著者

鈴木 恵祐 塚本 充紀 永井 二郎

出版者

一般社団法人日本機械学会

雑誌

熱工学コンファレンス講演論文集

巻号頁・発行日

vol.2013, pp.329-330, 2013-10-18

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A new type of heat pipe, called BACH (Bubble-Actuated Circulating Heat pipe), was revised so as to be capable of both top-heat mode and bottom-heat mode by valve switching. In this research, heat transport characteristics of the BACH between underground and ground surface were measured experimentally. The working fluid was R134a. The obtained results show that at bottom-heat mode, BACH can transport heat of 200W maximum, while it can transport heat of 300W maximum at top-heat mode. The heat transport characteristics were affected by underground length and cooling method of intermediate cooled section, and in general the underground length 4m was optimal.

著者

影山 拓也 吉田 周平 曽根 宏隆 田中 学 渡辺 隆行

出版者

一般社団法人 日本機械学会

雑誌

熱工学コンファレンス講演論文集

巻号頁・発行日

vol.2016, 2016

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<p>The purpose of this study is to synthesize lithium transition-metal oxide nanoparticles by induction thermal plasmas. Six different systems of Li-Mn, Li-Cr, Li-Fe, Li-Co, Li-Ti, and Li-Ni were compared to understand the formation mechanism. The obtained results indicated that lithium metal oxide nanoparticles were successfully synthesized in Li-Mn, Li-Cr, Li-Fe, Li-Co, and Li-Ti systems, while those nanoparticles were rarely synthesized in Li-Ni system. This difference was discussed on the basis of thermodynamic consideration. The yield of prepared lithium metal oxides depends on the ratio of Gibbs free energy change of lithium transition-metal oxides to that of metal oxides.</p>

著者

冨沢 祐介 黒田 明慈 佐々木 克彦 海藤 義彦 松田 和幸

出版者

一般社団法人日本機械学会

雑誌

熱工学コンファレンス講演論文集

巻号頁・発行日

vol.2013, pp.255-256, 2013-10-18

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As smart phones become more complex, higher in performance and smaller in size, heat concentration at localized areas is becoming a problem. Therefore, the aim of this paper is to examine the effect of high thermal conductive materials for heat dissipation in order to solve this problem. The thermal conductivity of the outer case of the smart phone was changed using finite element method (FEM) to simulate high thermal conductive materials or composite materials with anisotropy. The maximum temperature gradually decreased and the minimum temperature gradually increased with increasing the thermal conductivity of the outer case. Moreover, the thermal conductivity in the longer direction of the smart phone was important for lowering the maximum temperature. In this paper, it is found that applying high thermal conductive materials to the outer case is effective for uniforming the heat dispersing.

著者

加藤 秦生 永田 龍一 SISWANTO Eko 葛山 浩

出版者

一般社団法人日本機械学会

雑誌

熱工学コンファレンス講演論文集

巻号頁・発行日

vol.2012, pp.309-310, 2012-11-16

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The purpose of this study is to find out influence of wettability on condensate film behavior. We used two material balls, Alumina Ball (AB) and Coated Alumina Ball (CAB). CAB have higher wettability than AB. This study was conducted by streaming the humidity-air over the porous media surface in a chamber covered by ambient-air. Condensation film behavior in the system was visualized by use of video camera. The main result mention that condensate film behavior of AB media was channel flow, whereas its of CAB media was almost drop wise condensation under low humidity-air temperature.

著者

宮崎 康次 黒崎 潤一郎 笠井 哲郎 原田 一興 塚本 寛

出版者

一般社団法人日本機械学会

雑誌

熱工学コンファレンス講演論文集

巻号頁・発行日

vol.2007, pp.421-422, 2007-11-23

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We fabricated bismuth-telluride based thin films and their in-plane thermoelectric micro-generators on a free standing silicon nitride thin film by using the flash evaporation method through shadow masks. The shadow masks are fabricated by standard micro-fabrication processes. The fabricated micro-generators are just put on a heated plate, and the open-circuit output voltages of micro-generators are measured by a digital voltmeter. The maximum measured voltage is about 40mV at 10K temperature difference. The output voltage is comparable to the bulk value although the device consists of as-grown thin films.

著者

谷 彰太 川口 清司 五十嵐 隼 渡辺 大輔

出版者

一般社団法人 日本機械学会

雑誌

熱工学コンファレンス講演論文集

巻号頁・発行日

vol.2010, pp.61-62, 2010

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Heat transfer enhancing method is more and more needed to decrease power consumption. This study was carried out to develop a high performance vortex generator, and find out the relationship between vortex structure and heat transfer. Double delta winglet pair was developed to reduce pressure drop with keeping up vortex strength. It was clarified that double delta winglet pair had higher performance than delta winglet pair by 10% at flow velocity of 1.4m/s by measuring average heat transfer coefficient and pressure drop. It was found out that double delta winglet pair had the position of vortex core at short distance from heat transfer surface than delta winglet pair. Therefore, the heat transfer coefficient was larger than delta winglet pair's one, even though it's vortex strength was smaller than that.

著者

劉 留 朱 寧 天野 勝弘 福田 一人

出版者

一般社団法人 日本機械学会

雑誌

熱工学コンファレンス講演論文集

巻号頁・発行日

vol.2018, 2018

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<p>After nature disaster such as earthquakes, flood or typhoon, usually electric breakout will occur during which portable power generators are necessary. Since conventional portable power generators use gasoline as the fuel, the exhaust gas and the smell will do damage to people's health. In this paper, we try to develop the portable power generator whose power capacity is 1 kW by reforming the conventional reciprocal gasoline engine and using hydrogen gas as fuel. An experimental system was established to measure the thermal efficiency and the output power of the reformed engine by adjusting some factors such as compression ratio, position of the intake and engine oil and so on. Based on the experimental results, it is found that output power over 1 kW and the maximum thermal efficiency was 23.42%, respectively.</p>

著者

棚橋 晃毅 安里 勝雄 宮坂 武志 渡辺 裕太

出版者

一般社団法人日本機械学会

雑誌

熱工学コンファレンス講演論文集

巻号頁・発行日

vol.2011, pp.321-322, 2011-10-28

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The effects of blockage ratios (BR) of the Shchelkin spiral on characteristics of deflagration-to-detonation transition (DDT) in a vortex flow were examined in order to control the DDT distance without losing the simplicity inherent pulse detonation engines. The DDT distance decreases with increasing the BR of the Shchelkin spiral. However, the optimum value of BR exists. The DDT distance is deteriorated if the BR exceeds the optimum value. Optimizing the BR of the Shchelkin spiral is another way to shorten DDT distance in a vortex flow.

著者

渡辺 裕太 安里 勝雄 宮坂 武志 石川 聡真 棚橋 晃毅

出版者

一般社団法人日本機械学会

雑誌

熱工学コンファレンス講演論文集

巻号頁・発行日

vol.2010, pp.131-132, 2010-10-29

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The effects of lengths and blockage ratios (BR) of Shchelkin spiral on characteristics of deflagration-to-detonation transition (DDT) in a vortex flow were examined in order to control the DDT distance without losing the simplicity inherent pulse detonation engines (PDEs). A vortex flow field was established in the ignition and transition domains of the detonation tube using a vortex flow type injection. The DDT process was observed by measuring the pressure and ionization current in the detonation tube. The DDT distance decreases with increasing the length of Shchelkin spiral. However, the optimum length of Shchelkin spiral exists. The DDT distance is reduced by about 12.0% when the BR is increased from 38.2% to 45.1%.

著者

チルコティ ハリクリシュナ 菊川 豪太 小原 拓

出版者

一般社団法人 日本機械学会

雑誌

熱工学コンファレンス講演論文集

巻号頁・発行日

vol.2014, pp._B222-1_-_B222-2_, 2014

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In this paper, thermal conductivity of liquid n-alkanes in the vicinity of three crystal planes of a-quartz substrate terminated with H and OH-groups have been investigated using nonequilibrium molecular dynamics simulations. Methane and decane molecules are considered as alkane molecules in this study. It is found that the thermal conductivity fluctuates in an oscillating manner in the solid-liquid interface region. These fluctuations are typically in proportion to the oscillations in the density profile.

著者

鈴木 巧 柿本 益志

出版者

一般社団法人 日本機械学会

雑誌

熱工学コンファレンス講演論文集

巻号頁・発行日

vol.2013, pp.39-40, 2013

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A numerical study has been done for natural convection heat transfer in the joint part of a cylindrical thermal insulation structure with a metallic outer shell. If the joint is relatively narrow, the effect of natural convection which occurs inside the joint on the thermal insulation performance is small. Although the heat transfer rate increases as joint width becomes large, the increase in the heat transfer rate is less than 10 percent, even when the joint width is 10mm.

著者

高橋 真一 中村 祐二 山下 博史 鎌田 祐一 矢野 賢司 橋本 みゆき 伊藤 誠

出版者

一般社団法人日本機械学会

雑誌

熱工学コンファレンス講演論文集

巻号頁・発行日

vol.2004, pp.59-60, 2004-11-10

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In this paper, a dependence factor of soot emissivity on wavelength, a is studied in a counterflow propane diffusion flame by spectroscopic measurement. The spectrometer is set vertically to the nozzle and radiation of luminous flame is obtained each height from the lower burner. The emissivity is calculated from emissive power of luminous flame and blackbody furnace, and a is obtained by analysis of the emissivty. The relations between a and temperature, wavelength and distance from lower burner are examined. Results show that a is smaller with longer wavelength in the range of 600nm - 1000nm. Additionally, it is suggested that a also depends on soot conditions.