重型静压轴承扇形腔和圆形腔温度场数值模拟与分析

针对重型静压轴承油腔结构优化问题,利用有限体积法,模拟了扇形腔和圆形腔间隙流体的温度场,并建立了旋转坐标系下的控制方程,探讨了在转速、腔深及有效承载面积相同时两种腔形的温度分布规律,优化了油腔结构.结果表明:油腔结构对间隙流体温度场有较大影响,圆形油腔油膜剪切面积较大导致圆形腔温度分布较扇形腔高.数值计算结果真实反应了轴承内部流态,仿真结果为工程实际轴承油腔结构优化设计提供了理论依据.     

THE EFFECT OF OIL CAVITY DEPTH ON TEMPERATURE FIELD IN HEAVY HYDROSTATIC THRUST BEARING

For a heavy hydrostatic bearing with a high linear velocity,the results of numerical calculations often differ from practical conditions if the viscosity is considered as constant.In this article,the influence of the oil cavity depth on the temperature field in the heavy hydrostatic bearing is discussed in the context of variable viscosity.The viscosity-temperature relations for the gap oil film are first established by fitting B-Spline curves,then,numerical calculations for the temperature field in the heavy hydrostatic bearing of different oil cavity depths are carried out based on Finite Volume Method (FVM) under the same rotating speed,and the influence of the oil cavity depth on the temperature distribution in the gap oil film of the hydrostatic bearing is discussed.The results of numerical calculations provide the temperature distribution state inside the hydrostatic bearing,which would help the selection and the design of hydrostatic bearings in engineering practice.     

Thermal and tilt effects on bearing characteristics of hydrostatic oil pad in rotary table

Hydrostatic pads are key components of a constant flow compensation hydrostatic rotary table.The tilt and thermal effects due to the partial load,the manufacturing errors and the friction must be considered.However,designers are more likely inclined to ignore these effects.In this work,the coupled characteristics of the tilt and thermal effects are studied.A coupled mathematical model to calculate the bearing properties of the pads is built.This model takes into consideration of tilt and thermal effects and is used to solve the flow problem by the finite difference method.The characteristics of the oil pad,including,the recess pressures,the load carrying capacity and the damping coefficients,are obtained and the tilt and thermal effects are analyzed.It is observed that the tilt has a tremendous impact on the bearing characteristics of the hydrostatic pad.The recess pressure,the load carrying capacity and the stiffness are reduced by 50% and the pressure distribution and the temperature distribution of the oil film also change significantly.When the pads work under a tilt operation,a larger land width is better for its bearing properties.It is also observed that the thermal effect is significant and cannot be ignored.     

三峡VGS机组推力轴承及下导轴承结构与问题分析

三峡左岸电站VGS机组推力轴承、下导轴承和高压减载系统均由GE加拿大设计，由VGS联营体轮流制造；推力轴承为多点小弹簧支撑结构；下导瓦共计42块，采用球头抗重螺栓加抗重平衡块结构。整个轴承有它的特点也存在一些问题。     

水轮机水导轴承旋转油杯甩油的原因分析及处理

分析广西博白县汇能电站水轮机水导轴承转油杯甩油的原因,提出了在旋转油杯与旋转油盖结合面之间加密封胶垫,加大旋转油杯盖回油槽与回油孔尺寸以及对安装中不合格的工艺返工的处理方案,解决了旋转油杯甩油的问题.     

二滩水电厂水导轴承甩油原因分析及改造

二滩水力发电厂水导从首台机第一次启动就一直存在严重的甩油问题。经其对甩油做了定性、定量试验,准确的分析、判断出了甩油的原因。提出了切实可行的改造方案．由GYBD负责施工首先在5号机组获得成功。其它机组陆续采用该方案,水导油槽甩油问题得以根治。     

大型水力发电机组推力油槽油雾防治研究

通过对二滩电厂推力／下导油槽油雾产生原因的分析和油雾治理过程的介绍,阐述了大型半伞式发电机组推力油槽油雾防治的一般方法。     

百色右江水力发电厂2#水轮发电机组推力轴承甩油原因及技改方案

分析了右江水力发电厂2#水轮发电机推力轴承甩油原因,提出了相应的技改方案,实施后机组运行良好。     

大型水轮发电机组水导油槽漏油分析及处理工艺

目前已投产的大中型水轮发电机组的各部油槽一般都存在着不同程度的渗漏问题,这样不仅会造成资源的浪费,而且还会污染环境,甚至会严重影响到机组的安全生产。为了保证水电站机组的安全运行,考虑到造成渗漏的原因各不相同,以瀑布沟水电站3号水轮发电机组的水导油槽油位异常事件为例展开了分析研究;通过查阅相关资料和图纸,以及实际考察和运行实践,找出了水导轴承漏油的真正原因。根据漏油原因,有针对性地制定出处理措施和方法,并进行了相应处理,取得了良好的效果。     

水电机组推力轴承镜板泵及油循环冷却系统的水力优化设计

针对水电机组推力轴承镜板泵流体动力设计过程中孔的布置形式以及集油槽的断面形状、面积和出口管路直径等几何参数优化问题,提出适合镜板泵流道设计的镜板泵性能预测及优化设计方法。通过不同几何参数组合,采用基于多工况数值模拟的性能预测方法来分析镜板泵的主要过流部件的关键尺寸、形状等对其性能的影响,并在此基础上提出一种基于整个循环系统协同的镜板泵水力优化设计方法,可提高自循环系统设计中流体动力系统的性能及可靠性。对比试验表明,在原试验循环系统参数不变的条件下,某大型水电机组推力轴承镜板泵在优化设计后平均扬程提高4 m,平均效率提高5.5%,且H-Q曲线能更好保证变工况运行时系统的稳定性。     

An iterative Rankine BEM for wave-making analysis of submerged and surface- piercing bodies in finite water depth

A 3-D iterative Rankine Boundary Element Method （BEM） for seakeeping problem in time domain is developed in the framework of linear potential theory. Waves generated by both submerged and surface-piercing bodies moving at a constant forward speed in otherwise calm water, and the resultant steady wave pattern, wave profile and resistance are computed to validate this newly-developed code. A rectangular computational domain moving with the same forward speed as the body is introduced, in which an artificial damping beach is installed at an outer portion of the free surface except the downstream side for satisfying the radiation condition. The velocity potential on the ship hull and the normal velocity on the free surface are obtained directly by solving the boundary integral equation, with the Rankine source used as the kernel function. An iterative time-marching scheme is employed for updating both kinematic and dynamic free surface boundary conditions to stabilize the calculation. Extensive results including the wave patterns, wave profiles and wave resistances for a submerged spheroid and a Wigley hull with forward speed are presented to validate the efficiency of the proposed 3-D time-domain higher-order approach. Finally, the sensitivity of ship-generated waves to the water depth is investigated. Computed results show satisfactory agreement with the corresponding experimental data and other numerical solutions.     

成都市中心城区暴雨内涝模拟及内涝特征分析

针对成都市内涝灾害频发的问题,本文利用IFMS/Urban构建了成都市中心城区一二维耦合内涝模型。模拟了不同重现期(2 a、5 a、10 a)及不同降雨历时(1 h、3 h、6 h)下中心城区内涝积水情况,结果表明:(1)三环以内区域管网现状排水能力为2年重现期,三环至绕城高速区域为1~1.5年重现期;(2)依据积水深度将内涝灾害划分为无(h<0.15 m)、低(0.15 m ≤ h ≤ 0.2 m)、中(0.2 m<h ≤ 0.4 m)、高(h>0.4 m)4个风险等级,分析表明成都市中心城区内涝以中等风险为主;(3)成都市地形及降雨的空间分布导致中心城区南部区域的内涝更为严重。