Cutting Tool Temperature Analysis in Heat-Pipe Assisted Composite Machining

2007 ◽  
Vol 129 (5) ◽  
pp. 902-910 ◽  
Author(s):  
Jie Liu ◽  
Y. Kevin Chou
Keyword(s):  
Heat Flux ◽  
Finite Element ◽  
Heat Source ◽  
Heat Pipe ◽  
Heat Dissipation ◽  
Cutting Tool ◽  
Advanced Materials ◽  
Chemical Vapor Deposition Diamond ◽  
Rake Face ◽  
Coating Failure

Machining of advanced materials, such as composite, encounters high cutting temperatures and rapid tool wear because of the abrasive nature of the reinforcement phases in the workpiece materials. Ultrahard coatings, such as chemical vapor deposition diamond, have been used for machining such advanced materials. Wear of diamond-coated tools is characterized by catastrophic coating failure, plausibly due to the high stress developed at the coating-substrate interface at high temperatures because of very different elastic moduli and thermal expansion coefficients. Temperature reductions, therefore, may delay the onset of the coating failure and offer tool life extension. In this study, a passive heat-dissipation device, the heat pipe, has been incorporated in composite machining. Though it is intuitive that heat transfer enhanced by the heat pipe may reduce tool temperatures, the heat pipe will likely increase heat partitioning into the tool at the rake face, and complicate the temperature reduction effectiveness. A combined experimental, analytical, and numerical approach was used to investigate the heat-pipe effects on cutting tool temperatures. A machining experiment was conducted and the heat-source characteristics were analyzed using cutting mechanics. With the heat sources as input, cutting tool temperatures in machining, without or with a heat pipe, were analyzed using finite element simulations. The simulations encompass a 3-D model of a cutting tool system and a 2-D chip model. The heat flux over the rake-face contact area was used in both models with an unknown heat partition coefficient, determined by matching the average temperature at the tool-chip contact from the two models. Cutting tool temperatures were also measured in machining using thermocouples. The simulation results agree reasonably with the experiment. The model was used to evaluate how the heat pipe modifies the heat transport in a cutting tool system. Applying heat-pipe cooling inevitably increases the heat flux into the tool because of the enhanced heat dissipation. However, the heat pipe is still able to reduce the tool-chip contact temperatures, though not dramatically at current settings. The parametric study using the finite element analysis (FEA) models shows that the cooling efficiency decreases as the cutting speed and feed increase, because of the increased heat flux and heat-source area. In addition, increasing the heat-pipe volume and decreasing the heat-pipe distance to the heat source enhances the heat-pipe cooling effectiveness.

An Investigation on Cutting Tool Temperatures in Composite Machining Assisted With Heat-Pipe Cooling

2005 ◽  
Author(s):  
Jie Liu ◽  
Y. Kevin Chou ◽  
Mark T. North ◽  
Kirk A. Bennett
Keyword(s):  
Heat Flux ◽  
Partition Coefficient ◽  
Heat Pipe ◽  
Heat Dissipation ◽  
Cutting Tool ◽  
Heat Pipes ◽  
Rake Face ◽  
Heat Partition ◽  
Coated Tools ◽  
Coating Failure

Metal matrix composites (MMC) are difficult to cut materials, and yet only diamond tools have been successfully utilized for such machining applications. Wear of diamond-coated tools is characterized by catastrophic coating failure (peeling off) due to the adhered work materials at the flank wear-land surface and the high stress developed at the coating-substrate interface, associated with high temperatures, because of very different thermal expansion coefficients. Temperature reductions, therefore, may delay the onset of the coating failure and offer tool life extension. A passive heat-dissipation device, heat-pipe, has been tested for cutting temperature reductions in MMC machining. Though it is intuitive that heat pipes may enhance heat transfer and plausibly reduce the tool temperatures, heat pipes may also increase heat partitioning into the tool, and complicate its effects on the heat removal and temperature reduction efficiency. This paper reports aluminum composite machining by diamond-coated tools and investigates the heat-pipe effects on tool temperature reductions. Numerical simulation of heat conduction in the cutting tool system was performed to evaluate cutting tool temperatures without and with a heat-pipe. A 3-D thermal model of the cutting tool system including coating, insert substrate, and tool holder was established. The heat source was characterized as a heat flux, a portion of the frictional heat flux at the rake face, over the chip-tool contact area. To determine the heat-partition coefficient, a separate 2-D chip model was established with a heat flux, balanced the total rake-face heat flux, over the contact and moving with the chip speed. With the tool and chip thermal models and by matching the average temperature at the tool-chip contact of the two models, the heat partition coefficient can be numerically determined. The model has been used to evaluate how the heat-pipe modifies the cutting tool temperatures. Applying heat-pipe cooling inevitably increases the heat partition into the tool despite the enhanced heat dissipation. However, the heat pipe still effectively reduces the tool-chip contact temperatures, depending upon machining conditions. Cutting tool temperatures have also been measured in machining using thermocouples. The simulation results reasonably agree with the experimental measurements.

Heat Transfer Characterizations of Heat Pipe in Comparison With Copper Pipe

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Chen-Ching Ting ◽  
Jing-Nang Lee ◽  
Chien-Chih Chen
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Source ◽  
Heat Pipe ◽  
Heat Conductivity ◽  
Cooling Efficiency ◽  
Copper Pipe ◽  
Heat Transfer Behavior ◽  
Transfer Behavior ◽  
Large Heat

The article presents some significant experimental data for studying the heat transfer behavior of heat pipe, which will further help the cooling efficiency improvement of the heat pipe cooler. It is well known that the heat pipe owns the extreme large heat conductivity and is often integrated with cooling plates for CPU cooling. The heat pipe uses special heat transfer techniques to obtain extremely large heat conductivity, which are the inside liquid evaporation for heat absorption and the inside microstructural capillarity for condensation. These special techniques yield the instant heat transfer from the heat source to the remote side directly, but the special heat transfer behavior is changed due to the integration with cooling plates. The destroyed heat transfer behavior of the heat pipe causes the cooling efficiency of the heat pipe cooler to be not able to reach a predicted good value. To improve the cooling efficiency of the heat pipe cooler we recover the original heat transfer behavior of the heat pipe integrated with cooling plates. This work first built a CPU simulator in accordance with the ASTM standard for heating the heat pipe, then uses the color schlieren technique to visualize the sequent heat flux nearby the heat pipe and the infrared thermal camera for quantitative temperature measurements synchronously. The result shows that the heat flux first appears at the opposite side from the heat source and there exhibits also the highest temperature. This is different from the heat transfer behavior of the copper pipe. Another very interesting result is that the heat flux of the cooling plate nearest to the heat source is first viewed than the others, which is similar to the integration with the copper pipe.

A Mathematical Modeling Method for Capillary Limit of Micro Heat Pipe with Sintered Wick

2011 ◽  
Vol 175 ◽  
pp. 335-341
Author(s):  
Xi Bing Li ◽  
Chang Long Yang ◽  
Gong Di Xu ◽  
Wen Yuan ◽  
Shi Gang Wang
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Pipe ◽  
Heat Dissipation ◽  
High Heat ◽  
Experimental Investigations ◽  
High Heat Flux ◽  
Micro Heat Pipe ◽  
Copper Powders ◽  
Capillary Limit

With heat flux increasing and cooling space decreasing in microelectronic and chemical products, micro heat pipe has become an ideal heat dissipation device in high heat-flux products. Through the analysis of its working principle, the factors that affect its heat transfer limits and the patterns in which copper powders are arrayed in circular cavity, this paper first established a mathematical model for the crucial factors in affecting heat transfer limits in a circular micro heat pipe with a sintered wick, i.e. a theoretical model for capillary limit, and then verified its validity through experimental investigations. The study lays a powerful theoretical foundation for designing and manufacturing circular micro heat pipes with sintered wicks.

scholarly journals Effect of phase change materials on heat dissipation of a multiple heat source system

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 797-807
Author(s):  
Kai Yu ◽  
Yao Wang ◽  
Yanxin Li ◽  
Jakov Baleta ◽  
Jin Wang ◽  
...  
Keyword(s):  
Heat Source ◽  
Phase Change ◽  
Heat Pipe ◽  
Phase Change Materials ◽  
Heat Dissipation ◽  
Experimental Tests ◽  
Equilibrium Temperature ◽  
System Structure ◽  
Heat Sources ◽  
Lower Temperature

AbstractThis paper experimentally investigates heat dissipation of a heat pipe with phase change materials (PCMs) cooling in a multiple heat source system. Two heat sources are fixed at one end of the heat pipe. Considering that a heat sink cannot dissipate all the heat generated by two heat sources, various PCMs are used due to a large latent heat. Different materials in a container are wrapped outside of the middle heat pipe to take away the heat from the evaporation section. The experimental tests obtain temperature data of heat source, evaporation section, and energy storage characteristics of PCMs are also determined under constant and dynamic values of the heat source powers. It is found that under this multiple heat source system structure, the phase change material RT35 maintains temperature variations of the evaporation section at a lower temperature and shortens the required time to reach the equilibrium temperature under a heating power of 20 W.

scholarly journals An Improved LPTN Method for Determining the Maximum Winding Temperature of a U-Core Motor

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1566
Author(s):  
Bin Li ◽  
Liang Yan ◽  
Wenping Cao
Keyword(s):  
Heat Flux ◽  
Heat Source ◽  
Heat Dissipation ◽  
Temperature Drop ◽  
Maximum Temperature ◽  
Heat Sources ◽  
Heat Generator ◽  
Thermal Network ◽  
Lumped Parameter ◽  
Flux Change

In a traditional lumped-parameter thermal network, no distinction is made between the heat and non-heat sources, resulting in both larger heat flux and temperature drop in the uniform heat source. In this paper, an improved lumped-parameter thermal network is proposed to deal with such problems. The innovative aspect of this proposed method is that it considers the influence of heat flux change in the heat source, and then gives a half-resistance theory for the heat source to achieve the temperature drop balance. In addition, the coupling relationship between the boundary temperature and loading position of the heat generator is also added in the lumped-parameter thermal network, so as to amend the loading position and nodes’ temperature through iterations. This approach breaks the limitation of the traditional lumped-parameter thermal network: that the heat generator can only be loaded at the midpoint, which is critical to determining the maximum temperature in asymmetric heat dissipation. By adjusting the location of heat generator and thermal resistances of each branch, the accuracy of temperature prediction is further improved. A simulation and an experiment on a U-core motor show that the improved lumped-parameter thermal network not only achieves higher accuracy than the traditional one, but also determines the loading position of the heat generator well.

Radial, Two-Phase Heat Transport Device Driven by Electrohydrodynamic Conduction Pumping

2011 ◽  
Author(s):  
Matthew R. Pearson ◽  
Jamal Seyed-Yagoobi
Keyword(s):  
Thin Film ◽  
Heat Flux ◽  
Heat Source ◽  
Liquid Film ◽  
Heat Pipe ◽  
Heat Transport ◽  
Working Fluid ◽  
Bottom Surface ◽  
Two Phase ◽  
Transport Device

Electrohydrodynamic (EHD) conduction pumping can be readily used to pump a thin film of a dielectric liquid along a surface, using electrodes that are embedded into the surface. This effect has been demonstrated under adiabatic conditions and has also been used to create a two-phase heat transport device that is similar to a heat pipe, but with the wicking structure replaced by an EHD conduction pump. In this study, a circular two-phase heat transport device is created. The device features circular electrodes that are arranged concentrically on the bottom surface and that pump a liquid film towards a heat source located at the center of the device. This heat source evaporates the liquid, and a large annular condenser at the periphery of the bottom surface provides a continuous supply of fresh liquid. This radial pumping configuration provides several advantages. Most notably, the heat source is wetted with fresh liquid from all 360 degrees, thereby reducing the amount of distance that must be travelled compared to a linear device. Consequently, the heat flux that can be removed from the central heat source far exceeds the normal critical heat flux of the working fluid. Electrodes are embedded in the condenser, adiabatic, and evaporator sections to maximize the amount of pumping head that can be generated and thereby maximize the heat flux removal.

Prediction of Heat Transfer Behavior of Carbide Inserts With Embedded Heat Pipes for Dry Machining

2002 ◽  
Author(s):  
Richard Y. Chiou ◽  
Jim S. J. Chen ◽  
Lin Lu ◽  
Ian Cole
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Distribution ◽  
Tool Wear ◽  
Heat Pipe ◽  
Cutting Tool ◽  
Heat Pipes ◽  
Clear Understanding ◽  
Dry Machining ◽  
Element Analysis

The temperature of a tool plays an important role in thermal distortion and the machined part’s dimensional accuracy, as well as in tool life in machining. The most significant factors in tool wear are temperature and the degree of chemical affinity between the tool and the workpiece. This research focuses on developing a clear understanding of the temperature distribution with cutting tool inserts embedded with heat pipes to eliminate the use of cutting fluids and reduce tool wealr in machining. A novel approach using the finite element analysis was developed to simulate the thermal behavior of a carbide cutting tool in three-dimensional dry machining. The carbide tools possess high material strengths at room temperature, but they cannot retain useful hardness at temperatures above 900°C (1700°F). Therefore, the reduction of tool wear typically requires maintaining the temperature of cutting tool inserts below some critical values. The particular temperature distribution depends on density, specific heat, thermal conductivity, shape and contact of the tool and heat pipe. Finite Element Analysis (FEA) shows that the temperature drops greatly at the tool-chip interface and that the heat flow to the tool is effectively removed when a heat pipe is embedded.

Advanced Micro-Channel Vapor Chamber for Cooling High Power Processors

2007 ◽  
Author(s):  
Masataka Mochizuki ◽  
Yuji Saito ◽  
Fumitoshi Kiyooka ◽  
Thang Nguyen ◽  
Tien Nguyen ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Pipe ◽  
Heat Dissipation ◽  
Metal Plate ◽  
Working Fluid ◽  
Micro Channel ◽  
Vapor Chamber ◽  
Processor Performance ◽  
Heat Spreading

After the introduction of Pentium™ processor in 1993, the trend of the processor performance and power consumption have been increased significantly each year. Heat dissipation has been increased but in contrast the size of die on the processor has been reduced or remained the same size due to nano-size circuit technology and thus the heat flux is critically high. The heat flux was about 10–15 W/cm2 in the year 2000 and had reached 100 W/cm2 in 2006. The processor’s die surface where the heat is generated is usually small, approximately 1 cm2. For effective cooling should required least temperature gradient between the heat source and radiating components. The best known devices for effective heat transfer or heat spreading with lowest thermal resistance is heat pipe and vapor chamber. Basically, heat pipe and vapor chamber are an evacuated and sealed container which contains a small quantity of working fluid which is water. When one side of the container is heated, causing the liquid to vaporize and the vapor to move to the cold side and condensed. Since the latent heat of evaporation is large, considerable quantities of heat can be transported with a very small temperature difference from end to end. The 2-phase heat transfer device has excellent heat spreading and heat transfer characteristics, is the key element in thermal management challenge of ever power-increasing processors. In this paper, authors presented case designs using vapor chamber for cooling computer processors. Proposed ideas of using micro-channel vapor chamber for heat spreading to replace the traditional metal plate heat spreader. Also included in the paper are ideas and data that showed performance improvement of heat spreading devices.

Modeling Transient Heat Transfer and Dry-Out Phenomena in Heat Pipes Using Finite Element Analysis

2020 ◽  
Author(s):  
Mustafa Özçatalbaş ◽  
Ramazan Aykut Sezmen
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Flux ◽  
Finite Element ◽  
Heat Pipe ◽  
Heat Removal ◽  
Heat Pipes ◽  
Heat Transfer Analysis ◽  
Transient Heat Transfer ◽  
Dry Out

Abstract Heat pipes are passive two-phase heat transfer devices that used in various heat transport applications because of their high thermal conductance capacities with low temperature differences. One of these applications is aerospace avionics that heat pipes are exposed to transient heat loads. Although heat pipes have been one of the heat removal alternatives for compact electronic devices, they have some restrictions during the usage in such high heat flux areas. In order to use heat pipes as effective heat removal devices, operating heat load range should not be exceeded during the operation of avionics or electronic devices. Out of these operating range, heat pipes no longer perform as effective heat removal devices because of phenomena called dry-out. In this study, a novel Finite Element (FE) Analysis Method was developed to model transient heat transfer behavior in heat pipes including dry-out phenomenon. Transient heat transfer analysis using Finite Element Method (FEM) was conducted to investigate heat pipe thermal performance considering heat flux dependent thermal conductivity under randomly varying heat inputs, which were assumed as heat dissipation of an electronic device. Validation of the FE model was done by using the results given in the literature. Heat pipe was made of Al with a length of LHP = 200 mm. Heat flux and convective heat transfer boundary conditions were used at the evaporator and condenser sections, respectively. Effective thermal conductivity of heat pipe, keff, was calculated by using the heat input depended thermal resistance, Rth, values given in literature. Under transient heat loads, heat flux dependent effective thermal conductivity was defined using user defined subroutines to simulate the dry-out. The transient heat transfer analysis was conducted using ABAQUS commercially available software. Temperature differences between evaporator and condenser sections, ΔT = Te−Tc, and thermal resistance, Rth, values are calculated for varying heat input values and compared with the results that provided in literature.

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