Testing of Load Capacity of a Foil Thrust Bearing

Choong Hyun Kim,Jisu Park 한국트라이볼로지학회 2018 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.34 No.6

In this study, the performance of foil thrust bearings was investigated by performing bearing takeoff and load capacity tests, using an in-house designed and manufactured vertical bearing test rig. The mean takeoff rotational speed and maximum load capacity of the bearing specimen were ~18,000 rpm and ~80 kPa, respectively. The vertical bearing test rig was observed to yield higher coefficients of friction and frictional torques than a horizontal bearing test rig under identical test conditions. This was a result of its structural characteristics, in that the bearing specimen is placed atop the thrust runner, which keeps it from being separated from the runner after the bearing take-off. In addition, bearing take-off was observed at a higher runner rotational speed as this structure keeps air from flowing between the top foil and runner surfaces, which requires a higher runner speed. The parallel alignment between the bearing specimen and runner surfaces can be maintained within a certain range more easily in a vertical test rig than in a horizontal test rig. Because of these advantages, Korean Industrial Standard, KS B 2060, recommends a vertical bearing test rig as the standard test device for foil thrust bearings.

Testing of Load Capacity of a Foil Thrust Bearing

Kim, Choong Hyun,Park, Jisu Korean Tribology Society 2018 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.34 No.6

In this study, the performance of foil thrust bearings was investigated by performing bearing take-off and load capacity tests, using an in-house designed and manufactured vertical bearing test rig. The mean take-off rotational speed and maximum load capacity of the bearing specimen were ~18,000 rpm and ~80 kPa, respectively. The vertical bearing test rig was observed to yield higher coefficients of friction and frictional torques than a horizontal bearing test rig under identical test conditions. This was a result of its structural characteristics, in that the bearing specimen is placed atop the thrust runner, which keeps it from being separated from the runner after the bearing take-off. In addition, bearing take-off was observed at a higher runner rotational speed as this structure keeps air from flowing between the top foil and runner surfaces, which requires a higher runner speed. The parallel alignment between the bearing specimen and runner surfaces can be maintained within a certain range more easily in a vertical test rig than in a horizontal test rig. Because of these advantages, Korean Industrial Standard, KS B 2060, recommends a vertical bearing test rig as the standard test device for foil thrust bearings.

Testing of Load Capacity of a Foil Thrust Bearing

김충현,박지수 한국트라이볼로지학회 2018 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.34 No.6

In this study, the performance of foil thrust bearings was investigated by performing bearing takeoff and load capacity tests, using an in-house designed and manufactured vertical bearing test rig. The mean takeoff rotational speed and maximum load capacity of the bearing specimen were ~18,000 rpm and ~80 kPa, respectively. The vertical bearing test rig was observed to yield higher coefficients of friction and frictional torques than a horizontal bearing test rig under identical test conditions. This was a result of its structural characteristics, in that the bearing specimen is placed atop the thrust runner, which keeps it from being separated from the runner after the bearing take-off. In addition, bearing take-off was observed at a higher runner rotational speed as this structure keeps air from flowing between the top foil and runner surfaces, which requires a higher runner speed. The parallel alignment between the bearing specimen and runner surfaces can be maintained within a certain range more easily in a vertical test rig than in a horizontal test rig. Because of these advantages, Korean Industrial Standard, KS B 2060, recommends a vertical bearing test rig as the standard test device for foil thrust bearings.

150kW급 시험리그 추력 성능 검증 및 비교

김현빈(Hyun-Bin Kim),배호섭(Ho-Seob Bae),맹창준(Chang-Jun Meang),이일환(Il Hwan Lee),김대광(Dae-Kwang Kim),조국현(Kuk-Hyun Cho) 한국추진공학회 2023 한국추진공학회 학술대회논문집 Vol.2023 No.11

본 논문은 프로펠러 CFD 및 단일 프로펠러 시험의 추력과 시험리그에서 측정된 추력을 비교한다. 시험리그는 150kW급 전기추진시스템의 통합 성능을 확인하기 위해 설계 및 제작되었다. 정밀한 측정을 위해, 모든 센서는 검교정되었다. 추력 측정에 영향을 미치는 지면효과를 줄이기 위해, 구조물은 이에 따라 설계되었고 로드셀은 시험리그에 통합되는 동안 재 보정되었다. 시험리그의 틸트 프롭추력 시험 결과는 CFD 해석과 1.9%의 차이와 단일 프로펠러 시험에서 0.6% 차이를 확인하였고, 리프트 프롭 시험 결과는 CFD 해석과 단일 프로펠러 시험에서 각각 1% 차이를 확인하였다. 결과에 따라, 시험리그가 앞서 언급한 프로펠러의 추력 측정에 적합함을 확인하였다. This paper compares the thrust between CFD of the propeller, single propeller test, and the thrust measured by the test rig. The test rig was designed and manufactured to verify the performance of manufactured and integrated 150kW-level electric propulsion system. For accurate measurements, all of the sensors were calibrated and verified. To reduce the ground effect, which affect the thrust measurement, the structure was designed accordingly and the loadcells were calibrated again while integrated into the test rig. The test rigs tilt prop thrust test results confirmed a 1.9% difference from the CFD analysis and a 0.6% difference from the single propeller test, and the lift prop test results confirmed a 1% difference between the CFD analysis and the single propeller test. Therefore, based on the results, it is confirmed that the test rig is appropriate for thrust measurement of th aforementioned propeller.

Modeling and experimental evaluation of torque loss in turbine test rig for accurate turbine performance evaluation

Jeong-Seek Kang,양수석 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.2

The performance of a turbine is evaluated through a turbine rig test by measuring the torque or power generated from the test turbine using a dynamometer or torque sensor installed in the test rig. Highly precise assessment requires accurate measurement of the torque or power. However, an intrinsic difficulty exists such that not all power generated by the turbine is measured by the dynamometer or torque sensor. A small portion of power generated from the test turbine is dissipated between the test turbine and torque sensor as bearing and windage losses. The dissipated energy is called mechanical loss of test rig. Therefore, measuring the mechanical loss of the test rig is necessary for the accurate evaluation of the turbine performance. The present paper classifies mechanical loss into bearing, disk windage,and extra windage losses. Spin-down tests are performed in a 1-stage axial turbine test rig to evaluate each loss. The total mechanical loss amounts to 0.78% to 1.4% of energy generated at the turbine. Bearing loss is dominant. Mechanical loss is dependent on and increases with decreasing bearing temperature.

냉각수 유동을 고려한 핵연료 조사 리그의 조립 플러그 설계

양태호,홍진태 한국기계기술학회 2017 한국기계기술학회지 Vol.19 No.1

In this paper, a structural integrity on the test rig with assembly plug to perform intermediate examination is evaluated. Structural analysis results between the test rig with non assembly plug and assembly plug are compared, because the assembly plug has an effect on the flow of the coolant in the test rig. A equivalent stress value on the test rig with assembly plug is increased more than the stress on the test rig with non-assembly plug. A shape optimization of the assembly plug is performed to decrease the stress. Considering a connection with the transport tool, a optimized shape of the assembly plug is presented to minimize the stress on the test rig. Using the optimized assembly plug, the equivalent stress on the test rig with the optimized plug is less than the stress on the test rig with the non-optimized plug.

축소형 틸트로터 무인기의 안전줄 호버 시험

강영신 ( Young Shin Kang ),박범진 ( Bum Jin Park ),유창선 ( Chang Sun Yoo ),장성호 ( Sung Ho Chang ),최성욱 ( Seong Wook Choi ),구삼옥 ( Sam Ok Koo ) 한국항공운항학회 2007 한국항공운항학회지 Vol.15 No.4

Tilt rotor aircraft can take off and land vertically and cruise faster than any other helicopter. A scaled flight demonstration model of a tilt rotor aircraft has been developed by KARI. Because the flight characteristics of tilt rotor are not well known, the developed scaled model would be helpful to evaluate flight control algorithm of a full scale aircraft. The tethered hover test has been performed in order to improve hover flight characteristics of tilt rotor aircraft prior to flight test of the small scaled model. During the tethered hover test, the performance of rotor speed governor, rate SAS (Stability Augmentation System) and control surface mixers have been evaluated. We expect that the results of real flight hover test would be quite same as tethered hover test. Therefore the tethered hover test results will reduce the risk of flight test properly by fixing some of hidden problems which might occur during the flight test. This paper presents the results of tethered hover test in detail and shows how it could be final ground test before flight test. The control mixer gain and rate SAS feedback gains were modified in order to get higher controllability and stability during the tethered hover flight. The rotor governor showed that it could keep rotor RPM constant with very small deviation even during severe pilot collective input change. The tethered hover test results gave pilot and engineers confirmation and experience about the scheduled flight test.

핵연료조사리그 냉각수 유동 모의장치 개발

홍진태(Jintae Hong),정창용(Chang-Young Joung),허성호(Sung-Ho Heo),김가혜(Ka-Hye Kim) 대한기계학회 2015 大韓機械學會論文集A Vol.39 No.1

핵연료 연소시험 도중 핵연료봉에서 발생하는 열을 효과적으로 제거하기 위해서는 핵연료의 발열량을 정확하게 계산하고 충분한 유속을 갖는 냉각수를 순환시켜야 한다. 하나로는 개방형 수조 형태로서 핵연료 연소시험을 위한 별도의 냉각수 순환 루프를 갖추고 있는데, 여기에 핵연료 조사리그를 장착하고 냉각수를 순환시킴으로써 조사중인 핵연료봉의 온도를 일정온도 이하로 유지시킨다. 특히 순환되는 냉각수의 유속이 매우 높은 상태에서 조사리그 내에 부착된 부품이나 센서들이 유체유발 진동에 의해 파손되거나 기능을 상실하는 경우 매우 큰 기회비용을 야기한다. 본 연구에서는 조사리그 부품의 건전성 사전 검토 및 고속 유동에서의 센서 동작 특성에 대한 사전검토를 위해 냉각수 모의 순환장치를 개발하였다. To remove heat generated during a burn-up test of nuclear fuels, the heat generation rate of nuclear fuels should be calculated accurately, and a coolant should be circulated in the test loop at an adequate flow rate. HANARO is an open pool?type reactor with an independent test loop for the burn-up test of nuclear fuels. A test rig is installed in the test loop, and a coolant is circulated through the test loop to maintain the temperature of the nuclear fuel rods within a desired temperature during an irradiation test. The components and sensors in the test rig can be broken or malfunction owing to the flow-induced vibration. In this study, a coolant flow simulation system was developed to verify and confirm the soundness of components and sensors assembled in the test rig with a high flow rate of the coolant.

리그시스템을 활용한 항공기 모드별 전원설계 검증에 관한 연구

이재문,박근석,엄정호 대전대학교 안보군사연구원 2023 안보군사학연구 Vol.- No.23

Rig test that test the performance of mechanical and electrical devices are applied to shorten the aircraft development period, reduce costs, and ensure quality. This study proposed a method of verifying the power design using rig test to develop an aircraft electrical system. The power design is divided into four modes : normal mode in which power is supplied under normal interfaces with all components, abnormal mode in which power is normally supplied to all power buses from another normally operating component if one component fails, emergency mode in which battery power is supplied to the essential power bus for flight safety if all generators fail, fault isolation and reset mode for fault isolation in case of overloading of components. To verify the power design for each operating mode, it was verified through rig test that the aircraft power requirements specified in MIL-STD-704F, the military standard of the Ministry of National Defense applied during aircraft system development. The rig system was constructed by electrical system components such as power supply, power distribution, power conversion, battery, and various test devices such as DC/AC loaders. By identifying test items for each operation mode and conducting comprehensive system interface tests, it was possible to verify whether the power requirements were met under normal, abnormal, and emergency operating conditions and the interface stability between components through fault isolation and reset tests.

Ground Test Results of Flight Control System for the Smart UAV

Young-shin Kang,Bum-jin Park,Chang-sun Yoo,Yu-shin Kim,Sam-Ok Koo 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10

The ground test results of Smart UAV are described. The ground test consists of HILS, iron-bird test, 4-DOF (degrees of freedom) ground rig test, and tethered hover test. One of the main purposes of ground test is to evaluate the integrated flight control system including a digital flight control computer, GPS/INS sensor, air data sensors, etc as well as ground control system (GCS). The performances of whole flight control systems were evaluated. Rotor speed was kept constantly by the rotor governor even during collective sweep and pitch/roll attitude SCAS (Stability and Control Augmentation System) showed good handling qualities performance during 4-DOF and tethered hover test. These control laws and guidance law will be evaluated during the flight test of envelope expansion planed for this year. This paper presents the ground test results and the procedure for Smart UAV.