• Title/Summary/Keyword: Breakup point

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Analysis of the Spray Distribution Characterization of Impinging Jet Injectors for Liquid Rockets Using PLIF Technique (PLIF 기법을 이용한 액체로켓용 충돌분사 인젝터의 분무분포 특성 해석)

  • 정기훈;윤영빈;황상순
    • Journal of the Korean Society of Propulsion Engineers
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    • v.4 no.1
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    • pp.36-45
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    • 2000
  • Most researches for impinging jet spray have been focused on under-standing the breakup mechanism of a liquid sheet formed by the collision of jets and modeling the spray breakup using experimental data. For this reason, there have been few studies on the characteristics of the spatial spray distribution which affects significantly the combustion efficiency. Hence, we measured the radial distribution of fuel massflux using a like-doublet type injector. Instead of PDPA(Phase Doppler Particle Analyzer) which has been used only for the point measurement of the drop size of spray, PLIF(Planar Laser Induced Fluorescence) technique was developed lot the 2-D measurement of the massflux distribution of spray Indirect photography technique was also used to verify PLIF data.

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A Study on the Psychological Contract Violation of Company Members by Affiliates Separation of LX HAUSYS (LX하우시스 계열분리에 따른 기업 구성원이 인지한 심리적 계약위반에 관한 연구)

  • Kim, SungGun;Lee, SungJun
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.18 no.2
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    • pp.111-125
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    • 2022
  • The general view of the division of affiliates of many large corporations is a reorganization of the governance structure, and the smooth division of affiliates is often well wrapped up in a beautiful breakup. However, the parties to the breakup are not only the owners of the company, but all employees as well. Separation of the owner family can be done with joy and good feelings, because they are separated according to the will of the owner family, and each becomes the owner of the company. As Commitment decreases and turnover behavior appears, it is necessary to take a strategic approach to members, along with consideration. This study looked into the recent separation of LG Group's affiliates based on this point of view. To this end, we focused on the case of LX Hausys of LX Group, which was separated from LG Group. To this end, through a meeting with the person in charge of LX Hausys, the company's response to the division was investigated, and FGI was conducted for retired and current members. As a result, it was confirmed through the person in charge that no appropriate measures were taken due to the separation of the company. Through FGI with the retirees and incumbents, the psychological resistance of the members and the decrease in organizational commitment and the increase in turnover intention was confirm.

Effect of Injection Angle and Length to Diameter Ratios on Drop and Penetration Characteristics in Cross-flow (아름속 횡단 기체 유동장에서 노즐 형상 변화와 분사각 변화가 액적크기와 침투거리에 미치는 영향)

  • Lee, Bong-Soo;Ko, Jung-Bin;Cho, Woo-Jin;Koo, Ja-Ye
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.6
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    • pp.51-58
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    • 2006
  • The spray characteristics of liquid jet injected into subsonic cross-flow were investigated experimentally. Spray trajectories were captured using CCD camera. Droplet sizes were measured using PDPA and Image Express. The nozzle diameter was 0.5 mm, and its length-to-diameter ratios (L/D) ran$4.11{\times}10^6$ged from 1.0 to 6.0. Experimental results indicate that the breakup point is delayed by increasing gas momentum ratio and the penetration length is decreased by increasing Weber number. At low injection angle(${\theta}$ < $90^{\circ}$), Weber number is dominant parameter for trajectories, but at high injection angle(${\theta}$ > $90^{\circ}$), L/D is dominant parameter for trajectories rather than Weber number.

Study on the Atomization Characteristics of a Counter-swirling Two-phase Atomizer with Variations of Swirl angle (역선회 이류체 미립화기의 선회각 변화에 따른 미립화 특성연구)

  • Kim, N.H.;Lee, S.G.;Ha, M.H.;Rho, B.J.;Kang, S.J.
    • Proceedings of the KSME Conference
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    • 2001.06e
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    • pp.125-130
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    • 2001
  • Experimental and analytical researches have been conducted on the twin-fluid atomizers for better droplet breakup during the past decades. But, the studies on the disintegration mechanism still present a great challenge to understand the drop behavior and breakup structure. In an effort to describe the aerodynamic behavior of the sprays issuing from the internal mixing counter-swirling nozzle, the spatial distribution of axial (U) radial (V) and tangential (W) components of droplet velocities are investigated across the radial distance at several axial locations of Z=30, 50, 80, 120 and 170mm, respectively. Experiments were conducted for the liquid flow rates which was kept constant at 7.95 g/s and the air injection pressures were varied from 20 kPa to 140 kPa. Counter-swirling internal mixing nozzles manufactured at angles of $15^{\circ},\;30^{\circ},\;45^{\circ}$ and $60^{\circ}$ the central axis with axi-symmetric tangential-drilled holes was considered. The distributions of velocities and turbulence intensities are comparatively analyzed. PDPA is installed to specify spray flows, which have been conducted along the axial downstream distance from the nozzle exit. Ten thousand of sampling data was collected at each point with time limits of 30 second. 3-D automatic traversing system is used to control the exact measurement. It is observed that the sprays with all swirl angle have the maximum SMD for on air injection pressure of 20 kPa and 140 kPa with centerline, respectively. The nozzle with swirl angle of $60^{\circ}$ has vest performance.

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The Effect of Impact Velocity on Droplet-wall Collision Heat Transfer Above the Leidenfrost Point Temperature (Leidenfrost 지점 온도 이상에서 액적-벽면 충돌 열전달에 대한 충돌 속도의 영향)

  • Park, Jun-seok;Kim, Hyungdae;Bae, Sung-won;Kim, Kyung Doo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.39 no.7
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    • pp.567-578
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    • 2015
  • Single droplet-wall collision heat transfer characteristics on a heated plate above Leidenfrost temperature were experimentally investigated considering the effects of impact velocity. The collision characteristics of the droplet impinged on the heated wall and the changes in temperature distribution were simultaneously measured using synchronized high-speed video and infrared cameras. The surface heat flux distribution was obtained by solving the three-dimensional transient heat conduction equation for the heated substrate using the measured surface temperature data as the boundary condition for the collision surface. As the normal impact velocity increased, heat transfer effectiveness increased because of an increase in the maximum spreading diameter and a decrease in the vapor film thickness between the droplet and heated wall. For We < 30, droplets stably rebounded from a heated wall without breakup. However, the droplets broke up into small droplets for We > 30. The tendency of the heat transfer to increase with increasing impact velocity was degraded by the transition from the rebounding region to the breakup region; this was resulted from the reduction in the effective heat transfer area enlargement due to the breakup phenomenon.

Influence of Critical Point of Hydrocarbon Jet Injected into Near-Critical Environment on Injection Behavior (근임계 환경으로 분사되는 탄화수소 제트의 임계점이 분사거동에 미치는 영향)

  • Yoon, Taekyung;Shin, Dongsoo;Lee, Keonwoong;Koo, Jaye
    • Journal of the Korean Society of Propulsion Engineers
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    • v.22 no.5
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    • pp.32-39
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    • 2018
  • Supercritical injection behavior of liquid hydrocarbon compounds, which are used as main components of propellant fuel, was analyzed. Decane and Methylcyclohexane (MCH) with different critical points were selected as experimental fluid and Shadowgraphy technique was used. Decane and MCH behave differently in the initial state under the subcritical condition. However, near the critical point, the enthalpy of evaporation became close to 0, so that phase change into supercritical fluid occurred, not vaporization process, and no breakup of both fluids occurred.

Spray Characteristics of a Liqud-Liquid Swirl Coaxial Injector (액체-액체 스월 동축형 인젝터의 분무특성)

  • Kim Dong-Jun;Im Ji-Hyuk;Han Poong-Gyoo;Yoon Young-Bin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2006.05a
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    • pp.147-150
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    • 2006
  • The influences of injection conditions and recess configuration of liquid-liquid swirl coaxial injector on spray characteristics were investigated. The characteristics of the coaxial spray in internal mixing injection region were mai y controlled by the merging phenomenon and momentum balance between two liquid sheets, but those in internal mixing injection region were influenced by the impingement phenomenon as well as momentum balance between two liquid sheets.

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Spray characteristics of misaligned impinging injectors

  • Subedi, Bimal;Son, Min;Kim, Woojin;Choi, Jangsu;Koo, Jaye
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.10
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    • pp.1257-1262
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    • 2014
  • The variances of atomization characteristics with the misalignment of injectors defined as the fraction of skewness for various angles of impingement and pressure conditions were studied using the doublet impinging injectors with a like-on-like arrangement. Water was used as simulant and the spray characteristics along with the changes in the skewness were analyzed using the methods of spray image photography. Experiment was carried for the impinging nozzles of orifice diameter of 1.2 mm within Reynolds numbers ranging from $9{\times}10^3-4.5{\times}10^4$ and the fraction of skewness considered for the experiment ranges from 0.0 to 0.9 at ambient temperature condition. Flat sheet with a distinct rim produced perpendicular to the plane of impinging jets goes ondisappear and sheet appears comparatively shorterwith the increase in fraction of skewness resulting the atomization of fluid droplet very close to impingement point with decrease in breakup length and increase in spray angle up to certain extent. The maximum allowable skewness was found as the result. The skewness up to the certain extent can be considered as the parameter to control the atomization characteristics of simulant inside the combustion chamberproviding the high economic performance of fuel and time.

Effect of Gas-liquid Ratio on Characterization of Two-Phase Spray Injected into a Cross-flow (횡단유동에 분사된 이유체 분무의 기체 액체비가 분무특성에 미치는 영향)

  • Cho, Woo-Jin;Lee, In-Chul;Lee, Bong-Su;Koo, Ja-Ye
    • Journal of the Korean Society of Propulsion Engineers
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    • v.12 no.1
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    • pp.16-22
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    • 2008
  • The effect of two-phase spray injected into subsonic cross-flow was studied experimentally. External-mixing of two-phase spray from orifice nozzle with L/d of 3 was tested with various air-liquid ratio that ranges from 0 to 59.4%. Trajectory of spray and breakup phenomena were investigated by shadowgraph photography. Detailed spray structure was characterized in terms of SMD, droplet velocity, and volume flux using PDPA. Experimental results indicate that penetration length was increased and collision point of liquid jets approached to nozzle exit and distributions of mist-like spray were obtained by increasing air-liquid ratio.

Spray Characteristics of a Liquid-Liquid Swirl Coaxial Injector Part I : Effect of Injection Condition (액체-액체 스월 동축형 인젝터의 분무특성 Part I : 분사조건에 따른 특성)

  • Kim, Dong-Jun;Im, Ji-Hyuk;Han, Poong-Gyoo;Yoon, Young-Bin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.10 no.3
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    • pp.1-8
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    • 2006
  • The influences of injection conditions and recess configuration of liquid-liquid swirl coaxial injectors on spray characteristics were investigated. The characteristics of the coaxial spray in internal mixing injection region were mainly controlled by the merging phenomenon and momentum balance between two liquid sheets, but those in internal mixing injection region were influenced by the impingement phenomenon as well as momentum balance between two liquid sheets.