Numerical Simulation of Sand Erosion Phenomena in Rotor/Stator Interaction of Compressor

沙侵蚀是侵犯到一面墙的稳固的粒子引起严重机械损坏到墙表面的现象。这现象是典型煤气粒子的二阶段的狂暴的流动和流动地，粒子轨道和墙变丑与对方一起交往的一个多物理问题。在另一方面，在微粒环境操作的飞机引擎由于沙侵蚀受到表演和一生恶化。特别，飞机引擎的压缩机严重地被损坏。压缩机的流动地强烈有三个维、不稳定的性质。以便由于沙侵蚀估计恶化，为一台压缩机的沙侵蚀模拟在转子定子相互作用的考虑下面被要求。在现在的学习，我们把我们的三维的沙侵蚀预言代码用于一台单个阶段轴流压缩机。我们数字地在压缩机调查流动领域，粒子轨道，和侵蚀的墙形状的变化，到在压缩机澄清沙侵蚀的效果。

Numerical Investigation on Detonation Wave through U-bend

Pulse detonation engine (PDE) is expected for a next-generation propulsion system. PDE is a promising engine that can generates power and thrust by using intermittent detonation. Promotion of deflagration to detonation transition (below DDT) is a key issue to realize this system. PDE has experimentally been investigated, and it was confirmed that detonation tubes with U-shaped bends are useful for fast DDT. However, the mechanism of DDT promotion due to U-bends has not been well clarified. In the present study, the influence of a U-bend on detona-tion wave propagation is researched with computational fluid dynamics (CFD). The numerical results show that detonation wave disappears once near the U-bend inlet and restarts after passing through it. In addition, it was found that the use of the U-bend with small channel width and curvature radius can induce fast DDT.

Multi-Physics CFD Simulations in Engineering

Nowadays Computational Fluid Dynamics (CFD) software is adopted as a design and analysis tool in a great number of engineering fields. We can say that single-physics CFD has been sufficiently matured in the practical point of view. The main target of existing CFD software is single-phase flows such as water and air. However, many multi-physics problems exist in engineering. Most of them consist of flow and other physics, and the interactions between different physics are very important. Obviously, multi-physics phenomena are critical in developing machines and processes. A multi-physics phenomenon seems to be very complex, and it is so difficult to be predicted by adding other physics to flow phenomenon. Therefore, multi-physics CFD techniques are still under research and development. This would be caused from the facts that processing speed of current computers is not fast enough for conducting a multi-physics simulation, and furthermore physical models except for flow physics have not been suitably established. Therefore, in near future, we have to develop various physical models and efficient CFD techniques, in order to success multi-physics simulations in engineering. In the present paper, I will describe the present states of multi-physics CFD simulations, and then show some numerical results such as ice accretion and electro-chemical machining process of a three-dimensional compressor blade which were obtained in my laboratory. Multi-physics CFD simulations would be a key technology in near future.

Numerical Simulation of Ice Accretion Phenomena on Rotor Blade of Axial Blower

Ice accretion is the phenomenon that super-cooled water droplets impinge and accrete on a body. It is well known that ice accretion on blades and airfoils leads to performance degradation and severe accidents. For this reason, experimental investigations have been carried out using flight tests or icing tunnels. However, it is too expensive, dangerous, and difficult to set actual icing conditions. Hence, computational fluid dynamics is useful to predict ice accretion. A rotor blade is one of jet engine components where ice accretes. Therefore, the authors focus on the ice accretion on a rotor blade in this study. Three-dimensional icing phenomena on the rotor blade of a commercial axial blower are computed here, and ice accretion on the rotor blade is numerically investigated.

Numerical Simulation of Tip Leakage Vortex Effect on Hydrogen-Combustion Flow around 3D Turbine Blade

在这些年里，象空气污染和石块燃料的疲劳那样的很多环境问题强烈地被讨论了。在我们的实验室，一个造成氢的推进系统作为常规系统的一种选择被研究了。一个造成氢的推进系统被期望有更高的力量，更轻的重量和更低的排出物。为实际使用，在那里然而存在必须被克服的许多问题。就这些背景而言，有在一个汽轮机片段落以内的造成氢的燃烧的喷气引擎被学习了。尽管一些研究在从一个定子注射和燃烧的氢燃料上被做了，出现，很少在一个转子尖端和造成氢的燃烧的吸方面附近对在一个尖端漏旋涡之间的相互作用被知道。这研究的目的是在一个汽轮机片段落以内与造成氢的燃烧在 3-dimensional 流动领域的特征上澄清尖端漏旋涡的影响。平均 Reynolds 的可压缩的海军司烧方程与合并骚乱和减少的化学机制建模的 k-ε 被解决。用计算结果， 3-dimensional 有化学反应的狂暴的流动地数字地被设想，并且三维的狂暴的流动与氢回答燃烧和尖端漏旋涡的结构被调查。

Numerical Investigation on Super-cooled Large Droplet Icing of Fan Rotor Blade in Jet Engine

Icing(or ice accretion) is a phenomenon in which super-cooled water droplets impinge and accrete on a body.It is well known that ice accretion on blades and vanes leads to performance degradation and has caused severe accidents.Although various anti-icing and deicing systems have been developed,such accidents still occur.Therefore,it is important to clarify the phenomenon of ice accretion on an aircraft and in a jet engine.However,flight tests for ice accretion are very expensive,and in the wind tunnel it is difficult to reproduce all climate conditions where ice accretion can occur.Therefore,it is expected that computational fluid dynamics(CFD),which can estimate ice accretion in various climate conditions,will be a useful way to predict and understand the ice accretion phenomenon.On the other hand,although the icing caused by super-cooled large droplets(SLD) is very dangerous,the numerical method has not been established yet.This is why SLD icing is characterized by splash and bounce phenomena of droplets and they are very complex in nature.In the present study,we develop an ice accretion code considering the splash and bounce phenomena to predict SLD icing,and the code is applied to a fan rotor blade.The numerical results with and without the SLD icing model are compared.Through this study,the influence of the SLD icing model is numerically clarified.

3D Computation of Hydrogen-Fueled Combustion around Turbine Blade-Effect of Arrangement of Injector Holes

最近，从石块燃料燃烧引起的很多个环境问题上被集中了。与石块精力资源的最终的弄空，另外，氢气体被期望在不久的将来是一个其他的精力资源。它被高精力每统一重量描绘，高反应率，宽范围易燃并且低排放性质。在另一方面，许多研究在几个国家是在进行之中的为一架先进飞机改进一个推进系统。系统被要求比存在的有更高的力量，更轻的重量和更低的排出物。在如此的一个未来推进系统，氢气体将是为认识到要求的有希望的燃料之一。就这些背景而言，我们的组为造成氢的飞机推进系统建议了一个新周期概念。在现在的学习，我们在汽轮机片附近与造成氢的燃烧执行狂暴的流动领域的 3 维的计算。主要目的是澄清氢注射者洞的安排的影响。改变洞，流动的 3 维的性质和热领域的 chordwise 和 spanwise 间距数字地被学习。