| Project/Area Number |
14550196
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thermal engineering
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| Research Institution | Kogakuin University |
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Principal Investigator |
OHTAKE Hiroyasu Kogakuin University, Faculty of Engineering, Mechanical Engineering, Associate Professor, 工学部, 教授 (40255609)
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| Co-Investigator(Kenkyū-buntansha) |
KOIZUMI Yasuo Kogakuin University, Faculty of Engineering, Mechanical Engineering, Professor, 工学部, 教授 (20215156)
MIYASHITA Toru Kogakuin University, Faculty of Engineering, Mechanical Engineering, Lecturer, 工学部, 講師 (00100371)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2004: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2003: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2002: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | Mechanical Engineering / Thermal Engineering / Heat Transfer / Mist Cooling / Machining / Correlations and Modeling / Evaporation / Boiling / Ecology / 整理式・モデリング / 整理式 |
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| Research Abstract |
A kind of semi or near dry machining is Minimum Quantity Lubrication. The machining is expected as an Ecological technology. In the method, material is cut with lubrication blended on the basis of vegetable oils of a few cc/h. The liquid also serves as coolant during the machining. In this study, heat transfer characteristics in mist cooling with commercial machining oil and water were investigated experimentally and analytically. Especially, the heat transfer in the mist cooling was examined focusing on the effects of droplet size, droplet velocity and liquid mass flux on the heat transfer characteristics.
Steady state experiments of heat transfer were conducted using a pure copper cylinder and mist flow of commercial machining oil or pure water with air at room temperature. Liquid flow rates were 0.3,0.9,1.8,4 and l/hr, respectively ; each air flow rate was 0,40,75 and 120 l_N/min.
Experimental results showed that heat fluxes increased with an increasing liquid flow rate for every air flow rate. Maximum cooling rate in the present experimental range was 6 MW/m^2. The heat transfer mechanism in oil mist was only cooling of liquid film without boiling formed on a heated surface, whereas the heat transfer mechanism in water mist cooling was classified into three regions: non-boiling, evaporation of droplets and evaporation of the liquid film. A cooling limit (critical heat flux-CHF-) model of water mist flow was presented by focusing on maximum evaporation rate of liquid mass flux on a heater. The heat transfer coefficient in oil mist was well expressed by the heat removal capacity on sensible heat of supplying oil-droplets to the heated surface. Finally, four dimensionless correlations of heat transfer were derived from a dimension analysis and experimental data for both the water mist flow and the oil mist flow.
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