• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.12
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• pp.1080-1085
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• 2012

In this paper a sharp-edged type damping orifice for an aircraft door damper were designed, where the dynamic viscosity of working fluid were assumed to change up to 400cSt. The discharge coefficient of the damping orifice were investigated by CFD analyses and experiments. In particular, the influences of orifice diameter, edge angle, flow direction and the Reynolds number were taken into consideration. Based on this, it has been deduced how high Coulomb friction forces of damper seals is to be allowed to meet the performance criterion with respect to the orifice size.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.188-191
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• 2005

In this paper, a design optimization technique is presented for determining the stiffness and the damping coefficient of the shock absorber that is used in the Gullwing door system of passenger car. The contact force between the shock absorber and stopper link, when the door is opened, is set up as objective function, and the stiffness and the damping coefficient are set up as design variables. ADAMS optimization module (SQP method) is applied in the design optimization process. This study shows that the stiffness and the damping coefficient of the shock absorber can be effectively determined in initial design stage of the Gullwing door.

• Fire Science and Engineering
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• v.27 no.3
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• pp.66-71
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• 2013

The purpose of this study is to assess the criteria on a floor hinge and door closer for the optimum design of the access door of a smoke control room. The door opening force due to differential pressure is 60.75 N, 40.5 N, 32.91 N and 12.66 N when the differential pressure is 60 Pa, 40 Pa, 32.5 Pa and 12.5 Pa, respectively. The door opening force of the floor hinge and door closer to which the criteria of KS F 2806 are applied is 27.5 N, 40 N, 75 N, 100 N and 125 N for the Nos. 1, 2, 3, 4 and 5 class floor hinges and door closers, respectively. This study compared the differential pressure and opening force limits of floor hinges and door closers with the values specified in NFSC 501A and found that they exceeded the criteria specified in NFSC 501A. Therefore, it is necessary to reflect the differential pressure and smoke control wind speeds as well as the opening forces specified in NFSC 501A on the design of floor hinges and door closers. The installation conditions of floor hinges and door closers of access doors differ depending on the type and name of a smoke control damper. This study found that Nos. 1, 2 and 3 floor hinges and door closers could be installed for access doors with low differential pressure and that Nos. 1 and 2 floor hinges and door closers could be installed for access doors with normal differential pressure.

• Fire Science and Engineering
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• v.26 no.5
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• pp.99-104
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• 2012

This study investigated the pressure change in the fire room and elevator lobby during the air pressurization to the Elevator lobby with the various egress scenarios and the existence of vent holes in the fire room. The experiments revealed that pressure change was significantly affected by the open/closure scenarios of the front door and stairway door resulting in over pressure, under pressure and performance drop of the door closure. It also revealed that the required smoke defensive air velocity can be obtained only with the existence of vent holes in the fire room by the removal of back pressure in the fire room.

• Journal of Drive and Control
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• v.9 no.3
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• pp.23-28
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• 2012

In this study the flow rate-to-pressure difference characteristics of short-tube type damping orifices for an aircraft door damper were investigated by CFD analyses and experiments. As the design parameters of the damping orifice its diameter, inlet and outlet angle, tube length and the viscosity of the working fluid were taken into consideration. The results showed that the discharge coefficient of the orifices are dependant on the inlet and outlet angle and the oil viscosity, while their length plays an little significant role. Although the short-tube type damping orifice was employed to induce a turbulent flow, their discharge coefficient decreases rapidly as the oil viscosity gets higher than 50mm2/s. Therefore, in order to determine the orifice size, satisfying the working temperature range of the door damper, the oil viscosity as well as the friction force on the damper piston should be kept within proper values. For the verification of the CFD analysis results the actual performance of a door damper was measured and compared with them.