斜接管射流流动特性数值模拟

Numerical Simulation of Flow Characteristics of Lean Jet to Cross-Flow in Safety Injection of Reactor Cooling System

采用数值模拟方法对受限斜射流的流动特性、射流发展影响区域、射流发展关键因素及射流涡特性进行研究。研究表明:受限斜射流存在附壁斜射流、离升斜射流和冲击斜射流3种基本流型。流速比(VR)是斜接管射流流动特性的关键特征参数;射流影响区域随VR的增大而越大;在高VR下,射流强烈冲击主管底面,并在上游形成明显回流区。射流涡特性决定斜射流近区域流场特性和射流的混合;VR越大,射流涡强度越大,射流涡发展、破碎和耗散越快。

In the present work,a numerical simulation was performed to study the flow characteristics of lean jet to cross-flow in a main tube in the safety injection of reactor cooling system.The influence scope and mixing characteristics of the confined lean jet in cross-flow were studied.It can be concluded that three basic flow regimes are marked,namely the attached lean jet,lift-off lean jet and impinging lean jet.The velocity ratio VR is the key factor in the flow state.The depth and region of jet to main flow are enhanced with the increase of the velocity ratio.The jet flow penetrates through the main flow with the increase of the velocity ratio.At higher velocity ratio,the jet flow strikes the main flow bottom and circumfluence happens in upriver of main flow.The vortex flow characteristics dominate the flow near region of jet to cross-flow and the mix-ture of jet to cross-flow.At different velocity ratio VR,the vortex grows from the same displacement,but the vortex type and the vortex is different.At higher velocity ratio,the vortex develops fleetly,wears off sharp and dies out sharp.The study is very important to the heat transfer experiments of cross-flow jet and thermal stress analysis in the designs of nuclear engineering.