研究者業績

小倉 裕直

オグラ ヒロナオ  (Hironao Ogura)

基本情報

所属
千葉大学 大学院工学研究院 教授
学位
博士(工学)(名古屋大学)

連絡先
hiro_ogurafaculty.chiba-u.jp
J-GLOBAL ID
200901000653517619
researchmap会員ID
5000023161

外部リンク

論文

 59
  • Yawen Ren, Hironao Ogura
    Energy and Buildings 313 114256 2024年6月  査読有り最終著者責任著者
  • 廣瀬 裕二, 渡邊 くるみ, 平野 優香, 小倉 裕直
    化学工学論文集 50(3) 65-70 2024年5月20日  査読有り最終著者
  • Yawen Ren, Hironao Ogura
    Energies 16(7) 3075-3075 2023年4月  査読有り招待有り最終著者責任著者
    Facing the goal of carbon neutrality, energy supply chains should be more low-carbon and flexible. A solar chemical heat pump (SCHP) is a potential system for achieving this goal. Our previous studies developed a silicone-oil-based phase-change material (PCM) mixture as a PCM fluid for enhancing heat recovery above 373 K in the solar collector (SC) of the SCHP. The PCM fluid was previously tested to confirm its dispersity and flow properties. The present study proposed a 3D computational fluid dynamics model to simulate the closed circulation loop between the SC and reactor using the PCM fluid. The recovered heat in the SC was studied using several flow rates, as well as the PCM weight fraction of the PCM fluid. Furthermore, the net transportable energy is considered to evaluate the ratio of recovered heat and relative circulation power. As a result, it was verified that the recovered heat of the SC in the experiment and simulation is consistent. The total recovered heat is improved using the PCM fluid. A lower flow rate can enhance the PCM melting mass and the recovered heat although sensible heat amount increases with the flow rate. The best flow rate was 1 L/min when the SC area is 1 m2. Furthermore, the higher PCM content has higher latent heat. On the other hand, the lower content PCM can increase the temperature difference between the SC inlet and outlet because of the lower PCM heat capacity. For the 1 L/min flow rate, 2 wt% PCM fluid has shorter heat-storing time and larger net transportable energy than 0 wt% PCM fluid (426 kJ←403 kJ) for the SCHP unit.
  • Hironari Sakamoto, Shigehisa Uchiyama, Ayana Sato, Tomohiko Isobe, Naoki Kunugita, Hironao Ogura, Shoji F. Nakayama
    International Journal of Environmental Research and Public Health 19(23) 15813-15813 2022年11月  査読有り
    Few studies have investigated personal exposure concentrations of not only some volatile organic compounds but also more types of chemicals including acidic gases and acrolein. We measured the personal exposure concentrations of 35 chemicals including these chemicals in indoor and outdoor air in Chiba-shi, Japan, for 7 days in summer and winter to assess the associated health risks in 22 people. The personal exposure concentrations of nitrogen dioxide were higher in winter than in summer, and those of formaldehyde, p-dichlorobenzene, and tetradecane were higher in summer than in winter. The personal exposure concentrations were mostly equal to or lower than the concentrations in indoor air, contrary to the results of a lot of previous studies. The high-risk chemicals based on personal exposure concentrations were identified as acrolein (max. 0.43 μg/m3), benzene (max. 3.1 μg/m3), and hexane (max. 220 μg/m3) in summer, and acrolein (max. 0.31 μg/m3), nitrogen dioxide (max. 320 μg/m3), benzene (max. 5.2 μg/m3), formic acid (max. 70 μg/m3), and hexane (max. 290 μg/m3) in winter. In addition, we estimated personal exposure concentrations according to the time spent at home and the chemical concentrations in indoor and outdoor air. We found that the estimated concentrations of some participants largely differed from the measured ones indicating that it is difficult to estimate personal exposure concentrations based on only these data.
  • Yawen REN, Hironao OGURA
    Journal of Thermal Science and Technology 17(2) 2022年5月  査読有り最終著者責任著者
  • Hironari SAKAMOTO, Shigehisa UCHIYAMA, Moka SHIMIDZU, Hironao OGURA
    Analytical Sciences 37(12) 1713-1718 2021年12月10日  査読有り最終著者
  • Hironari Sakamoto, Shigehisa Uchiyama, Tomohiko Isobe, Naoki Kunugita, Hironao Ogura, Shoji F. Nakayama
    International Journal of Environmental Research and Public Health 18(21) 11511-11511 2021年11月1日  査読有り
    Indoor air quality (IAQ) can greatly affect health in people spending much time indoors. However, the influence of IAQ on personal exposure to chemical compounds in Japan remains poorly investigated. Hence, this study aimed to clarify this influence thoroughly within one apartment. We surveyed the concentrations of 61 chemical compounds in the air in nine different spaces within an apartment unit, as well as the personal exposure of two residents in Japan. Using three kinds of diffusive samplers, this study was conducted continuously for 7 days in summer and winter. Health risks were evaluated by calculating the margin of exposure (MOE) using the measured concentrations. Some chemical concentrations showed large spatial variations and the personal exposure concentrations of these compounds also differed among residents. According to the calculated MOE, the chemicals with the highest health risk were acrolein, p-dichlorobenzene, and acetaldehyde in summer and acrolein, nitrogen dioxide, formic acid, p-dichlorobenzene, and benzene in winter. The IAQ of the house could be divided in two, and the IAQ in the space where residents spent much time (i.e., bedroom) highly affected each of the residents’ exposure. Investigating chemical concentrations in multiple spaces (including bedroom and living room) is necessary to understand the effect of IAQ on personal exposure.
  • Yawen Ren, Hironao Ogura
    Solar Energy 224 1247-1259 2021年8月  査読有り最終著者責任著者
  • 小林 英資, 廣瀬 裕二, 小倉 裕直
    日本冷凍空調学会論文集 37(3) 2020年9月30日  査読有り最終著者責任著者
  • LanXin Lai, Toshio Imai, Motohiro Umezu, Mamoru Ishii, Hironao Ogura
    Energies 13(4) 803-803 2020年2月12日  査読有り最終著者責任著者
    Improving energy recycle is an important way to save energy resources and preserve the global environment. Chemical heat pump (CHP) is a technology for saving energy, which utilizes chemical reactions to store thermal energy such as waste heat and solar heat, then release it to provide heat for heating/cooling/refrigeration. For a practical CHP, it is necessary to find cheaper and more stable supply materials. In order to evaluate the possibility of calcium oxide from natural Ofunato natural limestone including impurities, we compare Ofunato limestone with Kawara natural limestone and Garou natural limestone from Japan. These calcium oxides worked as a reactant for CaO/H2O/Ca(OH)2 CHP by repeated hydration/dehydration reaction cycle experiments in a thermogravimetric analyzer. As a result, Ofunato CaO exhibits a high hydration reaction rate after decarbonization at 1223 K for 5 h. The reactivity increased by the repeated hydration reaction although the first hydration rate was low. Furthermore, the sintering of impurities in Ofunato limestone occur easier than that in Kawara limestone with lower impurities. The impurities adhered to the surface of the CaO particle to make specific surface area of CaO particle smaller, which could inhibit hydration reaction of CaO particle. Even if Ofunato limestone contains some impurities, it can be utilized as a raw material for chemical heat pumps.
  • 菊地 良鷹, 石山 雄大, 藤田 浩樹, 平田 一弘, 中條 晃伸, 小倉 裕直
    エネルギー・資源学会論文誌 40(4) 111-118 2019年7月  査読有り最終著者責任著者
  • H. Zhang, H. Ogura, M. Umezu, T. Imai, M. Ishii
    Journal of Materials Science 52(19) 11360-11369 2017年10月  査読有り責任著者
  • 小倉 裕直, 藤田 浩樹
    自動車技術会論文集 47(2) 579-585 2016年3月  査読有り筆頭著者責任著者
  • Hongxia Zhang, Hironao Ogura
    JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 47(7) 587-594 2014年7月  査読有り最終著者責任著者
    From the viewpoints of energy and environmental problems in the world, the development of effective energy utilization technologies such as chemical heat storage/pump and their practical uses are required. In this paper, the hydration reaction rates of various size CaO particles for calcium oxide/water chemical heat storage/pump were studied using thermogravimetric analysis based on the grain model. Firstly, we calculate a reaction rate equation using the coefficient eta(r) for the particle size effects as model I, which is based on our previous method for calcium sulfate considering the effects of the particle size. Furthermore, the catalyst effectiveness factor taking into account the mass transfer resistance within the porous particles, the particle expansion and the pore size changes along with the hydration reaction is proposed and introduced into a new reaction model II, because the shapes of the calculated data in model I and the experimental data are different. As a result, it is demonstrated that the intraparticle mass transfer resistance increases as the particle size increases. Further, the proposed applied grain model I enables evaluation of this experiment roughly. Furthermore, the applied grain catalyst model II shows that the calculated conversion lines are consistent with the experimental data for 106-1,000 mu m phi particles considering the pressure drop inside the particles by the introduction of the catalyst effectiveness factor. In addition, the expansion ratio of the CaO particles is lower than that of the grains in the reaction model II.
  • 清水 喬暢, 小倉 裕直
    日本機械学会論文集 B編 79(808) 2597-2601 2013年  査読有り最終著者責任著者
    From the viewpoints of energy saving and environmental impacts, we have been studying Chemical heat pumps (CHP) especially focusing on using calcium systems. The CaSO4/ CaSO4·1/2H2O gas-solid reversible reaction is used to store around 393K and release hot/cold heat. In this paper, we studied the energy efficiencies of CaSO4 CHP in heat enhancement mode for commercial use with various cases. As a result, it is found that the stored heat is converted/released at 353K /278K level hot/cold heat. The CaSO4 CHPs could be commercially used for wider operating temperature ranges in appropriate heat source conditions. Furthermore, the thermal efficiency was obtained to be more than 1.3, and the coefficient of performance (COP) was obtained to be about 18. It means the CaSO4 CHPs could be more efficiently than other types of heat pumps
  • 王 剣虹, 小倉 裕直, 佐々木 賢知
    Journal of the Society of Inorganic Materials, Japan : セッコウ・石灰・セメント・地球環境の科学 20(362) 15-20 2013年1月1日  査読有り責任著者
  • 小倉裕直, 中村泰拓, 重松佑亮, 川崎公一, 岩田一夫, 勝矢晃弘
    自動車技術会論文集 43(6) 1293-1298 2012年11月  査読有り筆頭著者責任著者
  • 石河 正寛, 村木 美貴, 小倉 裕直
    都市計画. 別冊, 都市計画論文集 = City planning review. Special issue, Papers on city planning 45(3) 541-546 2010年10月25日  査読有り最終著者
    本研究は、経済開発と環境負荷低減の両立が求められる都心の低炭素化をいかに実現させうるか、エネルギーシステムの更新・整備に着目して計画立案の基礎資料を提供することを目的とする。具体的には、東京都千代田区を対象に、当該区が地球温暖化防止条例で定めるCO2削減目標の達成のあり方を、複数のエネルギーシステム整備シナリオの検討による実施可能性を提示する。2章では、地方自治体のCO2排出量特性と対策枠組みに着目し、千代田区が過去のCO2排出量、開発需要から多面的な施策展開の方向性が必要であることが明らかとなった。3章では、千代田区のエネルギー需要を開発トレンドから推計し、2020年に2006年比1.22倍であることが明らかとなった。4章では排出量削減のために(1)建物内既存熱源の高効率化、(2)地域冷暖房の導入、(3)区外の未利用熱エネルギーの活用の3パタンについて検討を行った。結論として、今後の低炭素型都市づくりの実現には、目標市街地像の明確化とその実現担保手段の構築、将来的な技術革新に対応可能な形での空間管理が必要であることを提言した。
  • Kazutoshi Tsuda, Yuji Hirose, Hironao Ogura, Yasufumi Otsubo
    Colloids and Surfaces A: Physicochemical and Engineering Aspects 360(1-3) 57-62 2010年5月  査読有り
    The electrorheological (ER) behavior of suspensions was measured in nonuniform electric fields generated between pattern electrodes consisting of radial line and space. In spite of small areas of conductive parts on pattern electrodes, the suspensions show striking ER effects, which are comparable to those in uniform fields The particles may be concentrated and the columns are fully developed between conductive lines The striking ER effects can be attributed to the formation of columns with high particle concentrations. When the neighboring conductive lines on a fixed electrode are alternatively subjected to high voltage, other movable electrode causes the oscillating motion Since the stable columns are always developed in direction parallel to the field vector, the excess dipolar interaction energy stored in inclined columns is relaxed by the arrangement of column conformation For precise controls and rapid responses of motion, the thin and long columns should be developed between the electrode gap In the process, the electrical energy is directly converted to mechanical motion Therefore, the ER fluids have great potential as working fluids for a new type of actuators (C) 2010 Elsevier B.V. All rights reserved
  • 小倉 裕直, 久保田 将幸, 鈴木 彦司郎, 山川 達也
    化学工学論文集 35(5) 506-510 2009年9月  査読有り筆頭著者責任著者
  • Kazutoshi Tsuda, Yuji Hirose, Hironao Ogura, Yasufumi Otsubo
    Colloids and Surfaces A: Physicochemical and Engineering Aspects 324(1-3) 228-233 2008年7月  査読有り
    The surface deformation induced in electric fields is studied on the comb pattern electrodes for silica suspensions. On the application of electric fields, a fine pattern with a waveform is developed from the smooth surface. The surface profiles can be approximated by single sinusoidal waves or their superposition depending on the sample thickness. In electric fields, the silica suspensions shows the viscosity decrease in steady shear and yield stress in the limit of zero shear rates. The viscosity decrease can be attributed to electrophoretic migration of particles to one electrode and the development of yield stress to eletrorheological effects due to chain formation of particles between electrodes. In thick liquid films, the dielectric polarization forces are predominant and the sinusoidal profiles with a wavelength of pitch of electrodes are formed. In thin films, the electrophoretic forces are predominant and the wavelength coincides with twice the pitch of electrodes. At intermediate thicknesses, the surface profiles can be expressed by a superposition of two sinusoidal waves. (C) 2008 Elsevier B.V. All rights reserved.
  • Kazutoshi Tsuda, Yasuto Takeda, Hironao Ogura, Yasufumi Otsubo
    Colloids and Surfaces A: Physicochemical and Engineering Aspects 299(1-3) 262-267 2007年5月  査読有り
    The theological properties of suspensions of sphere and whisker particles were measured under oscillatory shear on the application of electric fields. Because the suspensions are converted from viscous fluids to plastic bodies with high yield stresses, the complex shear modulus is markedly increased in electric fields. When the stress amplitude is increased beyond the yield stress, the complex shear modulus shows a drastic reduction due to the structural rupture. However, the complex shear modulus of whisker suspensions electrified during oscillatory shear is increased to a great extent, under the conditions where the stress amplitude exceeds the yield value attained by electrification in a quiescent state. The development of yield stress is attributed to the chain structures of particles in direction parallel to the field vector. In actual ER suspensions, the most important factor determining the yield stress is the column structure consisting of aggregations of many chains. The microscopic observation indicates that the particle concentration in aggregated region is increased by external oscillatory motion. The enhancement of ER performance for whisker suspensions electrified under oscillatory shear can be explained by the column thickening induced by oscillatory shear. (c) 2006 Elsevier B.V. All rights reserved.
  • 上林 将史, 小倉 裕直, 大坪 泰文
    日本レオロジー学会誌 35(1) 27-34 2007年2月15日  査読有り
    1本の高分子鎖がいくつかの粒子表面に吸着して分散系を凝集させる現象を架橋凝集という。通常の条件では粒子表面に対する高分子吸着が不可逆であるため、凝集形成も不可逆となり、高度に凝集した分散系は固体的応答を示す。一方、ナノ粒子表面に対しては架橋が可逆的に起こるようになるため、分散系は液体として振る舞う。さらにある条件下でのナノ粒子分散系において、ダイラタント流動の発現と架橋構造の可逆的な形成破壊が観測された。本講演では架橋形成の可逆性と分散系のレオロジー的性質との関係について考察する。
  • Ogura Hironao, Haguro Masahiro, Shibata Yasuhiro, Otsubo Yasufumi
    JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 40(13) 1252-1256 2007年  査読有り筆頭著者責任著者
    We had proposed chemical heat pumps using a reversible calcium sulphate/water reaction system for effective waste energy utilization. However, more reaction kinetics studies are necessary for this reaction system, especially for different atmosphere condition and different materials. As a result, the reaction equilibrium line of CaSO4 in the closed system like CHP system was found to be close to that in the open system. It means that the CHP using CaSO4/CaSO4·1/2H2O reversible reaction stores under 373 K level thermal energy, and releases the same level hot heat and 273 K level cold heat. Furthermore, the effects of material size on the reaction rates could be calculated by the proposed equations, which enable the effective CHP reactor design.
  • 小倉 裕直, 岡野 聡史
    都市計画. 別冊, 都市計画論文集 = City planning review. Special issue, Papers on city planning 41(3) 821-826 2006年10月25日  査読有り筆頭著者責任著者
  • アブリズ ショクライティ, 小倉 裕直, 鹿毛 浩之
    化学工学論文集 31(4) 253-258 2005年7月20日  査読有り
    Ca/Ca(OH)2可逆反応系の水和反応を常圧開放系と減圧密閉系内において検討し,前報で報告した減圧半密閉系での水和反応の結果と比較した.<br>等温度下において常圧開放系の反応可能な圧力は減圧半密閉系の反応可能な圧力より水和反応では高くなり,脱水反応では低くなった.減圧密閉系の各温度における水和反応の最終到達反応率は常圧開放系および減圧半密閉系に比べて低くなった.減圧半密閉系における反応後の酸化カルシウムの比表面積は減圧密閉系に比べ約1.2倍となった.減圧半密閉系に対して先に提出したモデルを常圧開放系および減圧半密閉系にも適用することを試みた結果,十分に適用できることが明らかになった.
  • OGURA Hironao, YAMAMOTO Tstsuya, OTSUBO Yasufumi, ISHIDA Hiroki, KAGE Hiroyuki, MUJUMDAR Arun S
    Drying Technology 23(6) 1189-1203 2005年  査読有り筆頭著者責任著者
  • Abliz Shokrat, Fujioka Osamu, Ogura Hironao, KAGE Hiroyuki
    Journal of chemical engineering of Japan 37(7) 815-821 2004年7月1日  査読有り
    From the viewpoints of energy and environmental problems in the world, development of chemical heat pump technology and its practical uses are required. A chemical heat pump using a reversible calcium oxide/water reaction system has been proposed to promote thermal energy utilization. In this report three CaCO3 materials, namely, lime, scallop and coral powder, were examined on the reactivity of the hydration/dehydration of CaO/Ca(OH)2 and the possibility of scallop and coral as the alternates of limestone was discussed.<BR>CaO particles used as a reactant were prepared by the calcination of the three CaCO3 materials. The difference of the CaCO3 resource in the hydration and the dehydration reactivity of the CaO/Ca(OH)2 system was studied by the use of a closed system reactor with forced convection.<BR>The compositions of the lime, coral and scallop powder were almost the same, while hydration conversions of the three materials were different from each other. Especially the reactivity of the scallop powder was considerably low in comparison with the other two materials. However, the difference among these hydration conversions disappeared by the repetition of hydration/dehydration reactions. The hydration conversions of three materials prepared by the repetition of reactions agreed well with one calculated by a model proposed by the authors. CaO made from the scallop with reaction repetition has almost as high a reaction capacity as CaO made by calcination of lime and coral.
  • OGURA H, YAMAMOTO T, KAGE H
    Energy 28(14) 1479-1493 2003年11月  査読有り筆頭著者責任著者
  • 村木 美貴, 小倉 裕直
    都市計画. 別冊, 都市計画論文集 = City planning review. Special issue, Papers on city planning 38(3) 331-336 2003年10月25日  査読有り最終著者
  • 藤本 真司, 小倉 裕直, 岩元 博嗣, 阿部 学, 鹿毛 浩之, 松野 儀三, 馬場 誠一郎, 牟田 信次
    化学工学論文集 29(1) 20-26 2003年1月20日  査読有り責任著者
    余剰電力の有効利用システムの一つとして提案された深夜電力蓄熱-冷・温熱回収型酸化カルシウム/水反応系ケミカルヒートポンプ改良型試作機において,その最適蓄・放熱運転条件の検討を行った.<br>その結果,本試作機において以下のことがわかった.1)蓄熱実験では,凝縮器内の凝縮性能の向上により蓄熱性能の向上が期待される.2)多段トレー方式の充填層では,トレー間に隙間が生じるため反応材の充填密度は小さくなるが,放熱実験では水蒸気の物質移動が向上して反応性が大幅に増大する.最高745MJ/m3の温熱が生成された.3)放熱実験において,熱回収量は十分ではなく熱交換器等の改良の必要性が示唆された.しかしながら,353K以上の温水と278Kレベルの冷水が回収でき,給湯器および空調用冷熱生成器として十分利用可能な機器であることが確認された.
  • H Ogura, H Ishida, H Kage, AS Mujumdar
    DRYING TECHNOLOGY 21(2) 279-292 2003年  査読有り筆頭著者責任著者
    In earlier studies we have shown by simulation and experimental studies that the proposed chemical heat pump (CHP) unit can be used to recover waste heat from dryers and reuse it by storing and releasing heat with upgrading the temperature or by dehumidification. However, the final thermal energy production efficiency of the CHP for drying was found to be low. In this paper we present experimental results to demonstrate the potential for improved heat-recovery/ storage and the heat-release/production of hot dry air for batch drying applications using the heat enhancement mode of the CHP. A new laboratory scale experimental CHP dryer system was built utilizing the calcium oxide/calcium hydroxide hydration/dehydration reversible reaction. The aim of this study is to improve the efficiencies of the heat recovery from heat source in the heat-storage step and the hot dry air production in the heat-release step of the CHP for heating up the air to around 100 degreesC. The results of this experimental study utilizing a new reactor design showed that the shallow reactor/heat exchanger could accomplish 94% chemical heat storage and produce 100 degreesC air at better than 75% efficiency for the reaction heat by controlling the preheating condition. The reaction conversion reached 90% in these experiments. The proposed CHP-assisted convective dryer system is found to be energy-efficient over a wide temperature range of industrial interest.
  • KAGE HIROYUKI, KAWAHARA HIDEAKI, HAMADA NAOMICHI, KOTAKE TSUTOMU, OE NOBUHIRO, OGURA HIRONAO
    Advanced powder technology : the international journal of the Society of Powder Technology, Japan 13(4) 377-394 2002年10月1日  査読有り最終著者
  • Zhou Tao, Kage Hiroyuki, Funaoka Shunpei, OGURA Hironao
    Journal of chemical engineering of Japan 35(8) 737-743 2002年8月1日  査読有り最終著者
    The bubble sizes and distribution were measured in a horizontally two-dimensional vibro-fluidized bed. Glass bead of group B particles was fluidized at varying gas velocities, while the bed was vibrated at different frequencies and amplitudes to study the effect on the bubble behavior. Experimental results show that the local average bubble sizes under the vibration field are generally smaller than those without vibration. The local average bubble sizes are hardly affected with the change of vibration frequency, but increase with an increase in the vibration amplitude. Few bubbles were observed in the both side-well of a bed in the experiment at a gas velocity of 0.0907 m/s. Due to horizontal vibration, bubbles were too small to measure the bubble size in the lower area (H < 50 mm). The ratio of the maximum diameter to the minimum diameter of a bubble is not correlated well with vibration, superficial gas velocity and bed height.
  • アブリズ ショクライティ, 小倉 裕直, 鹿毛 浩之, 松野 儀三
    化学工学論文集 28(3) 345-349 2002年5月20日  査読有り責任著者
    未だに解明されていない密閉系化学蓄熱システムで実際に起こっている反応の解析を目的として,試作した密閉系実験装置を用いてCaO/Ca(OH)2可逆化学反応系に対する減圧強制対流下での化学速度論的検討を行った.試料粒径53μm以下,反応温度503~550K,水蒸気圧1.0~2.3kPaの範囲において,熱天秤による重量変化に基づいて水和反応の反応速度を測定した.熱重量分析法によって得られた減圧強制対流下での実験結果は,著者らが提出した容積反応モデルを適用することにより矛盾無く説明できた.このモデルは,以下の2つの仮定に基づいて導出された.1.CaOの水和反応は可逆反応であり最終反応率は平衡反応率となる.2.平衡反応率は反応温度と水蒸気圧に大きくに依存し反応速度に反映される.モデルと実験結果の比較から,反応は固体濃度および反応気体のいずれに関しても1次反応であることが確認された.反応速度定数は533Kを境に異なることが明らかになった.さらに以上の検討から,反応器内を減圧することで反応温度域の拡大が可能となることが示された.
  • ZHOU TAO, KAGE HIROYUKI, FUNAOKA SHUNPEI, OGURA HIRONAO, MATSUNO YOSHIZO
    Advanced powder technology : the international journal of the Society of Powder Technology, Japan 12(4) 559-575 2001年10月1日  査読有り
  • OGURA Hironao, ISHIDA Hiroki, KAGE Hiroyuki, MUJUMDAR Arun S.
    Thermal science and engineering 9(4) 19-20 2001年7月1日  査読有り筆頭著者責任著者
  • Kage Hiroyuki, Nishihara Keiichi, Ishimatsu Hiromichi, Ogura Hironao, Matsuno Yoshizo
    Drying Technology 19(2) 359-373 2001年2月  査読有り
    Glass beads of 43 m were coated in a vibro-fluidized bed by atomizing a fine silica powder together with polyvinyl alcohol aqueous solution. The coating efficiency and weight fraction of the agglomerated particles were measured under various experimental conditions, and their dependencies on the frequency and the direction of vibration were investigated. The coating efficiency and the degree of the agglomeration among core particles correlated well with an index R. The index R was introduced to evaluate quantitatively the drying conditions in a fluidized bed. Application of vertical vibration on the fluidized bed lowered the coating efficiency somewhat, while it prevented agglomeration. From the experimental results it was confirmed that coating with high quality and high efficiency, where few agglomerates were produced and silica powder was utilized efficiently, was possible in a vibro-fluidized bed with adequate vibration frequency and orientation of the vibration vector.
  • KAGE HIROYUKI, AGARI MICHIYO, OGURA HIRONAO, MATSUNO YOSHIZO
    Advanced powder technology : the international journal of the Society of Powder Technology, Japan 11(4) 459-475 2000年10月1日  査読有り
  • Kage Hiroyuki, Kawaji Koichi, Ogura Hironao, MATSUNO Oshizo
    Journal of chemical engineering of Japan 33(4) 605-611 2000年8月  査読有り
    Attrition experiments with granular slugs were performed in a fluidized bed. A single horizontal nozzle was equipped on the sidewall of the fluidized bed in order to distinguish the effect of jet gas flow on attrition from the auxiliary fluidizing gas supplied from the distributor. The analysis was mainly focussed on the change in the granular slug weight. Reduction of particle size was mainly due to the attrition of its surface or irregularities, and breakage into two or more small particles was not observed.<br>A new attrition model, where the generation rate of fines is assumed to be in proportion to the weight of particle, and the effect of fluidizing gas supplied from the distributor on the attrition was assumed to be neglected, is proposed. The measured attrition data were correlated well by this model, and its reliability was examined. The coefficient K included in the proposed model, which is concerned with energy transfer to attrition, is almost independent of the initial weight of particles, and increases with jet flow rate.
  • 鹿毛 浩之, 小川 秀和, 桑本 孝哉, 重弘 拓也, 小倉 裕直, 松野 儀三
    粉体工学会誌 37(3) 168-175 2000年  
    In our previous investigation on the elutriation from a gas-solid fluidized bed, we found a very interesting phenomenon that the ratio of elutriation rate to particle concentration in the bed gradually decreased with the increase in particle concentration. A new model, which accounts for the obstructive effect on elutriation due to collisions between particles ascending in the core and those descending in the annulus at the boundary of these two regions, is proposed in order to explain this obstructive effect and the interaction between particle behavior in the freeboard and the particle elutriation. Particle velocity and concentration profiles in the freeboard are measured by optical fiber probes, as well as the elutriation rate at the top of fluidized bed. These experimental results are successfully explained by the proposed model.
  • H Ogura, AS Mujumdar
    DRYING TECHNOLOGY 18(4-5) 1033-1053 2000年  査読有り筆頭著者責任著者
    A new chemical heat pump (CHP) system for ecofriendly effective utilization of thermal energy in drying is proposed from the viewpoints of energy saving and environmental impact. CHPs can store thermal energy in the form of chemical energy by an endothermic reaction and release it at various temperature levels for heat demands by exo/endothermic reactions. CHPs have potential for heat recovery and dehumidification in the drying process by heat storage and high/low temperature heat release. In this study, we estimate the potential of the CHP application to drying systems for industrial use. Some combined systems of CHPs and dryers are proposed as chemical heat pump dryers (CHPD). The potential for commercialization of CHPDs is discussed.
  • KAGE HIROYUKI, OBA MOTOHISA, ISHIMATSU HIROMICHI, OGURA HIRONAO, MATSUNO YOSHIZO
    Advanced powder technology : the international journal of the Society of Powder Technology, Japan 10(1) 77-87 1999年1月1日  査読有り
  • 小倉 裕直, 藤本 真司, 岩本 博嗣, 鹿毛 浩之, 松野 儀三, 金丸 靖, 灘 秀利, 粟谷 茂
    化学工学論文集 24(6) 856-861 1998年11月10日  査読有り筆頭著者責任著者
    電力の有効利用に関する新たな技術として, 深夜電力を化学蓄熱により蓄え, 昼間に冷・温熱を同時生成してこれを空調用冷房熱源および給湯用熱として回収するCaO/H2O/Ca(OH)2系ケミカルビートポンプ応用装置を開発した.本報では, 本試作機の基本作動特性に加えて, 反応材充填量ならびに熱回収条件の作動特性への影響について検討を行った.<BR>その結果, 1) 本試作機において, 1.86MJ/kg-CaOの密度で化学蓄熱された電力が, 放熱時には273Kレベルの冷熱ならびに500Kレベルの温熱が生成され, 278Kレベルの冷房空調用出力ならびに350Kレベルの給湯として熱回収されることが確認された.2) 反応材が少なく充填層高が小さくなるほど放熱は促進されるが, 反応材の総合充填量は熱ロス等とのバランスにより決定される必要性が認められた.3) 放熱時には, 熱回収速度の調整により反応材の活性を高め回収量の増大が可能なことがわかった.
  • KAGE HIROYUKI, TAKAHASHI TORU, YOSHIDA TAKAYUKI, OGURA HIRONAO, MATSUNO YOSHIZO
    Advanced powder technology : the international journal of the Society of Powder Technology, Japan 9(3) 245-259 1998年7月1日  査読有り
  • 鹿毛 浩之, 高橋 達, 吉田 孝之, 小倉 裕直, 松野 儀三
    粉体工学会誌 35(1) 4-11 1998年  査読有り
    Glass beads were coated in a fluidized bed by atomizing the suspension of nylon or silica fine powder. Polyvinyl alcohol (PVA) was used as a binder. The influences of the weight ratio of fine powder to binder in the suspension and index R, which quantitatively evaluates the drying condition in a fluidized bed on the coating efficiency, on the agglomeration among the core particles and on the coated layer surface were investigated. When the index R became high and the weight ratio of powder to binder decreased, the core particles easily agglomerated. Once agglomeration occurred, both the coating efficiency and the circularity, which evaluates the smoothness of coated surface, became worse. Furthermore, the addition of the surfactant in the suspension made the circularity high and inhibited the agglomeration. In contrast, the hydrophobic surface of the core material made the coating efficiency at the early coating stage and circularity low, and it encouraged the agglomeration.
  • 鹿毛 浩之, 河原 英昭, 小倉 裕直, 松野 儀三
    化学工学論文集 23(5) 652-658 1997年9月10日  査読有り
    安定で粒子径が良く揃ったケロシン液滴をモデル粒子として芯物質に用い, ゼラチン-アラビアゴム系の複合コアセルベーション法によってマイクロカプセルを製作し, カプセル化時の操作諸条件が生成カプセルの膜厚に及ぼす影響を検討した.本報では, 細孔径の揃った多孔質ガラス膜を用いた膜乳化法によって安定で滴径が揃ったケロシン液滴を調整し, これを芯物質とすることにより, 液芯カプセルに一般的に見られる一次乳化時の複雑な影響を排除し, 二次乳化時の操作条件の生成カプセルへの影響のみを取り出して検討することに成功した.<BR>膜乳化法によって得られたエマルションの滴径分布および安定性が検討され, さらに系統立ったカプセル化実験の結果から, 界面活性剤濃度および撹拌速度によって生成カプセルの形状が敏感に影響を受けること, 芯物質量の増加によってカプセルの多核化が進行することなどが明らかとなった.
  • 鹿毛 浩之, 河原 英昭, 小倉 裕直, 松野 儀三
    化学工学論文集 23(5) 659-665 1997年9月10日  査読有り
    マイクロポーラスグラスを用いた膜乳化法によって滴径が良く揃って安定なケロシンエマルションを調整し, このケロシン液滴を芯物質としてゼラチン-アラビアゴム系複合コアセルベーション法によってマイクロカプセルの製作を行った.カプセル化過程での酢酸添加量, 冷却速度, 芯物質添加時期, 更にカプセル被膜硬化過程での水酸化ナトリウム添加量, ホルマリン添加量, 昇温速度の各操作条件が生成マイクロカプセルの膜厚やカプセル内に含有される核数に与える影響を検討した結果, 冷却過程における30から20℃迄の温度領域がカプセル化において極めて重要であること, 低酢酸添加量と低冷却速度が生成カプセルの多核化を防止すること, 硬化過程での操作条件は膜厚, 含有核数のいずれにも大きな影響を与えないことが明らかとなった.さらに, これらの結果は芯物質が固体の場合のカプセル化のデータと比較検討された.
  • 小倉 裕直, 藤本 真司, 佐藤 将, 鹿毛 浩之, 松野 儀三
    化学工学論文集 23(3) 397-403 1997年5月10日  査読有り筆頭著者責任著者
    CaO/H2O/Ca(OH)2反応系ケミカルヒートポンプにおける冷凍モードでの性能向上を目的として, ガラス製冷熱生成ケミカルヒートポンプ装置を試作し, 装置工学的な観点から実験的検討を行なった.特に, 反応器内の熱・物質移動状態に着目して, 装置形状および作動温度条件の冷熱生成特性への影響の検討を行なった.<BR>その結果, 1) 多段反応粒子トレーと反応器内側壁とのすき間が約2.5倍に拡大されて粒子層間距離と等しくなることにより, 水蒸気が反応器全体により均一に供給されて冷熱生成速度および生成冷熱量が増加することがわかった.2) 装置を横型から縦型にして水蒸気流入口を反応器上部から下部へ変更することにより, 反応器内への水蒸気流入状態が向上し, 特に初期反応が促進されることが確認された.3) 反応器側熱交換媒体温度の違いにより粒子の平衡圧力および反応活性が変化し, これらのバランスが生成冷熱温度および冷熱生成速度に大きく影響することがわかった.
  • 鹿毛 浩之, 矢田 直樹, 国正 真佐江, 小倉 裕直, 松野 儀三
    化学工学論文集 22(2) 342-349 1996年3月10日  査読有り
    芯物質に粒子径が揃い表面の疎水化処理が可能なガラスビーズをモデル粒子として用い, ゼラチン-アラビアゴム系の複合コアセルベーション法によってマイクロカプセルを製作し, カプセル化時の操作諸条件が生成カプセルの膜厚に及ぼす影響を検討した.本報ではコアセルベーション法の特徴を生かし粒子径の揃った固体芯物質を利用することにより, 一次乳化の影響を排除し, 二次乳化に当たる機構のみを取り出して検討することに成功した.系統立ったカプセル化実験の結果から, 酢酸添加量の増加によってより厚いカプセル膜が得られるが, 多量の添加では膜硬化時の pH を下げるため, 逆にカプセルの生成を阻害すること, 芯物質表面の疎水化はカプセル化に必要な酢酸添加量の減少をもたらすこと, 共存塩の添加はカプセル膜を薄くするが, 極少量の添加では逆に厚くする効果のあることが明らかとなった.

MISC

 4

書籍等出版物

 2
  • 小倉裕直, 小林敬幸 (担当:分担執筆, 範囲:5.3化学蓄熱・ヒートポンプシステムの高性能化)
    日本工業出版・日本冷凍空調学会 2023年3月 (ISBN: 9784819035057)
  • 技術情報協会 (担当:共著, 範囲:第8章第2節 ケミカルヒートポンプを利用した廃熱回収システムの開発)
    技術情報協会 2020年12月 (ISBN: 9784861048197)

講演・口頭発表等

 36

共同研究・競争的資金等の研究課題

 10