• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.2
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• pp.304-309
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• 2013

In chemical, medical or biology laboratories Fume Hoods are basic facilities which can protect researchers from dangerous gas as blowing the contaminated air outside. After the air inside the laboratory room is sucked into the hume hood, then, it is blew out by a fan rotated by an AC induction motor. In addition, a damper controls the inside opening of a duct, which the air flows through. The face velocity, air velocity through the front door, have to be kept constant as the set value even though the opening of the door is varied. However, conventional fume hood used to be operated by operator's manual switches. So that, in this paper an automatic control system is developed which controls the face velocity by adjusting the rotating speed of the blow motor and the opening of the damper. Experiments show that this developed system can be used at such laboratories.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.142-143
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• 2012

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.11a
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• pp.11-14
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• 2007

Noise level and Airflow amount of a kitchen hood are affected by the conditions of airflow path. Thus this study is expected to be used as a basic reference in designing airflow path of apartment housing throughout analysing changes in noise level and airflow amount from the various conditions of airflow path. Noise level generated by the kitchen hood is estimated in a kitchen and a living room of two constructed apartment houses, and an experiment is conducted in an half anechoic chamber to analyze noise level and airflow amount by the different length, diameter and number of windings of a round shaped soft duct which is connected to the kitchen hood. The measured results in apartment houses show that the noise level in both apartments exceeds the NC standard greatly in living spaces. In apartment A, a regular apartment house, the noise level was $NC-65{\sim}75$, $NC-45{\sim}60$ and NC-70, NC-45 in the kitchen and living room with an operation of kitchen hood in 1 and 3 stages. In apartment B, an apartment complex, the noise level was NC-55 and NC-60 in the kitchen and living room with an operation of kitchen hood in 3 stages. In particular, there was an increase of noise level at 125Hz-band resulted from an amplification of sound, which requires adequate measures in noise reduction. The results measured in Half anechoic chamber show 99% of airflow amount increase with the modification of a duct' s diameter from ${\Phi}$ 100mm to ${\Phi}$ 125mm, 37% of airflow amount increase with the modification of a duct' s diameter from ${\Phi}$ 125mm to ${\Phi}$ 150mm, and 173% of airflow amount increase with the modification of a duct' s diameter from ${\Phi}$ l00mm to ${\Phi}$ 150mm. The noise level was lower than the level measured in apartment housing about 20 in NC-value and 11.4 in dB(A)-value, which was interpreted as the effect of the load by the pressure condition at the rear end of the duct. Also, an amplification of sound in 125Hz-band influenced NC-value considerably, therefore effective measure is needed.

• Transactions of Materials Processing
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• v.20 no.2
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• pp.160-166
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• 2011

Weight reduction while maintaining functional requirements is one of the major goals in the automotive industry. The use of lightweight magnesium alloys offers great potential for reducing weight because of the low density of these alloys. However, the formability and the surface quality of the final magnesium alloy product for auto-body structures are not acceptable without a careful optimization of the design parameters. In order to overcome some of the main formability limitations in the stamping of magnesium alloys, a new approach, the so-called "hybrid technology", has been recently proposed for body-in-white structural components. Within this approach, necessary level of mechanical joining can be obtained through the use of lightweight material-steel adhesion promoters. This paper presents the development process of an automotive hybrid hood assembly using magnesium alloy sheets. In the first set of material pairs, the selected materials are magnesium alloy AZ31B alloy and steel(SGCEN) as inner and outer panels, respectively. In order to optimize the design of the inner panel, the stamping process was analyzed with the finite element method (FEM). Laser welding by CW Nd:YAG were used to join the magnesium alloy sheets. Based on the simulation results and mechanical test results of the joints, the determination of die design variables and their influence on formability were discussed. Furthermore, a prototype based on the proposed design was manufactured and the static stiffness test was carried out. The results demonstrate the feasibility of the proposed hybrid hood with a weight reduction of 25.7%.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.6
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• pp.100-107
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• 2013

Although automotive safety technologies have been developed steadily, the efforts for pedestrian protection still seems to be insufficient. In a car-pedestrian accident, the structures such as the engine under a hood, the lower part of a windshield and the A-pillar are the major causes of fatal pedestrian injuries. Recently, there have been several studies on the active safety system to reduce the pedestrian injuries. The safety system consists of an active hood lift system and a pedestrian airbag. In this research, the safety performance of the active hood lift system and the pedestrian airbag is investigated by using the finite element method. The finite element model of the system is set up based on the head impact test, and the impact analyses are performed. The necessity and the usefulness of the safety system are verified.

• Journal of the Korean Society of Visualization
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• v.16 no.2
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• pp.7-15
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• 2018

The fluid-flow characteristics of flue-gas-recirculation (FGR) system can have a significant effect on system efficiency of a sintering plant. The flow characteristics in the system were investigated. A sintering plant with FGR system was modeled. Numerical visualization was performed and flow characteristics were analyzed. Characteristics of the flow distribution of the branch ducts, the inflow of air into the recirculating hood, and the flow in the hood were discussed. Based on the results three suggestions were proposed: (1) distribution of branch duct flowrate upstream, (2) installation of external air ducts in the hood, and (3) installation of baffles at the hood corners. The suggestions were tested numerical and experimental visualization methods. The suggestions were effective and confirmed to be applicable to the actual sinter plant.

• Journal of the Korean Dietetic Association
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• v.10 no.1
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• pp.34-46
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• 2004

The purpose of this study was to investigate disinfection state and effective factors of foodservice facilities and utilities of elementary schools in Busan area. Foodservice facilities and utilities investigated in this study were ceiling, wall, floor, trench, greasetrap, hood, pest and dumb waiter. The questionnaire which was administered to 196 dietitians was used as a survey method. The results were as follows. The washing method of foodservice facilities and utilities was mainly used by detergent washing-natural dry. The disinfection method of foodservice facilities and utilities was mainly sanitized by sodium hypochlorite. Dumb waiter and hood were sanitized by 70% ethyl alcohol and iodine. In washing and disinfection frequencies of foodservice facilities and utilities ceiling was twice/year, wall, hood and pest control facilities were once/week, floor, trench, greasetrap and dumb waiter were everyday, respectively. Floor, trench, greasetrap and dumb waiter were disinfected properly, whereas ceiling, wall, hood and pest were not disinfected properly. The washing method was related to dietitian's marital status and education. The disinfection state was related to dietitian's age and career, having of sanitation check list. The disinfection method was also affected dietitian's marital status, number of employee, duration of foodservice, number of total serving and having of sanitation check list. Therefore based on the results of this study, it should be given to the microbiological study on disinfection of facilities and utilities such as ceiling, wall, floor, trench, greasetrap, hood, pest and dumb waiter and the dietitian and employee's sanitation training also should be conducted continuously.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.12
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• pp.867-872
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• 2010

Numerical analysis has been conducted to investigate the fluid flow and fume mixing ratio characteristics of scattering fume in a push-pull ventilation system and optimally improve the flow patterns of scattering fume in the existing ventilation system. This ventilation system has been simulated by using commercial CFD code. In the case of the existing system, although the air is sprayed from air-curtain to prevent the fume from being scattered in upper hood, the improved air supply hood can remove the fume from the wide area in the high pressure. It is verified that the deeper plating storage is more advantageous. Also, by installing the shied around the plating storage, the scattering of the fume to the atmosphere was prevented effectively by surrounding flux.

• International Journal of Automotive Technology
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• v.8 no.3
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• pp.337-342
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• 2007

A multi-objective optimization technique was implemented to obtain optimal topologies of the inner reinforcement for a vehicle's hood simultaneously considering the static stiffness of bending and torsion and natural frequency. In addition, a smoothing scheme was used to suppress the checkerboard patterns in the ESO method. Two models with different curvature were chosen in order to investigate the effect of curvature on the static stiffness and natural frequency of the inner reinforcement. A scale factor was employed to properly reflect the effect of each objective function. From several combinations of weighting factors, a Pareto-optimal topology solution was obtained. As the weighting factor for the elastic strain efficiency went from 1 to 0, the optimal topologies transmitted from the optimal topology of a static stiffness problem to that of a natural frequency problem. It was also found that the higher curvature model had a larger static stiffness and natural frequency than the lower curvature model. From the results, it is concluded that the ESO method with a smoothing scheme was effectively applied to topology optimization of the inner reinforcement of a vehicle's hood.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.673-679
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• 2000

LNG Carriers are currently known as sole commercial means of shipping natural gas on the sea. They are designed to proven dangerous explosion for shipping a lot of gas over long distance. In this study. In this study, a scaled model chamber was made to investigate ventilation characteristics of the hood room in LNG carrier. Experimental study was performed in model using visualization equipments with laser apparatus and image intensifier CCD camera gated by an AOM controller Twelve different kinds of measuring area were selected as experimental condition. Instant simultaneous velocity vectors at whole field were measured by using 2-D PIV system which software adopts two-frame grey-level cross correlation algorithm. To look into stagnation area of hood room for LNG carrier, a three-dimensional numerical simulation with standard ${\kappa}-{\varepsilon}$ model was carried out by using PHOENICS for three kinds of Reynolds number, $6.5{\times}10^3$, $9.7{\times}10^3\;and\;1.29{\times}10^4$, based on the cavity inlet velocity and cavity height. The flow pattern showed the large scale counter-clockwise forced-vortex rotated at center area, small eddies at each corner and stagnation area located at left-back upper side of model.