2014 年 9 巻 1 号 p. JFST0008
In this study, numerical simulations of supercritical-water flows over an arbitrary geometry are presented. In the present method, the supercritical-fluids simulator (SFS) developed by the authors is coupled with the building-cube method (BCM). Further, an immersed boundary (IB) method is applied to the wall boundary treatment, and the mathematical models for water programmed in PROPATH are used for thermophysical property estimation. First, as a classical case, steady laminar flows over a circular cylinder are simulated for numerical validation because of the simplicity of the model. Next, as another classical case, unsteady laminar flows past two side by side circular cylinders are computed with more complex physics of flow interactions. Finally, an E-shaped fin geometry is employed as an arbitrary geometry model in practical applications, and natural and forced convection flows over the E-shaped fin are investigated using the present method. The obtained results indicate that the aerodynamic characteristics of supercritical water are identical to that of conventional fluid based on the same Reynolds number, whereas the heat transfer effects are significantly different based on the distinctive Prandtl numbers. In addition, it is revealed that in the practical applications of supercritical-water flows, the intensity of the natural convection flow tends to be much stronger than that in liquid and gas state water flows at the same scale of geometry. The present method is demonstrated to be a promising tool for two-dimensional practical supercritical-fluid flow simulations with arbitrary geometry and complex physics.
