• 제목/요약/키워드: Static Pressure

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고고도환경을 고려한 SRM 압력계측배관에 관한 연구 (Study of a Pressure Tube for Measuring pressure of a Solid Rocket Motor at High Altitude Environment)

  • 이동원;이원복;고현석;길경섭
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2008년도 제30회 춘계학술대회논문집
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    • pp.53-56
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    • 2008
  • 일반적으로, 고체로켓모타에 대한 지상연소시험을 실시할 경우, 연소관 내부의 압력을 계측하기 위해 압력 계측용 배관에 기름을 채우고 그 끝에 압력센서를 연결하여 사용한다. 통상적으로 사용되어지는 이 방법은 지상연소시험을 실시할 경우에는 특별한 문제가 되지 않으나, 고고도 환경에서 점화되는 고체로켓모타의 압력계측은 배관 기름의 누출로 인한 점화성능 저하가 문제시된다. 이는 배관의 부착 위치가 통상적으로 전방 점화기 부위인 것에 기인한 것이며, 이러한 문제를 해결하기 위하여 본 논문에서는 기름을 사용하지 않는 압력배관을 어떻게 설계하고 검증하였는지에 대해 기술하도록 하겠다.

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이젝터 기술을 활용한 주방후드용 기류유인 덕트 시스템의 개발에 관한 연구 (Study on Development of Inducing Airflow Duct System for Kitchen Hood Using Ejector Method)

  • 손유라;홍성규;양정훈
    • 한국태양에너지학회 논문집
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    • 제39권6호
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    • pp.27-40
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    • 2019
  • Kitchen hoods are limited in discharging all contaminants produced during cooking. Contaminants that have not been discharged can rise to the upper part of the kitchen and become stacked. To solve this problem, there is a way to increase the air volume of the kitchen hood, but there are limits, so a new system is required. This study proposes the Duct System (IADK : Inducing Airflow Duct system for Kitchen hood )through 3D printers and experiments. To do this, the pressure is measured to verify the three levels of air volume provided by the kitchen hood. To check the degree of loss of flow in the existing kitchen hood system, install flexible ducts alone to measure the pressure. Change the internal diameter and type of connection of the IADK and measure the pressure. The air pressure, static pressure difference, and loss factor are calculated and analyzed using the pressure measured through the experiment.

압력센서 개발을 위한 탄소 나노 튜브 기반 지능형 복합소재 전왜 특성 연구 (A Study on Piezoresistive Characteristics of Smart Nano Composites based on Carbon Nanotubes for a Novel Pressure Sensor)

  • 김성용;김현호;최백규;강인혁;이일영;강인필
    • 드라이브 ㆍ 컨트롤
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    • 제13권1호
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    • pp.43-48
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    • 2016
  • This paper presents a preliminary study on the pressure sensing characteristics of smart nano composites made of MWCNT (multi-walled carbon nanotube) to develop a novel pressure sensor. We fabricated the composite pressure sensor by using a solution casting process. Made of carbon smart nano composites, the sensor works by means of piezoresistivity under pressure. We built a signal processing system similar to a conventional strain gage system. The sensor voltage outputs during the experiment for the pressure sensor and the resistance changes of the MWCNT as well as the epoxy based on the smart nano composite under static pressure were fairly stable and showed quite consistent responses under lab level tests. We confirmed that the response time characteristics of MWCNT nano composites with epoxy were faster than the MWCNT/EPDM sensor under static loads.

가스터빈용 소형 원심압축기의 탈설계점 성능에 관한 실험연구 (Experimental Study on Off-Design Performance of a Small Centrifugal Compressor for Gas Turbine Applications)

  • 오종식;이헌석;오군섭
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 2000년도 유체기계 연구개발 발표회 논문집
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    • pp.211-218
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    • 2000
  • Off-design experimental performance was investigated for a small centrifugal compressor, whose impeller diameter is about 125mm, used in an industrial gas turbine. Test rig was designed and manufactured with a radial inflow turbine and a combustor to supply driving power to the compressor. Static pressure was measured on the casing of the impeller, vaneless diffuser, vaned diffuser and volute. Total pressure was obtained using specially fabricated rakes at the vaned diffuser throat and exit. Circumferential nonuniformity was found, near surge, in the Impeller, vaned diffuser and volute region. Spanwise nonuniform flow from the impeller affected the total pressure defects in the vaned diffuser region. Static pressure distortion in the circumferential direction in the volute was found near surge, where the minimum occurred near 140 degree position.

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단이 진 경사벽면에 부착되는 2차원 제트유동에 관한 연구 (An investigation on flow characteristics of two dimensional inclined wall attaching offset jet)

  • 송흥복;심재경;윤순현
    • Journal of Advanced Marine Engineering and Technology
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    • 제22권1호
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    • pp.52-66
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    • 1998
  • An experimental study on the flow characteristics was performed for a two-dimensional turbulent wall attaching offset jet at different oblique angles to a surface. The flow characteristics were investigated by using a split film probe with the modified Stock's calibration method. The jet mean velocity, turbulent intensity, wall static pressure coefficient profiles, and time-averaged reattachment point were measured at the Reynolds number Re (based on the nozzle width, D) ranging from 17700 to 53200, the offset ratio H/D from 2.5 to 10, and the inclined angle .alpha. from 0.deg. C to 40.deg. C. The Correlations between the maximum pressure position, minimum pressure position, and reattachment point and offset ratios, and inclined angles are presented.

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유입 선회류에 대한 원추디퓨져내의 속도분포와 정압회복특성에 관한 연구 (A Study on Flowfield and Pressure Recovery in a Conical Diffuser with a Swirl Flow)

  • 정효민;고대권;양정규
    • 수산해양기술연구
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    • 제28권2호
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    • pp.151-156
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    • 1992
  • The purpose of this paper is to investigate the relationship between static pressure recovery and velocity distributions in case of swirling flow into a conical diffuser. In this research, velocity distribution is measured by a multi-hole yaw-meter. The following conclusions can be drawn from the experiments. (1) The static pressure recovery depends strongly on the strength of a swirl. (2) A high pressure recovery coefficient is achieved by inserting a solid core into the diffuser center.

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가스터빈 베인 끝벽의 열전달 특성 및 정압분포 측정 (Measurement of Heat Transfer and Pressure Distributions on a Gas Turbine Vane Endwall)

  • 이용진;신소민;곽재수
    • 한국항공운항학회지
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    • 제14권2호
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    • pp.33-38
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    • 2006
  • Heat transfer coefficients and static pressure distributions on a gas turbine vane endwall were experimentally investigated in a 5 bladed linear cascade. The Reynolds number based on an axial chord length and the cascade exit velocity was 500,000. Both heat transfer and pressure measurements on the vane endwall were made at the two different turbulence intensity levels of 6.8% and 10.8%. Detailed heat transfer coefficient distributions on the vane endwall region were measured using a hue detection based transient liquid crystals technique. Results show various regions of high and low heat transfer coefficients on the vane endwall surface due to several types of secondary flows and vortices. Heat transfer coefficient and endwall static pressure distributions showed similar trends for both turbulence intensity, however, the averaged heat transfer coefficients for higher turbulence intensity case was higher than the lower turbulence intensity case by 15%.

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비례감압밸브의 압력제어특성 (Pressure Control Characteristics of Proportional Pressure Reducing Valve)

  • 윤소남;함영복;조정대
    • 동력기계공학회지
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    • 제7권1호
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    • pp.68-73
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    • 2003
  • The purpose of this study is to develop a new proportional pressure reducing valve and to verify the validity of a new mechanism with pressure control pin. The dynamic characteristics of the object pressure reducing valve was studied by numerical analysis of the mathematical model. Also, static and dynamic characteristics of the new pressure control valve were tested with a testing system based on the test standard.

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휠체어 추진속도 및 등받이 경사각도에 따른 둔부 압력 변화 특성 (Characteristics of the Buttock Interface Pressure According to Wheelchair Propulsion Speed and Various Back Reclined Seating Position)

  • 권혁철;공진용
    • 한국전문물리치료학회지
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    • 제12권2호
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    • pp.1-10
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    • 2005
  • Pressure ulcers are serious complications of tissue damage that can develop in patients with diminished pain sensation and diminished mobility. Pressure ulcers can result in irreversible tissue damage caused by ischemia resulting from external loading. There are many intrinsic and extrinsic contributors to the problem, including interface tissue pressure, shear, temperature, moisture, hygiene, nutrition, tissue tolerance, sensory and motor dysfunction, disease and infection, posture, and body support systems. The purposes of this study were to investigate the relationship between buttock interface pressure and seating position, wheelchair propulsion speed. Seated-interface pressure was measured using the Force Sensing Array pressure mapping system. Twenty subjects propelled wheelchair handrim on a motor-driven treadmill at different velocities (40, 60, 80 m/min) and seating position used recline ($100^{\circ}$, $110^{\circ}$, $120^{\circ}$) with a wheelchair simulator. Interface pressure consists of average (mean of the pressure sensor values) and maximum pressure (highest individual sensor value). The results of this study were as follows; No significant correlation in maximum/average pressure was found between a static position and a 40 m/min wheelchair propulsion (p>.05). However, a significant increase in maximum/average pressure were identified between conditions of a static position and 60 m/min, and 80 m/min wheelchair propulsion (p<.05). No significant correlation in maximum pressure were found between a $90^{\circ}$ recline (neutral position) and a $100^{\circ}$, $110^{\circ}$, or $120^{\circ}$ recline of the wheelchair back (p>.05). No significant difference in average pressure was found between conditions of a $90^{\circ}$ recline and both a $100^{\circ}$ and $110^{\circ}$ recline of wheelchair back. However, a significant reduction in average pressure was identified between conditions of a $90^{\circ}$ and $120^{\circ}$ recline of wheelchair back (p<.05). This study has shown some interesting results that reclining the seat by $120^{\circ}$ reduced average interface pressure, including the reduction or prevention in edema. And interface pressure was greater during dynamic wheelchair propulsion compared with static seating. Therefore, the optimal seating position and seating system ought to provide postural control and pressure relief. We need an education on optimal seating position and a suitable propulsion speeds for wheelchair users.

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폭굉을 고려한 압력용기 최대허용압력 결정방법의 제안 (Method for Determination of Maximum Allowable Pressure of Pressure Vessel Considering Detonation)

  • 최진복
    • 한국전산구조공학회논문집
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    • 제31권5호
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    • pp.235-241
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    • 2018
  • 압력용기의 내압은 압력용기 설계의 중요한 인자이며 이를 바탕으로 관련 설계기준 및 구조해석결과에 따라 압력용기의 두께 및 직경과 같은 기하학적 형상이 결정된다. 그러나 압력용기 내부에서 폭굉이 일어날 경우 이 폭굉압력을 적절히 고려하여 압력용기를 설계할 수 있는 설계기준은 미흡한 실정이다. 일반적으로 폭굉이 발생할 경우, 초기 폭굉압력이 용기 벽면에 도달하여 반사하는 반사압력은 초기압력의 2배 이상이라고 알려진다. 그러나 폭굉압력은 구조물의 고유주기보다도 짧은 시간 안에 최대치에 도달한 후 급격하게 감소하는 경향을 보이며, 이 경우 실제 용기벽면이 받게 되는 압력은 반사압력에 비해 매우 작을 수 있다. 따라서 본 연구에서는 이러한 폭굉의 특성을 고려하여 압력용기가 견뎌야 하는 적절한 등가의 폭굉압력을 산정하는 방법을 제안함으로써 폭굉을 고려한 효율적인 압력용기 설계기준을 제시하고자 하였다.