• 한국추진공학회지
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• 제19권5호
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• pp.62-70
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• 2015

액체로켓엔진은 시동단계에서 갑작스런 압력 및 온도 등의 부하변동이 발생할 수 있다. 따라서 성공적인 액체로켓엔진 개발과 함께 비용, 시간을 절감하기 위해 시동 해석이 필요하다. 본 연구에서는 다단연소사이클 액체로켓엔진 파워팩에 대한 시동 해석 시뮬레이터를 개발하여 압력 및 유량 밸런스를 통한 유량을 결정하고 터빈 및 펌프의 수학적 모델링을 통해 최종적으로 시간에 따른 터보펌프의 회전속도를 구하였다. 시동 해석 결과, 정상상태도달까지 약 1.3초가 소요되었으며 이때의 회전속도로는 27,500 rpm을 얻었다. 또한 안정적 시동을 위한 적절한 시퀀스 제시가 가능함을 확인했다.

• Journal of Chest Surgery
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• 제16권2호
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• pp.213-220
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• 1983

Pulmonary function is the determinant of blood gas tension. However, Acid-Base disturbances can also alter partial pressures of oxygen and carbon dioxide in arterial blood. During respiratory acidosis $PO_2$ will be lowered and reverse changes will be produced during respiratory alkalosis. On the other hand, in metabolic acidosis $PO_2$ will be elevated and $PCO_2$ will be lowered by the respiratory compensation, and reverse response will be induced in metabolic alkalosis. Urinary gas tension has many influencing factors than arterial blood and difficult to estimate the tendency of its alterations. Urinary $PO_2$ and $PCO_2$ are not always identical level as venous blood. It is to be altered by blood gas tension, flow rate of urine, metabolic rate of kidney, and Acid-Base status of blood. Particularly countercurrent exchange of oxygen and carbon dioxide in the renal medulla will make larger alteration of gas tension than venous blood. After induction of Acid-Base disturbances [disturbances] arterial and urinary $PCO_2$, $PO_2$, urinary volume, and osmolarity were determined in dogs, and the relationships between arterial and urinary $PCO_2$ , $PO_2$ Acid-Base disturbances, urinary volume, and osmolarity were investigated. 1. During the acute Metabolic and Respiratory disturbances urinary pH did not respond on respiratory origin. However, there were immediate urinary response in pH on metabolic origin. 2. Urinary $PO_2$, $PCO_2$, did not always follow arterial or venous gas tension and Acid-Base disturbance. Urinary $PCO_2$, correlate well with the urinary volume. The larger the urinary volume, $PCO_2$ lowered to the venous level. The smaller the urinary volume, urinary $PCO_2$ tends to be higher. However urinary $PO_2$ did not have any particular correlation with urinary volume. 3. Correlation between urinary $PCO_2$ and $PO_2$ were inversely proportional to arterial blood. Differences of $PCO_2$ between arterial blood and urine also did not have any particular correlation with urinary volume. This may suggest that changes on blood gas tensions can influence on urinary $PCO_2$. 4. There were eminent clear inverse correlation between urinary $PCO_2$ and osmolar concentrations of urine. Above results strongly suggest that partial pressure of gas in urine primarily depend upon counter-current exchanges in renal medullary tissues.