• Title/Summary/Keyword: Pressure generation part

Search Result 68, Processing Time 0.032 seconds

Development of PC-NC Water Jet Cutting System and Cutting of Titanium (PC-NC 제어 Water Jet 가공기의 개발과 티타늄의 시험 절삭)

  • Choi, Byung-Mun;Hong, Seong-Ki;Ryuh, Beom-Sahng;Park, Sang-Min
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.18 no.3
    • /
    • pp.53-60
    • /
    • 2001
  • Water jet cutting is a new technology using very high pressure water as a cutting tool. Water jet cutting system consists of water preparation part, pressure generation pate, cutting head, and motion part. A PC-based numerical controlled (PC-NC) X-Y table is developed and water get cutting system is installed thereon. Water jet machining is applicable to various kinds of materials ranging from soft materials such as rubber and meat to hard-to-cut materials such as titanium. This paper shows the application of the abrasive waterjet system to titanium cutting.

  • PDF

An Electrical Characteristics Analysis of Electronic Blood Pressure Depressor (전자혈압강하기의 전기적 특성 분석)

  • Lee, K.S.;Suh, J.H.;Lee, J.W.
    • Journal of Power System Engineering
    • /
    • v.10 no.1
    • /
    • pp.83-89
    • /
    • 2006
  • Recently, the seriousness of high blood pressure was appeared as the most frequent disease of a the whole sickness in the world. However, the treatment of this disease is uncertain and produces an adverse reaction of a medicine therapy. Also, the patients are burdened with a fee for medical treatment. Therefore, in this paper, we studied effectively and financially to execute the treatment of high blood pressure using the Chinese medicine theorem that is recently arousing the great interest of the people. The main theories in this paper are blood vessel theory and acupuncture, respectively. Especially, the composed circuit systems are classified the blood pressure depressor part and the meridian points discrimination part, respectively. The blood pressure depressor part is composed generally of low-frequency generation circuit, charging-discharging circuit, and micro-computer circuit. Finally, this research have the advantage of discrimination parts such as regular voltage generating circuit, stimulus circuit, amplifying circuit, and alarm circuit.

  • PDF

Effect of Boss Wall Thickness on Sink Mark in Injection Molding (보스 벽 두께가 사출성형의 싱크마크 발생에 미치는 영향)

  • Kim, H.P.;Kim, Y.J.
    • Design & Manufacturing
    • /
    • v.6 no.1
    • /
    • pp.5-11
    • /
    • 2012
  • The sink mark on boss parts is generated by the volumetric shrinkage that is caused by both the molding thickness and the boss wall thickness. The volumetric shrinkage is caused by packing pressure and its amount tends to decrease by increasing the packing pressure. The packing pressure can therefore increase the flow rate to a boss part and causes the depth of sink mark to increase. As the molding thickness and the boss wall thickness in the boss part can increase the part volume, these may yield bad solidifying and also extend the molding cycle. In this paper, both the injection molding test and the flow analysis were carried out to investigate the effect of sink mark that was generated in the boss wall thickness of injection molded products. The sink mark could also be caused by thickness ratio of boss part. For a given thickness ratio of boss, several molding process parameters such as packing pressure, packing time and melt temperature, affecting to generation of the sink mark were discussed.

  • PDF

Effect of Boss Wall Thickness on Sink Mark in Injection Molding (보스 벽 두께가 사출성형의 싱크마크 발생에 미치는 영향)

  • Kim, Hyun-Pil;Kim, Yohng-Jo
    • 한국금형공학회:학술대회논문집
    • /
    • 2008.06a
    • /
    • pp.103-109
    • /
    • 2008
  • The sink mark on boss parts is generated by the volumetric shrinkage that is caused by both the molding thickness and the boss wall thickness. The volumetric shrinkage is caused by packing pressure and its amount tends to decrease by increasing the packing pressure. The packing pressure can therefore increase the flow rate to a boss part and causes the depth of sink mark to increase. As the molding thickness and the boss wall thickness in the boss part can increase the part volume, these may yield bad solidifying and also extend the molding cycle. In this paper, both the injection molding test and the flow analysis were carried out to investigate the effect of sink mark that was generated in the boss wall thickness of injection molded products. The sink mark could also be caused by thickness ratio of boss part. For a given thickness ratio of boss, several molding process parameters such as packing pressure, packing time and melt temperature, affecting to generation of the sink mark were discussed

  • PDF

The Aerodynamic Origin of Abrupt Thrust Generation in Insect Flight (Part 1: Vortex Staying and Vortex Pairing Phenomena) (곤충비행에서 갑작스런 추력발생의 공기역학적 원인 Part 1: 와류 정지 및 와류 짝 현상)

  • Lee, Jung-Sang;Kim, Jin-Ho;Kim, Chong-Am
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.35 no.1
    • /
    • pp.1-9
    • /
    • 2007
  • Numerical simulation is conducted to investigate aerodynamic force generation mechanism for the "figure-of-eight" motion of Dipteran fly, Phormia-Regina. Wing trajectory is referred to experimental result, which was observed from the tethered flight under freestream condition. Numerical simulation shows that the lift is mainly generated during downstroke motion and the large amount of thrust is generated abruptly at the end of upstroke motion. In the present work, vortical structure in the wake and the pressure field around the airfoil are examined to understand the generation of lift and thrust. Consequently, the lift generation is related with the leading edge vortex which is developed by an effective angle of attack. And the thrust generation can be explained by vortex pairing in the flow field and by vortex staying in the pressure field.

3-D Finite Element Mesh Generation of Tires Considering Detailed Tread Pattern (상세 트레드 패턴을 반영한 3차원 타이어 유한요소 격자 생성)

  • Cho, Jin-Rae;Kim, Ki-Whan;Hong, Sang-Il;Kim, Nam-Jeon;Kim, Kee-Woon
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.27 no.10
    • /
    • pp.1615-1622
    • /
    • 2003
  • Being contacted directly with. ground, the tire tread part is in shape of complex patterns of variable ASDs(anti-skid depth) to satisfy various tire performances. However, owing to the painstaking mesh generation job and the extremely long CPU-time, conventional 3-D tire analyses have been performed by either neglecting tread pattern or modeling circumferential grooves only. As a result, such simplified analysis models lead to considerably poor numerical expectations. This paper addresses the development of a 3-D tire mesh generation considering the detailed tread pattern and shows that the contact pressure and frictional energy distribution of tires considering the detailed pattern become better than those by the simplified tire model.

Development of Cardiovascular Simulator with Control of Pulse Pressure for Pulse Wave Study (맥압조절이 가능한 맥파 연구용 심혈관계 시뮬레이터 개발)

  • Lee, Ju-Yeon;Kim, Jeauk U.;Shin, Sang-Hoon
    • Journal of the Institute of Electronics and Information Engineers
    • /
    • v.51 no.10
    • /
    • pp.204-209
    • /
    • 2014
  • The purpose of this study is to produce a simulator that can control a pulse pressure keeping the pulse wave transfer phenomenon. For this, the elastic tube is combined with a compliance chamber for the vessel part. The simulator is comprised of four parts; a pressure generation part with slider-crank mechanism, a vessel part with resistance controller, water reservoirs and a measurement part. The changes of waveform depending on the location of a chamber is examined to determine the position of a chamber. The effects of a chamber on the pulse pressure and the pulse wave transfer phenomenon were investigated. It showed that the simulator which had the chamber in upstream of tube produces pressure wave, being more similar to the clinical waveform than in downstream of tube. Furthermore, with the chamber, the simulator generates a pulse pressure, being more similar to the normal physiological values than without one. The chamber had little effect on the pulse wave velocity.

Investigation on Recuperative Cycle Gas Turbine Engine for Power Generation (발전용 가스터빈에서의 Recuperative 사이클 적용성 검토)

  • Kim SooYong;Son Ho-Jae;Goldenberg Victor
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • v.y2005m4
    • /
    • pp.225-230
    • /
    • 2005
  • It is theoretically known that recuperator can bring a significant increase in thermal efficiency of the gas turbine unit, but it also has disadvantages such as pressure loss in the flow channel, thermal stress and increase in weight. Therefore it is necessary to consider all pros and cons of this equipment in view of economic aspects throughout its life cycle. Recuperator has been applied mostly in the power ranges of $20\sim300kW$ class industrial units but hasn't been used as a larger power generation unit except for naval applications in mid twentieth century. Present paper considered the applicability of a recuperator cycle in term of pressure loss, part load aspects for power generation purpose.

  • PDF

Development of a Software System for Measurements of Combustion Dynamics of a Dry Low NOx Gas Turbine (건식 저 NOx 가스터빈의 연소동압 측정용 소프트웨어 시스템 개발)

  • Jang, Wook;Seo, Seok-Bin;Jung, Jae-Hwa;An, Dal-Hong;Kim, Jong-Jin;Cha, Dong-Jin
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.14 no.11
    • /
    • pp.931-938
    • /
    • 2002
  • Combustion dynamics of a dry low NOx gas turbine have been measured by utilizing a dynamic pressure measurement system. The software part of the measurement system, implemented with a commercial general-purpose DASYLab version 5.6 code, basically acquires combustion dynamics signals, performs the FFT analysis, and displays the results. The gas turbine often experiences momentary combustion instability, especially when its combustion mode changes. It is found that the measurement system developed in the study may outperform the other commercial dynamic pressure measurement system. The developed system currently serves to monitor the combustion dynamics of the gas turbine.

Noise Generation Of The Rotary Compressors From The Shell Vibration (로터리 컴프레서 쉘 진동에 의한 소음 방사)

  • 왕세명;박종찬;황인수;권병하
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2003.05a
    • /
    • pp.1206-1212
    • /
    • 2003
  • Shell vibrations of the rotary compressor, which account for considerable portion of the noise from compressor, are caused by various sources. Among them is the vibration of the in nor part or cylinder assembly, which undergoes severe compression process and rotational motion. But little researches have been carried out about the behavior and effect of the inner part because of its structural complexity. Furthermore, the shell of the rotary compressor is hermetic type that experimental approach is very difficult. This research studied the structure-born noise of the Rotary compressor using FE an analysis. The comparison between sound pressure spectrum and natural frequencies of the shell vibration implies that shell vibrations contribute significantly to the noise. It is found that inner part vibrations are responsible for those through the FE analysis. Design modification of the inner part, which shifts the target frequencies, reduced overall noise level of the compressor.

  • PDF