• Title/Summary/Keyword: 와류 분무

Search Result 55, Processing Time 0.025 seconds

Spray Characteristics of Superheated Swirl Spray Vertically Introduced into Convective Cross-flow (대류유동으로 수직 분사된 과열 와류분무의 분무특성)

  • Lee, Hae-Cheon;Yoon, Woong-Sup
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2010.11a
    • /
    • pp.395-398
    • /
    • 2010
  • 감압비등에 의한 미립화는 더 미세한 직경의 액적을 얻을 수 있고, 분무각이 증가하며, 더 좋은 혼합특성을 갖는 다는 점에서 단순 압력식 미립화와 차이가 난다. 감압비등이란 과열된 액체를 포화 압력 이하의 대기 중으로 분사하여 급격한 비등에 의해 이루어지는 미립화이다. 본 연구는 금속 연료를 이용한 추진기관의 산화제인 물 공급기술에 감압비등과정을 이용한 와류분무를 적용시키기 위해 수행됐다. 분열길이와 같은 거시적 특성은 Charge-Couple Device(CCD) 카메라를 이용해 측정하였고, Sauter Mean Diameter(SMD)와 SMD분포와 같은 미시적 특성은 Global Sizing Velocimetry(GSV) 시스템을 이용해 측정했다. 실험은 압력과 온도, 대류 속도를 변화시키며 진행했다.

  • PDF

Spray Characteristics of Coaxial Swirl Injector under Ambient High Pressure Conditions (고압환경에서 동축 와류형 분사기의 분무특성)

  • Lim Byoungjik;Kim Jong-Gyu;Moon Il-Yoon;Kim Seung-Han;Han Yeoung-Min;Seol Woo-Seok
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2004.10a
    • /
    • pp.288-291
    • /
    • 2004
  • The spray characteristics of coaxial swirl injector under ambient high pressure conditions were investigated in this paper. Three injectors were used to study the effect of recess length and fuel injector type(open or closed). In this research, experimental conditions(ambient gas density) were calculated by Buckingham Pi-theory and spray characteristics of the injectors were represented by mass flow rate according to the injection pressure, the spray angle, mass distribution, and mean diameter of droplet.

  • PDF

Spray Angle of Hollow Cone Liquid Sheet Discharged from Simplex Swirl Spray Nozzle (단순 와류 분무 노즐에서 분사되는 중공 원추형 액막의 분무각)

  • Koh, K.U.;Lee, S.Y.
    • Journal of ILASS-Korea
    • /
    • v.7 no.4
    • /
    • pp.1-8
    • /
    • 2002
  • This paper investigates the spray angle and the outline shape of the liquid sheet discharged from a simplex swirl nozzle. A theoretical model was proposed and the corresponding experimental data were presented for comparison. Axial and tangential velocities and thickness of the liquid sheet at the nozzle exit were also predicted. The liquid sheet thickness at nozzle exit, as well as the discharge coefficient, turned out to be a sole function of the swirl Reynolds number. However, the axial and tangential velocities at nozzle exit and the spray angle could not be expressed only with the swirl Reynolds number. The predicted outline shape and spray angle of the liquid sheet agreed reasonably with the measured data.

  • PDF

Spray Characteristics of Effervescent Swirl Injectors for Variable Thrust (가변추력을 위한 기체주입식 와류형 분사기의 분무특성)

  • Lee, Wongu;Hwang, Donghyun;Ahn, Kyubok;Yoon, Youngbin
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.23 no.2
    • /
    • pp.1-12
    • /
    • 2019
  • A fundamental study on a gas injection variable thrust method for thrust throttling in a liquid rocket engine was conducted. The gas injection variable thrust has the advantage of not only being able to control the thrust with a simple structure but it also increases the atomization performance through the injection pressure drop that increases in direct proportion to the density reduction. In this study, spray characteristics such as spray instability, spray pattern, spray angle, and breakup length based on changes in the liquid mass flow rate and amount of injected gas were investigated using effervescent swirl injectors.

A Study on the Spray Characteristics of Swirl Injectors Using ANSYS Fluent (ANSYS Fluent를 이용한 와류형 분사기의 분무특성 연구)

  • Yoon, Wonjae;Lee, Bom;Ahn, Kyubok
    • Journal of ILASS-Korea
    • /
    • v.22 no.4
    • /
    • pp.159-168
    • /
    • 2017
  • Numerical studies on the spray characteristics of closed-type and open-type swirl injectors were conducted using ANSYS Fluent. By changing injection pressures, discharge coefficient and spray angle were calculated using the Reynolds stress BSL turbulent model. The numerical results were compared with previous experimental data to examine their accuracy. For a closed-type swirl injector, spray angles matched well with experimental results and discharge coefficients showed approximately 8% differences. On the contrary, discharge coefficients of an open-type swirl injector were similar with experimental result but its spray angles presented around 15% differences. Though the numerical results were not perfectly consistent with experimental data, it is thought that they could be sufficiently used for analyzing spray characteristics, specially which is hard to be measured from experiments. Numerical simulation with different turbulent models was also performed to examine their effects on the numerical results.

Spray Characteristics of Air-assisted Vortex Nozzle at Low Pressure Condition (공기보조식 와류 노즐의 저압 분무특성)

  • Kim, Woojin;Subedi, Bimal;Choi, Jang-Soo
    • Journal of ILASS-Korea
    • /
    • v.20 no.2
    • /
    • pp.82-87
    • /
    • 2015
  • A nozzle with vortex generator was used to develop the low pressure nozzle with high atomization performance and the nozzle atomized the liquid by centrifugal shear forces. In order to analyze the atomization characteristics, a shadowgraphy method was used and the measurement of droplet size was performed by using laser diffraction analyzer. The liquid injection pressure was fixed as 0.03 bar which is very low pressure and the gas injection pressures were changed from 0 bar to 2.0 bar. As a result, the breakup was achieved at the air injection pressure of 0.25 bar and over. The nozzle with the orifice diameter of 0.4 mm and the orifice gap of 0.25 mm presented small droplet diameters under 50 at the air injection pressure of 0.75 bar.

Numerical Study on Swirl Coaxial Injectors with Different Recess Lengths (리세스 길이가 다른 동축 와류형 분사기들에 대한 수치해석)

  • Lee, Bom;Yoon, Wonjae;Yoon, Youngbin;Ahn, Kyubok
    • Journal of ILASS-Korea
    • /
    • v.23 no.2
    • /
    • pp.49-57
    • /
    • 2018
  • Numerical study under single-injection on bi-swirl coaxial injectors with different recess lengths was performed using ANSYS Fluent. The bi-swirl coaxial injectors which consisted of inner closed-type and outer open-type swirl injectors, had three different recess lengths. By changing mass flow rates, numerical simulation was repeated using the Reynolds stress BSL turbulent model. The numerical results such as discharge coefficient and spray angle were compared with previous experimental data and were found to be approximately matched well with them, irrespective of recess length. Quantitative data which was hard to be measured from experiments, were successfully obtained through the present numerical study.

Visualization and Numerical Analysis of Non-evaporating Spray with a Swirl-Type GDI Injector (GDI 와류 분사노즐에 의한 비증발 분무의 가시화 및 수치해석)

  • 원영호;강수구
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.11 no.4
    • /
    • pp.22-28
    • /
    • 2003
  • Predictions of the fuel spray dispersion and mixing processes are very important to improve the fuel consumption and exhaust emissions in GDI engines. Numerical and experimental analysis of the sprays with a swirl injector have been conducted. A numerical analysis is carried out using KIVA-II code with modified spray models. Experimental measurements are performed to show the global spray images and the local images near nozzle tip using laser sheet visualization technique. Computed and measured spray characteristics such as spray width, tip penetration are compared, and good agreements can be achieved. The spray head vortex is stronger as the injection pressure increases, but numerical calculations cannot show the head vortex properly.

Spray Characteristics of Gas-centered Swirl Coaxial(GCSC) Injector in High Pressure Condition (고압환경에서의 기체-액체 분사기 분무 특성 연구)

  • Kim, Jong-Gyu;Han, Yeoung-Min;Bae, Tae-Won;Choi, Hwan-Seok;Yoon, Young-Bin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2010.11a
    • /
    • pp.5-8
    • /
    • 2010
  • The GCSC injectors studied in this paper are those applied to the combustion chamber of staged combustion engines. Liquid fuel is injected through tangential holes along the outer wall of the GCSC injector forming a swirling sheet and oxygen rich gas generated by a preburner enters axially through the center orifice of the injector to form a gaseous jet. The spray characteristics of GCSC injectors under ambient/high pressure conditions and the effect of recess on spray characteristics have been examined in this paper. These results are expected to be used as fundamental data to develop of a staged combustion engine.

  • PDF

Study on Breakup Characteristics of Gel Propellant Using Pressure Swirl Injector (압력선회형 인젝터를 이용한 젤 추진제의 분열특성 연구)

  • Cho, Janghee;Lee, Donghee;Kim, Sulhee;Lee, Donggeun;Moon, Heejang
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.25 no.5
    • /
    • pp.10-17
    • /
    • 2021
  • In this study, cold-flow test of simulant gel is conducted using a pressure swirl injector to identify spray characteristics according to gellant weight percent. Experiment results show the aircore is developed locally at the nozzle and expanded to the entire swirl chamber as the supply pressure increases. The aircore formation of simulant gel showed no significant difference compared to Newtonian fluid. The spray pattern was classified into four distinct shapes where relationship between the breakup regimes and dimensionless numbers were investigated. In the future, additional study is necessary to understand the aircore formation mechanism, stability and spray characteristics at different configuration of the swirl chamber shape.