Model Configuration for the Validation of Thermal-Mechanical Fluid-Structure-Interactions

2012 ◽  
Author(s):  
Matthias C. Haupt ◽  
Daniel Kowollik ◽  
Peter Horst ◽  
Reinhold Niesner ◽  
Burkard Esser ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Modelling ◽  
Hypersonic Flow ◽  
Experimental Investigations ◽  
Fluid Structure Interactions ◽  
Flow Conditions ◽  
Fluid Structure ◽  
Model Configuration ◽  
Transfer Mechanisms ◽  
Good Agreement

A simple configuration is described and used for computational and experimental investigations including thermal and mechanical fluid structure interactions for hypersonic flow conditions. The numerical modelling includes all relevant heat transfer mechanisms, takes into account the changes due to the heated and deformed structure and shows a good agreement with experiments.

Thermal Fluid-Structure Coupling for Atmospheric Entries

2011 ◽  
Author(s):  
Ojas Joshi ◽  
Pe´ne´lope Leyland
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Thermal Response ◽  
Space Vehicle ◽  
Structural Components ◽  
Fluid Structure ◽  
Coupling Techniques ◽  
Heat Loads ◽  
Transfer Mechanisms

This paper deals with the modeling of aero-thermal aspects of a space vehicle during its entry phase into an atmosphere. We treat the numerical coupling techniques between the external and internal aero-thermo-dynamics (ATD) produced by the interaction of ATD fields with the structural components. The thermal properties induced within the structure via heat transfer mechanisms of convection, conduction and radiation is taken into account presenting multi-disciplinary coupling between the aero-thermo-dynamics, the heat loads and the structural thermal response.

Analysis of Thermocouple Responses to Turbulent Radiating Environments

2011 ◽  
Author(s):  
Craig Weinschenk ◽  
O. A. Ezekoye
Keyword(s):  
Heat Transfer ◽  
Unsteady Flow ◽  
Temperature Measurement ◽  
Thermal Characteristics ◽  
Flow Conditions ◽  
Computational Simulations ◽  
Computational Perspective ◽  
Measurement Devices ◽  
Unsteady Flame ◽  
Transfer Mechanisms

With increasing requirements for model validation when comparing computational and experimental results, there is a need to incorporate detailed representations of measurement devices within the computational simulations. Thermocouples are the most common temperature measurement transducers in flames and fire environments. Even for the relatively simple thermocouple transducer, the coupling of heat transfer mechanisms particularly under unsteady flow conditions leads to interesting dynamics. As experimentalists are well aware, the experimentally determined thermocouple values are not the same as the local gas temperatures and corrections are often required. From the computational perspective, it is improper then to assume that the predicted gas temperatures should be the same as the temperatures that an experimentalist might measure since the thermal characteristics of the thermocouple influence the indicated temperature. In this study we investigate the thermal characteristics of simulated thermocouples in unsteady flame conditions. Validation exercises are presented to test the underlying thermocouple model. Differences are noted between the predicted thermocouple response and expected response. These differences are interpreted from the perspective of what modeling artifacts might drive the differences.

Finite Element Simulations and Experimental Investigations of Simple 2-D Geometries in Slamming

2008 ◽  
Author(s):  
Adrian Constantinescu ◽  
Alain Neme ◽  
Nicolas Jacques ◽  
Philippe Rigo
Keyword(s):  
Finite Element ◽  
Water Surface ◽  
Free Water ◽  
Experimental Tests ◽  
Experimental Investigations ◽  
Convergence Criterion ◽  
Numerical Work ◽  
Fluid Structure ◽  
The Impact ◽  
Good Agreement

This paper presents a numerical and experimental study of fluid structure interaction during the impact of a solid body on a water surface. The main request is the modeling of the slamming forces acting on the ship structure in severe sea conditions. The numerical work uses the finite element modeling of a structure impact with free water surface. The first analysis use the commercial finite element code ABAQUS/Standard and combines the assumption of small displacements for the ideal fluid and the solid with an asymptotic formulation for accurate pressure evaluation on the boundary of the wet surface. For deformable strickers, two methods are developed. The first method employs a weak fluid-structure coupling. The second method, more accurate, uses an implicit fluid-structure coupling using a convergence criterion. The second analysis is represented by the simulations of slamming with ABAQUS/Explicit. The simulation uses a viscous, compressible fluid and a soft-exponential law to manage the contact between fluid and solid. The results in term of pressure and total effort applied to the rigid structure are in good agreement with first numerical results and especially with the FLUENT CFD. In order to validate the numerical methods, slamming experimental tests were carried out with a new hydraulic shock press at the ENSIETA laboratory.

scholarly journals Thermal Conductivity of Nanofluids-A Comprehensive Review

2020 ◽  
Vol 7 (3) ◽  
Author(s):  
S. Mishra ◽  
M.K. Nayak ◽  
A. Misra
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Experimental Investigations ◽  
Heat Transfer Characteristics ◽  
Comprehensive Review ◽  
Ultrasonic Time ◽  
Type Particle ◽  
Transfer Mechanisms

The present study deals with a comprehensive review on the enhancement of effective thermal conductivity of nanofluids. The present article summarizes the recent research developments regarding the theoretical and experimental investigations about thermal conductivity of different nanofluids. The current study analyzes several factors those strongly affecting thermal conductivity of nanofluids include solid volume fraction, temperature, particle size, particle type, particle shape, different base fluids, magnetic field, pH, surfactant and ultrasonic time. In addition, different reasonably attractive models contributing augmentation of thermal conductivity of nanofluids are invoked. Finally, important heat transfer mechanisms namely Brownian motion, nanoclustering, thermophoresis, osmophoresis and interfacial nano-layer responsible for significant role in ameliorating the thermal conductivity and therefore the heat transfer characteristics of nanofluids are discussed.

Cooling of a Very Hot Vertical Surface by a Falling Liquid Film

1974 ◽  
Vol 96 (2) ◽  
pp. 126-131 ◽  
Author(s):  
K. H. Sun ◽  
G. E. Dix ◽  
C. L. Tien
Keyword(s):  
Heat Transfer ◽  
Liquid Film ◽  
Vertical Surface ◽  
Temperature Profiles ◽  
Continuous Film ◽  
Falling Liquid Film ◽  
Biot Numbers ◽  
Transfer Mechanisms ◽  
Two Temperature ◽  
Good Agreement

The present study analyzes the cooling of a very hot vertical surface by a falling liquid film. An analytical model is developed to characterize this phenomenon in three distinctive regions: a dry region ahead of the wet front, a sputtering region immediately behind the wet front, and a continuous film region further upstream. The analysis leads to predictions of the wet front velocity, the sputtering length, and the temperature profiles with respect to the wet front. The heat transfer mechanisms are shown to be dependent upon two temperature parameters characterizing the initial wall temperature and the temperature range for sputtering, and two Biot numbers comparing the convective heat transfer in the liquid film region and the sputtering region with longitudinal heat conduction. The predictions are in good agreement with existing experimental results.

Heat Transfer and Forces on Concave Surfaces in a Free Molecular Flow

1973 ◽  
Vol 95 (1) ◽  
pp. 107-112 ◽  
Author(s):  
Chien Fan
Keyword(s):  
Heat Transfer ◽  
Monte Carlo ◽  
Spherical Surface ◽  
Speed Ratio ◽  
Molecular Flow ◽  
Flow Conditions ◽  
Incident Flow ◽  
Half Angle ◽  
Drag And Lift ◽  
Good Agreement

A Monte Carlo modeling technique is described for mathematically simulating free molecular flows over a concave spherical surface and a concave cylindrical surface of finite length. The half-angle of the surfaces may vary from 0 to 90 deg, and the incident flow may have an arbitrary speed ratio and an arbitrary angle of attack. Partial diffuse reflection and imperfect energy accommodation for molecules colliding with the surfaces are also considered. Results of heat transfer, drag, and lift coefficients are presented for a variety of flow conditions. The present Monte Carlo results are shown to be in very good agreement with certain available theoretical solutions.

scholarly journals Investigation of magnetohydrodynamics flow and heat transfer in the presence of a confined square cylinder using SM82 equations

2017 ◽  
Vol 21 (2) ◽  
pp. 889-899 ◽  
Author(s):  
Shahri Farahi ◽  
Nezhad Hossein
Keyword(s):  
Heat Transfer ◽  
Strouhal Number ◽  
Hartmann Number ◽  
Experimental Investigations ◽  
Blockage Ratio ◽  
Average Deviation ◽  
Flow And Heat Transfer ◽  
Secondary Vortices ◽  
D Model ◽  
Good Agreement

In this paper, magnetohydrodynamics flow and heat transfer of a liquid metal (GaInSn) in the presence of a confined square obstacle is studied numerically, using a quasi-2-D model known as SM82. The results of the present investigation are compared with the results of the other experimental investigations and a good agreement with the average deviation of about 2.8% is achieved. The effects of Reynolds number, Hartmann number, and blockage ratio on the re-circulation length, Strouhal number, averaged Nusselt number, and isotherms are examined. The numerical results indicate that based on the Reynolds and Hartmann numbers in a fixed blockage ratio, due to the direct interactions of the secondary vortices and the Karman ones, the Strouhal number may increase or decrease. Some correlations are also provided to determine the re-circulation length in terms of the Reynolds and Hartmann numbers for various blockage ratios.

scholarly journals A numerical analysis of a convective straight fin with temperature-dependent thermal conductivity

2017 ◽  
Vol 21 (2) ◽  
pp. 939-952 ◽  
Author(s):  
Gokhan Sevilgen
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Cfd Analysis ◽  
Flow Conditions ◽  
Heat Transfer Characteristics ◽  
Temperature Dependent ◽  
Fin Efficiency ◽  
Conductivity Property ◽  
Temperature Dependent Thermal Conductivity ◽  
Good Agreement

In this paper, heat transfer characteristics of a straight fin having temperature-dependent thermal conductivity were computed by using 3-D CFD analysis and MATLAB differential equation solver. The computations were performed with two different cases having both constant and linear function for thermal conductivity property. The CFD and MATLAB results were in good agreement with the data available in the literature. With the help of using these numerical techniques, fin efficiency can be improved and heat transfer rate of fins can be augmented by changing fin materials with variable thermal properties and air-flow conditions. Application of the proposed method can be effectively extended to solve the class of similar non-linear fin problems in engineering and sciences.

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