• Title/Summary/Keyword: EMP shield

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Design Optimization for Air Ducts and Fluid Pipes at Electromagnetic Pulse(EMP) Shield in Highly Secured Facilities (EMP 방호시설의 덕트 및 배관 최적 설계 방안)

  • Pang, Seung-Ki;Kim, Jae-Hoon
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.10 no.4
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    • pp.15-24
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    • 2014
  • This study conducted a computational fluid dynamics(CFD) analysis to find an appropriate diameter or sectional area of air ducts and fluid pipes which have an electromagnetic pulse(EMP) shied to protect indoor electronic devices in special buildings like military fortifications. The result shows that the optimized outdoor air intake size can be defined with either the ratio of the maximum air velocity in the supply duct to the air intake size, or the shape ratio of indoor supply diffuser to the outdoor air intake. In the case of water channel, the fluid velocity at EMP shield with the identical size of the pipe, decreases by 25% in average due to the resistance of the shield. The enlargement of diameter at the shield, 2 step, improves the fluid flow. It illustrated that the diameter of downstream pipe size is 1step larger than the upstream for providing the design flow rate. The shield increases friction and resistance, in the case of oil pipe, so the average flow velocity at the middle of the shield increase by 50% in average. In consideration of the fluid viscosity, the oil pipe should be enlarged 4 or 5 step from the typical design configuration. Therefore, the fluid channel size for air, water, and oil, should be reconsidered by the engineering approach when EMP shield is placed in the middle of channel.

Evaluation of Local Loss Coefficients for Different Waveguide-Below-Cutoff (WBC) Arrays of Electromagnetic Pulse (EMP) Shied in Buildings (도파관 배열에 의한 국부저항계수 산정)

  • Pang, Seung Ki;Chae, Young Tae
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.7
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    • pp.366-372
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    • 2017
  • The objective of this study was to characterize Waveguide-Blow-Cutoff (WBC) array for Electromagnetic Pulse (EMP) shield in air duct or water pipe, the typical pathway of pulse in indoor space with critical electronic device. A numerical investigation with three different WBC designs (circular, rectangular, and hexagonal or honeycomb) was conducted to satisfy recommended shielding effectiveness (SE) levels from 80 dB to 140 dB. Pressure drop between upstream and downstream of EMP shields based on WBC arrays was also investigated to understand air flow feature in air duct of HVAC system. Results showed that honeycomb geometry outperformed other shapes in terms of reducing the depth of EMP shield, thus providing better air flow in duct path with lower local loss coefficient in HVAC system under SE requirements.

A Design Optimization on Coupling Joint between Exhaust Chimney of Electricity Generator and Electromagnetic Pulse (EMP) Shield (EMP 차폐를 위한 비상발전기 연도의 최적 형상 결정)

  • Pang, Seung-Ki;Kim, Jae-Hun
    • Journal of Energy Engineering
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    • v.24 no.4
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    • pp.159-165
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    • 2015
  • The article presents a parametric study on geometrical design optimization for coupling the joint between a large exhaust air chimney and electromagnetic pulse (EMP) shield for gas turbine electricity generator. We conducted computational fluid dynamics (CFD) simulations on hydraulic diameters of waveguide below cutoff(WBC) ranges 800mm~1025mm, the connection distance ranges 150~450mm, and exhaust gas flow velocities at 15, 20, and 25m/s. The results show that the diameter of main chimney, connection distance, and exhaust gas velocity had impacts on flow stream at the EMP shield. To provide a fully developed stream line at three different flow velocity cases, the WBC diameter and distance of connection should be larger than 1050mm and longer than 300mm, respectively.

An Experimental Study on Development of EMP Shielding Concrete Using Carbon-Based Materials and Industrial By-Products (카본계 재료 및 산업부산물을 활용한 EMP 차폐 콘크리트 개발에 관한 실험적 연구)

  • Min-Sung Kim;Cheol-Hyun Yoon;Seung-Ho Byun;Tae-Beom Min
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.11 no.1
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    • pp.48-54
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    • 2023
  • In this research, The basic physical properties and EMP shielding performance by thickness were evaluated for optimum composition of EMP shield concrete that can be applied on-site by mixing carbon-based materials with high conductivity into concrete that uses electric furnace oxidized slag (EOS). As a result of the evaluation, it was confirmed that the slump decreased as the amount of mixed carbon fib er (CF) increased, and increased when milled carb on (MCF) was mixed. As for the compressive strength, it was confirmed that EOS enhanced the strength compared to NA, and it was confirmed that the strength decreased when CF and MCF were mixed. As the thickness of the EMP shielding measurement increases, the shielding rate increases, and it was confirmed that the type of conductive material and the thickness of the test specimen have a greater influence on the shielding rate than the Amount of conductive material added. As a result of a comparative evaluation, EOS CF 0.2 is considered suitable for EMP shield concrete formulation.

Assessment of the Electromagnetic Pulse Shield Effectiveness of the Wave-guided Below Cutoff Filled with Water and Oil for Guaranteeing the Operational Sustainment of the Command Post (지휘소 작전지속성 보장을 위한 도파관의 전자기파 차폐성능 향상방안)

  • Yoon, Sangho;Son, Kiyoung;Kim, Suk Bong;Park, Young Jun
    • Journal of the Korea Institute of Building Construction
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    • v.13 no.6
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    • pp.579-584
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    • 2013
  • The stable fueling and water supply should be prerequisites to guarantee the operational sustainment of military command post. Meanwhile, in terms of the operational sustainment, it is verified that the current wave-guided below cutoff (WBC) system cannot satisfy the requirement of control associated with water supply and fueling within the command post. In this study, as the dielectric substance can block electromagnetic pulse (EMP), it was tried to identify the shielding effectiveness of the multi WBCs filled with water and diesel for attenuating the EMP effect using experiment based on the MIL STD 188-125-1. According to the experimental results, used water in the experiment show the shielding effectiveness from around 640 MHz frequency because of minerals contained in the water. Furthermore, it was noted that EMP attenuating strength of the WBC filled with diesel was enlarged from around 1,680 MHz frequency. Resultingly, it could be concluded that it is enough to supply stable water and diesel through the multi WBC to block EMP within the military command post for guaranteeing the military operations sustainment.

An Experimental Study on the Measurement of Electrical Conductivity of Cementitious Composites According to the Type of Steel Fiber (강섬유 종류에 따른 시멘트 복합체의 전기전도도 측정에 대한 실험적 연구)

  • Lee, Yae-Chan;Kim, Gyu-Yong;Nam, Jeong-Soo;Lee, Sang-Kyu;Shu, Dong-Kyun;Eu, Ha-Min
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2020.06a
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    • pp.191-192
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    • 2020
  • The purpose of this study is to measure the electrical conductivity of cementitious composites as an early step to obtain shielding performance by mixing various type of steel fiber into cementitious composites, the main building material of protection facility, to shield electromagnetic pulse (EMP) damage. Fiber such as conductors as amorphous metallic fiber, hooked steel fiber, and smooth steel fiber are mixed into cementitious composites to give electrical conductivity and measure the impedance of concrete using LCR meter. By doing this, the electrical conductivity of each type of steel fiber reinforced cementitious composites (FRCC) is compared.

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