• 대한두개안면성형외과학회지
• /
• 제14권2호
• /
• pp.102-106
• /
• 2013

Background: When using the anterior approach for performing superficial parotidectomy, the first thing to do is to find the buccal branch of the facial nerve and the parotid duct. The buccal branch usually runs transversely with the parotid duct from the anterior border of the parotid gland. We wanted to check the relationship between the two structures during the operation and to get clinically helpful information. Methods: Twelve patients with parotid mass were treated with superficial parotidectomy between May 2012 and August 2012. The outline of superficial and deep lobes of the parotid gland, parotid duct, and the buccal branch of the facial nerve were drawn on the transparent film by tracing the structures intraoperatively. Results: In 7 (58.3%) of 12 cases, the buccal branch of the facial nerve was located more caudally than the parotid duct at the anterior border of the superficial lobe of the parotid gland. In 3 cases (25%), the buccal branch was located more cephalically than the parotid duct. The mean distance between two structures were $2.54{\pm}1.48$ mm. In 11 cases, the parotid duct was located deeper than the buccal branch. Conclusion: The buccal branch of the facial nerve tends to be located more caudally than parotid duct and runs more superficially than parotid duct in all cases. We identified the relationship between the parotid duct and the buccal branch of the facial nerve during the operations on living subjects, not from the cadavers, so it would be a clinically helpful study which supplied more accurate anatomical information.

• 대한조선학회논문집
• /
• 제43권2호
• /
• pp.236-245
• /
• 2006

The ventilation performance for the various venting duct arrays has been experimentally compared in the scaled model of the container hold. Most container ships have the ventilation duct system to remove effectively the condensing heat released from container refrigerator. The existing duct system is vertically installed and basically has the number of duct as many as the columns of reefer container stack. In this study, to make up for the weak points having stagnantly hot legions in the centered area of container hold for the present system, the horizontal upward jotting duct system was proposed and proved by temperature rising tests on the scaled model. In this paper, the expected flow regimes and the thermal and hydrodynamic analogies as well as the measured temperature distributions in a hold for various duct types and heat released rates are deeply discussed.

• 대한기계학회논문집B
• /
• 제20권4호
• /
• pp.1416-1425
• /
• 1996

A numerical method has been proposed to predict 3-dimensional flow in a duct system with multiple outlets. For the duct system, it is supposed that the pressure values are given at multiple outlets while the velocity profile is given at a inlet. To maintain the continuity of pressure distribution between main and branch duct, present method allows that the pressure value taken from analysis of branch duct can be converted to the main duct analysis. The result from present method which can handle the pressure boundary condition closely coincided with that from regular method which can handle the velocity boundary condition only. Furthermore the flow distribution from present method showed good agreement with that from the single block method. From the comparison of the present method with the total pressure method used for engineering duct design, 13% of discrepancy in pressure loss was shown between the main duct inlet and the branch duct outlet.

• 한국해양공학회지
• /
• 제26권5호
• /
• pp.1-4
• /
• 2012

A energy saving device "Crown duct" has been developed and its efficiency gain has been verified experimentally in the towing tank of SSPA. The preswirl stator is well known as one of energy saving devices, which recovering the rotational energy of propeller slipstream. Crown duct has two functions of recovers the rotational energy by three blades on top of duct and of flow concentration by semi-duct. The model tests showed 4.4% efficiency gain with Crown Duct at full load condition and 6.9% at ballast condition compared with the bare hull ones for the middle class tanker.

• 대한조선학회논문집
• /
• 제53권5호
• /
• pp.343-352
• /
• 2016

In this study, a pre-swirl duct for the 180,000 DWT bulk carrier has been designed from a propulsion standpoint using CFD. The stern duct - designed by NMRI - was selected as the initial duct. The objective function is to minimize the value of delivered power in model scale. Design variables of the duct include duct angle, diameter, chord length, and vertical and horizontal displacements from the center. Design variables of the stators are blade number, arrangement angle, chord length, and pitch angle. A parametric design was carried out with the objective function obtained using CFD. Reynolds averaged Navier-Stokes equations have been solved; and the Reynolds stress model applied for the turbulent closure. A double body model is used for the treatment of free-surface. MRF and sliding mesh models have been applied to simulate the actuating propeller. A self-propulsion point has been obtained from the results of towing and self-propelled computations, i.e., form factor obtained from towing computation and towing forces obtained from self-propelled computations of two propeller rotating speeds. The reduction rate of the delivered power of the improved stern duct is 2.9%, whereas that of the initial stern duct is 1.3%. The pre-swirl duct with one inner stator in upper starboard and three outer stators in portside has been designed. The delivered power due to the designed pre-swirl duct is reduced by 5.8%.

• 대한조선학회논문집
• /
• 제55권6호
• /
• pp.474-481
• /
• 2018

This paper is to compare by numerical analysis the flow characteristics and propulsion performance of stern with the shape change of K-duct, a pre-swirl duct developed by Korea Research Institute of Ships & Ocean Engineering (KRISO). First, the characteristics of the propeller and the resistance and self-propulsion before and after the attachment of the K-duct to the ship were verified and the validity of the calculation method was confirmed by comparing this result with the model test results. After that, resistance and self-propulsion calculations were performed by the same numerical method when the K-duct was changed into five different shapes. The efficiency of the other five cases was compared using the delivery horsepower in the model scale and the flow characteristics of the stern were analyzed as the velocity and pressure distributions in the area between the duct end and the propeller plane. For the computation, STAR-CCM +, a general-purpose flow analysis program, was used and the Reynolds Averaged Navier-Stokes (RANS) equations were applied. Rigid Body Motion (RBM) method was used for the propeller rotating motion and SST $k-{\omega}$ turbulence model was applied for the turbulence model. As a result, the tangential velocity of the propeller inflow changed according to the position angle change of the stator, and the pressure of the propeller hub and the cap changes. This regulated the propeller hub vortex. It was confirmed that the vortex of the portion where the fixed blade and the duct meet was reduced by blunt change.

• Journal of Chest Surgery
• /
• 제47권4호
• /
• pp.423-426
• /
• 2014

A 67-year-old male patient came to the hospital due to lung cancer and mediastinal cystic mass which was suspected to be esophageal duplication cyst. Video-assisted thoracoscopic surgery (VATS) was performed and intra-operative finding suggested it as a cystic mass along the thoracic duct. Thoracic duct was ligated and the cyst was completely resected. A 48-year-old female patient visited the hospital for dysphagia. Mediastinal cystic mass was suspected to be an esophageal duplication cyst. Intraoperative finding suggest a thoracic duct lymphangioma. After thoracic duct ligation, the mass was completely resected with VATS. Postoperative chylothorax did not develop in both cases.

• 대한기계학회논문집B
• /
• 제24권12호
• /
• pp.1683-1691
• /
• 2000

In this study, it is numerically revealed that the secondary flow due to the Coriolls force in a straight duct rotating about an axis perpendicular to that of the duct is analogous to that caused by the centrifugal force in a stationary curved duct. Dimensionless parameters $K_{LR}=Re/\sqrt{Ro}$ and Rossby number in a rotating straight duct were used as a set corresponding to Dean number and curvature ratio in a stationary curved duct. When the value of Rossby number and curvature ratio is large, it is shown that the flow field satisfies the `asymptotic invariance property`, that is, there are strong quantitative similarities between the two flows such as friction factors, flow patterns, and maximum axial velocity magnitudes for the same values of $K_{LR}$ and Dean number.

• Investigative Magnetic Resonance Imaging
• /
• 제22권3호
• /
• pp.182-186
• /
• 2018

Dynamic enhanced magnetic resonance lymphangiography can be used to provide anatomic and dynamic information for various lymphatic diseases, including thoracic duct injury, and can also help to guide the thoracic duct embolization procedure. We present a case of postoperative chylothorax demonstrated by dynamic enhanced MR lymphangiography. In this case, the chyle leakage site and location of cisterna chyli were clearly visualized by dynamic enhanced MR lymphangiography, thus allowing for management with thoracic duct embolization.

• 설비공학논문집
• /
• 제17권4호
• /
• pp.386-395
• /
• 2005

With the development of a living standard, the importance of indoor air conditioning system in all kinds of buildings and vehicles has increased. A lot of researches on energy losses in a duct and various kinds of flow pattern in branches or junctions have been carried out over many years, because the primary object of a duct system used in HVAC is to provide equal flow rate in the interior of each room by minimizing pressure drop. In this study, to get equal flow distribution in each branch, a blockage is applied to the rectangular duct system. The flow analysis for flow distribution of a rectangular duct with two branches was performed by CFD. By using SIMPLE algorithm and finite volume method, flow analysis is performed in the case of 3-D, incompressible, turbulent flow. Also, the standard $k-{\varepsilon}$ model and wall function method were used for analysis of turbulent fluid flow. The distribution diagrams of static pressure, velocity vector, turbulent energy and kinetic energy in accordance with variation of Reynolds number and blockages location in a rectangular duct show that flow distribution at duct outlets is improved by a blockage. In this rectangular duct system, mean velocity and flow rate distribution in two branch outlets are nearly constant regardless of variation of Reynolds number, and a flow pattern of the internal duct has a same tendency as well.