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이현규,이정수,김동화,조진수 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.10
Hole-type pre-swirl nozzle was optimized using CFD analysis and experiments. CFD methodologies were validated by comparing the CFD results with experiments. Four design variables were considered in the optimization process: nozzle inlet length ( L ), outlet length ( l ), inlet diameter (D), and radial location (r p ). The optimization process included the optimal Latin hypercube design sampling method with the Kriging surrogate model and genetic algorithm. The single-objective optimization was performed to maximize the discharge coefficient. Results showed that the optimized nozzle reduced total pressure losses and increased mass flow rate. Total temperature drop effectiveness was increased from 0.07 to 0.29. The total temperature in pre-swirl system could be characterized as the reduction in temperature by nozzle acceleration and elevation by aerodynamic losses due to friction and viscous effects in the system. The optimized model showed a discharge coefficient of 0.846, which was 31.7 % higher than the baseline condition. By improving the discharge coefficient , the pre-swirl system reduced aerodynamic losses, and the mass flow rate was increased at certain pressure ratios or satisfied the pressure margin for blade cooling.
지연 진단된 외상성 횡격막 파열에 의한 횡경막 탈장 1예
이현규,지예섭,배종대,정기훈,오민구 東國大學校醫學硏究所 2004 東國醫學 Vol.11 No.1
외상성 횡격막 파열은 흉복부의 둔상 및 관통상 의해 횡격막이 파열되어 손상부위를 통하여 복강내 장기가 흉곽내로 탈출하는 질환이다. 횡격막 파열은 동반 장기손상이 없거나 초기 방사선 혹은 이학적 검사에서 복강내 장기의 흉곽내 탈출을 발견하지 못하면 지연진단 되는 경우가 매우 드물게 보고 되고 있다. 본 증례는 외상성 횡경막 파열이 50년이 지난 후 지연성 횡격막 탈장이 발생한 경우를 치험하였기에 보고하는 바이다. A diaphragmatic hernia in adult can result from delayed presenation of traumatic diaphragmatic rupture. If the diaphragmatic injury is not recognized at the time of the initial trauma, the patient may recover and remain symptom free, or suffer from chronic nonspecific abdominal and/or chest symptoms. After a variable interval acute symptom associated with intestinal obstruction or strangulation can arise because of a herniation the abdominal organs through the diaphragmatic defect. A delay in dagnosis may occur and be associted with a high morbidity and mortality, so a careful history and examination, are essential for the successful management of patient, as is maintaining an awareness of the possibility of the delayed presentation of traumatic diaphragmatic hernia and its complication. We present a 35 years-old male patient with delayed presenting, traumatic diaphragmatic hernia, and discuss a literature a review.