List of Titles

Authors: Zhu, Lin , Jen, Tien-Chien , Yen, Yi-Hsin , Kong, Xiao-Ling
Date: 2011
Subjects: Heat pipes , Heat pipe cooling
Type: Article
Identifier: http://ujcontent.uj.ac.za8080/10210/384755 , uj:5288 , http://hdl.handle.net/10210/14957
Description: In this paper, the feasibility and effectiveness of heat pipe cooling in end milling operations are investigated. A new embedded heat pipe technology was utilized to remove the heat generated at the tool-interface in end milling processes. Numerical studies involved four cases, including dry milling, ﬂuid cooling, heat pipe cooling, and heat pipe cooling with cutting ﬂuid supplied. The thermal, structural static, and dynamic characteristics of the endmill were investigated using a numerical calculation with fast ﬁnite element plus solvers based on explicit ﬁnite element analysis software. The results demonstrate that the heat pipe end-mill is most feasible and effective in the actual end milling processes
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Authors: Zhu, Lin , Jen, Tien-Chien , Zhu, Mei , Yin, Cheng-Long , Kong, Xiao-Ling
Date: 2010
Subjects: Micro-combustors , Heat transfer
Type: Article
Identifier: uj:5281 , http://hdl.handle.net/10210/14950
Description: The aim of this investigation was to establish a methodology for designing highly stressed micro fabricated structures by studying the structural design issues associated with a silicon six–wafer micro combustor under the effect of heat transfer boundary condition at the outer walls. Some experimental and numerical simulation results have indicated that the flame can not be sustained in the micro combustor if the poor heat transfer coefficients at the outer wall are present. This could cause the combustor wall temperature higher than the auto ignition temperature of reactants and results in the upstream burning. Since silicon has relatively poor high temperature strength and creep resistance when the temperature is above the brittle to ductile transition temperature (BDTT), e.g. 900K, the combustion in the recirculation jacket could possibly damage the micro combustor due to the high wall temperature.
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Authors: Zhu, Lin , Jen, Tien-Chien , Yin, Cheng-Long , Kong, Xiao-Ling , Yen, Yi-Hsin
Date: 2012
Subjects: Heat pipe cooling , Drilling , Heat pipes
Type: Article
Identifier: uj:5289 , http://hdl.handle.net/10210/14958
Description: This paper presents an experimental investigation to verify the feasibility and effectiveness of heat pipe cooling in drilling operations. The basic idea is to insert a heat pipe at the center of the drill tool with the evaporator close to the drill tip and the condenser at the end of the drill. Consequently, the heat generated at the tool–chip interface can be removed by convection heat transfer. Experimental studies were involved in three cases, including solid drill without coolant, solid drill with coolant, and heat pipe drill. Drilling tests were conducted on a CNC machining center with full immersion cutting. The cast iron square block was used as the workpiece, and the high-speed steel was chosen for the drill tool material. Flank wear is considered as the criterion for tool failure, and the wear was measured using a Hisomet II Toolmaker’s microscope. The tests were conducted until the drill was rejected when an average flank wear greater than 0.10 mm was recorded. The results demonstrate that using a heat pipe in the drilling process can effectively perform thermal management comparable to the flooding coolant cooling used pervasively in the manufacturing industry, extending the tool life of the drill.
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