• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.4
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• pp.433-438
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• 2011

A machine that makes paper cups has many parts, including a barrel cam, an index, and a turret. When the barrel cam, which is the main operating part of the machine, rotates, it pushes the roller fixed on the index, and paper cups are formed as the turret connected to the index rotates. Therefore, the performance of the machine is affected by the barrel cam. In this study, the program for designing barrel cam, which creates the profile of the cam is developed using MATLAB. This profile is used to develop a 3D CAD model by using a 3D CAD program. Dynamic models containing the barrel cam are created on the basis of the profile and 3D laser scan of the barrel cam. Further, the rotation angle of the index in the machine is measured using a high-speed camera. The rotation angles of the dynamics models are compared to verify the effectiveness of the program.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.10
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• pp.923-929
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• 2017

Generally, the sound emitted from a vehicle powered by an electric motor is lower than that of internal combustion engine vehicles. Therefore, pedestrians often cannot detect approaching electric vehicles. Therefore, a certain additional warning sound is required for these types of automobiles. In this study, to develop an audible warning sound, nine warning sounds are designed based on signal processing and chord theory. The background noise measured on the road is also added to these synthetic sounds. The detectability of these warning sounds is evaluated by subjective tests. The sound metric is correlated to detectability and is investigated through psychoacoustic theory and subjective evaluation. It is determined that known psychoacoustic parameters such as loudness, sharpness, and roughness have a low correlation with detectability. However, it is found that the interval of harmonic sound correlates well with detectability.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.10
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• pp.833-839
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• 2013

Thermal vacuum test should be performed prior to launch to verify satellites' functionality in a harsh space environment which is represented by extremely cold temperatures and vacuum conditions. A thermal vacuum chamber which consists of a vacuum vessel, a pumping system, and a thermal control system are used to perform thermal vacuum tests of a satellite system and its components. A cryogenic blower is a core component of the closed loop thermal control system for thermal vacuum chambers. This paper describes the fan design of the cryogenic blower, the design of the thermal protection interface between the driving part and the fluid part, which were verified by thermal and structural analyses. The performance of the cryogenic blower is confirmed by similarity test on the test bench.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.2
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• pp.140-147
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• 2017

This paper describes the design and implementation of previously developed PMU (Power Monitoring Unit) for LiPB (Lithium-ion Polymer Battery) that is electric propulsion used as unmanned aerial vehicle's power source. Improved PMU provides stable voltage and current to various sensors and elctric motors necessary during flight. Voltage and current monitoring function that is measured by improved PMU more precisely be enhanced and the monitoring channel and temperature sensor is added. To verify the improved performance of the equipment, it is integrated to electric propulsion system of unmanned aerial vehicle. PMU is calibrated through the ground test. And PMU's performance is checked through the flight test.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.12
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• pp.1201-1207
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• 2012

This study was performed to develop a high-efficiency submersible nonclogging pump impeller. Toward this end, we simulated the effect of some parameters such as the outlet position of a blade ($h_I$), outlet width of a blade ($b_2$), and hub profile on the pump efficiency by using the commercial codes ANSYS CFX and BladeGen. The results showed that the pump efficiency was proportional up to $h_I$= 38 mm and $b_2$= 55 mm. It remained constant over these values. However, the head and shaft power were proportional to $h_I$ and $b_2$ in the simulated ranges. The effects of hub profile changes on the pump efficiency were relatively small compared to those of the other parameters.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.2
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• pp.166-173
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• 2012

Plug-in Hybrid Electric Vehicle is driven by the engine, the primary traction motor, and the secondary auxiliary motor generating the electric power for battery charging. Secondary auxiliary motor should be connected to the engine or separated from the engine by the clutch system. This paper presents the position controller of the BLDC motor for the clutch system of Plug-in Hybrid Electric Vehicle. The BLDC motor can be applied to the clutch system in spite of it's low accuracy of the position control due to high gear ratio between the clutch and the motor. Since the attachment and the detachment between the motor and the engine should be carried out within 0.3 seconds, the position controller with fast acceleration and deceleration is implemented. For the torque control with braking operation for the BLDC motor, the modified bipolar PWM method with low current ripple compared to the conventional unipolar PWM is presented. The position control performance of the BLDC motor for the clutch system is verified through the simulation and experiments.

• Proceedings of the KOSOMBE Conference
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• v.1991 no.11
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• pp.70-74
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• 1991

좌심실보조기의 임상응용범위를 넓히기 위해서 개심술을 하지 않고 좌심실보조기를 적용할 수 있도록 캐뉼라형 좌심실보조기를 이용한 보조순환 실험을 하였다. 좌심실 보조기는 모터의 회전력이 PVC 벨로우즈를 수측, 팽창시키는 전기유압식으로 구동되며 환자는 양쪽 대퇴동맥을 통하여 보조순환을 받도록 되어 있다. 두차례의 동물실험을 통하여 대퇴동맥을 통한 보조 순환방식의 가능성 및 그 효과에 대해서 관찰하였다. 첫 실험은 12kg 개를 이용하여 셀딩거 방법으로 뮬린형 카테터를 디퇴동맥으로 삽입히여, 캐뉼라형 보조순환방법의 가능성을 확인하였고, 두번째 동물실험에서는 내경 4.8 mm의 PVC 카테터를 이용하여 좌심방에 유입카테터를 연결하고 대동맥에 유출카테터를 연결하여 보조순환에 의한 대동맥압의 변화와 혈류량의 변화를 관찰하였다. 보조순환동안 개의 동맥압을 100mmHg로 유지할 수 있었으며, 좌심실내압이 감소하는 것을 관찰할 수 있었다.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.5
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• pp.19-28
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• 2005

It is of great economic importance to minimize the cylinder wear and the consumption rate of cylinder oil in a large two-stroke diesel engine. The motor-driven cylinder lubricator was first developed fur a large two-stroke marine diesel engine made in $W{\ddot{a}}rtsil{\ddot{a}}a$ Switzerland Ltd. by the joint research of industry-university. In this study, the effects of revolution speed, plunger stroke and cylinder back pressure on maximum discharge and delivery pressures, delivery delay duration, and oil feed rate are experimentally investigated by the home-manufactured cylinder lubricator. The maximum discharge pressure with a spot of 0.03 m and the maximum loss pressure at spots of 5, 6.78 and i 0 m away from the end of lubricator slot are increased as plunger stroke, revolution speed and back pressure are elevated, and the delivery delay duration is shortened as plunger stroke, revolution speed and oil pipe length are increased. Also, oil feed rate is increased as plunger stroke and revolution speed are raised, but lowered as the back pressure is increased.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.11
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• pp.1008-1015
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• 2015

Thermal vacuum test should be performed prior to launch to verify satellites' functionality in extremely cold/hot temperatures and vacuum conditions. A thermal vacuum chamber used to perform the thermal vacuum tests of a satellite system and its components. A cryogenic blower is a core component of the gaseous nitrogen (GN2) closed loop thermal control system for thermal vacuum chambers. A final goal of this research is development of cryogenic blower. Design requirements of a blower are 150 CFM flow rate, 0.5 bara pressure difference, hot and cold temperatures. This paper describes the performance analysis of impeller by 1D, CFD commercial software, the design of the thermal protection interface between the driving part and the fluid part. The performance of the cryogenic blower is confirmed by test at the standard air condition and is verified by on the thermal vacuum chamber at the real operating condition.

• Fire Science and Engineering
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• v.19 no.3 s.59
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• pp.20-27
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• 2005

This paper evaluates the fire safety level of eight pump rooms in the nuclear power plant using a fire model, CFAST We estimate the Conditional Core Damage Probability (CCDP) of each room based on the analyzed results of CFAST Eight rooms located on the primary auxiliary building of the nuclear power plant are high pressure safety injection pump room A/B, low pressure safety injection pump room Am. containment sprdy pump room A/B, and motor-driven auxiliary feed water pump room A/B. The upper layer gas temperature of each room is estimated and the integrity of cable is reviewed. Based on the results, the integrity of the cable located at the upper part of compartment is maintained without thermal damage. The Conditional Core Damage Probability Is reduced to half of the old values. Accordingly, the fire safety assessment for eight pump rooms using the fire model will be capable of reducing the uncertainty and to develop a more realistic model.