Refine your search:     
Report No.
 - 
Search Results: Records 1-6 displayed on this page of 6
  • 1

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

JAEA Reports

A Study for a fire gas behavior by using a vertical shaft model (Contract research)

Abe, Hironobu; Hatakeyama, Nobuya; Yamazaki, Masanao; Okuzono, Akihiko*; Sakai, Tetsuo*; Inoue, Masahiro*

JAEA-Research 2009-019, 192 Pages, 2020/02

JAEA-Research-2009-019.pdf:8.07MB

Construction of the underground facility is on going at the Horonobe Underground Research Center, a division of the Japan Atomic Energy Agency. The facility is consisted of three shafts and horizontal drifts at the completion of construction and it is excavated in geological environment with methane gas, so it is important to secure the workers and visitors security in case of fire in the underground. However, it is known that the fire gas such as methane shows a complicated behavior by drift effect and so on and very difficult to predict its behavior, even if under enforced ventilation. In order to construct new prediction method of the fire gas behavior, the model scaled experiments were conducted by using the basic model which consists of shafts and drifts. As a results, fundamental data of the fire gas behavior was grasped and complicated behavior of the fire gas such as three-dimensional backflow and main flow inversion phenomena at the underground structure were ascertained. A new fire gas behavior analysis system has been designed and a prototype system has been programmed which is able to simulate the phenomena noted above. Coupling analysis method is adapted to the system, which consists of mainly one-dimensional ventilation network analysis and simplified computational fluid dynamics program named M-CFD. To minimize calculation time, M-CFD was designed as two-dimensional calculation with simulators multi area analysis system. Using the prototype system, several experimented models representing typical behavior of fire gas have been simulated for model scaled experiments. The system qualitatively reappeared the phenomena such as back flow or main flow inversion, and most of calculations completed in expected time. This indicates appropriateness of the prototype system, but some upgrade such as heat conductivity analysis in the wall rock mass transfer calculation, user friendly interface system and others will be required.

JAEA Reports

Report of Horonobe technical review meetings (FY 2004); 1st to 4th meetings (Document on present state of affairs)

Shirato, Nobuaki*; Matsui, Hiroya; Morioka, Hiroshi; Hatanaka, Koichiro; Takeuchi, Ryuji; Hatakeyama, Nobuya; Ohara, Hidefumi; Nakajima, Takahiro; Kunitomo, Takahiro

JNC TN5440 2005-001, 412 Pages, 2005/06

JNC-TN5440-2005-001.pdf:20.87MB

We held Horonobe technical review meeting 4 times a year. The first meeting is for the plan of Horonobe underground research laboratory and others. The secound meeting is for geology of Horonobe area and modeling study and data acquisition for safety assessment methodology and others. The third meeting is for ventilation network analyses on URL plan. The fourth meeting is for the remote monitoring system using ACROSS. This report is records of these meetings.

Oral presentation

Estimation of methane gas emission for Horonobe URL project, 2

Sakai, Tetsuo*; Hatakeyama, Nobuya; Fuse, Masato*; Narita, Minoru*

no journal, , 

no abstracts in English

Oral presentation

Experimental research into the behavior of ventilation air around shafts during a fire

Inoue, Masahiro*; Hidaka, Yuki*; Yamakami, Mitsunori; Hatakeyama, Nobuya; Okuzono, Akihiko*; Sakai, Tetsuo*

no journal, , 

A series of experimental study using a scaled model concerning the behavior of ventilation air during a mine fire was carried out. The model consists of two vertical shafts, three horizontal ducts and a exhaust fan. The cross section of the shaft and duct is 0.2m square. The height of the shafts is 3.4m. The length of the ducts is 1.5m. The airflow rate can be adjusted by regulators installed in each duct. The behavior of the fire gas was measured by anemometer, thermometer, and visualized image using laser light. Some amount of fire gas of high temperature rose upward gradually along the shaft wall regardless of the downward ventilation. Then the direction of main ventilation air suddenly reversed upward in the shaft. The direction of ventilation reversed in many places in the model and the fire gas reached even the part not anticipated. It was also found that the direction of ventilation in the shaft reversed upward entirely when the initial velocity of the airflow was small.

Oral presentation

Study on the diffusion of fire gas in deep subsurface structure

Inoue, Masahiro*; Hidaka, Yuki*; Nakaba, Nozomi*; Yamakami, Mitsunori; Hatakeyama, Nobuya; Okuzono, Akihiko*; Sakai, Tetsuo*

no journal, , 

A fire in a deep underground structure has a potential threat that it may result in a big disaster because the ventilation system is fully disturbed and the fire gas spread to unanticipated places by the effect of buoyancy of the fire gas. The result of the study using scaled model experiment and computer simulation on the fire gas movement is described in the report.

Oral presentation

Experiments and the computer simulation of the behavior of ventilation air around shafts during a mine fire

Inoue, Masahiro*; Nakaba, Nozomi*; Yamanishi, Takeshi; Yamakami, Masanori*; Hatakeyama, Nobuya; Yamazaki, Masanao; Sakai, Tetsuo*; Okuzono, Akihiko*

no journal, , 

The fire gas generated by a mine fire changes ventilation system by the buoyancy and the throttling effect, the adverse airflow along the roadway ceiling. As the result, the fire gas can reach upwind areas where was thought that the fire gas will never reach. These phenomena are remarkable around shafts which have large altitude differences. In order to prevent the accidents, it is important to make an accurate prediction of the behavior of ventilation air during a mine fire and the effective control of the ventilation air. However, this behavior has not been studied well so far. For this reason, the authors studied this behavior using a scaled model experiments and ascertained the major change of ventilation air. Then the effect of ventilation air control was studied. Following the results, a computer program to simulate the behavior of the fire gas by CFD method. It was confirmed that the program shows sufficient accuracy within the practical calculation time.

6 (Records 1-6 displayed on this page)
  • 1