• Proceedings of the KSME Conference
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• 2001.06e
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• pp.499-505
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• 2001

The objective of the paper was to measure the pressure drop and to investigate the recirculation region of the conical orifices used in Kwang-yang Iron & Steel Company. The flow field with water used as a working fluid was the turbulent flow for Reynolds number of $2{\times}10^4$. The effective parameters for the pressure drop and the recirculation region were the conical orifice's inclined angle (${\theta}$) against the wall, the interval(L) between orifices, the relative angle of rotation(${\alpha}$) of the orifices, the shape of the orifice's hole(circle, rectangle, triangle) having the same area. It was found that the shape of the orifice's hole affected the pressure drop and the flow field a lot, But the other parameters did not make much differences to the pressure drop. The PISO algorithm with FLUENT code was employed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.2
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• pp.278-287
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• 2002

The objective of the paper was to calculate the pressure drop and to investigate the recirculation region of the conical orifices used in Kwang-yang Iron & Steel Company. The flow field with water used as a working fluid was the turbulent flow for Reynolds number of 2$\times$10$^4$. The effective parameters fur the pressure drop and the recirculation region were the conical orifice\`s inclined angle ($\theta$) against the wall, the interval(S) between orifices, the relative angle of rotation($\alpha$) of the orifices, the shape of the orifice's hole(circle, rectangle, triangle) having the same area, the number(N) of the orifice's holes having the same mass flow rate, and the thickness(t) of the orifices. It was fecund that the shape of the orifice's hole, the number of the orifice's holes and the thickness of the orifice affected the total pressure drop a lot and that the conical orifice's inclined angle against the wall, the relative angle of rotation of the orifices, the number of the orifice's holes and the thickness of the orifices affected the center location of the recirculation region. The PISO algorithm with FLUENT code was employed to analyze the flow field.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.10
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• pp.1371-1379
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• 1997

The high pressure drop is frequently required in the by-pass line of the pump or of the heat exchanger in power plants. However, cavitation produced by a high pressure drop could damage the pipe and pump blades. Conical orifices are adopted to reduce cavitation due to high pressure drop. The discharge coefficients of conical orifice plates were measured by weighing method in the standard water flow system. The discharge coefficients were larger when the ratios of thickness of orifice edge to throat diameter were larger. The noise generated from a conical orifice due to cavitation was measured with a sound level meter and a hydrophone. With increasing the bore diameter of the orifice, the sound pressure level or the noise level due to cavitation became higher. The noise level was suddenly increased at the inception of cavitation.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.291-294
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• 2002

This study describes the external spray characteristics of deflector nozzle such as the breakup procedures of liquid sheet, spray angle, discharge coefficient and bubble behaviors of spray and SMD at deflector nozzle. In order to visualize the spray behaviors shadow graphy technique were used. According to the increase of injection pressure, development of the spray passes through the dribbling, distoted jet, closed bubble due to the contraction by surface tension forces, the bubble opens into hollow tulip shape, and the curved surface straightened to form a conical sheet like as the simplex swirl atomizer. Spray cone angle was nearly 90 deg. Variations of SMD were examined in order to describe the dependency of SMD on the injection pressure and orifice diameter. The shape of deflector and oriffice diameter had an effect on the discharge coefficient.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.6
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• pp.559-566
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• 2011

This paper presents the flow passage design for a window cooling device, which have a conical poppet valve and an emissive orifice. Computational flow analysis and experiment are conducted according to the poppet strokes. The results show satisfactory flow characteristics that pressure is reduced enough to endure material strength and the flow does not choked inside window. The correction factor of discharge coefficients is found between 2-dimensional analysis and experiments, which is applied to control coolant flow rates of the window cooling device.

• Journal of Chest Surgery
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• v.8 no.1
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• pp.51-56
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• 1975

The typical traction diverticulum of the mid-thoracic esophagus is conical or funnel shaped with a wide orifice, is small (rarely exceeding 2cm in length), and is situated horizontally or extends superiorly. It is a true diverticulum, having a complete investment by the esophageal muscle coats. Each of these characteristics promotes easy emptying of the diverticulum. Since food accumulation is presented, there is no tendency to progressive enlargement of the sac, and no associated dysphagia. The diverticula of mid-esophagus rarely develop and rarely produce symptoms. When symptoms develop, they are usually caused by granulomatous infections of the mediastinal lymph nodes. And also such diverticula only rarely give rise to significant complications, the most serious of which is a tracheobronchial fistula. Generally when such complications develop or a diverticulum itself produces symptoms, moderate or severe, surgery intervenes. A case of mid-esophageal diverticulum, traction type, which surgically treated with good results, was experienced at the Department of Thoracic Surgery of Kyung-Pook University. School of Medicine. In this case, there were substernal discomfort, acid regurgitation, and back pain for about 6 months. On the operative findings, it was noticed that the diverticulum was developed by traction and adhesion of perihilar nodes to the esophageal wall. The diverticulum was a small finger tip size and the neck of it was obscure. The surrounding inflammatory change was minimal.

• Journal of Mechanical Science and Technology
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• v.18 no.7
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• pp.1222-1235
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• 2004

This study examines the influence of geometry on the internal flow and macroscopic behavior of the spray in Diesel nozzles. For this investigation, two bi-orifice nozzles were employed: one cylindrical and one conical. The first step is to use a non-destructive characterization method which is based on the production of silicone moulds so that the precise internal geometry of the two nozzles can be measured. At this stage the nozzles have been characterized dimensionally and therefore the internal flow can be studied using CFD calculations. The results gained from this experiment make it possible also to ascertain the critical cavitation conditions. Once the critical cavitation conditions have been identified, the macroscopic parameters of the spray can be studied in both cavitating and non-cavitating conditions using a test rig pressurized with nitrogen and with the help of a image acquisition system and image processing software. Consequently, research can be carried out to determine the influence that cavitation has on macroscopic spray behavior. From the point of view of the spray macroscopic behavior, the main conclusion of the paper is that cavitation leads to an increment of the spray cone angle. On the other hand, from the point of view of the internal flow, the hole outlet velocity increases when cavitation appears. This phenomenon can be explained by the reduction in the cross section of the liquid phase in the outlet section of the hole.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.1
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• pp.18-25
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• 2001

The results of systematic numerical experiments of secondary gas injection thrust vector control are presented. The effects of secondary injection system such as injection location and nozzle divergent cone angle onto the overall performance parameters such as thrust ratio, specific impulse ratio and axial thrust augmentation, are investigated. Complex nozzle exhaust flows induced by the secondary jet penetration is numerically analyzed by solving unsteady three-dimensional Reynolds-averaged Navier-Stokes equations with Baldwin-Lomax turbulence model for closure. Numerical simulations compared with the experiments of secondary air injection into the rocket nozzle of $9.6^{\cire}$ divergent half angle showed good agreement. The results obtained in terms of overall performance parameters showed that locating the secondary injection orifice further downstream of primary nozzle ensures the prevention of occurrence of reflected shock wave, therefore is suitable for efficient and stable thrust vectoring over a wide range of use.