Compressible flow dynamics and heat transfer control of helium near the critical point

本研究主要通过直接数值模拟来阐明层流-湍流过渡过程、边界层内的涡旋结构以及气液临界点附近超临界氦的平均场和波动场特征。本研究不仅考虑开放系统（即等压系统），也考虑封闭系统。在封闭系统中，系统中不仅存在对流效应，而且存在活塞效应。采用GPGPU （TESLA C2075）和CUDA 4.2架构进行仿真。这些结果将应用于氦在临界点附近的湍流控制和湍流模型的建立，以预测流体流动现象和控制大型超导磁体系统的实际冷却通道。

In this study, direct numerical simulations were mainly performed in order to clarify laminar-turbulent transition process, vortical structures in the boundary layer and characteristics of mean field and fluctuation field in the supercritical helium near the gas-liquid critical point. Not only open system which means isobaric system but also closed system are considered in this study. In the case of the closed system, not only convection but also piston effect simultaneously occurs in the system. The simulations are performed by means of GPGPU (TESLA C2075) and CUDA 4.2 architecture are employed. These results will be applied to establishment of turbulent control and turbulent model construction for the helium near the critical point in order to predict the fluid flow phenomena and to control actual cooling channel of large scale superconducting magnet system.