• Title/Summary/Keyword: 도플러속도계

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A Study on the Disintegration and Spreading Behavior of Fuel-spray Emanating from a Liquid-thruster Injector by Pseudo-3D Spatial Distribution Measurement (준3차원적 공간분포 계측에 의한 액체추력기 인젝터 연료분무의 분열 및 확산 거동에 관한 연구)

  • Kim, Jin-Seok;Kim, Jeong-Soo
    • Journal of the Korean Society of Propulsion Engineers
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    • v.12 no.5
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    • pp.9-17
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    • 2008
  • Pseudo-3D spatial distribution of spray droplets is investigated by using Dual-mode Phase Doppler Anemometry (DPDA) in order to examine the disintegration and spreading behavior of spray exiting from liquid-propellant thruster injector. Spray injected from nozzle orifice with length-to-diameter ratio ($L/d_o$) of 1.67 and under the injection pressure of 27.6 bar is aligned to the vertical. Vertical and horizontal mean velocities of droplets, Sauter Mean Diameter (SMD), and volumetric flux decrease as droplets travel from center/upstream toward outer region/downstream of spray. Although the distribution of spray characteristic parameters is symmetric against the geometric axis of nozzle orifice, their absolute values are asymmetric.

Atomization Characteristics of Small LRE-Injector Spray According to Injection Pressure Variation (소형 액체로켓엔진 인젝터 분무의 분사압력 변이에 따른 미립화 특성)

  • Jung, Hun;Kim, Jin-Seok;Kim, Jeong-Soo;Park, Jeong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.05a
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    • pp.125-128
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    • 2008
  • Atomization characteristics of small LRE-injector spray are investigated by using dual-mode phase Doppler anemometry (DPDA). Velocity, size, number density, and volume flux were measured at various injection pressures along the radial distance to make a close inquiry into spatial distribution characteristic of spray droplets. As the injection pressure increases, the velocity, turbulence intensity, number density, and volume flux of spray droplets become higher, whereas the droplet size ($D_{10}$ or $D_{32}$) gets smaller. Also, velocity and volume flux are proportional to Sauter mean diameter (SMD, $D_{32}$).

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A Pseudo 3-Dimensional Structure of the Liquid-propellant Spray Emerging from Nonimpinging-type Injector (비충돌형 인젝터로부터 발생하는 액체추진제 분무의 준3차원 구조)

  • Jung, Hun;Kim, Jeong-Soo;Park, Jeong
    • Journal of the Korean Society of Propulsion Engineers
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    • v.14 no.6
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    • pp.17-24
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    • 2010
  • This study was performed to make a close inquiry into a pseudo 3-dimensional structure of the liquid-propellant spray emerging from nonimpinging-type injector. Spray configuration near the injector exit was captured by a high-speed camera, and then its periodic phenomena (shedding) was observed. Detailed spatial structure of spray was investigated by spray characteristic parameters (velocity, diameter, volume flux, etc.) with the aid of a Dual-mode Phase Doppler Anemometry (DPDA). Experiment was carried out at various locations along the geometric axis of the nozzle orifice and on the plane normal to the spray stream with the injection pressures of 17.2 to 27.6 bar.

Measurement of Spray Characteristic Parameters for Inquiry into Small LRE-Injector's Injection Performance (소형 액체로켓엔진 인젝터의 분사성능 고찰을 위한 분무특성 매개변수 측정)

  • Jung, Hun;Kim, Jin-Seok;Kim, Jeong-Soo;Park, Jeong;Choi, Jong-Wook
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.05a
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    • pp.141-144
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    • 2009
  • An injector plays an important role in the process of an efficient combustion in liquid-rocket engines (LRE). This paper is focused on the injection performance of a small LRE-injector by employing the spray characteristic parameters made up of the velocity, Sauter mean diameter, and turbulence intensity. An experimental investigation is carried out with the aid of a dual-mode phase Doppler anemometry (DPDA) according to the injection pressure variation and along transverse axis, spatially. The Weber number and Reynolds number are used to characterize the atomization and turbulence nature of injector spray.

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Two-Dimensional Distribution of Spray Droplets Emanating from an Injector of Liquid-Propellant Thruster (액체추진제 추력기 인젝터 분무액적의 2차원 공간분포)

  • Jung, Hun;Kim, Jin-Seok;Kim, Jeong-Soo;Kim, Sung-Cho;Park, Jeong;Jang, Ki-Won;Su, Hyuk
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.11a
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    • pp.135-138
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    • 2007
  • Two-dimensional distribution characteristics on the spray droplets emanating from an injector employed in a liquid-propellant thruster are investigated through dual-mode phase Doppler anemometry (DPDA). Spray-breakup characteristic parameters such as spray droplet velocity, turbulent intensity, Sauter mean diameter (SMD), number density, and volumetric flux are quantified to scrutinize the macroscopic behavior of injector-spray breakup. The present study will be able to contribute to the comprehension for performance features of the thruster in current use and to the design engineering of a brand-new thruster as well.

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Spatial Distribution Characteristics of Small LRE-injector's Spray-droplet According to the Variation of Fuel-injection Pressure (소형 액체로켓엔진 인젝터 분무의 연료분사압력 변이에 따른 액적의 공간분포 특성)

  • Jung, Hun;Kim, Jeong-Soo
    • Journal of the Korean Society of Propulsion Engineers
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    • v.12 no.5
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    • pp.1-8
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    • 2008
  • Dual-mode Phase Doppler Anemometry (DPDA) was used to scrutinize the spatial distribution characteristics of spray emanating from a small Liquid-Rocket Engine (LRE) injector. Droplet size and velocity were measured according to the variation of injection pressure along the plane normal to the spray stream and then the spray characteristic parameters such as Arithmetic Mean Diameter (AMD), Sauter Mean Diameter (SMD), number density, span of drop size distribution, and volume flux were deduced for an investigation of spray breakup characteristics. As the injection pressure increases, the number density, span, and volume flux of spray droplets become higher, whereas the AMD gets smaller.

An Analysis on Spray Behavior of Liquid-thruster Injector through Pseudo-3D Distribution Measurement (준 3차원 공간분포 계측에 의한 액체 추력기 인젝터의 분무거동 해석)

  • Kim, Jin-Seok;Jung, Hun;Kim, Jeong-Soo;Kim, Sung-Cho
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.05a
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    • pp.141-144
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    • 2008
  • Atomization characteristics and spatial distribution of the spray emanating from an injector of liquid-propellant thruster are investigated by using dual-mode phase Doppler anemometry (DPDA). Spray characteristic parameters such as the mean velocity, Sauter mean diameter (SMD), and velocity fluctuation are measured at various locations along the spray axis as well as on the radial direction. Those data are quantified in radial profile and also used to scrutinize the correlation between diameter and turbulence intensity of spray droplets. For the better visual grasp, dynamic behavior of spray droplets along the spray stream is presented through the velocity vectors projected on the plane of geometric axis of nozzle orifice and radial coordinate.

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Disintegration and Spreading Behavior of the Spray emanating from a Liquid-thruster Injector (액체추력기 인젝터로부터 발생하는 분무의 분열 및 확산 거동)

  • Kim, Jin-Seok;Jung, Hun;Kim, Jeong-Soo;Kim, Sung-Cho;Park, Jeong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.113-116
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    • 2008
  • Pseudo-3D Spatial distribution of spray droplets is investigated by using Dual-mode Phase Doppler Anemometry (DPDA) in order to examine the disintegration and spreading behavior of spray exiting from liquid-thruster injector. Spray injected from nozzle orifice with length-to-diameter ratio $(L/d_o)$ of 1.67 and at the injection pressure of 27.6 bar is aligned to the vertical. Vertical and horizontal mean velocities of droplets, Arithmetic Mean Diameter (AMD), Sauter Mean Diameter (SMD), and volumetric flux decrease as droplets travel from center/upstream toward outer region/downstream of spray.

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An Experimental Study on the Injector-spray Behavior of a Liquid-propellant Thruster (액체추진제 추력기의 인젝터 분무 거동에 대한 실험적 연구)

  • Kim, Jin-Seok;Kim, Sung-Cho;Park, Jeong;Kim, Jeong-Soo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.35 no.9
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    • pp.799-804
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    • 2007
  • The behavior of spray emanating from an injector to be employed in a liquid-propellant thrust chamber is investigated by optical measurement techniques. The injector has eight holes, each of which has 30 cant angle from the center-axis with the diameter of 0.406 mm. In order to examine an atomization process according to the spray-generation conditions and the evolution along spray downstream, variational features in the velocity and size of droplets obtained through Dual-mode Phase Doppler An 799emometry (DPDA) are delineated and discussed together with instantaneous plane images captured by using Nd:Yag laser sheet beam. A categorization of spray-flow regime representing the atomization and turbulent nature is made through evaluating the non-dimensional parameters, i.e., Reynolds number and Weber number based upon the theoretical injection velocity. These qualitative and quantitative data of spray breakup will be a firm basis for the design of brand-new thruster

Sensor Fusion for Underwater Navigation of Unmanned Underwater Vehicle (무인잠수정의 수중합법을 위한 센서융합)

  • Sur, Joo-No
    • Journal of the Korea Institute of Military Science and Technology
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    • v.8 no.4 s.23
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    • pp.14-23
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    • 2005
  • In this paper we propose a sensor fusion method for the navigation algorithm which can be used to estimate state vectors such as position and velocity for its motion control using multi-sensor output measurements. The output measurement we will use in estimating the state is a series of known multi-sensor asynchronous outputs with measurement noise. This paper investigates the Extended Kalman Filtering method to merge asynchronous heading, heading rate, velocity of DVL, and SSBL information to produce a single state vector. Different complexity of Kalman Filter, with. biases and measurement noise, are investigated with theoretically data from MOERI's SAUV. All levels of complexity of the Kalman Filters are shown to be much more close and smooth to real trajectories then the basic underwater acoustic navigation system commonly used aboard underwater vehicle.