• Title, Summary, Keyword: Absorber

Search Result 1,441, Processing Time 0.036 seconds

Numerical Analysis of Vertical Plate Absorber for Optimal Design

  • Yoon, Jung-In;Moon, Choon-Geun;Phan, Thanh-Tong
    • Journal of the Korean Society of Marine Engineering
    • /
    • v.28 no.2
    • /
    • pp.252-262
    • /
    • 2004
  • A model of simultaneous heat and mass transfer process in absorption of refrigerant vapor into a lithium bromide solution of water-cooled vertical plate absorber. which was considered to the change of refrigerant vapor pressure along the plate width direction. was developed to evaluate the compactness of plate absorber and supply basis data for optimal design of plate absorber. The effects of plate interval as well as the effect of capacity for one piece of plate absorber on plate absorber size such as plate height. plate heating area and plate absorber volume have been investigated. It is confirmed that there is exist an optimal plate interval minimizing plate absorber volume. And the smaller capacity for one piece of plate absorber. the smaller plate absorber volume is obtained.

A Study on Development of the Hybrid Shock Absorber for Lunar Lander (달 착륙선 하이브리드 충격 흡수장치의 개발에 관한 연구)

  • Lee, Jaehyeong;Hwang, Jai-hyuk;Bae, Jae-sung;Lim, Jaehyuk
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • /
    • pp.81-86
    • /
    • 2012
  • The shock absorber is very important in various mechanical field. Without the shock absorber, the structure might be broken. For lunar lander, honeycomb shock absorber to absorber the shock by using plastic deformation of honeycomb has been used. It is cheap and simple to use but impossible using again without changing the honeycomb. The oleo-pneumatic type shock absorber is not able to use in the cosmos because it is vacuum and its temperature. This study suggests the hybrid shock absorber combined spring-ratchet mechanical shock absorber and eddy current electromagnetic damper. The ratchet restricts rebound of lunar lander and the spring converts the impact energy to the potential energy of the spring. The eddy current damper dissipates the impact energy by eddy current force without contact between the parts. This hybrid shock absorber is reusable while the honeycomb shock absorber isn't. The impact absorbing test of the hybrid shock absorber was carried out. This paper shows that the compared results the hybrid shock absorber with ratchet and without ratchet and evaluates the possibility of using for lunar lander.

  • PDF

Performance Comparison Analysis of Frequency Sensing Shock Absorber and Passive Shock Absorber (주파수 감응식 쇽업소버와 수동형 쇽업소버의 성능비교 분석)

  • Noh, Daekyung;Seo, Wonjin;Yun, Jooseop;Jang, Joosup
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.23 no.4
    • /
    • pp.380-387
    • /
    • 2015
  • Various forms of passive shock absorber have developed to supplement performance which is poorer than that of active shock absorber. It is called 'Hybrid Conventional Damper (HCD)'. Frequency sensing shock absorber that this study will cover belongs to the HCD. This study aims to demonstrate that performance of frequency sensing shock absorber is superior than that of passive shock absorber. Study process is as follows. Firstly, analysis models for both passive shock absorber and frequency sensing shock absorber are developed to secure reliability. Then, elements which cause difference of ride quality are found out through comparison of hysteresis characteristics. By comparison of frequency characteristic, furthermore, damping principle of frequency sensing shock absorber is understood. Also, it determines if the absorber performs well even though maximum excitation speed is changed. Finally, the study proves that performance of frequency sensing shock absorber is superior than that of passive shock absorber after comparing change of damping power in excitation condition that various frequencies are mixed.

A Simulation and Property Analysis according to Electromagnetic Wave Absorber Shape

  • Kwon, Seok Hun;Hwang, Hyun Suk;Kang, Hyunil
    • International Journal of Internet, Broadcasting and Communication
    • /
    • v.10 no.4
    • /
    • pp.1-5
    • /
    • 2018
  • The property of magnetic field and properties of EMW(Electro Magnetic Wave) absorption with multi-shaped EMW absorber was simulated. As a magnetic field having high density was showed at bottom of EMW absorber, simulation showed that overall EMW was absorbed at the bottom of multi-shaped absorber. The absorption properties of EMW according to thickness of absorber showed that it enhanced about 50-60 percent. Also, EMW absorption properties was checked with surface area of EMW absorber. A cylinder-shaped EMW absorber exhibited good property among multi-shaped EMW absorber based on these result.

THE MICROWAVE ABSORBING CHARACTERISTICS OF FERRITE GRID ABSORBER

  • Kwon, H.J.;Shon, H.J.;Hur, W.D.;Naito, Yoshiyuki;Takahashi, Michiharu
    • Journal of the Korean Magnetics Society
    • /
    • v.5 no.5
    • /
    • pp.805-809
    • /
    • 1995
  • In order to widen the band-width of ferrite absorber, compositional effect on the complex permeability of Ni-Zn ferrite and the structure of grid absorber were studied. From the experimental results, we could determine the optimum composition composition of Ni-Zn ferrite and the structure of grid absorber. Also, we manufactured grid absorber and investigated its microwave absorbing characteristics. Calculation shows that the ferrite frid absorber suppresses reflection ${\leq}-20dB$ from 30 MHz to 700 MHz and the conventional ferrite tile absorber suppresses reflection ${\leq}20dB$ in the frequency range of 30 MHz-400 MHz. It was found that the microwave absorbing performance of the ferrite grid absorber was superior to the ferrite tile absorber.

  • PDF

A Study on Performance of Flat Water-type PVT Modules According to Absorber Type (흡열판의 종류에 따른 Unglazed PVT 모듈의 성능 실험 분석)

  • Chun, Jin-Aha;Jeong, Seon-Ok;Kim, Jin-Hee;Kim, Jun-Tae;Cho, In-Soo;Nam, Seung-Baeg
    • 한국태양에너지학회:학술대회논문집
    • /
    • /
    • pp.93-98
    • /
    • 2011
  • A photovoltaic/thermal(PVT)collector produces both thermal energy and electricity simultaneously. The heat from PV modules should be removed for better electrical performance, and can be converted into useful thermal energy. A PVT module is a combination of PV module with a solar thermal collector which forms one device that converts solar radiation into electricity and heat. In general, there are two different types of PVT module: glazed PVT module and unglazed PVT module. On the other hand, two types of the PVT module can be distinguished according to absorber on PV module rear side: the sheet-and-tube absorber PVT module and the fully wetted absorber PVT module. The absorber collector plays an important function in PVT system. It cools down the PV module, while collecting the thermal energy produced in the form of hot water. The aim of this study is to compare the electrical and thermal performance of two different PVT collectors, one with the rectangular tube and the other with fully wetted absorber PVT collectors. For this paper, the PVT collectors with two different types of thermal absorber were made, and both the thermal and electrical performance of them were measured in outdoor, and the results were compared. The experimental results were analyzed that the thermal efficiency of the fully wetted absorber PVT collector is about 8.7% higher than the sheet-and-tube absorber PVT collector, and for the electrical efficiency, the fully wetted absorber PVT collector had about 7% higher than the rectangular tube absorber.

  • PDF

Continous rail absorber design using decay rate calculation in FEM

  • Molatefi, Habibollah;Izadbakhsh, Soroush
    • Structural Engineering and Mechanics
    • /
    • v.48 no.4
    • /
    • pp.455-466
    • /
    • 2013
  • In recent years, many countries have added railway noise to the issues covered by noise regulations. It is known that the rail is the dominant source of rolling noise at frequency range of 500Hz-2000Hz for the conventional speeds (<160km/h). One of the effective ways to reduce noise from railway track is using a rail vibration absorber. To study the acoustic performance of rail absorber, the decay rates of vibration have long been used by researcher. In this paper, A FE model of a periodic supported rail with infinite element in ABAQUS is developed to study the acoustic performance of the rail absorber. To compute the decay rates, acceleration responses along the rail transferred to MATLAB to obtain response levels in frequency domain and then by processing the response levels, the decay rates obtained for each1/3octav band. Continous rail absorber is represented by a steel layer and an elastomer layer. The decay rates for conventional rail and rail with one-side absorber and also, the rail with two side absorber are obtained and compared. Then, to improve the system of rail absorber, a steel plate with elastomer layer is added to bottom of the rail foot. The vertical decay rate results show that the decay rate of rail vibration along the track is significantly increased around the tuned frequency of the absorber and thus the rail vibration energy is substantially reduced in the corresponding frequency region and also effective in rail noise reduction.

Vibration Reduction of Marine Air Compressor using Dynamic Vibration Absorber (동흡진기를 이용한 선박용 공기압축기의 진동저감)

  • Kim, Hyung-Jin;Hwang, Sang-Jae;Kim, Ue-Kan
    • Proceedings of the Korean Society of Marine Engineers Conference
    • /
    • /
    • pp.35-36
    • /
    • 2006
  • This study is mainly concerned with vibration control of L-type reciprocating air compressor by a dynamic vibration absorber. The dynamic vibration absorber of reciprocating air compressor was designed for constant revolution running condition. For the review, Vibration test was conducted for the performance appraisal of installed dynamic vibration absorber in the reciprocating air compressor. As a result of the test, the performance of dynamic vibration absorber was satisfactory.

  • PDF

A Numerical Analysis on Thermal and Fluid in Solar Concentration Absorber with Tilt Angle and Opening Ratio of Absorber Entrance (태양열 집광 흡수기 입구의 개방비와 경사각도에 따른 열유체 유동에 관한 수치해석)

  • Lee, Snag-Chul;Lee, Yong-Hun;Choi, Seuk-Cheun;Shin, You-Sik;Jeong, Hyo-Min;Jeong, Han-Sik
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.1485-1490
    • /
    • 2003
  • This paper is the analysis of thermal and fluid in solar concentration absorber with various tilt angle and opening ratio of absorber entrance. The purpose of this study is to develop optimum solar concentration absorber, and the parameters for the study are the opening ratio of absorber entrance and the tilt angle. The aspect ratio of absorber was fixed at 0.64, and opening ratio was changed from 0.1 to 1.0. The finite volume method with SIMPLE computational algorithm are used and analyzed the heat transfer in absorber inside walls.

  • PDF

Design of a Vibration Absorber for an Elastically Suspended Rigid Body (단일 진동체의 진동 흡진기 설계 기법)

  • Kim, Dong-Wook;Choi, Yong-Je
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • /
    • pp.190-197
    • /
    • 2002
  • A new design methodology is presented for the multi-degree-of-freedom vibration absorber for an elastically suspended rigid body with planes of symmetry in general motion. Unlike the common single degree-of-freedom vibration absorber, the presented methodology makes use of both linear and rotational properties of the absorber. It is suggested that an absorber is designed separately for the in-plane and out-of-plane vibration modes and thereby combined the two cases for a six-degree-of-freedom absorber. The nine possible design methods are suggested for the six-degree-of-freedom absorber when an elastically suspended rigid body has one, two, or three planes of symmetry.

  • PDF