海水绕流场矿管边界层分析

介绍不同雷诺数下海水绕深海扬矿管的流动情况，分析管面形成层流及湍流边界层的分离过程，比较二者分离点的位置及压差阻力情况，分析绕流阻力和举力的形成过程、计算方法、影响因素及相应的减阻措施。     

基于有限元和虚拟样机技术的螺纹与球铰连接扬矿管整体水平运动

为了研究螺纹与球铰连接两种情况下的扬矿管系统的整体水平运动,建立了螺纹连接和球铰连接扬矿管系统的几何模型,分析了系统的受力和约束情况,并分别用有限元和虚拟样机技术进行了4级海况时瞬时动态分析和动力学分析.结果表明:螺纹连接扬矿管系统的最大横向偏移量较小,但是管体承受很大的弯矩;在球铰连接的系统中偏移量为6m左右,管体不受弯矩,相当于柔性管,接头应选用耐磨性较好的材料.     

加权残值法解两平板间圆柱绕流问题

本文针对两平板间统圆柱二维势流问题的特点,构造一种特殊形式的有理对称试函数φ=∑Cijx~2ly~2j+1/(x~2+y~2)。该函数部分地满足边界条件。用配点法和最小二乘法对问题进行解算,对结果进行了讨论并与文献(2)中的近似解析解进行比较。     

大洋多金属结核1km海上开采实验系统扬矿管水平液动力分析和计算

大洋多金属结核1km海上开采实验系统的扬矿管所受水平液动力由多个参数决定.本文从系统总体设计参数出发,得出了其他各种参数值,并根据Morison方程详细推导了海浪和海流的速度和加速度的表达式,最后采用数值积分的方法得出了液动力随时间和深度的变化曲线.在同一水深处,总液动力随时间的变化规律接近于正弦(余弦)曲线;而在同一时刻,总液动力则随水深绝对值的增加而递减,在水深0m至水深-200m内,递减速度很快;总液动力最大值为3.790kN.     

深海采矿扬矿硬管弹性体建模分析

深海采矿系统中,扬矿管受采矿船的航行速度及海浪、海流等因素的影响会发生横向偏移的问题.对带有集中质量的阶梯式扬矿管的横向偏移进行了建模,并用枷辽金（Galerkin）方法进行求解,通过计算机的模拟计算,分析了扬矿管在不同情况下横向偏移的特性.     

5000m深海采矿扬矿管所受水平液动力分析与计算

大洋多金属结核深海采矿扬矿管所受水平液动力不仅受系统参数、海浪和海流的速度和加速度的影响,而且还随着时间和水深等因素而变化。分析了海浪水质点的速度和加速度与深度的关系,并根据Morison方程详细推导了液动力的修正方程,得出了液动力随时间和深度的变化曲线。在同一水深处,总液动力随时间的变化规律接近于余弦曲线,而在同一时刻,总液动力从海面至水深200m内迅速递减至67.54N,其最大值为32084.45N。为整体方案的可行性分析以及扬矿系统的设计和校核提供依据。     

幂律流体延伸表面逆来流边界层特性分析与数值模拟

首先利用量级分析理论对幂律流体延伸表面边界层流动进行分析,得到边界层厚度的量级和影响因素;引入量纲为1变量,将动量边界层的控制方程转化为量纲为1的控制方程组.数值求解了具有不同幂律指数n的流体在平板逆来流且平板运动参数ζ不同的情况下的层流边界层流场,分析了幂律指数n和平板运动参数ζ对动量边界层厚度、量纲为1速度分布和量纲为1剪切力分布的影响规律.结果表明,速度边界层的分布不仅和平板运动参数有关,而且和幂律指数有关.     

高密度管流中上集管断流对钢板淬火和控冷系统的影响

在常化炉后NAC快速冷却系统中,通过对高密度管流U形集管流量特性的分析,调整上集管数目,降低上集管发生断流时的流量值,选择合适的上下集管水量和水量比,实现对高温钢板的快速冷却或淬火工艺,得到平直的板形。     

Turbulent Boundary Layer Flows Above a Porous Surface Subject to Flow Injection

A new analytical expression for velocity profile in a fully developed turbulent boundary layer above a porous surface subject to flow injection is derived by solving the coupled Reynolds equations and turbulent kinetic energy equation. The advection of turbulent kinetic energy is considered during the derivation, whereas the earlier studies have neglected it. The new solution reduces to the universal logarithmic law in the case of no flow injection. For the small injection, the solution can be expanded into a series form in terms of the normalized injection velocity. The leading order terms are found to be equivalent to those in the earlier works in which the advection of turbulent kinetic energy has been neglected in the derivation. The new solution can provide more accurate prediction of bed shear stress for a wide range of flow injection rate, fluid type (e.g., from air to water), and surface roughness. On the other hand, the earlier theories may significantly underestimate bed shear stress under high injection rates.     

Modeling of a Rough-Wall Oscillatory Boundary Layer Using Two-Equation Turbulence Models

The standard k?ω turbulence model and two versions of blended k?ω/k?ε models have been used to study the characteristics of a one-dimensional oscillatory boundary layer on a rough surface. The wall boundary condition for the specific dissipation rate of turbulent kinetic energy at the wall is specified in terms of a function based on wall roughness. A detailed comparison has been made for mean velocity, turbulent kinetic energy, Reynolds stress, and wall shear stress with the available experimental data. The three models predict the above properties reasonably well. In particular, the prediction of turbulent kinetic energy for the rough case by the blended models is much better than that for smooth oscillatory boundary layers as reported in previous studies. As a result of the present study, the use of one of the blended models in calculating the sediment transport in coastal environments may be recommended.     

Timescale Behavior of the Wall Shear Stress in Unsteady Laminar Pipe Flows

Based on two-dimensional (2D) flow model simulations, the effects of the radial structure of the flow (e.g., the nonuniformity of the velocity profile) on the pipe wall shear stress, τw, are determined in terms of bulk parameters such as to allow improved 1D modeling of unsteady contribution of τw. An unsteady generalization, for both laminar and turbulent flows, of the quasi-stationary relationship between τw and the friction slope, J, decomposes the additional unsteady contribution into an instantaneous energy dissipation term and an inertial term (that is, based on the local average acceleration-deceleration effects). The relative importance of these two effects is investigated in a transient laminar flow and an analysis of the range of applicability of this kind of approach of representing unsteady friction is presented. Finally, the relation between the additional inertial term and Boussinesq momentum coefficient, is clarified. Although laminar pipe flows are a special case in engineering practice, solutions in this flow regime can provide some insight into the behavior of the transient wall shear stress, and serve as a preliminary step to the solutions of unsteady turbulent pipe flows.     

给水管网爆管原因分析及防治对策

从邯钢历年爆管事故统计分析入手,阐述了爆管原因,从管材的选用、排气系统的完善、水锤作用的消除、接口工艺的改进、温度应力的防止、施工质量的提高、给水管道的更新等方面提出了防止爆管的对策。     

钢骨架塑料复合管及其在冶金企业给排水中的应用

介绍了近年来出现的建设部科技成果重点推广的一种新型管材，即钢骨架塑料复合管，并以实例的形式阐述了其在冶金企业给排水中的现场应用，以及推广应用中应该注意的几个问题。     

中间库控制系统改造项目分析

对中间库控制系统改造项目从硬件配置、系统结构、软件新增功能等方面进行了详细介绍。改造后的系统运行稳定。生产能力有显著提高，完全达到预期效果，经济效益显著。     

Analysis of Atmospheric Boundary Layer Height Characteristics over the Arctic Ocean Using the Aircraft and GPS Soundings

Utilizing aircraft sounding data collected from the Surface Heat Budget of the Arctic Ocean (SHEBA, 1998) campaign, the authors evaluated commonly-used profile methods for Arctic ABL height estimation by validating against the 'true' ABL height from aircraft sounding profiles, where ABL height is defined as the top of the layer with significant turbulence. Furthermore, the best performing method was used to estimate ABL height from the one-year GPS soundings obtained during SHEBA (October 1997-October 1998). It was found that the temperature gradient method produces a reliable estimate of ABL height. Additionally, the authors determined optimal threshold values of temperature gradient for stable boundary layer (SBL) and convective boundary layer (CBL) to be 6.5 K/100 m and 1.0 K/100 m, respectively. The maximum ABL height during the year was 1150m occurred in May. Median values of Arctic ABL height in May, June, July, and August were 400 m, 430 m, 180 m, and 320 m, respectively. Arctic ABL heights are clearly higher in the spring than in the summer.     

高压水除鳞厚壁管道施工工艺分析

主要介绍了在莱钢4300 mm宽厚板工程中高压水除鳞管道施工过程中总结出来的施工工序控制要点,重点叙述了在此强调了厚壁管道焊接的施工工艺。     

高压锅炉用水冷壁管失效开裂分析

应用扫描电镜、光学显微镜及X射线能谱仪等实验分析方法，对高压锅炉用水冷壁管失效开裂原因进行分析研究，结果表明．高压锅炉用水冷壁管开裂为应力腐蚀开裂，同时还有氢脆的作用。