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Suppression of Surface Burn in Grinding of Titanium Alloy TC4 Using a Self-inhaling internal cooling Wheel

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Chinese Journal of Aeronautics 2011年第1期24卷 96-101页

作者： LI Xun CHEN Zhitong CHEN Wuyi School of Mechanical Engineering and Automation Beijing University of Aeronautics and Astronautics Beijing 100191 China

Based on analysis of surface average temperature and burn degree, this article obtains the threshold temperature of surface burn in grinding titanium alloy with cup wheels. Meanwhile, the impact of the burn degree on the metallographic structure of workpiece surface and metallurgical phase transformations is investigated. In order to reduce the grinding temperature and improve the grinding efficiency, a self-inhaling structure cup segmented wheel is developed to generate internal cooling effect. The internal cooling technology is compared with traditional cooling conditions in the grinding experiments on TC4 （Ti-6Al-4V）. The results indicate that the self-inhaling internal cooling wheel can reduce the grinding surface temperature by 30% or more, and the grinding efficiency doubles. Utilizing water-based semi-synthetic coolant, the segmented wheel with the self-inhaling structure can further reduce the grinding temperature by about 50%.

关键词： grinding temperature measurement surface burn internal cooling self-inhaling

Magnetohydrodynamic‑based internal cooling System for a Ceramic Cutting Tool:Concept Design,Numerical Study,and Experimental Evalidation

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Nanomanufacturing and Metrology 2023年第4期6卷 60-80页

作者： John O’Hara Fengzhou Fang Center of Micro/Nano Manufacturing Technology(MNMT-Dublin) University College DublinDublin 4Ireland State Key Laboratory of Precision Measuring Technology and Instruments Laboratory of Micro/Nano Manufacturing Technology(MNMT)Tianjin UniversityTianjin 300072China

The efective removal of the heat generated during mechanical cutting processes is crucial to enhancing tool life and produc-ing workpieces with superior surface *** internal cooling systems used in cutting inserts employ a liquid water-based solvent as the primary medium to transport the excess thermal energy generated during the cutting *** limitations of this approach are the low thermal conductivity of water and the need for a mechanical input to circulate the coolant around the inner chamber of the cutting *** this context,this paper proposes an alternative method in which liquid gallium is used as the coolant in combination with a magnetohydrodynamic(MHD)pump,which avoids the need for an external power *** computational fuid dynamics,we created a numerical model of an internal cooling system and then solved it under conditions in which a magnetic feld was applied to the liquid *** was followed by a simulation study performed to evaluate the efectiveness of liquid gallium over liquid *** results of experiments conducted under non-cooling and liquid gallium cooling conditions were analyzed and compared in terms of the tool wear *** results showed that after six machining cycles at a cutting speed Vc=250 m min−1,the corner wear VBc rate was 75µm with the coolant of and 48µm with the MHD-based coolant on,representing a decrease of 36%in tool *** Vc=900 m min−1,the corner wear VBc rate was 75µm with the coolant of and 246µm with the MHD-based coolant on,representing a decrease of 31%in tool *** external cooling using liquid water was added,the results showed at Vc=250 m min−1,the diference between the tool wear rate reduction with the internal liquid gallium coolant relative to the external coolant was 29%.When the cutting speed was increased to Vc=900 m min−1,the diference observed between the internal liquid gallium coolant relative to the external coolant was 16%.The study proves the feasibility of using liqu

关键词： internal cooling Heat transfer Liquid metal Magnetic feld Cutting tool

Fuel Economy Opportunities for internal CombustionEngines by Means of Oil-cooling

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Journal of Thermal Science 1997年第2期6卷 132-140页

作者： C.F. Ma J.C. Li W.X. Qin Z.Y. Wei J. Chen (Department of Thermal Science and Engineering, Beijing Polytechnic University Beijing 100022,China) Department of Thermal Science and Engineering Beijing Polytechnic University Beijing China

Comparative experiments of oil and water-cooling were performed on a 4-cylinder automotive gasoline engine and a single-cylinder direct injection Diesel engine. Measurements were made to investigate the variation of fuel consumption, combustor wall temperature and engine emissions (HC, CO, NOx and smoke) with two cooling media at steady-state conditions. Significant improvement of fuel economy was found mainly at partial load conditions with oil-cooling in comparison with the baseline waer-cooling both for the two engines. The experimental results also showed general trend of reduction in engine emissions using oil as the coolant. Measurements of wall temperature demonstrated that oil-cooling resulted in considerable increase of the combustor wall temperature and reduce of warmup period in starting process. For automotive gasoline engine, road tests indicated the same trend of fUel economy improvement with oil-cooling. The performance of the automotive oil-cooled engine was fUrther improved by internal cooling with water or methanol injection.

关键词： internal combustion engines oil cooling internal cooling

Experimental and Theoretical Study of an internally Cooled Liquid Desiccant Dehumidifier

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Journal of Thermal Science 2023年第4期32卷 1684-1696页

作者： ZHENG Xin LU Yuan WANG Bo ZHAO Lifeng XIAO Yunhan Key Laboratory of Advanced Energy and Power Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing100190China Research Center for Clean Energy and Power Chinese Academy of SciencesLianyungang222069China University of Chinese Academy of Sciences Beijing100049China

Liquid desiccant dehumidifiers are useful for simultaneously recovering heat and water from flue *** cooled dehumidifiers are generally superior to adiabatic dehumidifiers in terms of the consumption of the desiccant and the size of the equipment *** study examines the performance of a counter-flow dehumidifier through experiments and simulations under different operating conditions,and analyzes the moisture effectiveness and enthalpy effectiveness as performance *** applying correlations from the literature,the theoretical model can predict the performance of the dehumidifier within an acceptable range of *** to the experimental results,droplets were visible at a low desiccant flow rate when the velocity of the gas was above 4.88 m/***,a higher cooling ratio and a higher temperature of the solution enhanced the effectiveness of the dehumidification.A temperature cross occurred between the gas and the solution when the mass transfer was sufficiently high,which reflects better heat transfer performance than the conventional convective heat exchanger.

关键词： flue gas recovery water heat internal cooling calcium chloride

Investigation on heat transfer enhancement and pressure loss of double swirl chambers cooling

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Propulsion and Power Research 2013年第3期2卷 177-187页

作者： Gang Lin Karsten Kusterer Dieter Bohn Takao Sugimoto Ryozo Tanaka Masahide Kazari B&B-AGEMA GmbH Juelicher Str.338Aachen 52070Germany RWTH Aachen University Templergraben 55Aachen 52056Germany Kawasaki Heavy Industries LTD.Gas Turbine&Machinery CompanyAkashi 673-8666Japan Kawasaki Heavy Industries LTD.Technical InstituteAkashi 673-8666Japan

By merging two standard swirl chambers,an alternative cooling configuration named double swirl chambers(DSC)has been *** the DSC cooling configuration,the main physical phenomena of the swirl flow in swirl chamber and the advantages of swirl flow in heat transfer augmentation are ***,three new physical phenomena can be found in DSC cooling configuration,which result in a further improvement of the heat transfer:(1)impingement effect has been observed,(2)internal heat exchange has been enhanced between fluids in two swirls,and(3)“∞”shape swirl has been generated because of cross effect between two chambers,which improves the mixing of the *** of all these improvements,the DSC cooling configuration leads to a higher globally-averaged thermal performance parameter(Nu/Nu_(∞)/(f/f0)^(1/3))than standard swirl *** particular,at the inlet region,the augmentation of the heat transfer is nearly 7.5 times larger than the fully developed non-swirl turbulent flow and the circumferentially averaged Nusselt number coefficient is 41%larger than the standard swirl *** the present work,a further investigation on the DSC cooling configuration has been focused on the influence of geometry parameters *** ratio of chambers and aspect ratio of inlet duct on the cooling *** results show a very large influence of these geometry parameters in heat transfer enhancement and pressure drop *** with the basic configuration of DSC cooling,the improved configuration with 20%to 23%merging ratio shows the highest globally-averaged themal performance *** the same cross section area in tangential inlet ducts,the DSC cooling channel with larger aspect ratio shows larger heat transfer enhancement and at the same time reduced pressure drop ratio,which results in a better globally-averaged themal performance parameter.

关键词： Gas turbine internal cooling Double swirl chambers Thermal performance Heat transfer enhancement

Evolution of globular microstructures during processing of aluminium slurries

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Transactions of Nonferrous Metals Society of China 2013年第1期23卷 1-6页

作者： Yucel BIROL Materials Institute Marmara Research CenterTUBITAK GebzeKocaeliTurkey

Slurry processing experiments were performed with AlSi7Mg0.6 to identify the globularization *** melt sample water quenched slightly above the liquidus point is predominantly dendritic while that cooled into the semi-solid temperature range internally via stirring the melt with a rotating cylindrical block of the alloy itself becomes fully *** globules are much smaller when internal cooling and stirring are employed longer to achieve higher solid fractions before *** dendrite fragments of various sizes are revealed,in the case of stirring after an initial fraction of solid is first formed without the benefit of additional internal cooling.

关键词： Al alloys AlSi7Mg0.6 alloy solidification microstructure internal cooling stirring solid fraction