• Title/Summary/Keyword: High-Differential Pressure

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An Experimental Study on the Analyze the Pressure Difference in case of Fire in Vertical Space of High-Rise Buildings (고층건축물 수직공간의 화재 시 압력차 분석을 위한 실험적 연구)

  • Huh, Yerim;Kim, HyeWon;Jin, SeungHyeon;Kwon, YoungJin
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2020.06a
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    • pp.111-112
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    • 2020
  • As buildings in South Korea become more skyscrapers, the risk of fire is also emerging. Thus, regulations, regulations, and guidelines are being improved to prevent the spread of smoke in the event of a fire in high-rise buildings, but research on smoke flow and pressure distribution in vertical spaces is insufficient. Therefore, in this study, the temperature of each floor in the vertical space according to the size of the fire is measured through the miniature model experiment, and the pressure difference is calculated to establish the basic data for the improvement of the performance of domestic air supply facilities in the future. Thus, a scale model of one-sixth the size of the actual building was produced to measure the temperature, and the pressure difference was derived by substituting the value for the expression. The pressure difference varies depending on the size of the cause of the fire, and it is believed that the differential pressure and conditions of the building should be taken into account before calculating the supply volume for the analysis of the pressure difference according to the size of the cause of the fire in the event of fire.

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Study on Static Pressure Error Model for Pressure Altitude Correction (기압 고도의 정밀도 향상을 위한 정압 오차 모델에 관한 연구)

  • Jung, Suk-Young;Ahn, Chang-Soo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.4
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    • pp.47-56
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    • 2005
  • In GPS/INS/barometer navigation system for UAV, vertical channel damping loop was introduced to suppress divergence of the vertical axis error of INS, which could be reduced to the level of accuracy of pressure altitude measured by a pitot-static tube. Because static pressure measured by the pitot-static tube depends on the speed and attitude of the vehicle, static pressure error models, based on aerodynamic data from wind tunnel test, CFD analysis, and flight test, were applied to reduce the error of pressure altitude. Through flight tests and sensitivity analyses, the error model using the ratio of differential pressure and static pressure turned out to be superior to the model using only differential pressure, especially in case of high altitude flight. Both models were proposed to compensate the effect of vehicle speed change and used differential and static pressure which could be obtained directly from the output of pressure transducer.

Power Generation and Control System Using Differential Pressure of District Heating Pipeline in a Substation (지역난방 사용자기계실 내 열수송관 차압을 이용한 발전 및 제어 기술)

  • Kim, Kyung Min;Park, Sung Yong;Oh, Mun Sei
    • Journal of Energy Engineering
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    • v.26 no.3
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    • pp.90-96
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    • 2017
  • When the hot water is supplied through the district heating (DH) pipeline, a pressure differential control valve (PDCV) protects the DH user equipment from the high pressure DH water and helps to supply DH water to long distance. It also controls the temperature and adjust the pressure in the main district heating pipeline. However, cavitation occurs in PDCV due to the use of high pressure DH water. It causes frequent failures and many problems. It also causes energy loss and complaints to both operators and users. In order to solve these problems, we will introduce the energy saving technology to replace the primary side PDCV with hydraulic turbine, convert the differential pressure into electricity, and utilize electricity as the power of the secondary side pump.

Fabrication of Single Capacitive type Differential pressure sensor for Differential Flow meter (차압식 유량계를 실장을 위한 Single Capacitive Type Differential 압력 센서 개발)

  • Shin, Kyu-Sik;Song, Sangwoo;Lee, Kyungil;Lee, Daesung;Jung, Jae Pil
    • Journal of the Microelectronics and Packaging Society
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    • v.24 no.1
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    • pp.51-56
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    • 2017
  • In this paper, we have developed a differential pressure flow sensor designed as a single capacitive type. And the sensor was fabricated using a MEMS process. Differential pressure flow sensors are the most commonly used sensors for industrial applications. The sensing diaphragm and bonding joint of the MEMS pressure sensor are easily broken at high pressure. In this paper, we proposed a structure in which the diaphragm of the sensor was not broken at a pressure exceeding the proof pressure, and the differential pressure sensor was designed and manufactured accordingly. The operating characteristics of the sensor were evaluated at a pressure three times higher than the sensor operating pressure (0-3 bar). The developed sensor was $3.0{\times}3.0mm$ and measured with a LCR meter (HP 4284a) at a pressure between 0 and 3 bar. It showed 3.67 pF at 0 bar and 5.13 pF at 3 bar. The sensor operating pressure (0-3 bar) developed a pressure sensor with hysteresis of 0.37%.

Numerical analysis of the differential pressure venturi-cone flowmeter (차압식 벤튜리콘 유량계에 대한 유동해석)

  • 윤준용;맹주성;이정원
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.10 no.6
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    • pp.714-720
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    • 1998
  • The differential pressure venturi-cone flowmeter is an advanced flowmeter which has many advantages such as wide range of measurement, high accuracy, excellent flow turn-down ratio, low headless, short installation pipe length requirement, and etc. Like other differential pressure flowmeters, the venturi-cone flowmeter uses the law of energy conservation, but its shape and position make it perform better than others. The cone acts as its own flow conditioner and mixer, fully conditioning and mixing the flow prior to measurement. For the analysis, we used Reynolds-averaged Wavier-Stokes equations and k-$\omega$ turbulence model. The equations were fully transformed into the computational domain, the pressure-velocity coupling was made through SIMPLER algorithm, and the equations were discretized using finite analytic solutions of the liberalized equations(Finite Analytic Method). To control the separation phenomenon on the cone surface, we proposed a new shape of cone, and analyzed the flowfield in the new flowmeter system, and found the improvement on the performance of the new cone flowmeter.

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Digital Blood Pressure Estimation with the Differential Value of the Arterial Pulse Waveform (맥파의 차동값에 의한 디지털 방식의 혈압 추정 기법)

  • Kim, Boyeon;Chang, Yunseok
    • KIPS Transactions on Computer and Communication Systems
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    • v.5 no.6
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    • pp.135-142
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    • 2016
  • We proposed the new method to estimate the blood pressure with the differential value of the digital arterial pulse waveform and BP relation equation. To get the digital arterial pulse waveform, we use the arterial pulse waveform measurement system that has digital air-pressure sensor device and smart phone. The acquired digital arterial pulse waveforms are classified as hypertension group, normal group, and hypotension group, and we can derive the average differential value between the highest point and lowest point of a single waveform of individuals along with the group. In this study, we found the functional correlation between the blood pressure and differential value as a form of BP relation equation through the regression process on the average of differential value and blood pressure value from a tonometer. The Experimental results show the BP relation equation can give easy blood pressure estimation method with a high accuracy. Although this estimation method has over 66 % error rate and does not give the high level of the accuracy for the diastolic compares to the commercial tonometer, the estimation results for the systolic show the high accuracy that has less than 10 % error rate.

A Study on the Performance Improvement Plan of Inflowing Air Emission (유입 공기의 배출 성능 개선방안에 관한 연구)

  • Lee, Hye-Young
    • Journal of the Society of Disaster Information
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    • v.18 no.2
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    • pp.241-251
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    • 2022
  • Purpose: In the event of a fire in a high-rise building, if the smoke control area is not effectively protected, smoke or flames enter the stairwell, making it difficult to evacuate. When inflowing air is discharged from a closed corridor, a negative pressure is formed in the corridor, the pressure in the smoke control area becomes excessively high, and the force required to open the door during evacuation is exceeded. Also, if the air introduced into the hallway is not exhausted, the smoke may flow back into the smoke control area. This paper tried to identify the problems caused by the inflowing air and to find out how to improve the performance. Method: Using the CONTAM program, simulations were performed with the basic conditions and the modified conditions. Result: If the inflowing air was discharged from the sealed corridor, overpressure occurred in the Smoke Control Area and exceeded the opening force, and the prevent smoke backflow was insufficient in the layer where the inflowing air was not discharged. Conclusion: "Differential pressure exhaust damper" application, simultaneous opening of two exhaust dampers, and automatic window installation between corridors and outdoors improved the exhaust performance of inflowing air.

A Study on the Flow Coefficient Test and Numerical Analysis about 1500lb High-Pressure Drop Control Valve for Boiler Feedwater Pump (보일러 급수펌프용 1500lb 고차압 제어밸브 유량시험 및 수치해석에 관한 연구)

  • Lee, Kwon-Il;Jang, Hoon;Lee, Chi-Woo
    • Journal of the Korean Society of Industry Convergence
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    • v.25 no.4_2
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    • pp.541-547
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    • 2022
  • Before making a prototype, we predicted the inlet/outlet differential pressure and flow coefficient, which are the most basic design data for the valve through the design and numerical analysis of the trim, which is the most important in the localization development of the 1500Ib high differential pressure control valve used for boiler feed water. As a result, the design value and the analysis value were found to be about 98% similar. The flow field within the fluid velocity of 23m/s to prevent cavitation was also found. The result of the numerical analysis on thermal stress due to the characteristics of valves exposed to high temperatures showed that it was found to be about 18% less than the allowable stress of the bolt fixing the trim. When all loads such as pressure, self-weight, and vibration are applied, however, it is judged to go beyond the currently calculated thermal stress, exceeding the allowable stress.

A Study on the Analysis of Various Characteristics for the High Pressure are Discharge System (고압 아아크 방전시스템의 각종 특성 해석에 관한 연구)

  • 지철근;박왕열;이진우
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.5 no.4
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    • pp.35-42
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    • 1991
  • Recently, HID lamps have been considered as important in regard to the trend of energy saving, and increasingly and diversely used in various ways. This paper will show the simulating models concerning high-pressure arc discharge system directly applicable for its design and manufacture, and analyze its various characteristics. For warm-up characteristics, the evaporating process of inner atoms is described in terms of second-order differential equation: for the thermal conduction from are axis to discharge wall and outer bulb, its transfer process is introduced according to five first-order differential equations. Under the steady state satisfying LTE, the time-variant characteristics are suggested by means of time-dependent energy balance equation derived from fluid equations, approximation of radiation energy and material functions in the discharge tube. The simulating models concerning these equations are then applied for high-pressure mercury lamp.

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A Study on the Bounding Value of Valve Performance Parameters for Motor Operated Flexible Wedge Gate Valve (모터구동 Flexible Wedge형 게이트밸브의 밸브 성능인자 Bounding Value에 대한 연구)

  • Kim, Dae-Woong;Yoo, Seong-Yeon;Park, Sung-Keun;Lee, Do-Hwan
    • The KSFM Journal of Fluid Machinery
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    • v.10 no.5
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    • pp.46-53
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    • 2007
  • Stem friction coefficient and valve factor are very important parameters for the evaluation of valve performance. In this study, the characteristics of stem friction coefficient and valve factor are analyzed, and thor bounding value is determined. The hydraulic testing is performed for many flexible wedge gate valves in the plant and statistical method is applied to the determination of bounding value. According to the results of this study, stem friction coefficient does not change much with differential pressure, and the bounding value of closing stroke is higher than that of opening stroke. The valve factor of valves with high differential pressure is higher than that of valves with medium differential pressure. It means valve factor is more sensitive to the differential pressure than the stem friction coefficient. Valve factor of the closing stroke is higher than that of opening stroke due to piston effect.