• Journal of the korean Society of Automotive Engineers
• /
• v.12 no.5
• /
• pp.26-35
• /
• 1990

This is an experimental study to investigate the characteristics of Diesel spray and Diesel engine performance using ultrasonic injection nozzle (A, B type) and conventional commercial injection nozzle (C type). The results are obtained as follows: 1. SMD and range of size distribution of Diesel spray using the ultrasonic nozzle are smaller than those using the conventional injection nozzle, and spray angle is spread. 2. Because of the difference of the ultrasonic vibration energy transfer in the same condition, the effects of A-type ultrasonic vibration are larger than those of B-type ultrasonic vibration. 3. Attaching the ultrasonic vibrator to the conventional injection nozzle of the Diesel engine, engine performances i.e. BMEP, BSFC, and cylinder peak pressure are improved.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
• /
• 2007.06a
• /
• pp.169-173
• /
• 2007

Slit-coater nozzle is one of core equipments of coating process in LCD panel manufactory. As a glass substrate size become bigger, a nozzle performance and a high-speed coating process are considered important issues. To design the optimal nozzle, the characteristics of fluid inside nozzle are studied using CFD (Computational Fluid Dynamics) method. Through research on design factors, we can know the coating uniformity influenced by lip length, cavity angle and gap size. The future work for this study is to find the factors in high-speed coating process and function between factors of design.

• Proceedings of the KSME Conference
• /
• 2001.11b
• /
• pp.693-698
• /
• 2001

An experimental study was carried out with an aerated nozzle. This nozzle was well known that the performance of the atomization is better than other ones even though the supplied air pressure is lower than that of them. The purpose of this investigation is to provide the essential information of the aerated nozzle from the nozzle exit. The experimental work was performed in order to analyze the characteristics of the overall flow field from the nozzle exit. The 2-D PDPA system was used to acquire the data in the concerned region. The characteristics of the mean velocity distribution, half-width, and SMD were mainly analyzed. Also the correlation between turbulent kinetic energy and SMD was described with ALR.

• Journal of Advanced Marine Engineering and Technology
• /
• v.38 no.10
• /
• pp.1232-1236
• /
• 2014

Numerical models of fluid dynamics inside the micro actuator chamber and nozzle are presented. The models include ink flow from reservoir, bubble formation and growth, ejection through the nozzle, and dynamics of refill process. Since high tapered nozzle is one of the very important parameters for overall actuator performance design. The effects of variations of nozzle thickness, diameter, and taper angles are simulated and some results are compared with the experimental results. It is found that the ink droplet ejection through the thinner and high tapered nozzle is more steady, fast, and robust.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.3
• /
• pp.18-27
• /
• 2000

The spray models incorporated into the GTT code were tested for free spray, spray in swirling flows and the sprays impinging on a flat wall. And the validity of the models has been confirmed by comparing the calculated results with the experimental data. Using this code, the spray behavior in the diesel combustion chamber have been numerically analyzed for variation of nozzle diameter. Also, the effects of nozzle diameter in diesel combustion was investigated experimentally by measuring the performance in a D.I engine. This study provides the information for the spray characteristics and emissions with variation of nozzle diameter. As a result, it has shown that decreasing nozzle diameter resulted in improving smoke and specific fuel consumption in a middle speed range.

• The KSFM Journal of Fluid Machinery
• /
• v.10 no.5
• /
• pp.34-40
• /
• 2007

An optimization approach is investigated for the design of new nozzle system in a automatic car wash machine. Three-dimensional computational fluid dynamics and design of experiment methods have been employed to know the mutual interaction between the nozzle shape in the automatic car wash machine and the airflow velocity distribution on the vehicle surface. The performances of air nozzle system were defined as the velocity magnitude and the uniformity of the velocity on the surface of the car. Predicted jet velocity distributions for the optimized geometry were compared with experimental data and the comparisons showed generally good agreements. Also, the performance of the dryer was improved with the optimized results.

• International Journal of Fluid Machinery and Systems
• /
• v.6 no.4
• /
• pp.213-221
• /
• 2013

The characteristics of the thrust for ship propulsion equipment directly driven by air compressed by pressure fluctuation in a blower piping system are investigated. The exhaust valve is positioned upon the air ejection hole in the discharge pipe in order to induce the large-scale pressure fluctuation, and the effects of the valve on the pressure in the pipes and the thrust for the propulsive nozzle are examined. The pressure in the pipes decreases immediately after the valve is opened, and it increases just before the valve is closed. The thrust for the propulsive nozzle monotonically increases with increasing number of revolutions and depth. The interfacial wave in the nozzle appears in the frequency of approximately 4Hz, and it is important for the increase of the thrust to synchronize the opening-closing cycle for the exhaust valve with the generation frequency of the interfacial wave. The finite difference lattice Boltzmann method is helpful to investigate the characteristics of the flow in the nozzle.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.11 no.5
• /
• pp.692-699
• /
• 1999

The vortex tube is a sample device for separating a compressed gaseous fluid stream into two flows of high and low temperature without any chemical reactions. The phenomena of energy separation through the vortex tube were investigated experimentally, to see the effects of the number of nozzle holes on the energy separation. The experiment was carried out with the number of nozzle holes from 1 to 10 by varying inlet pressure and cold mass fraction. The experimental results were indicated that the effective number of nozzle holes for the best cooling performance was found as 4. Also, to find effective use in a given operation conditions, the temperature difference of cold air and the cooling capacity of vortex tube was compared. The result is that cooling capacity was more important than temperature difference of cold air.

• Journal of Advanced Marine Engineering and Technology
• /
• v.29 no.4
• /
• pp.443-452
• /
• 2005

The purpose of this study is experimentally to analyze the effects of intake port swirl, injection system and turbocharger on the engine performance and the emission characteristics in a V8 type turbocharger intercooler D.I. diesel engine of the displacement 16.7L, and to suggest the improvement of engine performance. Generally to enhance engine power, TCI diesel engine is put to practically use turbocharged intercooler in order to increase volume efficiency which is cooled boost air. As results of considering the factors of the intake port of swirl ratio 2.25, compression ratio 17.5. re-entrant $8.5^{\circ}$ combustion bowl, nozzle hole diameter ${\phi}0.33{\ast}3+{\phi}0.35{\ast}2$. nozzle protrusion 3.18mm, injection timing BTDC $12^{\circ}CA$ and turbocharger(compressor 0.6A/R+46Trim. turbine 1.0 A/R+57Trim) is the best in the full load in the engine performance and the exhaust characteristics of NOx concentration. Therefore. their factors are appropriated as intake system, injection and turbocharger system.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.14 no.6
• /
• pp.25-30
• /
• 2010

Dual throat nozzle(DTN) is recently attracting much attention as a new concept of the thrust vectoring technique. This DTN is designed with two throats, an upstream minimum and a downstream minimum at the nozzle exit, with a cavity in between the upstream throat and exit. In the present study, a computational work has been carried out to analyze the performance of a dual throat nozzle(DTN) at various mass flow rate of secondary flow and nozzle pressure ratios(NPR). Two-dimensional, steady, compressible Navier-Stokes equations were solved using a fully implicit finite volume scheme. The present computational results were validated with some experimental data available. Based upon the present results, The control effectiveness of thrust-vector is discussed in terms of the thrust coefficient and the discharge coefficient.