Investigation of burr prediction in drilling using acoustic emission
- Authors: Lukoto, Ntendeleni Arnold
- Date: 2009-01-20T07:06:18Z
- Subjects: Acoustic emission , Drilling and boring
- Type: Thesis
- Identifier: uj:14809 , http://hdl.handle.net/10210/1935
- Description: M.Ing. , Please refer to full text to view abstract
- Full Text:
Thermal performance of heat pipe drill : experimental study
- Authors: Jen, Tien-Chien , Chen, Yau-Min , Gutierrez, Guatavo
- Date: 2003
- Subjects: Drilling and boring , Heat pipes
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/15756 , uj:15696 , Citation: • Jen, T.-C., Chen Y-M., and Gutierrez, G., 2003. Thermal performance of heat pipe drill: experimental study.Proceedings of NHTC03: ASME Summer Heat Transfer conference,July 21-23,2003 Las Vegas, Nevada, USA, pages 1-7.
- Description: Abstract: An experimental study is performed in this paper to verify the concept of thermal management of using a heat pipe in the drilling process. The basic idea is to insert a heat pipe at the center of the drill tool with the evaporator located close to the drill tip, and condenser located at the end of the drill. In this way, heat accumulated in the drill tip can be transported to the remote section of the drill and remove it there to the tool holder, which attaches the drill. Temperatures at the drill tip as well as tool wear can be reduced significantly. In this paper, experimental investigations on a heat pipe drill for various heat flux inputs, inclination angles and rotating speeds are presented. The effect of contact resistance and tool holder (acting as heat sink) on heat pipe performance will also be demonstrated. The results presented in this paper may be used for important design and practical implementation considerations
- Full Text:
Numerical analysis of the hydrodynamics of the flow in an axially rotating heat pipe
- Authors: Gutierrez, Gustavo , Jen, Tien-Chien
- Date: 2002
- Subjects: Hydrodynamics , Heat pipes , Drilling and boring
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/15688 , uj:15691 , Citation: Gutierrez, G. and Jen, T.-C. 2002. Numerical analysis of the hydrodynamics of the flow in an axially rotating heat pipe. Proceedings of IMECE2002 ASME International Mechanical Engineering Congress & Exposition, November 17-22, 2002, New Orleans, Louisiana, 5:1-13. , ISBN: 0-7918-3636-3
- Description: A numerical study is conducted on the vapor and liquid flow in a wick structure of an axially rotating heat pipe. For the vapor, the governing equations are the Navier-Stokes. For the liquid a space average of the Navier-Stokes equation is performed and a porous media model is introduced for the cross correlation that appears from the averaging process. A control volume approach on a staggered grid is used in the development of the computer program. Suction and blowing velocities are used as boundary conditions of the vapor and liquid, which are related to a local heat flux input in the evaporator section, and local heat flux output in the condenser section, respectively. The aim behind this study is the application of heat pipes in drilling applications. A triangular heat flux distribution is assumed in the evaporator due to the higher heat flux generated at the tip of the drill. A parametric study is conducted to analyze the effect of different parameters such as rotational speeds, saturation conditions, porosity, permeability and dimensions of the wick structure in the porous medium. These parameters significantly affect the pressure drop in the heat pipe and allow predicting failure conditions, which is critical in the design of heat pipes in drilling applications. The results of this study will be useful for the complete analysis of the heat pipe performance including the solution of the heat transfer on the solid wall as a conjugate problem.
- Full Text: