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환기분사장치 분사가스의 압력 변화에 따른 초공동 유동 특성에 관한 연구
김태순(T.S. Kim),고성호(S.H. Ko) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11
Cavity is generated by the fluid machine moves very high speed in the underwater, such as propellers, pump impellers, nozzles, injectors, torpedoes. And there are two main ways to generating cavitation. Natural cavitation is a phenomenon using a very high speed of the machine. It creates a bubble of gas to cover an object travelling underwater and it reduces the skin friction. It requires a very high speed while right after the launch of the underwater vehicle, such as a torpedo, proceeds at a very slow speed. So the ventilation devices add to make the cavity bubble cover the vehicle in the initial steps of launch. The ventilated cavity generation is related to the cavity pressure and the cavity pressure is related to the pressure of injected gas. This study shows the relationship between the pressure of ventilated gas and the flow characteristics. The cavity pressure is increased and the ventilated cavitation number is decreased as the pressure of the injected gas is increased.
환기분사장치의 분사면적변화에 따른 초공동 유동 특성에 관한 연구
김태순(T.S. Kim),권윤희(Y.H. Kwon),고성호(S.H. Ko) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11
Cavity is generated by the fluid machine moves very high speed under water, such as propellers, pump impellers, nozzles, injectors, torpedoes. And there are two main ways to generate cavitation. Natural cavitation is a phenomenon using a very high speed of the machine. It creates a bubble of gas to cover an object travelling under water and it reduces the skin friction. It requires a very high speed but right after the launch of the underwater vehicle, such as a torpedo, proceeds at a very slow speed. So the ventilation devices are added to make the cavity bubble cover the vehicle in the initial steps of launch. And the ventilated cavity generation is related to the volume airflow coefficient. This study shows the relationship between the ventilated volume airflow coefficient and the cavity pressure. If the volume airflow coefficient is the same regardless of a change of ventilation area, it represent a very similar cavity pressure and the ventilated cavitation number.
초공동 수중비행체의 공동영역 내부에서 분사된 배기가스가 수중비행체의 항력에 미치는 영향에 대한 수치해석적 연구
유상원(S.W. Yoo),이우근(W.K. Lee),김태순(T.S. Kim),곽영균(Y.K. Kwak),고성호(S.H. Ko) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11
Rocket propelled supercavitation under-water vehicle has very high speed. Exhaust gases are locked in cavity in the water. In other words, cavity in the water is consist of gas and vapor. So it is important how exhaust gas affect to under-water vehicle. In this paper, numerical analysis of supercavitating flows are performed 3 phase fluid consisted of water, vapor and exhaust gas. As a results, exhaust flow backward into vehicle because of density contrast between water and exhaust gas. back flow gas decrease drag force change of under-water vehicle. Numerical analysis are performed to investigate effect on drag force by back flow of exhaust by changing the shape of the underwater vehicle.