Measurement of the Cooling Effect of a Water Mist Fan on Personal Protection Equipment(PPE) and Work Clothing
| Project/Area Number |
21K04567
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 25020:Safety engineering-related
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| Research Institution | Osaka Metropolitan University (2022)
Osaka City University (2021) |
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Principal Investigator |
Farnham Craig 大阪公立大学, 大学院生活科学研究科, 准教授 (60638245)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Project Status |
Granted (Fiscal Year 2022)
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| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
Fiscal Year 2023: ¥390,000 (Direct Cost: ¥300,000、Indirect Cost: ¥90,000)
Fiscal Year 2022: ¥260,000 (Direct Cost: ¥200,000、Indirect Cost: ¥60,000)
Fiscal Year 2021: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
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| Keywords | mist / cooling / heat stroke / worker / PPE / clothing / evaporation / Mist / Cooling / Worker safety / Heat stress / Heat stroke / evaporation cooling |
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| Outline of Research at the Start |
熱ストレスと熱射病は、暑い環境で保護服を着用する労働者にとって危険である。 作業員が防護服を脱いだり、屋内で空調された部屋に移動したりする必要としない、現場での熱ストレス緩和が必要である。
ミストファンは、高温環境で低コストで強力な冷却効果を発揮します。 衣類は冷却効果の一部をブロックする。 作業服で覆われたときの皮膚に対するこの冷却効果の特性評価をする。 これにより、ミストファンを効果的に使用して作業者の熱ストレスを軽減する方法を決定できる。皮膚のような加熱表面に対するミストファンの冷却効果を測定する。 表面は作業服または個人用保護具で覆われる。
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| Outline of Annual Research Achievements |
The prototype low-cost thermal mannequin setup built in FY2021 was improved at low cost. Hand-made copper coil pipe heat-exchangers were inserted into each water tank rather than circulating hot water directly into the tanks. Tank warping and air gaps with heat flux sensors were prevented. The water temperature in each tank was much more stable than the previous year, easily maintaining at 36-37C. An outdoor low-cost wind tunnel was created using tents. This blocked the effect of natural wind on changing the direction of the misted air. A 3D ultrasonic anemometer recorded air velocity. Cost savings were used to increase Research Assistant work hours and experiment trials.
The prototype mannequin was also validated in a neutral indoor environment (20C) and shown to emit a heat flux similar to a human at 1.8met, which is an appropriate value in the range of light labor or office work.
Increased RA hours allowing more measruements of mist and fan cooling rates for unclothed, clothed, clothed with PPE, damp clothed, and damp clothed with PEE (to better represent a sweating human) on 15 days in hot summer weather.
After analysis of 4 days of data mist cooling is always significantly stronger (about 20-80%) than natural convection or fan cooling, even when PPE is used. When work clothes are damp, the cooling by natural convection and fan cooling are higher than dry clothes, reflecting the normal condition of a sweating worker. PPE over wet clothes only slightly reduced the cooling effect, this change less than the standard deviation of the heat flux over time.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Heat transfer coefficients of 5 types of cooling have been found from 4 days, but analysis continues on the remaining 11 days. Development of the 3D CFD simulation was deferred in favor of more experiments and conditions in FY2022. In FY 2023, the analyzed data results to yield heat transfer coefficients will be used to create the CFD model. The detailed 3D velocity profile of the misting fan is being measured by ultrasound anemometer in the improvised wind-tunnel set up outdoors. The components of the fan velocity field can be used to make the CFD simulation more accurate.
Publications
Conference papers:
1. Experiments on the Effect of Clothing and PPE(Personal Protection Equipment) on the Cooling Effect of a Water Mist Fan.
Presented at SHASEJ Annual Conference 2022, Sept 2022, Kobe.
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| Strategy for Future Research Activity |
A large amount of data from 15 days, with 5 clothing conditions on each day, and 3 cooling conditions for each (natural convection only, fan only, fan with mist) in being compiled.It will be desired to progress the CFD model to a transient model, which will require more computing power and more recent software. These results will hopefully be compared to actual human subjects wearing work clothes and PPE under mist fan cooling on hot days as a future research project, likely requiring collaboration with researchers in physiology and worker safety.
Planned publications
1.「ミストファンの冷却効果に対する作業服と防護服の影響に関する実験」To be presented at AIJ Annual Conference 2023, Sept 2023, Kyoto
2.「ミストファンの冷却効果と熱伝達率に対する作業服と防護服の影響に関する実験」To be presented at SHASEJ Annual Conference 2023, Sept 2023, Fukui.
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Report
(2 results)
Research Products
(4 results)
