• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.9
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• pp.1253-1262
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• 2001

Experimental study is conducted to investigate the heat/mass transfer and flow characteristics for the flow over backward-facing step and cavities. A naphthalene sublimation method has been employed to measure the mass transfer coefficients on the duct wall and LDV system has been used to obtain mean velocity profiles and turbulence intensities. Reynolds number based on the step height and free stream velocity is 20,000 and St numbers of acoustic excitations given to separated flow are 0.2 to 0.4. The spectra of streamwise velocity fluctuation show a sharp peak forcing frequency for an acoustically excited flow. The results reveal that the vortex pairing and overall turbulence level are enhanced by the acoustic excitation and a significant decrease in the reattachment length and the increased turbulence intensity are observed with the excitation. A certain acoustic excitation increases considerably the heat/mass transfer coefficient at the reattachment point and in the recirculation region. For the cavities, heat/mass transfer is enhanced by the acoustic excitation due to the elevated turbulence intensity. For the 10H cavity, the flow pattern is significantly changed with the acoustic excitation. However, for the 5H cavity, the acoustic excitation has little effect on the flow pattern in the cavity.

• Journal of Korea Foundry Society
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• v.20 no.5
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• pp.344-353
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• 2000

In order to find out the casting conditions of the thin wall stainless steel exhaust manifold for automobile, the melt flow and solidification behavior simulated by the Z-CAST program were evaluated, and experimental casting result on the test casting and exhaust manifold of SSC13 alloy were investigated. From the results of this study, it was shown that the calculated results on fluid flow were in good agreement with practical thin wall test castings under the same casting conditions, as pouring metal is austenitic stainless steel(SSC13) and pouring temperature is 1575, 1630, and $1665^{\circ}C$ respectively. That calculated result with designed thin wall exhaust manifold was predicted filling up into the mold cavity, and practical casting was sound. The solidification simulation was predicted shrinkages at the bosses for original exhaust manifold, and designed it without bosses was predicted no defect. Therefore practical exhaust manifold casting was sound and in good agreement with calculated solidification results.

• Journal of Chest Surgery
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• v.45 no.3
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• pp.177-182
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• 2012

Background: Tuberculous abscess of the chest wall is a very rare disease. Few articles have reported on it and those that have enrolled few patients. To determine the characteristics of this disease and to suggest an optimal treatment strategy, we reviewed patients treated by surgical management. Materials and Methods: Between October 1981 and December 2009, 68 patients treated by surgical management for a tuberculous abscess of the chest wall were reviewed retrospectively. Results: Of 33 men and 35 women, 31 patients had a current or previous history of tuberculosis. The main complaints were chest pain, a palpable mass, pus discharge, and coughing. A preoperative bacteriologic diagnosis was performed in 12 patients. Abscess excision was performed in 54 cases, abscess cavity excision and partial rib resection in 13, and abscess excision and partial sternum and clavicle excision in 1 case. Postoperative wound infection was noted in 16 patients and a secondary operation was performed in 1 patient. Recurrence occurred in 5 patients (7.35%). Reoperation with abscess excision and partial rib resection was performed in all of the 5 cases. Conclusion: Complete excision of the abscess and primary closure of the wound with obliteration of space would decrease postoperative complications. Anti-tuberculosis medication may reduce the chance of recurrence.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.285-288
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• 2003

The bending phenomenon during extruding one product using four billets can be obtain by the difference of hole diameters in the multi-hole container. The difference of hole diameter caused the difference of billet amount inserted in the die cavity. As results, it can bend during extruding products by the different amount of two billets and by the cohesion of billets in the porthole dies cavity. And the bending curvature can be controlled by the size of holes and billets. The experiments using aluminium material had been done for the rectangular and square curved tube product. The results of the experiment show that the curved aluminum tube product can be bended by the extru-bending process without the defects such as the distortion of section and the thickness change of the wall of tube and the folding and wrinkling. The curvature of product is affected by shape of cross section and the difference of billet diameters. It is known that the welding and extruding and bending can be done simultaneously in the die cavity when a rectangular hollow curved tube would be extruded by porthole dies using four different size billets made of aluminum material.

• The KSFM Journal of Fluid Machinery
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• v.12 no.1
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• pp.35-42
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• 2009

The flow and heat/mass transfer characteristics on the squealer tip surface of a high-turning turbine rotor blade have been investigated at a Reynolds number of $2.09{\times}10^5$, by employing the oil-film flow visualization and naphthalene sublimation technique. The squealer rim height-to-chord ratio and tip gap height-to-chord ratio are fixed as typical values of $h_{st}/c$ = 5.5% and h/c = 2.0%, respectively, for turbulence intensities of Tu = 0.3% and 15%. The results show that the near-wall flow phenomena within the cavity of the squealer tip are totally different from those over the plane tip. There are complicated backward flows from the suction side to the pressure side near the cavity floor, in contrast to the plane tip gap flows moving toward the suction side after flow separation/reattachment. The squealer tip provides a significant reduction in tip surface thermal load with less severe gradient compared to the plane tip. In this study, the tip surface is divided into six different regions, and transport phenomena at each region are discussed in detail. The mean thermal load averaged over the squealer cavity floor is augmented by 7.5 percents under the high inlet turbulence level.

• Journal of computational fluids engineering
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• v.10 no.3 s.30
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• pp.36-42
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• 2005

The present study numerically investigates the natural convection heat transfer in a 2-D square cavity containing a centered heat conducting body. Special emphasis is given to the influences of the Rayleigh number, the dimensionless conducting body size, and the ratio of the thermal diffusivity of the body to that of the fluid on the natural convection heat transfer in overall concerned region. The analysis reveals that the fluid flow and heat transfer processes are governed by all of them. Results for isotherms, vector plots and wall Nusselt numbers are reported for Pr = 0.71 and relatively wide ranges of the other parameters. Heat transfer across the cavity, in comparison to that in the absence of a body, are enhanced (reduced) in general by a body with a thermal diffusivity ratio less (greater) than unity. It is also found that the heat transfer attains a minimum as the body size is increased with a thermal diffusivity ratio greater than unity.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.1
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• pp.174-184
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• 1997

A shock wave, being an irreversible process, gives rise to entropy increase. A great deal of effort has been made to control shock wave and boundary layer interaction related to energy losses as well as problems of vibration and noise. In the present study, tests are performed on a roof mounted half circular arc in an indraft type supersonic wind tunnel to evaluate the effects of porosity, length and depth of cavity in passive control of shock wave on the attenuation of shock strength by reviewing the measured static pressures at the porous wall and cavity. Also the flow field is visualized by a Schlieren system. The results show that in the present study the porosity of 8% produced the largest reduction of pressure fluctuations and that for the same porosity, the strength of shock wave decreases with the increasings of the depth and length of cavity.

• Tuberculosis and Respiratory Diseases
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• v.69 no.3
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• pp.191-195
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• 2010

Abnormally located liver tissue has been described in the vicinity of the liver proper, near anatomical structures such as the gallbladder, the umbilical fossa, the adrenal gland, the pancreas, and the spleen. Supradiaphragmatic ectopic liver is a rare finding, but has been reported to have been found in the intrathoracic cavity and in the pericardium. In the majority of supradiaphragmatic ectopic liver cases, there was an accompanying transdiaphragmatic pedicle of the main liver body into the abdominal cavity. In a minority of supradiaphramatic ectopic liver cases, the liver was completely separated from the abdominal cavity without a connection between the thorax and the abdomen, with accompanying diaphragmatic anomalies. We describe one case of intrathoracic ectopic liver in a patient with a previous history of lower chest wall trauma, and a brief review of the English-language medical literature on this topic.

• Journal of Chest Surgery
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• v.18 no.3
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• pp.474-481
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• 1985

Pulmonary cavity is the result of necrosis of lung parenchyma with evacuation of the necrotic material via the tracheobronchial tree. A communication with the tracheobronchial tree permits air to enter the area of necrosis, so the radiologic result show the a lucent defect. The radiologic characteristics of the wall of a cavity are determined by the reaction of the lung parenchyma to the pathologic process. Therefore, the shadows of the chest films in cavitary lesion were variable in its nature. The author, in 42 cases which have a cavitary lesion in X-ray findings among 172 cases resected lung obtained in P.N.U.H. from 1979 to June, 1985, studied similarities and differences between the pathogenesis of these lesions and the radiologic findings. The author reviewed the 42 cavitary lesions and the following results were obtained. 1. The cavitary lesions were seen in 42 [24.4%] out of 172 cases of resected lung disease. 2. Histopathologically, pulmonary tuberculosis was 47.6% and primary lung cancer was 9.5%. 3. The most common site of the lesion was right upper lobe. 4. The most common size of the cavity was from 3 to 6 cm in diameter. 5. Lobectomy was the most common operated method.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.268-271
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• 2008

If a reactor vessel is failed to retain a molten corium in a postulated severe accident, the molten corium is released outside the reactor vessel into a reactor cavity. The molten corium would attack the concrete wall and basemat of the reactor cavity, which may lead to inevitable concrete decompositions and possible radiological releases. In the OECD/MCCI project, a series of tests were performed to secure the data for cooling the molten corium spread out at the reactor cavity and for the long-term CCI (Core Concrete Interaction). Also, a MCCI (Molten Core Concrete Interaction) analysis code, CORQUENCH was upgraded at Argonne National Laboratory with embedding the new models developed for the tests. This paper deals with analyses of MCCI at plant scale under the conditions of top flooding using the upgraded CORQUENCH code. The modeling approach is briefly summarized first, followed by presentation of a validation calculation that illustrates the predicative capability of the modeling tool. With this background in place, the model is then used to carry out a parametric set of scoping calculations that define approximate coolability envelopes for the LCS (Limestone Common Sand) concrete that has been evaluated in the OECD/MCCI project.