• Title/Summary/Keyword: 외부연료탱크

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Study on the numerical simulation of bird strike for composite container of external auxiliary fuel tank for rotorcraft (회전익항공기 외부 보조연료탱크용 복합재 컨테이너 조류충돌 수치모사 연구)

  • Kim, Hyun-Gi;Kim, Sungchan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.7
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    • pp.709-713
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    • 2017
  • In urgent situations such as crashes, the integrity of an aircraft's fuel tank is directly related to the survivability of the crew. Thus, an external auxiliary fuel tank should be robust against bird strikes. In this study, a numerical analysis was carried out using impact analysis software to analyze the influence of bird strike on a composite container for an external auxiliary fuel tank. The structure was modeled as a shell element, and the fluid and bird were modeled by the particle method. The behavior of the internal fluid was also examined. The maximum stress, deformation, and strain of the composite container were also calculated.

Analysis of the Longitudinal Static Stability and the Drop Trajectory of a Fighter Aircraft's External Fuel Tank (전투기 외부 연료 탱크의 종방향 정안정성 및 투하 궤적 해석)

  • Kang, Chi-Hang;Cho, Hwan-Kee;Jang, Young-Il;Lee, Sang-Hyun;Kim, Kwang-Youn
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.3
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    • pp.274-279
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    • 2010
  • The present work is to analyze the longitudinal static stability and the drop trajectory of fighter aircraft's external fuel tank, of which horizontal fin is modified as the 20% scale down size compared with the original one. The analytical results to the pitching stability of external fuel tank using a thin airfoil's aerodynamic force data show the corresponding tendency to results of wind tunnel experiment. Results of trajectory simulation by the 6 degree of freedom equations of motion, comparing with drop trajectories of wind tunnel experiment, are shown that aircraft's attitude affects strongly on horizontal movement but not on the vertical movement. Those results give the reliability to aircraft safety when the external fuel tank with the 20% reduced horizontal fins is released from aircraft based on the flight manual.

Assessment of Structural Soundness and Joint Load of the Rotorcraft External Fuel Tank by Sloshing Movement (슬로싱 운동에 의한 회전익항공기 외부연료탱크 체결부 하중 및 구조건전성 평가)

  • Kim, Hyun-Gi;Kim, Sung Chan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.5
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    • pp.605-611
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    • 2019
  • The fuel sloshing due to the rapid manoeuvre of the aircraft causes significant loads on internal components, which may break components or piping. In particular, a significant load is applied to the joint of the external fuel tank by sloshing movement, which may affect the safety of the aircraft when the joint of the external fuel tank is damaged. Therefore, in order to improve the survivability of aircraft and crew members, the design of external fuel tanks, and joints should be performed after evaluating the sloshing load through a numerical analysis of the fuel sloshing conditions. In this paper, a numerical analysis was performed on the sloshing test of the external fuel tank for rotorcraft. ALE (Arbitrary Lagrangian Eulerian) technique was used, and the test conditions specified in the U.S. Military Specification (MIL-DTL-27422D) was applied as the conditions for numerical analysis. As a result of the numerical analysis, the load on the joint of the external fuel tank was calculated. Moreover, the effects of sloshing movement on structural soundness were assessed through analysis of stress levels and margin of safety on metal fittings and composite containers.

Numerical Analysis of Crash Impact Test for External Auxiliary Fuel Tank of Rotorcraft (회전익항공기용 외부 보조연료탱크 충돌충격시험 수치해석)

  • Kim, Hyun-Gi;Kim, Sungchan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.3
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    • pp.724-729
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    • 2017
  • The crashworthiness of the fuel tank of a rotorcraft is verified through the crash impact test. The crash impact test has a high risk of failure due to the application of an excessive load, which can seriously affect the overall development schedule of the aircraft. Therefore, a lot of effort has been made to minimize the possibility of failure in the actual test by carrying out a numerical analysis of the crash impact test of the fuel tank in the initial design stage. Recently, an external auxiliary fuel tank was added to increase the cruising distance. In this study, the numerical analysis results of the crash impact test based on several different shapes of the external auxiliary fuel tank are presented, in order to evaluate its crashworthiness. For the numerical analysis, smoothed particle hydrodynamics (SPH), which is one of the fluid-structure coupled analysis methods, is applied and the test conditions prescribed by US military standards are reflected in the analysis conditions. In addition, the material property data previously obtained by the specimen test of the actual fuel tank is applied to the numerical analysis. As a result, the equivalent stress of the fuel tank material itself and the metal fitting is provided and the possibility of acquiring data for designing the crash-worthiness of the external auxiliary fuel tank is evaluated by examining the behavior and working load of the internal mounted components.

A Study of Flare Operation Method for The Fighter with An External Center Fuel Tank (동체 중앙에 연료탱크를 장착한 전투기의 섬광탄 운용 방안 연구)

  • Kang, Chi-Hang;Jang, Young-Il;Kwon, Ky-Beom;Yoon, Young-In
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.7
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    • pp.616-622
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    • 2012
  • In this paper, we examined the problems of the flare operation of tactic maneuvering flight of fighter aircraft with 150GL center external fuel tank and proposed the possible solution of it's operation. The damage scope of horizontal fin of fuel tank and flare trajectory when the flare ejected from the maneuvering aircraft were analyzed by the wind tunnel test and the numerical analysis. We investigated the two different option to avoid the damage of fin; i) the adjustment of flare dispenser angle and ii) the change of horizontal fin's shape. For the considering of practical operation of present system, we chose the second option. We estimated the drop safety of external fuel tank with redesigned fin by the wind tunnel experiments.

Transformation of Flight Load to Test Load for the Static Load Test of External Fuel Tank for Aircraft (항공기용 외부연료탱크 정하중시험을 위한 비행하중의 시험하중으로의 변환)

  • Kim, Hyun-gi;Kim, Sung Chan;Park, Sung Hwan;Ha, Byoung Geun;An, Su Hong;Kim, Jun Tae
    • Journal of Aerospace System Engineering
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    • v.15 no.1
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    • pp.80-85
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    • 2021
  • In this study, for conducting a static load test of an external fuel tank used for an aircraft, the flight load acting on the external fuel tank was converted to the test load and the suitability of the converted test loads was confirmed. In order to calculate the test load from the flight load, the external fuel tank was divided into several sections. Shear load, moment by unit shear load, and unit moment were calculated for each section. Test loads for each section were then calculated by computing the shear load, the moment of each section, and flight load condition. In actual static load tests, it might not be possible to impose the test load in the calculated position due to physical constraints. Therefore, after determining positions in which the load could be imposed in the actual test, the test load calculated for each section was redistributed to selected positions. Finally, a test load plan was established by applying a whiffle tree to enhance the efficiency of the test performance while making it easier to operate the actuator. The reliability of the test load plan was verified by comparing it with flight load conditions.

Prediction of Thermal Behavior of Automotive LNG Fuel Tank (LNG 자동차 연료 탱크의 열적 거동에 대한 예측)

  • NamKoong, Kyu-Won;Chu, Seok-Jae
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.9
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    • pp.875-883
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    • 2010
  • The thermal performance of LNG fuel tanks of vehicles is determined by the time for non-venting storage of fuel and the amount of fuel supplied to the engine. In this study, we selected a double-walled vacuum-insulated fuel tank with a volume of 450 liter, and the properties of the fuel contained in it were assumed to be the same as those of the methane($CH_4$). For the increasing the non-venting fuel storage time, we propose the use of shielded penetration pipes in the tank. We compared the storage times of the tank used in our study with those of the conventional fuel tank. Further, the additional heat input required to maintain the fuel pressure necessary for an appropriate fuel supply rate was predicted. For these parameters, we derived a thermodynamic relationship that can be used to estimate the rate of increase in pressure for a known heat input, and we obtained equations for estimating the rate of heat leaked by using the established heat transfer model. From the results of numerical computation, we found the non-venting storage time of the tank with shielded pipes to be 25-30% higher than that of the tank with unshielded pipes. Further, we determined the appropriate operation conditions by taking into consideration the transfer rate of additional heat provided to the fuel tank.

The Crack Analysis and Redesign of Horizontal Fin of F-5E/F's External Fuel Tank (F-5E/F 외부 연료탱크 수평 핀 균열 분석 및 재설계)

  • Kang, Chi-Hang;Yoon, Young-In;Jung, Dae-Han
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.4
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    • pp.382-388
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    • 2010
  • In this work the replacement material for magnesium alloy was investigated and an optimized design was suggested for the horizontal fin of a fighter's external fuel tank. For the replacement of magnesium alloy, Aluminum alloy, AL 2034-T351, was selected by considering material properties and its procurement. The strength and fracture toughness properties of AL 2034-T351 are stronger than those of magnesium alloy, but the specific weight of AL 2034-T351 is heavier than that of magnesium alloy by 65%. To meet the allowable limit of C.G. shift in the tank, the design of horizontal fin was optimized by reducing the original shape by 20% and resizing the maximum thickness to 7 mm. From the results of the static and dynamic stress analysis for improving the safety factor of the joint section and the joint hole, the radius of curvature in the aft joint section of the new fin was designed as 8.5mm.

Study on the Numerical Analysis of Crash Impact Test for External Auxiliary Fuel Tank based on ALE (ALE 기반 외부 보조연료탱크 충돌충격시험 수치해석 연구)

  • Kim, Hyun-Gi;Kim, Sungchan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.3
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    • pp.8-13
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    • 2018
  • A fluid-structure interaction analysis should be performed to evaluate the behavior of the internal fuel and its influence in order to confirm the structural soundness of the fuel tank against external impacts. In the past, fluid-structure interaction analyses have been limited to the obtention of numerical simulation results due to the need for considerable computational resources and excessive computation time. However, recently, computer performance has been dramatically improved, enabling complex numerical analyses such as fluid-structure interaction analysis to be conducted. Lagrangian and Euler coupling methods and Lagrangian based analysis methods are mainly used for fluid-structure interaction analysis. Since both of these methods have their advantages and disadvantages, it is necessary to select the more appropriate one when conducting a numerical analysis. In this study, a numerical analysis of a crash impact test for a fuel tank is performed using ALE. The purpose of the numerical analysis is to estimate the possibility of failure of the fuel tank mounted inside the container when it is subjected to a crash impact. As a result of the numerical analysis, the fluid behavior inside the fuel tank is investigated and the stress generated in the fuel tank and the container structure is calculated, thereby enabling the possibility of fuel tank failure and leakage of the internal fluid to be evaluated.

Dynamic Analysis of External Fuel Tank and Pylon Using Stick Model (스틱모델을 이용한 외부연료탱크 및 파일런 동특성 해석)

  • Kim, Hyun-gi;Kim, Sung Chan;Park, Sung Hwan;Choi, Hyun-Kyung;Hong, Seung Ho;Ha, Byung Kun
    • Journal of Aerospace System Engineering
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    • v.14 no.1
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    • pp.21-27
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    • 2020
  • Aircraft should be equipped with various external stores for mission performance. Since these external stores may cause structural instability of aircraft, an evaluation of the effects between the aircraft and the external stores is required. For this purpose, an aircraft dynamic characteristics analysis reflecting an external store was performed, and the finite element model for the analysis of aircraft dynamic characteristics should simulate the dynamic characteristics of the component as accurately as possible while using a minimum of the nodes and elements. In this study, a stick model was constructed for dynamic characteristics analysis of the external fuel tank and installation pylon using MSC Patran/Nastran. For the calculation of the equivalent stiffness of the stick model, a simple beam theory was applied to construct the stick model of each part, and the validity of each stick models was confirmed by mode comparison with the fine model. Additionally, the model analysis of the stick model assembly, simulating a pylon equipped with an external fuel tank was performed to confirm that the basic modes required for the analysis of aircraft dynamic characteristics are well extracted. Finally, it was confirmed that the developed stick model assembly could be used for analysis of aircraft dynamic characteristics by comparing the errors in modes between the fine model assembly and the stick model assembly.