• Journal of ILASS-Korea
• /
• v.16 no.4
• /
• pp.210-214
• /
• 2011

This paper presents the spray characteristics of the gun type burner nozzle with bio-diesel blending rate. The burner nozzle used in this experiment is a pressure swirl type nozzle. For the spray characteristics, visualization of spray was conducted to obtain the spray angle, and laser diffraction spectroscope (LDS) was used for the measurement of the droplet diameters. The results showed that the $D_{max}$, SMD and spray angle were decreased with increasing the bio-diesel blending rate and BD30 (30% bio-diesel blending rate) could be found to be the maximum blending rate for using without any modification of the gun type burner of the homesize kerosene fuel boiler.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.25 no.6
• /
• pp.811-818
• /
• 2001

The wave characteristics for a non-reacting high-speed liquid jet were investigated using a linear stability theory. In this study, 2-D incompressible viscid momentum equation for a liquid jet was considered, and the effects of injection parameters, such as Weber number, Reynolds number, and density ratio, on the wave characteristics were investigated. With the wavelength obtained from the stability analysis, the atomization model was suggested. The droplet sizes after breakup were determined by the wavelengths of fast growing waves, and the mass of the shed droplets was determined by the breakup time derived by ORouke et al. It was found that in comparison with measurements of diesel fuel spray, the results of calculation had a similar trend of the decrease of overall SMD with the increase of Reynolds number.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2002.05a
• /
• pp.61-65
• /
• 2002

The present study was numerically and experimentally performed to investigate the fire suppression performance of water mist spray subjected to thermal radiation in closed space. Downward-directed water mist sprays to interact with an under kerosine pool fire were investigated in test facility. The mass mean diameters of water mist droplet were measured by PMAS under various flow conditions. The developed water mist spray nozzle was satisfied to the criteria of NFPA 750, Class 1. The mechanism of the fire suppression by water mist was concluded to be cooling of the fire surface which lead to suppressed of fuel evaporation. It was proved that the water mist spray system under lower pressures could be applied to underground fire protection system.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.24 no.6
• /
• pp.852-859
• /
• 2000

The emission in the exhaust gas from diesel engine is effected by the fuel spray characteristics. The spray of D.I. diesel engine impinges on a piston cavity and a cylinder wall. It is very important to know exactly the distribution and behavior of the spray inside cylinder. The objective of this study is to develop more accurate evaporation model. The EPISO code was used to analyze the flow characteristics in the engine. The Wakil model and the Faeth model are applied to the EPISO code to analyze the behavior of impinging spray. And also experimental and numerical analysis were carried out. The spray behavior characteristics were investigated by changing injection pressure, ambient pressure and temperature. The behavior of impinging spray was strongly effected by the change of ambient pressure and temperature. The effects of evaporation and rebounding droplet should be considered.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.338-343
• /
• 2003

Computations were performed to investigate the spray characteristics of the twin fluid nozzle in three stage heavy-oil combustion burner. The burner geometry and flow conditions were provided by a burner company. The goal of the study is to estimate mean droplet size, initial velocity and spread factor of the nozzle through comparison between experiments and numerical analyses. Air stage ratio is 2:4:4 by mass, and O2 in exhaust gas is about 4 % by volume. Here, the agreement between the experiment and numerical analyses is evaluated by NOx generation. Spray characteristics will be linearly interpolated between fuel consumption rate l20L/h and 240 L/h.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.23 no.4
• /
• pp.36-41
• /
• 2015

The cyclone separator is a simple device, which causes the centrifugal separation of materials such as droplets or particles in a fluid stream. The cyclone separator utilizes the energy obtained from fluid pressure and linear motion to create rotational fluid motion. This rotational motion leads the materials suspended in the fluid to separate from the fluid quickly due to the centrifugal force. The rotation is produced by the tangential or involuted introduction of fluid into the vessel. These materials may be droplets of fuel in blow-by gas through an engine. Droplets suspended in the feed liquid may separate according to size, shape, or density. And the change of part dimension in a cyclone separator can yield the its performance variation. The current study shows the influence of design parameters on the performance of a cyclone separator for blow-by gas.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.7 no.5
• /
• pp.31-39
• /
• 1999

A good atomization in uniform size brings the elevation of thermal efficiency in spray combustion, the beautiful painting on surfaces, and the economical sprinkling of chemicals. Ultrasonic atomization has been expected as a good uniform atomization mechanism due to its uniform size distribution. Influx, load, and physical properties of liquids are the effecting factors to atomize liquids. In this study, distilled water and city water are selected as reference liquids and gasoline, kerosene, and petroleum as fuel liquids. Characteristics and affinity to get the maximum effect for the ultrasonic atomization are observed by using the two ultrasonic transducers with 28kHz and 2MHz. Results show that the size distributions of liquid spray dorplet by the direct vibration method prevail over those by the aerosol method in uniform droplet size and as a whole, sizes of spray liquid droplets are increased slightly according to increasing influx in the direct vibration method and quantities of spray droplets in the aerosol method decreasing according to increasing liquid load h.

• Journal of the Korean Society of Safety
• /
• v.19 no.3 s.67
• /
• pp.20-25
• /
• 2004

In order to obtain the flame Propagation speed in freely falling droplet suspension Produced by an ultrasonic atomizer, a light collecting probe named Multi-color Integrated Cassegrain Receiving Optics (MICRO) is applied to spark-ignited spherical spray flames. Two MICRO probes are used to monitor time-series signals of OH chemilumine-scence from two different locations in the flame. The flame propagation speed is calculated by detecting the arrival time difference of the propagating flame front. In addition, time-series images of OH chemiluminescence are simultaneously obtained by a high-speed digital CCD camera to ensure the validity of the MICRO system. Furthermore, relationship between the spray properties measured by phase Doppler anemometer (PDA) and the flame propagation speed are discussed with k different experimental conditions by changing the fuel injection rate. It was confirmed that the MICRO probe system was very useful and convenient to obtain the flame propagation speed and that the flame propagation speed was different depending on the spray properties.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.6
• /
• pp.27-33
• /
• 2002

This paper presents the comparison of prediction accuracy of hybrid models. To obtain the experimental results fur comparing with the numerical results, the macroscopic and microscopic structures of the hollow-cone spray such as spray development process, spray penetration and the distribution of mean droplet size are investigated by using a shadowgraph technique and phase Doppler particle analyzer. Also, the numerical researches using various hybrid models are performed. LISA model and WAVE model are used for the primary breakup, and TAB, DDB, and RT model are used for the secondary breakup.

• Nuclear Engineering and Technology
• /
• v.43 no.1
• /
• pp.45-62
• /
• 2011

The Korean nuclear industry is developing a thermal-hydraulic analysis code for safety analysis of pressurized water reactors (PWRs). The new code is called the Safety and Performance Analysis Code for Nuclear Power Plants (SPACE). The SPACE code adopts advanced physical modeling of two-phase flows, mainly two-fluid three-field models which comprise gas, continuous liquid, and droplet fields and has the capability to simulate 3D effects by the use of structured and/or nonstructured meshes. The programming language for the SPACE code is C++ for object-oriented code architecture. The SPACE code will replace outdated vendor supplied codes and will be used for the safety analysis of operating PWRs and the design of advanced reactors. This paper describes the overall features of the SPACE code and shows the code assessment results for several conceptual and separate effect test problems.