• Title/Summary/Keyword: 노즐

Search Result 2,445, Processing Time 0.107 seconds

Deep RIE를 이용하여 제작된 마이크로 노즐 내에서 유체의 거동에 대한 컴퓨터 시뮬레이션 분석

  • Jeong, Gyu-Bong;Song, U-Jin;Cheon, Du-Man;Yeo, Jun-Cheol;An, Seong-Hun;Lee, Seon-Yeong
    • Proceedings of the Materials Research Society of Korea Conference
    • /
    • /
    • pp.37.2-37.2
    • /
    • 2009
  • 다이렉트 프린팅 방식에 대한 수요가 높아지면서 마이크로 노즐에 대한 수요도 높아지고 있다. 마이크로 노즐은 Nano particle deposition system (NPDS)에서 가장 중요한 부분으로 금속이나 세라믹 분말을 음속으로 가속시키는 역할을 한다. 또한 마이크로 노즐은 마이크로 스페이스 셔틀과 주사바늘이 없는 약물 주사 시스템 등의 많은 분야에서 사용 가능하다. 이러한 마이크로 노즐은 대부분 기계적 절삭법을 이용하여 알루미늄으로 만들어져왔다. 하지만 알루미늄으로 만들어진 마이크로 노즐은 경도가 낮아 세라믹 나노 입자를 적층하는 것에 적절치 못하며 사용가능한 수명이 짧다는 단점을 가지고 있다. 또한 가장 큰 단점으로 노즐목을 1mm이하로 제작하는 것이 어렵다는 것이다. 따라서 본 연구에서는 Si wafer를 Deep RIE 방식을 이용하여 3차원적으로 제작하였다. Deep RIE 방식 중 BOSCH process를 이용하였다. 이렇게 만들어진 마이크로 노즐은 다이렉트 프린팅 방식중 하나인 NPDS에 적용하였다. Si wafer로 만들어진 마이크로 노즐이 적용된 NPDS를 이용하여 graphite 분말을 가속하여 적층 실험을 실시하였다 이와 함께 전산 유체 역학(CFD)를 이용하여 마이크로 노즐일 이용한 초음속 가속 가능 여부를 판단하였다. 전산 유체 역학은 유한 요소법을 이용하여 유체의 거동을 시뮬레이션을 통하여 예측하는 것으로 마이크로 노즐 내에서 유체의 흐름을 예상할 수 있다. 실제 실험의 결과와 전산 유체 역학을 이용한 시뮬레이션 결과dml 비교 분석을 실시하였다.

  • PDF

Performance Study of Supersonic Nozzle with Asymmetric Entrance Shape (유입부 비대칭 노즐의 성능연구)

  • Lee Ji-Hyung;Kim Joug-Keun;Lee Do-Hyung
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • /
    • pp.40-45
    • /
    • 2005
  • Techniques used for throcket motors are mainly classified as fixed nozzles with mechanical exhaust jet interferences on the expansion region (such as jet tabs and jet vanes) and movable nozzles(such as ball&socket md flexible seal). Using the numerical analysis and the cold-flow test, this paper evaluates the performance of supersonic nozzle for asymmetric entrance shape at tilted position of ball&socket nozzle. Numerical results show that the asymmetric effects in the flow fields are gradually diminished up to the nozzle throat and are not noticeable downstream of the nozzle throat. Although the calculated thrust and the lateral force are less than those of cold-flow test, two results show a flirty good agreement.

  • PDF

The Experimental Study of Thermal Stress at Supersonic Nozzle (초음속 노즐의 열구조 안전성에 관한 실험적 연구)

  • Kim, Seong-Jin;Han, Hyeok-Seop;Lim, Jae-Hyock;Park, Eui-Yong;Baek, Ki-Bong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • /
    • pp.497-500
    • /
    • 2011
  • The experimental study of thermal stress in the solid rocket engine nozzle with two different materials, SCM-440 and STS-630, was evaluated. SCM-440 has lager temperature increasing rate and higher temperature at the nozzle expansion region than STS-630. Thermal barrier efficiency and endurance of Zirconia coating were evaluated after making two more nozzles coated by Zirconica. Both coated materials showed about 70 percent higher thermal barrier efficiency than uncoated nozzles. Therefore, Zirconia coating using plasma spray method was useful in thermal safety at supersonic nozzle.

  • PDF

Design and Experimental Verification of Two Dimensional Asymmetric Supersonic Nozzle (이차원 비대칭형 초음속 노즐 설계와 실험적 검증)

  • Kim, Chae-Hyoung;Sung, Kun-Min;Jeung, In-Seuck;Choi, Byoung-Il;Kouchi, Toshinori;Masuya, Goro
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.37 no.9
    • /
    • pp.899-905
    • /
    • 2009
  • Most supersonic-flow test facility has axisymmetric nozzles or two-dimensional symmetric nozzles. Compared to these nozzles, a two-dimensional asymmetric nozzle has advantages of reducing low cost for various Mach number testing and undesirable flow structure such as shock wave reflection because the nozzle part can be directly connected to the test section part in this type of nozzle. The two-dimensional asymmetric nozzle, which was Mach number 2, was designed for supersonic combustion experiment. And it was verified with the numerical analysis and visualization of Mach wave. This study suggested the practical method for design and verification of supersonic two dimensional asymmetric nozzles.

An Experimental Study of Discharge Coefficient with Non-Circular Effervescent Type Twin-fluid Nozzle (비원형 Effervescent Type 이유체노즐의 Discharge Coefficient에 관한 실험적 연구)

  • Lee, Sang Ji;Park, Hyung Sun;Hong, Jung Goo
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • /
    • pp.682-685
    • /
    • 2017
  • An experimental study was carried out to investigate the injection characteristics of non-circular effervescent type twin-fluid nozzles. For this purpose, two types of non-circular nozzles (E1, E2) and one kind of circular nozzle (C) were used. At this time, the Aerorator mounted on the nozzle used three different diameters to match the aspect ratio with the nozzle exit area. Therefore, experiments were performed according to three aspect ratios for each nozzle, and a total experiments were conducted. Experiments were carried out by controlling the amount of air flowing after fixing the flow rate of the liquid, and the nozzle internal pressure and SMD were measured, and the jet image was taken from the nozzle. The discharge coefficients of the three kinds of nozzles were compared with the conventional equation and the Jedelsky's equation, and the Jedelsky's equation was found to be about 4 times larger. The droplet size (SMD) injected from the nozzle was found to be smaller in the non-circular shape than in the circular shape, which is expected to be caused by the difference of the discharge coefficient values.

  • PDF

Evaluation of Nozzle's Combustion Instability Suppression Effect by Linearized Euler Equation (선형 오일러 방정식을 이용한 노즐의 연소불안정 감쇠 효과 평가)

  • Kim, Junseong;Moon, Heejang
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.23 no.6
    • /
    • pp.1-10
    • /
    • 2019
  • The wave motion inside the nozzle is known as one of the major damping elements of the rocket's combustion instability by it's aeroacoustic effects that result from the flow passage through the nozzle throat. These effects can be quantitatively evaluated by the nozzle admittance. In this study, one-dimensional linearized Euler equation was adopted to calculate the nozzle admittance, and trend analysis was performed depending on the nozzle's main design variables. As a result, when nozzle converging part shortens, it is verified that the frequency dependency of the nozzle admittance is decreased due to the widened frequency range with lowered longitudinal nozzle admittance. Also, admittance estimation using the short nozzle theory is not appropriate when the first tangential mode of the pressure perturbation arises.

A Study on the Exhaust Gas Recirculation in a MILD Combustion Furnace by Using the Coanda Nozzle Effect (MILD 연소로에서 Coanda 노즐 효과를 이용한 배기가스 재순환에 관한 연구)

  • Ha, Ji Soo;Shim, Sung Hoon
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.35 no.12
    • /
    • pp.967-972
    • /
    • 2013
  • A MILD (Moderate and Intense Low oxygen Dilution) combustion, which is effective in the reduction of NOx, is considerably affected by the recirculation flow rate of hot exhaust gas to the combustion furnace. The present study used the MILD combustor, which has coaxial cylindrical tube. The outside tube of the MILD combustor corresponds to the exhaust gas passage and the inner side tube is the furnace passage. A numerical analysis was accomplished to elucidate the characteristics of exhaust gas entrainment toward the inner furnace with the changes of coanda nozzle geometrical parameters, nozzle passage gap length, nozzle passage length, nozzle angle and expansion length. The optimal configuration of coanda nozzle for the best entrainment flow rate was gap length, 0.5 mm, expansion angle, 4o and expansion length, 146 mm. The nozzle passage length was irrelevant to the exhaust gas entrainement.

Numerical Analysis of the Effect of Nozzle Shapes on the Performance of a Partial Admission Supersonic Turbine (노즐 형상에 따른 부분 흡입형 초음속 터빈의 성능특성에 관한 수치적 연구)

  • Cho, Jong-Jae;Kwon, Tae-Un;Kim, Kui-Soon;Jeong, Eun-Hwan;Park, Pyun-Goo
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.14 no.3
    • /
    • pp.23-29
    • /
    • 2010
  • A supersonic nozzle specially is one of the important part in a supersonic turbine usually adapted the impulse type, because the flow acceleration in the turbine theoretically is done only in the nozzle. The present study deals with numerical flow analysis to investigate the effect of nozzle shapes on the performance characteristics of a partial admission supersonic turbine. The flow analysis was performed for four different nozzle shapes. The shapes of the nozzles are circular, square, straight rectangular and bent rectangular nozzles. The results of the flow analysis showed that the aerodynamic loss of turbine is highly affected by the nozzle shapes, and the partial admission loss is also highly depended on nozzle shapes. Specially, bent rectangular nozzle had the best performance among the nozzle shapes

A Numerical Analysis of Partial Admission Turbine's Performance for Design Parameters of 3D Supersonic Nozzle (3차원 초음속 노즐 형상 변수에 따른 부분입사형 터빈 성능 특성에 관한 수치적 연구)

  • Shin Bong-Gun;Kwak Young-Jae;Kim Kui-Soon;Kim Jin-Han
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • /
    • pp.34-39
    • /
    • 2005
  • In this study, 3-D nozzle shape and the shape of nozzle at exit plane were adopted as design parameter of 3-D supersonic nozzle and numerical analyses for these parameters have been performed to investigate the flow and performance characteristics for design parameters of the turbine. Firstly, comparing results for nozzle shape, rectangular nozzle had less total pressure loss occurred in axial gap and more power by 1.5% than circular nozzle did. Next, comparing the results for the shape of nozzle at exit plane, it is found that the performance of partial admission turbine was largely depended upon the gap between nozzle wall at exit plane and the hub / tip of rotor blade and the length between nozzles.

  • PDF

An Experimental Study of the Infrared Signal Characteristics on the S-Nozzle Plume of the Micro Turbojet Engine (마이크로 터보제트엔진 S형상 배기노즐 플룸의 적외선 신호 특성 실험연구)

  • Kim, Sunmi;Lee, Jeonseok;Choi, Seongman;Myoung, Rho-Shin;Kim, Woncheol
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • /
    • pp.583-586
    • /
    • 2017
  • Infrared signal measurement are conducted from a micro-turbo jet engine with different nozzle configurations. The conventional cone type, a S-shaped type with aspect ratio 5.2 and five rectangular type nozzle with different aspect ratios are used for this experiment work. The result show that infrared signal from the exhaust gas decrease as the aspect ratio increase. In case of S-shaped nozzle, the maximum infrared signal is reduced about 28.4% when compared of rectangular nozzle with aspect ratio 5(AR5).

  • PDF