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1.
夏南 《上海大学学报(英文版)》1999,3(1):4-6
The stability condition for compressible and incompressible swirling flow is discussed and compared. It is found that Eckhoff and Storesletten's necessary condition for stability of inviscid compressible swirling flow seems incorrect. 相似文献
2.
SMITH Eiamsa-ard PONGJET Promvonge 《浙江大学学报(A卷英文版)》2006,7(8):1406-1415
INTRODUCTION Vortex tube is a device for producing hot and cold air when compressed air flows tangentially into the vortex chamber through the inlet nozzles. This causes the vortex and swirl flow movement inside the vortex tube. The air in the middle region of the tube has lower velocity and lower temperature than the inlet air. So the air near the tube wall has higher ve-locity and higher temperature than the inlet air. The cold air in the core region of the tube flows out through the o… 相似文献
3.
A k-ε-kp multi-fluid model was used to simulate confined swirling gas-solid two phase jet comprised of particle-laden flow from a center tube and a swirling air stream entering the test section from the coaxial annular. After considering the drag force between the two phases and gravity, a series of numerical simulations of the two-phase flow of 30μm, 45μm, 60μm diameter particles were performed on a x×r＝50×50 mesh grid respectively. The results showed that the k-ε-kp multi-fluid model can be applied to predict moderate swirling multi-phase flow. When the particle diameter is large, the collision of the particles with the wall will influence the prediction accuracy. The bigger the diameter of the particles, the stronger the collision with the wall, and the more obvious the difference between measured and calculated results. 相似文献
4.
Guo Jiahong Liu Gaolian 《上海大学学报(英文版)》1999,(2)
１ＩｎｔｒｏｄｕｃｔｉｏｎＵｐｔｏｎｏｗ,ａｌｔｈｅｐａｐｅｒｓｂｕｔＲｅｆ．［１］ｏｎｔｈｅｉｎｖｅｒｓｅａｅｒｏｄｙｎａｍｉｃｐｒｏｂｌｅｍａｒｅｓｏｌｅｌｙｃｏｎｆｉｎｅｄｔｏｓｔｅａｄｙｆｌｏｗ．ＩｎＲｅｆ．［１］ｔｈｅａｕｔｈｏｒｃａｒｉｅ... 相似文献
5.
In this paper, on the basis of the variational principles developed the finite element method (FEM) is employed for numerical solution of the inverse problem of 2-D unsteady compressible flow around oscillating airfoils by incorporating the non-reflecting far-field boundary conditions and a new unsteady Kutta condition. All unknown boundary (airfoil contour) and discontinuities(shocks and free trailing vortex sheets) are determined via the functional variation with variable domain and artificial density concept. For the numerical realization of the variable-domain variation, a special finite element with self-adjusting nodes is also suggested herein. The numerical results show that the present method is effective for the design of unsteady airfoil. 相似文献
6.
快速确定火炬系统配管尺寸 总被引：1，自引：0，他引：1
Zhan Shiping 《大连大学学报》1992,(4)
本文采用一种新的计算可压缩流体的方法用于火炬系统的配管尺寸设计,在管网布局确定后,可由已知的出口压力 P_2反算管道入口压力 P_1,进而确定各段管线的管径,同时还可得到各段管线出口处的马赫数、摩擦因子等参数.通过限制马赫数及将计算的入口压力与装置允许最大背压相比较,使设计参数进一步优化,同时通过增加计算的循环次数,可方便地处理带有支管的复杂管网系统。整个计算过程均编制了FORTRAN 计算程序,为火炬系统的配管问题提供了一个既安全又经济的最优化设计方案,以使化工厂或炼油厂在这方面的投资减至最少. 相似文献
7.
五孔球探针旋转流场测量的应用方法与误差探讨 总被引：2，自引：0，他引：2
介绍五孔球探针的基本结构和使用方法。通过深入探讨气体绕流球体的的原理,分析了在调节探针方位确定气流方向时出现多个平衡点的原因,并进行实验验证,提出在复杂流场中确定正确的气流方向角的三个基本判据。从压力测量、探针位置精度、速度梯度和静压梯度等方面分析了流场测量误差的来源,并指出了实现误差控制的相应措施。 相似文献
8.
This paper presents ak-ε-k
p
multi-fluid model for simulating confined swirling gas-solid two phase jet comprised of particle-laden flow from a center
tube and a swirling air stream entering the test section from the coaxial annular. A series of numerical simulations of the
two-phase flow of 30 μm, 45 μm, 60 μm diameter particles respectively yielded results fitting well with published experimental
data.
Project is supported by Zheijiana Provincial Natural Science Foundation (No. 598017) 相似文献
9.
The short-range property of interactions between scales in the compressible turbulent flow was examined. An estimation of the short-range scale scope and some formulae for the short-range eddy stress and heat transfer etc. were given. A concept of resonant-range interactions between extremely contiguous scales was introduced and some formulae for the resonant-range eddy stress and heat transfer etc. were also given. Multi-scale equations for the compressible turbulent flows were presented. The multi-scale equations are approximately closed and do not contain any empirical constants. The compressibility effects on turbulence are determined by the Farve averaged variables and the nonlinear relationships between the Farve- and physical-averaged variables. 相似文献
10.
In practical problems, the variation of the free surface around a circular pier is severe. For the Fluent CFD, the multiphase flow models cannot be used together with the LES model to calculate the free surface. Present paper provides a two-step method which joints the 2D compressible ideal-gas equations and the LES model to calculate the 3D flow field with free surface around the pier. The effects of the free surface on the flow structures are studied in detail. 相似文献
11.
结合国内液氧/煤油发动机的研究,针对2种外环管切向进液流、内管进气流的同轴旋流式喷嘴,以酒精和压缩空气为工质,进行了喷雾流常压燃烧实验研究。使用红外热像仪测量了常压条件下喷雾流燃烧的温度分布,分析了火焰结构,定性研究了喷嘴形式和工况对燃烧性能的影响。 相似文献
12.
Designing airfoils according to given pressure (or velocity) distribution is one kind of free boundary problems. Free boundary condition can be coupled with the flow governing equations by variable-domain variational calculus, which makes it possible to calculate simultaneously the flow field and the free boundary. An accurate deduction of the variable-domain variational principles is taken herein to design airfoils in compressible and incompressible flows. Furthermore, two grid types (H and O) are used in the calculation with better results for the O-type grid. It is shown that convergence is accelerated and good results can be obtained even if the initial guessed airfoil shape is a triangle, demonstrating the strong adaptability of this method. 相似文献
13.
秦训鹏 《黄冈职业技术学院学报》2009,11(4):10-13
可压缩烧结材料变形时体积发生变化,塑性理论只能建立在质量不变条件之上,金属塑性力学理论范畴的初等解析法、滑移线法、有限元法以及上限分析法为求解不同状况下的可压缩烧结材料塑性变形问题提供了有效的途径。 相似文献
14.
可调余隙调节气量是在固定余隙调节气量的基础上,对往复压缩机气量调节系统进行改造。通过实际应用表明,该系统较往复式压缩机传统的气量调节方法具有输出气量的稳定性好、气量无级调节、系统维护费用低、参数设置灵活、节能、系统可靠的特点。 相似文献
15.
CFD技术在流动相似性原理教学中的应用 总被引：1，自引：0，他引：1
杨向龙 《中国现代教育装备》2012,(7):5-7
流动相似性原理是流体力学教学的重要内容。对流动控制方程进行无量纲化,从理论上推导出动力学相似条件,再用CFD技术对简单流动问题进行数值模拟,以对动力相似条件进行验证。从理论和实践两方面帮助学生学习较为抽象的动力学相似条件,以期取得良好的课堂教学效果,提高学生解决实际问题的能力。 相似文献
16.
结合工程实践中大多数注浆工程都是在动水条件下进行注浆堵水,研制了动水条件下单裂隙注浆模型试验系统,并进行了验证性试验。模型试验系统主要包括动水水源、注浆系统、模拟裂隙和数据采集系统设备。研制的模型试验系统解决了动水水源进入裂隙时为裂隙流、水头稳定、水头高度可调,注浆系统设备的注浆量可调,注浆压力和注浆速度可控,模拟裂隙设备的裂隙开度可调,裂隙粗糙度可变,扩散规律易于观察和数据易于采集,监测系统中浆液扩散、渗流压力和流出液体重量实时记录等关键问题。验证试验结果表明,模型试验系统可以在动水条件下进行单裂隙注浆试验并能获得浆液扩散规律、流出液体重量和渗流压力变化规律。 相似文献
17.
基于流体网络理论,研究了通过改变回热器流阻对由双向进气阀诱发的直流流动进行抑制的可行性,计算结果表明,增加回热器流阻可以有效地抑制直流,进而有望提高脉管制冷机在高温区的稳定性能.在此基础上,采用不同的回热器填料布置方式,对脉管制冷机的稳定特性开展实验研究,通过采用直径0.25 mm的铅丸代替回热器冷端(0.3回热器长度)247目不锈钢丝网的方法,实现了制冷机在80 K温区长时间稳定工作.该研究为解决脉管制冷机存在的高温区性能不稳定提供了新的途径. 相似文献
18.
19.
研究了一维可压Korteweg型流体模型强稀疏波的渐近稳定性问题。假设相应的可压Euler方程的黎曼问题存在稀疏波解（ VR ,UR ,SR ）（ t,x）,如果Navier-Stokes-Korteweg系统的初值是近似稀疏波的小扰动,利用能量方法,可以证明其柯西问题存在一个唯一的整体光滑解,并随着时间渐近趋于（ VR ,UR , SR ）（ t,x）。 相似文献
20.
王锐俊 《现代远程教育研究》2005,17(6):58-61
沉浸是一种将个人精力完全投注在某种活动上的心理状态,产生时会有高度的兴奋及充实感.沉浸体验会导致最佳学习效果.基于网络的英语学习易于让学生获得沉浸体验.将沉浸理论引入英语学习的研究,探讨网络环境下如何促进学生的沉浸体验以提高英语学习效果,意义重大. 相似文献