• Journal of Industrial Technology
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• v.26 no.A
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• pp.3-15
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• 2006

To determine the optimum ventilation systems during long tunnel excavation, the velocity vector profile and the contaminant's distribution at working place are studied using 2-D, 3-D numerical analysis. The main results can be summarized as follow; In case of long tunnels, blower-exhaust-mixture types which enable to use soft blast ducts is most appropriate in terms of ventilation and economical efficiency. Of the same ventilation types, ventilation efficiency has a difference according to blast ducts and the distance between fan and working place. The 3-D numerical result shows that arranging blower and exhaust ducts in the right and left corners of the tunnel respectively is effective to discharge contaminant. The result of the real measurement shows that CO concentration can be reduced to below 50 ppm, which is regulation value, as 16-minutes fan operation goes on.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.594-599
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• 2007

This study represents numerical analysis on the fluid flow and concentration characteristics by scattering fume at push-pull ventilation system. And the principal point is making optimum on improve an existing ventilation system. This phenomenon simulated about local ventilation system by using commercial CFD tool and base on these fact has find improvements. Advanced model shows most low different pressure and velocity which are suction capability at inlet surface of pull hood has most uniformity. When compared with existing model, Improved model has more good ventilation performance.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.270-275
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• 2007

Pollutants emitted by Diesel trains seriously affected on the ventilation characteristics in the subway or railway tunnel network systems. Thus, numerical prediction results and analyses are required to engineers who should design ventilation facilities. So here, this paper presents some numerical results about the ventilation characteristics, such as pollutants distributions and a suitability of the ventilation facilities pre-designed in case that diesel trains use the same railway track with normal passenger trains

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.119-123
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• 2007

Ventilation performance in the storage hall of Janggyeongpan Jeon has maintained for more than 600 years. Janggyeongpan Jeon in Haein temple has window structure of bi-level ventilating opening which consists of upper and lower window. Also, different size and shape of windows are adopted for various locations of the hall. In the present study, to analyze effect of shape of windows on ventilation performance in the storage hall, various design alternatives were considered. Numerical analysis of ventilation in the storage hall was investigated under the same simulation condition except for the shape of windows. Through the comparison of numerical results for various window designs, it was evaluated that the current windows shape gives best ventilation performance.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.1
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• pp.30-35
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• 2017

This study is about distributions of flow in a ventilation system used in a louver for marine. In this study, to describe the flow in the ventilation opening louver, 3-dimensional steady-state turbulence was assumed to govern the equation. The flow field with pressure distribution according to the inlet velocity at the louver types is also compared. Flow analysis was performed for the louver numerical analysis on two types. The numerical analysis results in the louver blade indicated increased flow resistance at type-1.

• The KSFM Journal of Fluid Machinery
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• v.13 no.4
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• pp.25-30
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• 2010

Flow analysis and performa nce evaluation have been performed for a ventilation axial-flow fan with different positions of the motor. Two different positions of motor have been tested; one is in front of the impeller and the other is behind the impeller. Flow analyses are performed by solving three-dimensional Reynolds-averaged Navier-Stokes equations through a finite-volume solver. Preliminary numerical calculations are carried out to test the performances of different turbulence models, i.e., SST model, k-$\omega$ model, and k-$\varepsilon$ model with and without using empirical wall function in the flow analysis. The validation of numerical analyses has been performed in comparison with the experimental data. The numerical results for the performance characteristics of the ventilation axial-flow fan with two different positions of the motor have been presented.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.3
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• pp.240-249
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• 2009

HRSG(Heat Recovery Steam Generator) building is large enclosed structure included various heat sources. This building needs to appropriately keep internal air temperature for worker's safety and operability of control devices. In this study, ventilation analysis is performed to find proper ventilation method for temperature control. Ventilation analysis is applied to entire internal space of the building with standard $k-{\varepsilon}$ model and enhanced wall treatment because of large size of the structure. And the ventilation method is considered natural and forced convection with two louver structures which has damper or not. Louver structure affect directly air circulation in near HRSG and lower region of the building. Forced ventilation provides strong inertial force which cause upward airflow. From the analysis, it is found that design requirement for internal air temperature can be satisfied by forced ventilation method with louver structure without damper.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.3
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• pp.342-349
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• 2016

Objectives: The objective of this paper is to find flow and heat transfer characteristics numerically in boiler buildings for three different ventilation window configurations. Methods: Turbulent natural convection flow in boiler buildings with a constant heating wall temperature was analyzed numerically. Governing equations were solved with standard finite-volume method using the SIMPLE algorithm. Conclusions: Flow and heat transfer characteristics are found for three different ventilation types. In the lower area under furnace, velocity and temperature distributions show similar patterns among the three different ventilation types. In the upper area over furnace, however, air flow is well mixed with lower peak temperatures for types B and C, which have roof ventilation windows, compared to type A which has side wall louvers only. Also, type B, with a single large roof window, shows better ventilation effect than does type C with its distribution roof windows.

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.207-212
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• 2005

In designing a ventilation system of a road tunnel, a possibility of using the system as a smoke control system in case of a tunnel fire has to be considered. In the present study, a numerical simulation on ventilation system is performed considering jet fan operations and moving traffic. A fire-mode operation by reversing some fan operations in case of a tunnel fire is also simulated. The results show that ventilation operation can control the pollutants effectively, and fire-mode operation can control smoke and temperature effectively to prevent a disaster.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.4 no.4
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• pp.253-262
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• 1992

A numerical procedure is introduced to calculate local ventilation effectiveness using the definitions of local decay rate and local mean age. A low Reynolds number $k-{\varepsilon}$ model is implemented to calculate steady state turbulent velocity distributions, and a step-down method is used to calculate transient concentration distributions. Simulations are carried out for several different values of air change rates and several different diffuser angles in a two-dimensional model of a half scale office room. The results show that the local ventilation effectiveness within a room could vary significantly from one location to another. The nominal air change rate based on the assumption of complete mixing of room air does not provide the local ventilation effectiveness information. It is numerically proved that the local mean age distribution obtained from the transient calculation is equivalent to the steady state concentration distribution with homogeneously distributed contaminant sources.