Transient Thermo-Elasto-Plastic Spherical Contact Analyses Considering Effects of Thermal Softening and Heat Partition

2008 ◽  
Author(s):  
W. Wayne Chen ◽  
Q. Jane Wang
Keyword(s):  
Heat Transfer ◽  
Frictional Heating ◽  
Three Dimensional ◽  
Thermal Softening ◽  
Extensive Study ◽  
Temperature Dependent ◽  
Hardening Behavior ◽  
Heat Partition ◽  
Dependent Strain ◽  
Strain Hardening Behavior

Frictional heating leads to the temperature rise, thermal expansion, and the thermo-elasto-plastic deformation, which may be responsible for the failure of components under contact and relative motion. This paper reports the development of a three-dimensional thermo-elasto-plastic contact model of counterformal bodies, which account for the transient heat transfer, temperature-dependent strain hardening behavior of materials, and realistic heat partition between surfaces. An extensive study on the contact of a sliding half-space over a stationary ball is conducted using this model.

Thermomechanical Analysis of Elastoplastic Bodies in a Sliding Spherical Contact and the Effects of Sliding Speed, Heat Partition, and Thermal Softening

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
W. Wayne Chen ◽  
Q. Jane Wang
Keyword(s):  
Half Space ◽  
Frictional Heating ◽  
Three Dimensional ◽  
Numerical Algorithms ◽  
Thermomechanical Analysis ◽  
Thermal Softening ◽  
Sliding Speed ◽  
Dependent Strain ◽  
Steady State Heat ◽  
Strain Hardening Behavior

A thermomechanical analysis of elasto-plastic bodies is a necessary step toward the understanding of tribological behaviors of machine components subjected to both mechanical loading and frictional heating. A three-dimensional thermoelastoplastic contact model for counterformal bodies has been developed, which takes into account steady state heat flux, temperature-dependent strain hardening behavior, and interaction of mechanical and thermal loads. The fast Fourier transform and conjugate gradient method are the underlying numerical algorithms used in this model. Sliding of a half-space over a stationary sphere is simulated with this model. The friction-induced heat is partitioned into two bodies based on surface temperature distributions. In the simulation, the sphere is considered to be fully thermoelastoplastic, while the half-space is treated to be thermoelastic. Simulation results include surface pressure, temperature rise, and subsurface stress and plastic strain fields. The paper also studies the influences of sliding speed and thermal softening on contact behaviors for sliding speed ranging three orders of magnitude.

A new conjugate heat transfer method to analyse a 3D steam cooled gas turbine blade with temperature-dependent material properties

2011 ◽  
Vol 226 (5) ◽  
pp. 1309-1320 ◽  
Author(s):  
M M Jafari ◽  
G Atefi ◽  
J Khalesi ◽  
A Soleymani
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Power Plants ◽  
Conjugate Heat Transfer ◽  
Three Dimensional ◽  
Computer Code ◽  
Gas Turbine Blade ◽  
Temperature Dependent ◽  
Transfer Method

The erosion of the hot regions in a gas turbine is one of the most important challenges encountered by the power plants. Though several numerical simulations of the problem have been reported so far, little is known to give accurate results. In this article, the thermoelastic behaviour of a gas turbine blade with internal steam-cooled channels positioned within a three-dimensional cascade configuration has been studied. A computer code based on the conjugate heat transfer method using the simultaneous solution of Navier–Stokes and heat transfer equations has been developed. From this study, the temperature distribution along with the stress values at high temperatures has been obtained. The blade parameters such as E, α, and K were considered to be a function of the temperature. In the previous works, usually only one or two of these parameters was considered as temperature dependent and the others constant. In this article, all the blade parameters, though making the equations highly non-linear, were considered as a function of temperature. The results have been compared with the available experimental data and a good agreement is observed. According to these findings, taking the temperature dependency of materials into account increases the estimations accuracy and brings the results closer to the reality.

Analysis of Heat Transfer in a Cylindrical Spine Fin with Variable Thermal Properties

2018 ◽  
Vol 387 ◽  
pp. 10-22 ◽  
Author(s):  
Nkejane Fallo ◽  
Raseelo Joel Moitsheki ◽  
Oluwole Daniel Makinde
Keyword(s):  
Heat Transfer ◽  
Differential Equation ◽  
Thermal Conductivity ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Numerical Techniques ◽  
Temperature Dependent ◽  
Approximate Analytical Solutions ◽  
Differential Transform ◽  
The Heat Transfer Coefficient

In this paper we analyse the heat transfer in a cylindrical spine fin. Here, both the heat transfer coefficient and thermal conductivity are temperature dependent. The resulting 2+1 dimension partial differential equation (PDE) is rendered nonlinear and difficult to solve exactly, particularly with prescribed initial and boundary conditions. We employ the three dimensional differential transform methods (3D DTM) to contract the approximate analytical solutions. Furthermore we utilize numerical techniques to determine approximate numerical solutions. The effects of parameters, appearing in the boundary value problem (BVP), on temperature profile of the fin are studied.

Numerical Conjugate Heat Transfer Study of a Cooled Compressor Rear Cone

2014 ◽  
Author(s):  
Fabian Bleier ◽  
Max Hufnagel ◽  
Tim Pychynski ◽  
Hans-Jörg Bauer ◽  
Christian Eichler
Keyword(s):  
Heat Transfer ◽  
Conjugate Heat Transfer ◽  
Frictional Heating ◽  
Axisymmetric Flow ◽  
Three Dimensional ◽  
Parameter Study ◽  
Operational Parameters ◽  
Transfer Coefficients ◽  
Gap Width ◽  
Transfer Study

The paper presents the setup of a conjugate heat transfer study of an annular conical gap, its validation and a parameter study. The main goal of the work is to identify effects of gap width and swirl ratio on the local and global heat transfer in the annular conical gap. The validation of the numerical model is done by a comparison against experimental data from literature. It is shown that the non-axisymmetric flow in the gap can be well reproduced by a three-dimensional axisymmetric model. To identify influences of geometric and operational parameters on the cooling efficiency, a RANS parameter study of the cooling concept is performed. The parameter study includes variations of the gap width and the pre-swirl of the inlet air. The results are used to evaluate the quality of the cooling concept and to identify the effect of geometry on frictional effects and on heat transfer coefficients. In this respect it is important to separate frictional heating and convective heat transfer effects.

scholarly journals Experimental and Numerical investigation of Heat transfer enhancement using Al2O3-Ethylene Glycol/Water nanofluids in straight channel

2018 ◽  
Vol 225 ◽  
pp. 01019 ◽  
Author(s):  
Mohammed K. Mohammed ◽  
M. Kh Abdolbaqi ◽  
Thamir K. Ibrahim ◽  
Rizalman Bin Mamat ◽  
Omar I. Awad
Keyword(s):  
Heat Transfer ◽  
Ethylene Glycol ◽  
Friction Factor ◽  
Volume Concentration ◽  
Three Dimensional ◽  
Straight Channel ◽  
Temperature Dependent ◽  
Homogeneous Fluid ◽  
Turbulent Flow Regime ◽  
The Difference

A study of computational fluid dynamics has been conducted to study the characteristics of the heat transfer and friction factor of Al2O3/Ethylene glycol-water nanofluid flowing in straight channel. The three dimensional realizable k-e turbulent model with enhanced wall treatment was utilized. As well as were used Temperature dependent thermophysical properties of nanofluid and water. The evaluation of the overall performance of the tested channel was predicated on the thermohydrodynamic performance index. The obtained results showed that the difference in behaviour depending on the parameter that has been selected to compare the nanofluid with the base fluid. In addition, the friction factor and the heat transfer coefficient increases with an increase of the nanoparticles volume concentration at the same Reynolds number. The penalty of pressure drop is negligible with an increase of the volume concentration of nanoparticles. Conventional correlations that have been used in turbulent flow regime to predict average heat transfer and friction factor are Dittus-Boelter and Blasius correlations, for channel are also valid for the tested nanofluids which consider that the nanofluids have a homogeneous fluid behave.

A Method for the Evaluation of Heat Transfer Coefficient by Optimization Algorithm

2007 ◽  
Vol 124-126 ◽  
pp. 1637-1640 ◽  
Author(s):  
Jeong Tae Kim ◽  
Chae Ho Lim ◽  
Jeong Kil Choi ◽  
Young Kook Lee
Keyword(s):  
Heat Transfer ◽  
Inverse Problem ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Optimization Algorithm ◽  
Heat Conduction Problem ◽  
Three Dimensional ◽  
Temperature History ◽  
Temperature Dependent ◽  
The Heat Transfer Coefficient

New method for evaluation of heat transfer coefficient is proposed. In general, many researchers have been studied about inverse problem in order to calculate the heat transfer coefficient on three-dimensional heat conduction problem. But they can get the time-dependent heat transfer coefficient only through inverse problem. In order to acquire temperature-dependent heat transfer coefficient, it requires much time for numerous repetitive calculation and inconvenient manual modification. In order to solve these problems, we are using the SQP(Sequential Quadratic Programming) as an optimization algorithm. When the temperature history is given by experiment, the optimization algorithm can evaluate the temperature-dependent heat transfer coefficient with automatic repetitive calculation until difference between calculated temperature history and experimental ones is minimized. Finally, temperature-dependent heat transfer coefficient evaluated by developed program can used on the real heat treatment process of casting product.

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