为探究电磁发射原理在水下动力推进领域应用的可能性,以某小型艇为研究对象,通过计算流体力学(CFD)方法,运用 VOF均质多相流模型描述气、汽、液形成的多相流动,并求解基于 RANS 方程和Rayleigh-Plesset气泡方程建立的小型舰艇的 Schnerr and Sauer空化模型,以分析电磁力作用引起的流场变化规律以及艇的运动特性.开展了不同等效电磁力作用下流场的数值仿真,获得了运动过程中流场特性变化以及小型艇载荷、运动变化规律:电枢运动过程中会在其背面形成低压区伴随有大量空泡的产生,但电枢在快速回退过程不会产生较大的流场阻力,为满足流道内空穴填满的过渡期,可以增加流道的数量,使多个电枢交替运动;电枢运动激发的流场对船体的前行动力只发生运动的前半段,后期随着船体航速加大,阻力增大,船体的运动主要还是靠电磁反作用力,且流体阻力峰值约占推力峰值的 1/10.该研究可为电磁发射技术应用在小型舰艇动力推进提供参考.
Research on Underwater Electromagnetic Jet Propulsion Technology
To explore the possibility of applying electromagnetic launch principles in the field of un-derwater power propulsion,the VOF homogeneous multiphase flow model was used to describe the mul-tiphase flow formed by gas,steam and liquid by the computational fluid dynamics(CFD)method,the research object being a small boat.The Schnerr and Sauer cavitation model of small boats based on the RANS equation and Rayleigh-Plesset bubble equation was solved.The changing law of the flow field caused by the electromagnetic force and the motion characteristics of the boat were analyzed.Numeri-cal simulation of the flow field under different equivalent electromagnetic forces was also carried out,obtaining the variation of flow field characteristics,load and motion of the small boat.In the process of armature movement,a low pressure area will be formed on its back and accompanied by a large number of cavities,but the armature will not produce a large flow field resistance during the rapid regression process.In order to meet the transition period of hole filling in the flow channel,the number of flow channels can be increased to make multiple armatures move alternately.The forward force of the hull induced by the flow field of armature motion only occurs in the first half of the motion.In the later stage,with the increase of hull speed,resistance also increases.The movement of the hull mainly re-lies on the electromagnetic reaction force,and the peak value of the fluid resistance accounts for about 1/10 of the peak value of the thrust.The research can inform the application of electromagnetic launch technology to the propulsion of small boats.
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