• Title/Summary/Keyword: Pressure drop

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A New Correlation on Pressure Drop in Horizontal Multi Channels (수평 다채널에서의 압력강하에 관한 새로운 상관식)

  • CHOI, Yong-Seok;LIM, Tae-Woo;YOU, Sam-Sang;KIM, Hwan-Seong
    • Journal of Fisheries and Marine Sciences Education
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    • v.28 no.5
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    • pp.1273-1279
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    • 2016
  • Flow boiling pressure drop in multi channels was experimently investigated. The multi channel has a width and depth of 0.45 and 0.2mm respectively, and comprises 15 parallel channels. The measured total pressure drop is expressed by the sum of the frictional pressure drop and acceleration pressure drop. In order to predict the total pressure drop, it is required to obtain the correct frictional pressure drop. The existing correlations to predict the frictional pressure were compared with measured frictional pressure drop. The new correlation was developed in the form of the Chisholm correlation. It was related to Chisholm Constant B as a function of Martinelli parameter. The new correlation predicted the experimental data within a mean absolute error of 5.5%.

Static Pressure Drop of Airflow in Packed-bed of Fruits and Vegetables (청과물 퇴적층에서의 공기유동 정압강하)

  • 김의웅;김병삼;남궁배;정진웅;김동철;금동혁
    • Journal of Biosystems Engineering
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    • v.21 no.1
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    • pp.44-51
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    • 1996
  • The purpose of this paper is to obtain the basic data for design of pressure cooling system. Static pressure drop, as a function of superficial velocity, was measured for different stacking methods and stacking heights of some fruits and vegetables. At given superficial velocity, sphericity and void fraction had a much greater influence on static pressure drop than average diameter of spherical fruits such as apple, peach, tomato and kiwi fruit. Among cylindrical vegetables such as cucumber, carrot, radish and chinese cabbage, cucumber showed different pattern of static pressure drop because of its bended shape, radish showed less static pressure drop than other vegetables because its large sizes of voids. When cucumber and spinach were stacked vertically and horizontally to air flow, a much greater static pressure drop was shown in vertical than in horizontal type, therefore static pressure drop was affected not only by void fraction but also by void shape. Also, in packed-beds of fruits and vegetables, static pressure drop could be estimated very well by Ramsins equation.

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Pressure Drop in Two-Phase Flow Boiling of R134a, R123 and Their Mixture in Horizontal Tube

  • Lim, Tae-Woo
    • International Journal of Air-Conditioning and Refrigeration
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    • v.12 no.2
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    • pp.70-78
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    • 2004
  • An experimental study on the pressure drop during flow boiling for pure refrigerants Rl34a and R123, and their mixture was carried out in a uniformly heated horizontal tube. Tests were run at a pressure of 0.6㎫ and in the ranges of heat flux 5-50㎾/$m^2$, vapor quality 0-100 percent and mass velocity of 150-600 kg/$m^2$s. Generally, the two-phase frictional multiplier is used to predict the frictional pressure drop during the two-phase flow boiling. The obtained results have been compared to the existing various correlations for the two-phase multiplier. Also, the frictional pressure drop was compared to a few available correlations; The Lockhart-Martinelli correlation considerally overpredicted the frictional pressure drop data for mixture as well as pure components in the entire mass velocity ranges employed in the present study, while the Chisholm correlation underpredicted the present data. The Friedel correlation was found to satisfactorily correlate the frictional pressure drop data except for a low quality region.

Evaluation of Condensation Pressure Drop Correlations for Microfin Tubes

  • Han, Dong-Hyouck;Lee, Kyu-Jung
    • International Journal of Air-Conditioning and Refrigeration
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    • v.15 no.4
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    • pp.169-174
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    • 2007
  • The characteristics of nine existing condensation frictional pressure drop correlations for microfin tubes were evaluated with geometries, vapor quality, mass flux, and refrigerants. The $M\ddot{u}ller-Steinhagen$ and Heck [17] smooth tube frictional pressure drop correlation was utilized to evaluate the pressure drop penalty factor (PF). Except the Nozu et al. [2], the Kedzierski and Goncalves [3], the Choi et al. [10], and the Cavallini et al. [7], other pressure drop correlations did not consider the effect of tube geometry. The prediction values for R407C by pressure drop correlations show discrepancy with previous researcher's experimental trend. Additional efforts on the development of reliable condensation pressure drop correlation for microfin tubes are still required with the systematic investigation of various effects like geometries and working conditions.

Influence of Velocity on Pressure Drop of Flowing Ice Slurry in Elbow and its continued Inclined Tube (곡관과 연속된 경사관 내에서 유동하는 아이스슬러리의 압력손실에 미치는 유속의 영향)

  • Park Ki-Won;Kim Kyu-Mok
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.7
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    • pp.635-641
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    • 2005
  • This study experimented to understand the effects of transporting ice slurry through elbow and inclined tube. And at this experiment it used propylene glycol-water solution and a diameter of about 2mm ice particle. The experiments were carried out under various conditions, with velocity of water solution at the entry ranging from 1.0 to 3.5 w/s and elbows and inclined tubes of 4 kinds angle with $30^{\circ},\;45^{\circ},\;90^{\circ}\;and\;180^{\circ}$. The pressure drop between the tube entry and exit were measured. According to angle of bending, the highest pressure drop was measured at $30^{\circ}$ elbow and the lowest pressure drop was measured at $90^{\circ}$ elbow, and there are only a little differences of pressure drop between $45^{\circ}$ elbow and $180^{\circ}$ elbow. According to angle of inclined tube, the highest pressure drop was measured at $90^{\circ}$ inclined tube and the pressure drop at $45^{\circ},\;30^{\circ},\;180^{\circ}$ inclined tubes were lower successively. The lowest pressure drop in elbows and inclined tubes was measured at velocity of $2.0\~2.5$ m/s and concentration of $10\;wt\%$.

Pressure Drop in a Circular Pipe of Waste Collection Piping System (쓰레기 관로 이송 시스템의 관로 압력강하 평가)

  • Jang, Choon-Man;Lee, Sang-Yun;Suh, Sang-Ho
    • The KSFM Journal of Fluid Machinery
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    • v.10 no.4
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    • pp.55-60
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    • 2007
  • This paper describes an evaluation method of pressure drop in a circular pipe of waste collection piping system. Accurate pressure drop in a piping system is very important to determine the capacity of turbo blower, which is one of the main elements in the system. Three-dimensional Navier-Stokes analysis is introduced to analyze the pressure drop in the piping system. Organic waste is selected and modeled using the result of site survey performed in an apartment area. Evaluation method of pressure drop used In the present numerical simulation is performed in the shortened pipe line prior to the calculation of the real system. Throughout the numerical simulation, pressure drop in a waste pipe is obtained and compared to the value determined by analytical method. The pressure drop obtained by numerical simulation has a good agreement with that of the analytic method. It is noted that present evaluation method is effective to determine a pressure drop in the piping system. Detailed flow characteristics inside the pipe line are also analyzed and discussed.

CAE/CFD Analysis and Design of High-Pressure Drop Control Valve for Offshore Project (해양플랜트용 고차압 제어밸브의 해석 및 설계)

  • Jang, Sung Cheol;Park, Tae-Soo;Hur, Nam-Soo;Kim, In-Whan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.14 no.5
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    • pp.42-49
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    • 2015
  • In this study, the multi-disk of a high-pressure drop control valve is designed and manufactured. Then, the flow rate and high-pressure drop of fluids flowing in the high-pressure drop control valve is CAE/CFD. This study involves numerical analysis for the Zambil offshore project of a high-pressure drop control valve. ANSYS used a solver for offshore structures analysis. A high-pressure drop control valve, which transforms the power transfer of a system by reducing the inlet pressure of 345bar to the outlet pressure of 112bar, is a fundamental component in the offshore process. This study not only analyzes the relation between pressure drop and fluid velocity in a trim by using fluid analysis, but also examines the possibility of cavitation in a valve in addition to the plot for the extension of lifespan. It is demonstrated that the pressure drop from 345bar to 112bar is more feasible in the presence of the trim, which can induce a continuous and diminutive pressure drop in order to prevent cavitation in a high-pressure drop control valve.

Evaluation of Pressure Drop in a Circular Pipe of Refuse Collecting System (쓰레기 관로이송 시스템에서의 관로 압력손실 평가)

  • Kim, Dong-Woo;Jang, Choon-Man
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2615-2620
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    • 2007
  • This paper describes on pressure drop in a circular pipe of refuse collecting system. The flow characteristics inside the circular pipe are analyzed by three-dimensional Navier-Stokes analysis. In numerical analysis, an organic waste is modeled using the data obtained by site survey. Pressure drop obtained by numerical simulation is compared to the value obtained by experimental measurements for the two kinds of pipe; straight and bended type. The pressure drop obtained by numerical simulation has a good agreement with that of experiments. It is noted that the accurate prediction of pressure drop in the waste pipe is very important to determine the performance of turbo blower used in making a suction pressure in the waste pipe. Especially, the pressure drop for an organic waste is analyzed according to the mass flow rate of waste.

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The study on the measurement for the pressure drop and friction factor of corrugated metal pipes (주름관에서의 압력강하와 마찰손실 계측에 관한 연구)

  • Yun, Young-Sun;Kang, Jun-One;Yoo, Jai-Suk;Kim, Hyung-Jung
    • Journal of the Korean Society of Visualization
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    • v.4 no.2
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    • pp.76-80
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    • 2006
  • The data for friction factor of the pipe correlated by Reynolds number and relative roughness have been reported well as a Moody chart. However, the results for corrugated shapes have been not investigated sufficiently. In this research, therefore, the pressure drop and friction factor are obtained. Flexible metal tubes with corrugations for the measurement are made of stainless steel plates. The kinds of tubes for the measurement are 5 annular types and helical types. The pressure drop & the velocity of the flow are obtained by micromanometer & digital pressure sensor, supplying dry air at several steps. Then the pressure drop is calculated for each tube, using the obtained data. The result shows that the pressure drop is strongly influenced by the viscous dissipation of kinetic energy due to the circulation of flows, rather than a viscous friction loss. The pressure drop increased consistently as the Reynolds number increases.

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Experimental Study on Flow Patterns and Pressure Drop Characteristics of Ice Slurry in Small Size Pipe (2) (소구경 배관내 아이스슬러리의 유동형상 및 압력강하 특성에 관한 실험적 연구(2))

  • 이동원;윤찬일;주문창
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.14 no.5
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    • pp.391-397
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    • 2002
  • Pressure drop were experimentally investigated for ice slurry flowing in the acrylic pipes with inner diameter of 24 mm. Ice slurry was made from 6.5% ethylene glycol-water solution, and the pipes is consisted of horizontal, vertical (upward and downward) and $90^{\circ}$ elbow pipe. The ice Packing factor (IPF) and the flow rate of the experiments were varied from 0 to 30% and from 5 to 70kg/min respectively The measured pressure drop in various pipe positions were compared with those for the solution flow (IPF=0). The pressure drop was larder than that for solution flows as the IPF increased when the flow rate was low or very high. Sharp increases in pressure drop were observed for the cases when IPF is more than 70% in horizontal and vertical pipes, whereas the pressure drop increased with the IPF simultaneously in an elbow pipe.