method for the Determination of the Local Turbulent Friction Factor and Heat Transfer Coefficient in Generalized Geometries

1971 ◽  
Vol 93 (1) ◽  
pp. 61-68 ◽  
Author(s):  
E. Aranovitch
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Laminar Flow ◽  
Transfer Coefficient ◽  
Cross Section ◽  
Arbitrary Cross Section ◽  
Transfer Coefficients ◽  
Turbulent Friction ◽  
Heat Transfer Coefficients

A method is presented for the determination of the distributions of velocity, local friction, and heat transfer coefficients in a forced axial turbulent flow with an arbitrary cross section. The method uses as basis the characteristics of the laminar flow. A comparison is made with some experimental results concerning different geometries.

Heat Transfer Analysis of Turbulent Flow in Rectangular-Sectioned U-Bends

2004 ◽  
Author(s):  
Sassan Etemad ◽  
Bengt Sunde´n
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Aspect Ratio ◽  
Turbulent Flow ◽  
Secondary Flow ◽  
Cross Section ◽  
Heat Transfer Analysis ◽  
Reference Case ◽  
Aspect Ratios ◽  
The Impact

The turbulent flow in rectangular-sectioned U-bend ducts with bend mid-line radius 3.35 and with aspect-ratios AR=0.5, 1, 2, and 4 were explored using linear and non-linear high- and low-Re k-ε turbulence models at a Reynolds number of 56000. The impact of the cross-section aspect ratio on the flow field and the associated thermal field was studied. Experimental data were found [1–3] for the square-sectioned cross section (AR=1) and this case was chosen as the reference case for comparison and validation with experimental data. The other cases were evaluated in relation to the square-sectioned case. The predicted data for AR=1 agreed well with the experimental data. The velocity profile upstream the bend has fundamental influence on the strength of the secondary flow and heat transfer. Complex secondary motion was detected for all cases but in particular for AR=1. The mixing process due to the secondary flow decreased in general with increasing aspect ratio.

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