• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.5
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• pp.115-123
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• 2010

Cool-down performance after soaking is important because it affects passenger's thermal comfort. The cooling capacity of HVAC system determines initial cool down performance in most cases, the performance is also affected by location, and shape of panel vent, indoor seat arrangement. Therefore, optimal indoor designs are required in developing a new car. In this paper, initial cool down performance is predicted by CFD(computational fluid dynamics) analysis. Experimental time-averaging temperature data are used as inlet boundary condition. For more reliable analysis, real vehicle model and human FE model are used in grid generation procedure. Thermal and aerodynamic characteristics on re-circulation cool vent mode are investigated using CFX 12.0. Thermal comfort represented by PMV(predicted mean vote) is evaluated using acquired numerical data. Temperature and velocity fields show that flow in passenger's compartment after soaking is considerably unstable at the view point of thermodynamics. Volume-averaged temperature is decreased exponentially during overall cool down process. However, temperature monitored at different 16 spots in CFX-Solver shows local variation in head, chest, knee, foot. The cooling speed at the head and chest nearby panel vent are relatively faster than at the knee and foot. Horizontal temperature contour shows asymmetric distribution because of the location of exhaust vent. By evaluating the passenger's thermal comfort, slowest cooling region is found at the driver's seat.

• Journal of Advanced Navigation Technology
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• v.17 no.1
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• pp.80-89
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• 2013

The amount of object which reenter the Earth's atmosphere has been increasing after the Sputnik I launch in October 1957. Most of reentry objects were incinerated by aerodynamic heating so they hardly survive. But they may incur casualties and widespread property damages if they survive and fall to surface. The amount of reentry objects, such as Satellite, Rocket Booster, Pressure Tank, ISS shows continued growth as byproduct of space activities. Most of the re-entry objects are incinerated at between altitude of 50km~80km and 10%~40% of the objects are surviving and falling to the ground. Therefore, this paper try to piece together the reentry event and analysis the survival characteristics of re-entry object.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.933-935
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• 2017

This paper deals with the influence of fungi for the thermal protective cork-based exterior insulator which protect a missile system from aerodynamic loads and heating during flight of missile. We consider the adhesion of cork-based composite on the composite motor case which fabricated by filament winding process. We also consider the importance of the requirement analysis for effective, successful system development under given system conditions. In order to develop the basic requirement analysis for the thermal protective cork-based exterior insulator, an experimental requirement analysis was accomplished, and some experimental comparing results, the study for preventing fungi are presented.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.6
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• pp.536-541
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• 2012

An instrumented pod has been developed to measure the aeroacoustic environment as well as the conventional data such as load, vibration, and aerodynamic heating of fighters during flight tests, confirming to the recently developed external pod design for fighters. This study presents the development of the measurement system in detail, being the first indigenous effort in its kind. The pod was designed to meet the requirements of the MIL-HDBK-1763 and MIL-STD-810 Method 515, which are the base to determine the locations and range of sensors. The Endevco 8510B-2 was selected as the sensor to withstand the harsh environment during the flight tests. In order to assess the integrity of the fabricated pod design, a ground run-up test of a KF-16 has been conducted with the pod installed at Station 5. The test results show that the system works well but the sound level exceeds the predetermined sensor range. The sensor range has been readjusted for flight test performed later.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.10
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• pp.695-704
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• 2019

In hypersonic regime, the complicated interaction between the air and surface of aircraft results in intensive aerodynamic heating on body. Provided this phenomenon occurs on a hypersonic vehicle, the temperature of the body extremely increases. And consequently, thermal deformation is produced and material properties are degraded. Furthermore, those affect both the aerothermoelastic stability and thermal safety of structures significantly. With the background, thermal safety and dynamic stability are studied according to the altitude, flight time and Mach number. Based on the investigation, design guideline is suggested to guarantees the structural integrity of hypersonic vehicles in terms of both of thermal safety and dynamic stability.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.3
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• pp.187-194
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• 2019

The off-axis Infra-Red(IR) seeker is mounted on the nose cone side of the anti-air high speed missile to alleviate thermal shield effect due to aerodynamic heating. The seeker output can not be regarded as the Line-of-Sight(LOS) rate any more as missile's roll motion to keep the target tracking is associated. In this paper, we propose a method to calculate the LOS rate for off-axis seeker on a 2-axis gimbal. Firstly, true LOS rate equations are analytically derived but not implementable because boresight error rate is not measurable. And then the first order lag approximation to obtain boresight error rate is proposed. The proposed LOS rate calculation method can compensate the coupling effect by considering the rotations of missile and gimbal. The performance of the proposed method is verified via full nonlinear 6-DOF(Degree of Freedom) simulations.

• Journal of Powder Materials
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• v.29 no.6
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• pp.477-484
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• 2022

Thermal protection systems (TPS) are a group of materials that are indispensable for protecting spacecraft from the aerodynamic heating occurring during entry into an atmosphere. Among candidate materials for TPS, ceramic insulation materials are usually considered for reusable TPS. In this study, ceramic insulation materials, such as alumina enhanced thermal barrier (AETB), are fabricated via typical ceramic processing from ceramic fiber and additives. Mixtures of silica and alumina fibers are used as raw materials, with the addition of B4C to bind fibers together. Reaction-cured glass is also added on top of AETB to induce water-proof functionality or high emissivity. Some issues, such as the elimination of clumps in the AETB, and processing difficulties in the production of reusable surface insulation are reported as well.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.2
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• pp.127-134
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• 2020

High supersonic aircraft are exposed to high temperature environments by aerodynamic heating during supersonic flight. Thermal protection system structures such as double-panel structures are used on the skin of the fuselage and wings to prevent the transfer of high heat into the interior of an aircraft. The thin-walled double-panel skin can be exposed to acoustic loads by supersonic aircraft's high power engine noise and jet flow noise, which can cause sonic fatigue damage. Therefore, it is necessary to examine the behavior of supersonic aircraft skin structure under thermal-acoustic load and to predict fatigue life. In this paper, we designed and fabricated thermal-acoustic test equipment to simulate thermal-acoustic load. Thermal-acoustic testing of the titanium specimen under thermal-acoustic load was performed. The analytical model was verified by comparing the thermal-acoustic test results with the finite element analysis results.