固定床反应器低阻气流均布技术研究

作者从流体力学基本原理出发,提出了绝热轴向固定床反应器低阻气流均布装置的设计原则,并在三种不同直径的冷模试验装置中进行实验验证。实验结果表明,作者所设计的均布装置,均布效果好,损失小。速度均方差S_1<9％,损失系数ξ≈1.35。适用于绝热轴向固定床反应器,特别是薄床层反应器。     

大型水轮发电机冷却气流的仿真方法

提出了一种研究大型水轮发电机内气流的方法,该方法兼顾了由于长度尺度大幅变化引起的气流的复杂性和仿真过程的要求,从而使其成为对各种问题都行之有效的、可靠而经济的方法.该方法结合了两种不同的仿真,一种是转子和定子的整体仿真,一种是定子单槽的详细仿真.     

A COUPLING MODEL OF WATER FLOWS AND GAS FLOWS IN EXHAUSTED GAS BUBBLE ON MISSILE LAUNCHED UNDERWATER

The gas and water flows during an underwater missile launch are numerically studied. For the gas flow, the explicit difference scheme of Non-oscillation and Non-free-parameter Dissipation (NND) is utilized to solve the Euler equations for compressible fluids in the body-fitted coordinates. For the water flow, the Hess-Smith method is employed to solve the Laplace equation for the velocity potential of irrotational water flows based on the potential theory and the boundary element method. The hybrid Eulerian-Lagrangian formulation for the free boundary conditions is used to compute the changes of the free surface of the exhausted gas bubble in time stepping. On the free surface of the exhausted gas bubble, the matched conditions of both the normal velocities and pressures are satisfied. From the numerical simulation, it is found that the exhausted gas bubble grows more rapidly in the axial direction than in the radial direction and the bubble will shrink at its "neck" finally. Numerical results of the movement of the shock wave and the distribution of the Mach number and the gas pressure within the bubble were presented, which reveals that at some time, the gas flow in the Laval nozzle is subsonic and the gas pressure in the nozzle is very high. Influences of various initial missile velocities and chamber total pressures and water depths on both the time interval when the gas flow in the nozzle is subsonic and the peak of the gas pressure at the nozzle end were discussed. It was suggested that a reasonable adjustment of the chamber total pressure can improve the performance of the engine during the underwater launch of missiles.     

气流模型在水利科研中的应用

本文探讨了气流模型的相似准则，比尺选择，设备仪器及模型加糙方法，气流模型具有尺寸小，试验周期短，成本低的特点，但试验精度较低。文章例举了应用气流模型的几个实例，并与相应的水流模型，数学模型及工程建成后的运行情况进行了对比。     

外呼吸道入口的气流场计算

本文用数值模拟的方法计算了算孔前外呼唤道的运动，揭示了哇故纳新气体的过程，所得的结果可用作医疗和医疗器械设计的参考。     

断阶滑行艇气层减阻试验研究

本文研究了2种重心位置、2种断阶方式、5种喷气流量对断阶滑行艇气层减阻的影响，取得了总阻力减少25％的效果。阻力减少的主要原因在于喷气时形成的空穴所引起的浸湿面积的减少。     

厢式货车表面气流流动特性的研究

本文首次用三维数值模拟计算的方法结合风洞实验研究了厢式货车表面气流的流动特性。揭示了气流流动特性和厢式货车气动阻力特性之间的关系，厢式货车基本结构参数变化时阻力特性的变化规律。为厢式货车的气动造型设计提供了重要参考依据。     

对称翼透平在规则与不规则振荡气流中的自起动过程模拟

对称翼透平的起动性能是透平设计中必须考虑的一个重要因素。本文利用单向稳态流动试验中获得的透平力系数和电机测试中获得的电机阻尼力矩特性,对对称翼透平在规则振荡流与不规则振荡流中的自起动过程进行了数字模拟以分析透平在规则与不规则波下的起动性能。计算了不同的周期、振幅(内波高)和透平转动惯量下的自起动性能,分析了这些参数对自起动性能的影响。     

数值模拟在彭水水电站通风气流设计中的应用

利用CFD技术对彭水水电站地下厂房发电机层气流组织进行了数值模拟计算。对不同的风口大小、风口数量、风口布置位置形成的室内速度场、温度场分布进行了分析对比,提出适合于实际的送风方案,并对所选方案的不同运行工况进行了数值模拟研究,研究表明：风口的布置形式对通风效果至关重要,不同的风口布置形式将会产生不同的通风气流组织形式,从而影响到厂房内的热舒适性和能耗。