• Title/Summary/Keyword: J-노즐

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Effect of Swirl Angle on the Atomization Characteristics in Twin-Fluid Nozzle with Dual Air Supplying (이중공기공급 2-유체 노즐의 선회각 변화에 따른 미립화 특성)

  • Woo, J.M.;Kim, E.S.;Kim, D.J.;Lee, J.K.
    • Journal of ILASS-Korea
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    • v.13 no.3
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    • pp.126-133
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    • 2008

  • The atomization characteristics of the dual air supplying two-fluid nozzle were investigated experimentally using PIV and PDA systems. The twin-fluid nozzle is composed of three main parts: the feeding injector to supply fluid that is controlled by a PWM (pulse-width modulation) mode, the adaptor as a device with the ports for supplying the carrier and assist air, and the main nozzle to produce sprays. The main nozzle has the swirler with four equally spaced tangential slots, which gives the injecting fluid an angular momentum. The swirl angle in the swirler varied with $0^{\circ}$, $30^{\circ}$, $60^{\circ}$ and $90^{\circ}$. The ratios of carrier air to assist air and ALR (total air to liquid) were 0.55 and 1.23, respectively. The macroscopic behavior of the spray was investigated using PIV system, and the AMD and SMD distributions of the sprays were measured using PDA system. As a result, the SMD distribution increases along the radial distance, and it decreases with the increase of swirl angle in swirler.

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An Experimental Study on the Drop Size of a Twin-Fluid Swirl Jet Nozzle (이유체 선회분사 노즐의 액적크기에 관한 실험적 연구)

  • Oh, J.H.;Kim, W.T.;Kang, S.J.;Rho, B.J.
    • Journal of ILASS-Korea
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    • v.1 no.1
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    • pp.21-27
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    • 1996

  • This experimental study was to investigate spray angles and drop sizes in an external mixed twin-fluid swirl jet nozzle. Twin-fluid swirl jet nozzle with swirlers designed four swirl angles such as $0^{\circ},\;22.5^{\circ},\;45^{\circ},\;64.2^{\circ}$ was employed. A PDA system was utilized for the measurement of drop size and mean velocity. Water and air were used as the working fluids in this experiment. The mass flow rate of water was fixed as 0.03 kg/min, and air flow rates were controlled to have the air/liquid mass ratio from 1.0 to 6.0. As a result, swirl angle controlled to spray angles and drop sizes. It was found that swirl angle was increased with spray angle and with decreased SMD. However, the effect of swirl angle was reduced at large air/liquid mass ratio(Mr=6.0).

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Atomization Characteristics of 2-Phase Atomizer with the change of Mixing Chamber Structure (혼합실 구조 변경에 의한 2상 노즐의 미립화 특성)

  • Ha, M.H.;Kim, K.C.;NamKung, J.H.;Lee, S.G.;Rho, B.J.;Kang, S.J.
    • Proceedings of the KSME Conference
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    • 2001.11b
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    • pp.699-704
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    • 2001

  • The purpose of this study is to present the atomization characteristics of 2-phase internal mixing nozzle. The obtained results are considered as the essential information of understanding the spray characteristics from the nozzle exit of an aerated nozzle. In this study, SMD and AMD are mainly measured at the distance of Z=10, 20, 50, 80, 120 and 170mm from the nozzle tip. The liquid flow rate was kept at 1.8g/s and the air feeding pressure was changed from 10kpa to 100kpa increasingly. The analysis of the acquired data was performed by 2-D PDPA system and in order to get the realibility, the number of data used in calculating the SMD & AMD were 10,000 samples.

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Effects of Carrier Air Supplying Parameter on the Internal Flow Characteristics of an Adaptor in Two-Fluid Nozzle (이유체노즐의 액체이송공기 공급방법에 따른 어뎁터 내부유동특성에 관한 해석적 연구)

  • Park, S.H.;Cho, M.H.;Kim, D.J.;Lee, J.K.;Rho, B.J.
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.65-70
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    • 2008

  • The numerical simulation on the internal flow characteristics of the adaptor in a two-fluid nozzle has been performed to investigate the effects of carrier air supplying parameters using a commercial code. The four adaptor models with the different positions in the carrier air supplying port were considered at the fixed conditions of urea-water solution and carrier air supplying. As the results from the numerical analysis, the internal pressure of the adaptor was varied with the port position for carrier air supplying, and it shows lower pressure value than the atmospheric pressure. Consequently, the flowrate of urea-water solution issuing from the feeding injector with the adaptor varied up to 30% with the port positions for the carrier air supplying. When the carrier air is supplied from the side from the feeding injector axis and the upper part from the feeding injector tip, the flowrate of urea-water solution issuing from the feeding injector with the adaptor show higher value than other carrier air supplying conditions.

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Sensitivity Analysis of Nozzle Geometry Variables for Estimating Residual Stress in RPV CRDM Penetration Nozzle (원자로 상부헤드 관통노즐의 잔류응력 예측을 위한 노즐 형상 변수 민감도 연구)

  • Bae, Hong Yeol;Oh, Chang Young;Kim, Yun Jae;Kim, Kwon Hee;Chae, Soo Won;Kim, Ju Hee
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.3
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    • pp.387-395
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    • 2013

  • Recently, several circumferential cracks were found in the control rod drive mechanism (CRDM) nozzles of U.S. nuclear power plants. According to the accident analyses, coolant leaks were caused by primary water stress corrosion cracking (PWSCC). The tensile residual stresses caused by welding, corrosion sensitive materials, and boric acid solution cause PWSCC. Therefore, an exact estimation of the residual stress is important for reliable operation. In this study, finite element simulations were conducted to investigate the effects of the tube geometry (thickness and radius) on the residual stresses in a J-groove weld for different CRDM tube locations. Two different tube locations were considered (center-hole and steepest side hill tube), and the tube radius and thickness variables ($r_o/t$=2, 3, 4) included two different reference values ($r_o$=51.6, t=16.9mm).

  • https://doi.org/10.3795/KSME-A.2013.37.3.387 인용 PDF KSCI

A Study on the Characteristic of Impinging Pressure Distribution in the Three Dimensional Impinging Water Jet (삼차원(三次元) 수분류(水噴流)의 충돌(衝突) 압력(壓力) 분포(分布) 특성(特性)에 관(關)한 연구(硏究))

  • Lee, J.S.;Choi, K.K.
    • Solar Energy
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    • v.18 no.3
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    • pp.217-228
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    • 1998

  • The purpose of this research is to investigate the characteristics of static and total pressure distribution in the upward free water jet system impinged on a downward flat plate. The rectangular nozzle was used and its contraction and aspect ratio was five and about seven respectively. Experimental conditions considered were jet velocity, distance between nozzle and flat plate, height of supplementary water. It was founded that pressure distribution on the flat plate had the Gaussian curve when the pressure at stagnation point and impinging half width were chosen as the scaling parameters. The maximum pressure was shown at the stagnation point. The central impingement velocity decreased with the increment of distance between nozzle and flat plate, and its slop of decay was similar to that of chracteristics decay region in the three-dimensional free jet.

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