Heat Transfer at Aluminum-Water Interfaces: Effect of Surface Roughness

2012 ◽  
Author(s):  
H. Sam Huang ◽  
Jennifer L. Wohlwend ◽  
Vikas Varshney ◽  
Ajit K. Roy
Keyword(s):  
Heat Transfer ◽  
Finite Element Method ◽  
Surface Roughness ◽  
Finite Element ◽  
Thermal Conductance ◽  
Md Simulations ◽  
Macroscopic Scale ◽  
Microscopic Scale ◽  
Scale Surface ◽  
Element Method

In this paper, we studied the effect of microscopic surface roughness on heat transfer between aluminum and water by molecular dynamic (MD) simulations and macroscopic surface roughness on heat transfer between aluminum and water by finite element (FE) method. It was observed that as the microscopic scale surface roughness increased, the thermal boundary conductance increased. The thermal conductance increases 20% when the ratio of the amplitude of the surface roughness to the width of the system was changed from 0 to 1. At the macroscopic scale, different degrees of surface roughness were studied by finite element method. The heat transfer was observed to enhance as the surface roughness increases. The surface roughness was found to enhance the heat transfer both at the microscopic scale and at the macroscopic scale. Based upon the calculations at the microscopic scale by MD simulations and at the macroscopic scale by Finite Element method, a procedure was proposed to obtain the thermal conductance of surface roughness at the length scale of macroscopic and able to include the macroscopic scale surface roughness.

Heat Transfer at Aluminum–Water Interfaces: Effect of Surface Roughness

2012 ◽  
Vol 3 (3) ◽  
Author(s):  
H. Sam Huang ◽  
Vikas Varshney ◽  
Jennifer L. Wohlwend ◽  
Ajit K. Roy
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Finite Element ◽  
Md Simulations ◽  
Boundary Resistance ◽  
Thermal Boundary Resistance ◽  
Mesoscopic Scale ◽  
Macroscopic Scale ◽  
Microscopic Scale ◽  
Thermal Boundary Conductance

In this paper, we studied the effect of microscopic surface roughness on heat transfer between aluminum and water by molecular dynamic (MD) simulations and macroscopic surface roughness on heat transfer between aluminum and water by finite element (FE) method. It was observed that as the microscopic scale surface roughness increases, the thermal boundary conductance increases. At the macroscopic scale, different degrees of surface roughness were studied by finite element method. The heat transfer was observed to enhance as the surface roughness increases. Based on the studies of thermal boundary conductance as a function of system size at the molecular level, a procedure was proposed to obtain the thermal boundary conductance at the mesoscopic scale. The thermal boundary resistance at the microscopic scale obtained by MD simulations and the thermal boundary resistance at the mesoscopic scale obtained by the extrapolation procedure can be included and implemented at the interfacial elements in the finite element method at the macroscopic scale. This provides us a useful model, in which different scales of surface roughness can be included, for heat transfer analysis.

Hot Forging Comparative Analyses by Using a Combined Finite Element Method

2007 ◽  
Vol 340-341 ◽  
pp. 737-742
Author(s):  
Yong Ming Guo
Keyword(s):  
Heat Transfer ◽  
Finite Element Method ◽  
Finite Element ◽  
Hot Forging ◽  
Rigid Plastic ◽  
Numerical Examples ◽  
Comparative Analyses ◽  
Single Action ◽  
Element Method

In this paper, single action die and double action die hot forging problems are analyzed by a combined FEM, which consists of the volumetrically elastic and deviatorically rigid-plastic FEM and the heat transfer FEM. The volumetrically elastic and deviatorically rigid-plastic FEM has some merits in comparison with the conventional rigid-plastic FEMs. Differences of calculated results for the two forging processes can be clearly seen in this paper. It is also verified that these calculated results are similar to those of the conventional rigid-plastic FEM in comparison with analyses of the same numerical examples by the penalty rigid-plastic FEM.

The Finite-Element Method—Part I

1989 ◽  
Author(s):  
Shiro Kobayashi ◽  
Soo-Ik Oh ◽  
Taylan Altan
Keyword(s):  
Heat Transfer ◽  
Finite Element Method ◽  
Finite Element ◽  
Ritz Method ◽  
Approximate Solutions ◽  
Plane Elasticity ◽  
Heat Transfer Analysis ◽  
Deformation Analysis ◽  
The Finite Element Method ◽  
Element Method

The concept of the finite-element procedure may be dated back to 1943 when Courant approximated the warping function linearly in each of an assemblage of triangular elements to the St. Venant torsion problem and proceeded to formulate the problem using the principle of minimum potential energy. Similar ideas were used later by several investigators to obtain the approximate solutions to certain boundary-value problems. It was Clough who first introduced the term “finite elements” in the study of plane elasticity problems. The equivalence of this method with the well-known Ritz method was established at a later date, which made it possible to extend the applications to a broad spectrum of problems for which a variational formulation is possible. Since then numerous studies have been reported on the theory and applications of the finite-element method. In this and next chapters the finite-element formulations necessary for the deformation analysis of metal-forming processes are presented. For hot forming processes, heat transfer analysis should also be carried out as well as deformation analysis. Discretization for temperature calculations and coupling of heat transfer and deformation are discussed in Chap. 12. More detailed descriptions of the method in general and the solution techniques can be found in References [3-5], in addition to the books on the finite-element method listed in Chap. 1. The path to the solution of a problem formulated in finite-element form is described in Chap. 1 (Section 1.2). Discretization of a problem consists of the following steps: (1) describing the element, (2) setting up the element equation, and (3) assembling the element equations. Numerical analysis techniques are then applied for obtaining the solution of the global equations. The basis of the element equations and the assembling into global equations is derived in Chap. 5. The solution satisfying eq. (5.20) is obtained from the admissible velocity fields that are constructed by introducing the shape function in such a way that a continuous velocity field over each element can be denned uniquely in terms of velocities of associated nodal points.

Sign in / Sign up

Export Citation Format

Share Document