Hydrodynamics instability of natural and forced convection of helium near the critical point

在气液临界点（GLCP）附近，几个输运系数表现出明显的行为，如定压热容C_p，等温压缩系数在GLCP附近发散。定义为C_p的倒数的函数的热扩散率变得非常小。已知通过存在以下两种效果来改善传热特性。一种是高等温压缩性产生的活塞效应。二是重力场浮力作用下产生的热羽流。研究了氦在GLCP附近自然对流和强制对流中不稳定模态的生长机制、层流-湍流转变过程和换热特性。

The several transport coefficients indicate dramatic behavior near the Gas-Liquid Critical Point (GLCP), for example heat capacity at constant pressure, C_p, and isothermal compressibility is diverged near the GLCP. The thermal diffusivity defined as a function of the inverse of C_p becomes very small. It is known that the heat transfer characteristic improves by existence of the following two effects. One is piston effect generated by high isothermal compressibility. Second is thermal plume caused by buoyant force under the gravitational field. It was clear that growth mechanism of unstable mode, laminar-turbulent transition processes and heat transfer characteristics in natural and forced convection of helium near the GLCP.