Analytical Modeling of Heat Transfer in Polycrystalline Diamond Compact Cutters in Rock Turning Processes

Author(s):  
Demeng Che ◽  
Kornel Ehmann ◽  
Jian Cao

Heat transfer phenomena at the rock–cutter interface are extremely significant since they affect the polycrystalline diamond compact (PDC) cutter's performance in rock cutting/drilling processes. The understanding of how temperature and heat flux responses in the cutter influence the intrinsic mechanisms of the rock–cutter interactions is an essential prerequisite for providing insights to enhance the performance of PDC cutters and to optimize rock cutting/drilling processes. In this paper, a mixed boundary value heat transfer problem was formulated to analytically describe the heat transfer phenomena in the PDC cutters during two-dimensional (2D) orthogonal rock cutting under steady state conditions. An analytical solution in the form of an infinite series was derived based on the method of separation of variables, the use of appropriate simplifications in the formulated problem and the separation of the thermal from the mechanical phenomena. A series of experimental tests were conducted on a newly developed rock cutting testbed to calibrate the process parameters in the analytical solution and then to confirm the validity of the assumed boundary conditions. The comparison between the newly derived analytical solution and the experimental data shows a good match in terms of temperature responses during rock cutting performed by PDC cutters.

2008 ◽  
Vol 273-276 ◽  
pp. 740-745
Author(s):  
Gennady Mishuris ◽  
Michał Wróbel

This work deals with a stationary axisymmetrical heat transfer problem in a combined domain. This domain consists of half-space joined with a bounded cylinder. An important feature of the problem is the possible flux singularity along the edge points of the transmission surface. Domain decomposition is used to separate the subdomains. The solution for an auxiliary mixed boundary value problem in the half space is found analytically by means of Hankel integral transform. This allows us to reduce the main problem in the infinite domain to another problem defined in the bounded subdomain. In turn, the new problem contains a nonlocal boundary conditions along the transmission surface. These conditions incorporate all basic information about the infinite sub-domain (material properties, internal sources etc.). The problem is solved then by means of the Finite Element Method. In fact it might be considered as a coupled FEM-BEM approach. We use standard MATLAB PDE toolbox for the FEM analysis. As it is not possible for this package to introduce directly a non-classical boundary condition, we construct an appropriate iterative procedure and show the fast convergence of the main problem solution. The possible solution singularity is taken into account and the corresponding intensity coefficient of the heat flux is computed with a high accuracy. Numerical examples dealing with heat transfer between closed reservoir (filled with some substance) and the infinite foundation are discussed.


Author(s):  
Demeng Che ◽  
Weizhao Zhang ◽  
Kornel F. Ehmann

Polycrystalline diamond compact (PDC) cutter, as a major cutting tool, has been widely applied in oil and gas drilling processes. The understanding of the complex interactions at the rock and cutter interfaces are essential for the advancement of future drilling technologies, yet, these interactions are still not fully understood. Linear cutting of rock, among all the testing methods, avoids the geometric and process complexities and offer the most straightforward way to reveal the intrinsic mechanisms of rock cutting. Therefore, this paper presents an experimental study of the cutter’s cutting performance and the rock’s failure behaviors on a newly developed linear rock cutting facility. A series of rock cutting tests were designed and performed. The acquired experimental data was analyzed to investigate the influences of process parameter and the rock’s mechanical properties on chip formation and force responses.


Author(s):  
Demeng Che ◽  
Weizhao Zhang ◽  
Kornel Ehmann

Polycrystalline diamond compact (PDC) cutters, as a major cutting tool, have been widely applied in oil and gas drilling processes. The understanding of the complex interactions at the rock and cutter interfaces is essential for the advancement of future drilling technologies; yet, these interactions are still not fully understood. Linear cutting of rock, among all the testing methods, avoids the geometric and process complexities and offers the most straightforward way to reveal the intrinsic mechanisms of rock cutting. Therefore, this paper presents an experimental study of the cutter’s cutting performance and the rock’s failure behaviors on a newly developed linear rock cutting facility. A series of rock cutting tests were designed and performed. The acquired experimental data was analyzed to investigate the influences of process parameters and the rock’s mechanical properties on chip formation and force responses.


Author(s):  
Demeng Che ◽  
Peidong Han ◽  
Ping Guo ◽  
Kornel Ehmann

In Part I of this paper, the issues related to temperature, stress and force were reviewed and parallels were drawn between both metal machining and rock cutting. Part II discusses the issues more directly related to polycrystalline diamond compact (PDC) bit performance and rock mechanics. However, relevant issues in various metal cutting processes will continue to be presented to clarify the gaps and similarities between these two classes of processes.


2008 ◽  
Vol 130 (11) ◽  
Author(s):  
Steven B. Beale

This is a comparison of calculations performed with a scheme for handling streamwise-periodic boundary conditions with known solutions to the common problem of fully developed heat transfer in a plane duct. Constant value, constant flux, mixed boundary conditions, and linear wall flux (conjugate heat transfer) are all considered. Agreement is, in every case, near exact showing that the methodology may be applied with confidence to complex engineering problems with a variety of thermal wall boundary conditions.


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