• Title/Summary/Keyword: 액적 평균입경

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Experimental Study on the Spray Characteristics of Low Pressure Fog Nozzles in Cooling Fog System (쿨링 포그 시스템의 저압 안개 노즐 분무특성에 대한 실험적 연구)

  • Ji Yeop, Kim;Cheol, Jeong;Won Jun, Kang;Jeong Ung, Kim;Jung Goo, Hong
    • Journal of ILASS-Korea
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    • v.27 no.4
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    • pp.173-180
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    • 2022
  • Cooling fog is being used in various parts of society such as fine dust reduction, cleanliness, and temperature drop. Cooling fog has the advantage of low flow rate and ease of use compared to other spray systems. In the case of cooling fog, it was confirmed that the injection angle increased as the pressure increased and the nozzle diameter increased. In this study, the minimum injection angle was 33.61 degrees and the maximum injection angle was 107.38 degrees. It was confirmed that the larger the nozzle diameter and the smaller the pressure, the larger the droplet size. In addition, it was confirmed that the Sauter Mean Diameter (SMD) increased along the X and Y axis directions. It was confirmed that the size of the droplet decreases as it approaches the nozzle tip due to the characteristics of the nozzle design factor.

A Review on the Mixture Formation and Atomization Characteristics of Oxygenated Biodiesel Fuel (바이오디젤 연료의 혼합기 형성 및 미립화 증진 방안)

  • Suh, Hyun Kyu
    • Transactions of the Korean Society of Automotive Engineers
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    • v.22 no.1
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    • pp.183-192
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    • 2014
  • In this work, the mixture formation and atomization characteristics of biodiesel fuel were reviewed under various test conditions for the optimization of compression-ignition engine fueled with biodiesel. To achieve these, the effect of nozzle caviting flow, group-hole nozzle geometry and injection strategies on the injection rate, spray evolution and atomization characteristics of biodiesel were studied by using spray characteristics measuring system. At the same time, the fuel heating system was installed to obtain the effect of fuel temperature on the biodiesel fuel atomization. It was revealed that cavitation in the nozzle orifice promoted the atomization performance of biodiesel. The group-hole nozzle geometry and split injection strategies couldn't improve it, however, the different orifice angles which were diverged and converged angle of a group-hole nozzle enhanced the biodiesel atomization. It was also observed that the increase of fuel temperature induced the quick evaporation of biodiesel fuel droplet.

Effect of Injection Pressure on Atomization Characteristics of Fuel Spray in High-Pressure Gasoline Injector (가솔린 인젝터의 연료 분무 미립화 특성에 미치는 분사 압력의 영향)

  • Lee, Chang-Sik;Choi, Soo-Chon;Kim, Min-Kyu;Kwon, Sang-Il
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.4
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    • pp.555-560
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    • 2000
  • This paper describes the macroscopic behavior and atomization characteristics of the high-pressure gasoline injector in direct-injection gasoline engine. The global spray behavior of fuel injector was visualized by shadowgraph technique. The atomization characteristics of gasoline spray such as mean diameter and mean velocity of droplet were measured by the phase Doppler particle analyzer system. In order to obtain the influence of fuel injection pressure, the macroscopic visualization and experiment of particle measurement on the fuel spray were investigated at 3,5 and 7 MPa of injection pressure under different surrounding pressure in the spray chamber. The results of this work show that the fuel injection pressure of gasoline injector in GDl engine has influence upon the mean droplet diameter, mean velocity of spray droplet, the spray tip penetration, and spray width under the elevated ambient pressure.

Spray Characteristics of the Pressure Swirl Injector for the APU Gas Turbine Engine (APU 가스터빈엔진 압력식 스월인젝터의 분무특성)

  • Choi, Chea-Hong;Choi, Seong-Man;Lim, Byeong-Jun
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.11a
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    • pp.359-364
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    • 2007
  • Spray characteristics of the APU gas turbine engine were investigated. In order to understand blow out phenomena of the APU engine, we performed fuel spray test. In the test, four operating conditions such as sea level idle, sea level max power, 20,000 feet idle, 20,000 feet max power were used as spray experimental conditions. PDPA(phase Doppler Particle Analyzer) was used for measuring the particle diameter and velocity. Also spray visualization was performed by using ND-YAG sheet laser beam. From the test result, in the case of 20,000 feet idle condition, SMD is about 100 ${\mu}m$ and maximum particle velocity is about 10 m/s. For the flame stability, spray quality should be improved at 20,000 feet idle condition.

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Spray Characteristics of the Simplex Atomizer with Working Fluids (작동 유체에 따른 단순 압력식 연료노즐의 분무특성)

  • Choi, Chea-Hong;Lim, Byeong-Jun;Choi, Seong-Man
    • Journal of the Korean Society of Propulsion Engineers
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    • v.13 no.6
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    • pp.41-47
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    • 2009
  • This paper presents the spray characteristics of the simplex fuel nozzle with different working fluids for the gas turbine engine. Spray characteristics can be changed with viscosity, surface tension and density. In this research, water and test fluid type 2 which has similar characteristics of the kerosene are used as a working fluid. Spray visualization was performed by using ND-Yag laser and droplet size was measured by using PDPA(Phase doppler particle analyzer) system. The test results show that spray shapes and SMD distributions of two working fluids are similar at main spray region.

Spray Characteristics of the APU fuel injector with liquid properties (액체 물성치에 따른 APU 연료 노즐의 분무특성)

  • Choi, Chea-Hong;Jun, Yong-Min;Choi, Seong-Man
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.175-178
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    • 2008
  • Spray characteristics for the simplex atomizer are investigated. The atomizer was tested with kerosene which is generally used as a fuel for gas turbine engines. But it is very difficult and dangerous to measure spray performance. So water is used as a working fluid for measuring the droplet information. In this study, spray visualization was performed by using ND-Yag Laser and droplet size was measured by using PDPA system by using two different working fluid such as water and test fluid # 2 which has similar characteristics of the kerosene. The test results show that SMD of water bigger than test fluid # 2 about 5$\sim$15 mm because surface tension of water is higher by a factor of 3. But the spray angles and the spray shapes have similarity

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Experiment Study on the Spray Characteristics according to the Design Factors and SMD Measuring Direction of Y-jet Nozzle (Y-jet 노즐의 설계인자와 SMD 측정방향에 따른 분무특성의 실험 연구)

  • Lee, Sang Ji;Hong, Jung Goo
    • Journal of ILASS-Korea
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    • v.23 no.4
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    • pp.205-211
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    • 2018
  • Y-jet nozzle has various advantages over other twin-fluid nozzles and are used in industrial boilers. However, it costs large energy consumption because of assisted air and its design is complex. The Y-jet nozzle is consisted of a liquid and gas port and a mixing chamber. The diameter of the port and the length of the mixing chamber greatly affect spray and atomization characteristics, therefore, they are the most important factors in nozzle design. In this study, The experimental setup is consisted of a laboratory scale spray system. The characteristics of the Y-jet nozzle according to the design parameters were observed. As a result, it was found that the length of the mixing chamber did not have effect on the flow rate and the choking condition. The droplet size was measured using a Malvern type measuring device. In addition, measurements were conducted in the front and the right directions of the nozzles. Based on the results, the SMD View Ratio is defined. It is the asymmetrical design characteristics of the Y-jet nozzle.

Study of Design Factors and Injection Conditions of Effervescent Nozzles for Internal Pressure Compensation in Liquid Rocket Injectors (액체 로켓 인젝터 내부 압력 보상을 위한 Effervescent 노즐의 설계 인자 및 분사 조건 연구)

  • Won Young Na;Sang Ji Lee;Seung O Choi;Hyungseok Nam;Jung Goo Hong
    • Journal of ILASS-Korea
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    • v.29 no.3
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    • pp.140-146
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    • 2024
  • This study investigates the application of effervescent nozzles to liquid rockets using a laboratory-scale twin fluids spray test system. Typically, rocket engines using a single liquid propellant control thrust by adjusting the mass flow rate, which is influenced by the spray differential pressure between the fluid pressure at the injector front and atmospheric pressure. As the differential pressure decreases, uneven atomization and combustion instability can occur. To address this issue, this research explores an effervescent nozzle that mixes gaseous and liquid propellants to maintain injection pressure. Experiments were conducted on eight different nozzle types with varying orifice and aerator sizes. The experimental results demonstrated internal pressure variations and differences in spray characteristics based on nozzle design, which were analyzed and discussed. if these injection characteristics are applied in the future, it is expected that they could also be utilized in eco-friendly alternative fuels such as Sustainable Aviation Fuel (SAF).

Spray Characteristics of the Injector for the APU Gas Tubine Engine at Airplane Operating Conditions (항공기 작동조건에 따른 APU 가스터빈엔진 연료노즐의 분무특성)

  • Choi, Chea-Hong;Choi, Seong-Man;Lim, Byeong-Jun
    • Journal of the Korean Society of Propulsion Engineers
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    • v.12 no.1
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    • pp.29-36
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    • 2008
  • Spray characteristics for APU gas turbine engine are investigated. In the test, four flight conditions such as sea level idle, sea level max power, 20,000 feet idle, 20,000 feet max power are used as spray experimental conditions. Spray visualization was performed by using ND-YAG laser bean PDPA(Phase Doppler Particle Analyzer) was used for measuring the particle diameter and velocity from 20 mm to 100 mm from discharge orifice. From the test result, SMD is $90{\sim}95\;{\mu}m$ 맛 20,000 ft idle condition and SMD is $60{\sim}75\;{\mu}m$ at sea level idle condition. Also SMD is $55{\sim}65\;{\mu}m$ at 20,000 ft max power condition and SMD is $30{\sim}70\;{\mu}m$ at sea level max power condition. In the case of 20,000 ft idle condition, combustion instability could be occurred due to the higher drop diameter. Therefore it is necessary to decrease the droplet diameter in the high altitude condition.