• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.4 s.235
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• pp.469-476
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• 2005

Numerical modeling has been carried out to investigate the two-dimensional air flow in automobile interior with a forced exhaust close to main air inlet for typical ventilation modes. The characteristics such as streamlines and temperature fields in the passenger compartment room with the forced exhaust are analyzed with comparison of the cases without a forced exhaust. The simulation results show that air flow on the floor near the front seat is increased with the forced exhaust for all ventilation modes. Flow recirculation in the cabin is most active in mode 2 with a vertical suction inlet in comparison with other two modes. In particular, less time is taken for air temperature to reach the inlet temperature due to the forced exhaust for the ventilation modes. Finally, it could be predicted that ventilating air flow is much improved with the forced exhaust in the interior Modeling results in this study can be applied to the optimal design of automobile interior fur air ventilation system.

• Journal of Drive and Control
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• v.10 no.2
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• pp.23-29
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• 2013

The excavator is used in a variety of construction environments. There are many kinds of risk like falling rocks or harmful dust. The excavator cabin protects the operator not only from these harmful environments but also provides a comfortable working environment. By the way, the excavator cabin consumes a lot of energy for cabin air conditioner. For this reason, the research is required to reduce energy consumption. This study suggests the air conditioning system for excavator using forced exhaust. First, the forced exhaust system simulated by AMESim tool and surveyed the applicability. Using AMESim simulation, it was investigated the effect of cabin inside temperature by intake flow rate and intake air temperature. The experiment executed using the 1.5 ton excavator and field tested according to the intake flow rate. Finally, verified the applicability on the air conditioning system for excavator using forced exhaust.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.889-894
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• 2008

Exhaust system used in toilet and cooking place of high riser public house is roof fan of two basic types : natural roof ventilator and natural/forced roof ventilator. Natural/forced roof ventilator has a motor in the rotary shaft. There are many high riser public house in Korea. These buildings were not viewed as being major contributors to exhaust pollutants producted in indoor. It was because many engineers thought that exhaust in high riser building depend on stack effect. This study investigates on stack pressure determined by exterior pressure and the difference pressure control in exhaust stack used in high riser public house. This paper focuses mainly on the effect of the time interval for power supply of motor installed in roof fan with function of natural wind velocity and of exhaust air volume of toilet. It is observed there are higher exhaust efficiency than the existing natural roof ventilator.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.3
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• pp.60-67
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• 2014

Exhaust system used in toilet and cooking place of high riser public house is roof fan of two basic types : natural roof ventilator and natural/forced roof ventilator. Natural/forced roof ventilator has a motor in the rotary shaft. There are many high riser public house in Korea. These buildings were not viewed as being major contributors to exhaust pollutants producted in indoor. It was because many engineers thought that exhaust in high riser building depend on stack effect. This study investigates on stack pressure determined by exterior pressure and the difference pressure control in exhaust stack used in high riser public house. This paper focuses mainly on the effect of the time interval for power supply of motor installed in roof fan with function of natural wind velocity and of exhaust air volume of toilet. It is observed there are higher exhaust efficiency than the existing natural roof ventilator.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.6
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• pp.845-856
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• 2017

In the long railway tunnel, in order to secure safety in case of fire, it is required a emergency station. However, there is no standard or research results on smoke exhaust method and exhaust flow rate in emergency station, so it is necessary to study the smoke exhaust system for emergency station. In this study, we are created a numerical analysis model for emergency station where the evacuation cross passage connected to the service tunnel or the relative tunnel was installed at regular intervals (40 m intervals). And the fire analysis are carried out by varying the fire intensity (15, 30MW), the smoke exhaust method (only air supply, forced air supply and exhaust, forced air exhaust only), and the air flow rate (7, 14, $40m^3/s$). From the results of fire analysis, temperature and CO concentration are analyzed and ASET based on the limit temperature are compared at various condition. As a result, in the case with fire intensity of 15 MW, it is shown that a sufficiently safe evacuation environment can be ensured by applying forced air supply and exhaust method or forced air exhaust only method when the air flow rate is $7m^3/s$ above. In case of fire intensity of 30 MW, it is impossible to maintain the safety evacuation environment for more than 900 seconds when the exhaust air volume is below $14m^3/s$. And when the air flow rate is $40m^3/s$, the exhaust port is disposed at the side portion of the upper duct, which is most advantageous for securing the temperature-based safety.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1998-2004
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• 2003

Numerical study were performed to analyze for fire safety in railway tunnel with forced ventilation vents. For the condition of train fires with heat release rate of 30 MW, unsteady three dimensional analysis were carried out to investigate the effects of smoke movements, the heat transfer and $CO_2$ concentrations and in double track tunnel with two vents. Among three operation modes of forced ventilations at two vents, the exhaust-exhaust mode of the vent represents the best performance for the evacuation of passengers to avoid the fire.

• Journal of Biosystems Engineering
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• v.35 no.6
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• pp.393-400
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• 2010

Uniform and rapid pre-drying of mandarin is important to improve the storage quality. The aim of this study was to suggest the basic design of forced ventilated pre-drying facility for mandarin by thermal flow analysis using computational fluid dynamics software (FLUENT 6.2). Developed CFD simulation model was verified by comparison with experimental data. Airflows and temperature distributions in the five conceptional designs including existing ordinary temperature storage rooms were analyzed and appropriate basic design was determined. Analysis of the effect of arrangement of windows and exhaust fans on thermal flow in facility was carried out for more detailed design. The results of this investigation showed that the predicted airflow velocity by CFD simulation showed a good agreement with the measured value and optimum design condition for simulated forced ventilated pre-drying facility of mandarin has two exhaust fans and two windows on both sidewalls and cover on loaded mandarin.

• Safety and Health at Work
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• v.10 no.1
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• pp.47-53
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• 2019

Background: Despite growing concern over occupational exposure to particulate matter (PM) such as grain dust and diesel exhaust, information about the exposure level and health implications among workers in small-scale milling enterprises in developing countries like Nigeria has not been adequately documented. The purpose of this study was to assess the level of exposure to grain dust and diesel exhaust and effect on lung function among grain millers in food markets in Ibadan metropolis, Nigeria. Methods: The study adopted descriptive cross-sectional design with a comparative approach. Sixteen grain milling shops each were randomly selected from two major food markets in Ibadan metropolis for indoor $PM_{10}$ and $PM_{2.5}$ monitoring. Seventy-two respondents each were proportionately selected from grain millers and shop owners for forced expiratory volume in one second and peak expiratory flow rate tests. Results: The $PM_{2.5}$ concentrations for both market locations ranged between 1,269.3 and $651.7{\mu}g/m^3$, while $PM_{10}$ concentrations were between 1,048.2 and $818.1{\mu}g/m^3$. The recorded concentrations exceeded the World Health Organization guideline limit of $50{\mu}g/m^3$ and $25{\mu}g/m^3$ for $PM_{2.5}$ and $PM_{10}$, respectively. As compared with control group (2.1 L), significantly lower forced expiratory volume in one second value (1.61 L) was observed among the exposed group (p < 0.05). Likewise, significantly lower peak expiratory flow rate value (186.7 L/min) was recorded among the exposed group than the control group (269.51 L/min) (p < 0.05). Conclusion: Exposure to grain dust and diesel exhaust accentuated respiratory disorders with declines in lung functions amongst grain millers. Improved milling practices and engaging cleaner milling facilities should be adopted to minimize exposure and related hazards.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.1
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• pp.120-130
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• 1993

In the analysis of automobile exhaust system, the exciting forces from the engine determine the dynamic behavior of the system and the dynamic characteristics influence the riding quality. Therefore, the identification of the force in numeric value is quite important for the vibrational reduction. However, the value is difficult to obtain by experiments due to harsh conditions around the engine. In this research, an optimization technology is adopted to evaluate the exciting forces. An experimental method is conducted for the verification of the finite element modeling. Displacements on the end of the exhaust system are measured under the idling environment. cost function is set up to minimize the differences between the displacements of the numerical simulation and the experiment. Design variables are the components of the exciting forces. That is, optimization is utilized to estimate the forces with existing data. Excellent estimations have been calculated efficiently and the information is used again for the forced vibration of the exhaust system.

• KIEAE Journal
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• v.10 no.2
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• pp.57-62
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• 2010

In case of earth-covered storage, the condensation occurs on surface of wall and stores in summer with high humidity because of low temperature of constructional mass. Therefore, the preventive plans should be considered to protect stores from the damage by corrosion in earth-covered storages. This study aims to suggest the methods of forced ventilation by the air, to solve the problems of construction's surface condensation at the Magazine of igloo type which is similar to earth-covered storages. A fan was installed at the air outlet for exhaust gas to conduct forced ventilation. The surface and indoor temperature were measured, and then the influence of those on condensation was analyzed. The results of this research are follows; 1) Forced ventilation by a fan affects the rise in surface temperature of walls and stores. 2) The condensation on surface of walls and stores was reduced after operating a fan.