著者

円山 重直

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集B編 (ISSN:18848346)

巻号頁・発行日

vol.78, no.796, pp.2127-2141, 2012 (Released:2012-12-25)

参考文献数

13

被引用文献数

2 4 1

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An accident scenario of Fukushima Daiichi Nuclear Power Plant, Unit 2 is analyzed from the data open to the public. Phase equilibrium process model was introduced that the vapor and water are at saturation point in the vessels. Proposed accident scenario agrees very well with the data of the plant parameters obtained just after the accident. The estimation describes that the rupture time of the reactor pressure vessel (RPV) was at 22:50 14/3/2011. The estimation shows that the rupture time of the pressure containment vessel (RCP) was at 7:40 15/3/2011. These estimations are different from the ones by TEPCO, however; many measured evidences show good accordance with the present scenario.

著者

円山 重直

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.80, no.820, pp.TEP0377-TEP0377, 2014 (Released:2014-12-25)

参考文献数

30

被引用文献数

1

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In order to investigate the process of accident of Fukushima Nuclear Power Plants, an accident scenario of Fukushima Daiichi Nuclear Power Plant, Unit 1 is analyzed from the data open to the public. Phase equilibrium process model and adiabatic expansion model were introduced. Original data reported in the first stage of the accident were examined to clarify the behavior of the isolation condensers (ICs) which are generally believed unfunctional after the arrival of Tsunami and station blackout. The original data and observation reports verified that the so called “fail safe” system to close the valves in IC did not work properly due to the shutdown of AC power. The reports also showed the evidence that the operators injected water to the storage tank of IC. We proposed a scenario that IC was operational until approximately at 3/12 3:00, small leakage occurred at the reactor pressure vessel (RPV) at the initial stage of the accident, the RPV ruptured at 3/12 6:20, and it ruptured again in approximately at 3/12 16:00. We assumed that PCV ruptured at 3/12 3:00, and the area of rupture did not change after the hydrogen explosion occurred at 3/12 15:36. The present analysis model describes the data measured at the accident, and many evidences and witnesses reported at the early stage of the accident. We also simulated according to the scenario of Tokyo Electric Power Company (TEPCO) that the ICs did not work after the Tsunami arrival. The estimation by the present analysis agrees with the TEPCO's one, however, there are many discrepancies that cannot explain the behavior of the reactor accident.

著者

円山 重直

出版者

一般社団法人 ターボ機械協会

雑誌

ターボ機械 (ISSN:03858839)

巻号頁・発行日

vol.21, no.2, pp.99-105, 1993-02-10 (Released:2011-07-11)

参考文献数

14

被引用文献数

1

著者

アルマハドウリ アディル 江目 宏樹 岡島 淳之介 小宮 敦樹 円山 重直

出版者

一般社団法人日本機械学会

雑誌

年次大会 : Mechanical Engineering Congress, Japan

巻号頁・発行日

vol.2013, pp."G061052-1"-"G061052-5", 2013-09-08

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In the present study, a theoretical non-gray rigorous model was established to study the radiative heat transfer through greenhouse covering materials by using Radiative Element Method by Ray Emission Model (REM2). This model was applied to find the difference in thermal performances between silica glass, polyvinylchloride (PVC) and low density polyethylene (LDPE) covering materials. Using the advantage of the previously predicted spectral radiative properties of these materials, accurate estimations of greenhouse temperatures were achieved. In addition, an outdoor experiment was conducted to measure the thermal performances of three rectangular enclosures covered by the mentioned claddings. Enclosures inside, floor and cover temperatures calculated using the rigorous model showed a satisfactory correlation with the experimental measurements

著者

山田 昇 長谷川 豊 円山 重直

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. B編 (ISSN:03875016)

巻号頁・発行日

vol.74, no.748, pp.2615-2620, 2008-12-25

被引用文献数

1

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This paper describes the numerical simulation results of radiative heat transfer between the human body and an urban street canyon (building walls, pavement, and the sky) in the presence of participating non-gray gas mixtures consist of H_2O and CO_2. The ambient temperature of typical summer condition and the concentration of gas mixtures in summer Tokyo were assumed, and parallel infinite plane model and simple urban street canyon model were used. The results show that the participating gas significantly affects the infrared radiation field in urban street canyon. The radiation flux emitted by the participating gas is approximately 35% of the total incident radiation flux to the human body surface. This causes a homogenization of the infrared radiation field. Gas radiation plays an important role in the heat transfer between human and environment under hot and humid summer condition.

著者

山田 昇 徳原 真弥 円山 重直

出版者

社団法人空気調和・衛生工学会

雑誌

空気調和・衛生工学会論文集 (ISSN:0385275X)

巻号頁・発行日

no.150, pp.9-17, 2009-09-05

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夏期の都市街路空間における熱的快適性の重要な因子であるふく射について,ふく射性ガスによる吸収・放射の影響を考慮した路面-人体スケール物体間のふく射伝熱解析を行った結果を報告する。解析モデルは「路面」,「街路空間中のふく射性ガス」,「人体スケール物体」により構成され,日射を無視した際の人体スケール物体へ入射するふく射熱流束に着目した.ふく射性ガスとして水蒸気および二酸化炭素を考慮し,統計狭域バンドモデルにより単色吸収係数を求め,モンテカルロ法により放射・吸収挙動を非灰色解析した。解析スケール,路面温度,ふく射性ガス濃度および気温をパラメータとする解析によりふく射性ガスが及ぼす影響を明らかにした.ふく射性ガスの影響は解析スケールが大きくなるほど顕著になり,解析スケールが20m以上になると,ふく射性ガスを考慮した場合の解析結果は考慮しない場合よりも120〜160W/m^2ほど人体スケール物体に入射するふく射熱流束が大きくなり,日射を除く全入射ふく射熱流束の約50%をふく射性ガスから受けることが示された.また,路面から人体スケール物体へのふく射はふく射性ガスによって約30%が吸収されることが示された.現在および2100年頃の気温,相対湿度,二酸化炭素濃度を各「35℃,66%,400ppm」「40℃,66%,800ppm」として解析を行った結果,人体スケール物体に入射するふく射熱流束に顕著な差は生じなかった.さらに,水蒸気の影響に比べて二酸化炭素の影響は極めて小さいこと,人体スケール物体の下部が路面からのふく射を強く受けるのに対し,上部はふく射性ガスからのふく射を強く受ける傾向があることが示された.