水轮机活动导叶防护材料抗磨蚀性能研究

为避免水轮机活动导叶因磨损、空蚀而造成过流表面形态发生改变，机组效率下降，采用超声波振动空蚀机、高速加沙射流冲磨仪与圆环冲磨仪对环氧砂浆、复合树脂砂浆和聚氨酯及活动导叶基材45号钢进行空蚀与冲磨试验，基于试验结果，分析了不同材料的抗空蚀、抗冲磨性能，预测了材料在强空蚀作用下的使用寿命，研究了流速、冲角、含砂量等对材料磨损的影响，构建材料的磨损量预测模型。结果表明，材料的抗磨蚀性能为聚氨酯>复合树脂砂浆>环氧砂浆；材料的磨损量随流速的增长与流速呈线性或指数关系；磨损量与含砂量大体上呈线性关系；磨损量在冲角逐渐增大的情况下先达到冲击磨损峰值，随后逐渐下降，不同材料的临界冲角不同。     

闸门开度对泄洪排沙隧洞水力特性影响研究

为揭示闸门开度对泄洪排沙隧洞水力特性的影响规律，建立了不同闸门开度下的排沙隧洞二维模型，采用VOF法和标准κ-ε紊流模型对泄洪排沙隧洞易磨蚀断面流场进行三维数值模拟计算，获得了闸门附近的流态、流速、压强等水力特性，并对比分析了不同闸门开度下的水力特性，得到了闸门处至挑坎之前的空化数。结果表明，当闸门小于1/2最大开度运行时，闸门开度越大，隧洞水流流态越平顺，临底流速过渡越平顺，且隧洞底板上下游压力差越小；闸门开度越小，有压洞内流速越小，容易造成泥沙淤积；闸门开度越大，对隧洞整体运行越有利。研究结果对水工隧洞闸门的运行开度优化及闸门底坎抗磨修复具有指导意义。     

含沙水流对水轮机过流部件焊缝的影响

含沙水流对水轮机过流部件焊缝有很强的磨蚀破坏力,其主要原因是焊缝材料的疲劳强度很低,在相同的磨蚀强度下,焊缝材料最先被磨蚀破坏。研究结果表明,在焊接过程中,采取适当的表面强化工艺,提高焊缝材料的抗疲劳特性．是提高水轮机过流部件焊缝表面抗磨蚀能力的有效途经。     

轴流透平中煤灰粒径分布对粒子动态特性和叶片磨蚀的影响

本文提出了轴流式燃气透平中煤灰粒径分布对粒子动态特性和叶片磨蚀方面影响的研究结果。在透平叶片流道内应用三元流分析法求解粒子动态特性及其对叶片的冲击。用由实验测量导出的经验公式来描述粒子的回弹情况和叶片材料的磨蚀特性。对典型的煤灰粒径分布所做的研究结果表明,煤灰粒径分布对叶片磨蚀的程度和图样有着显著的影响。     

柴油机喷油器结构参数与磨料流加工效果关联的研究

基于磨蚀模型和多相流离散相模型建立了柴油机喷油器磨料流加工过程的CFD计算模型。在验证基础模型的有效性后,分别针对喷孔直径、喷孔锥角和交点位置三种结构参数进行变参数模拟计算。通过对加工域颗粒流速、湍流强度和磨蚀率的分析,获得了喷油器主要结构参数对液力研磨加工的影响机理:喷孔直径和喷雾锥度的变化对喷孔壁面磨蚀量的影响较大,随着两者的增大,喷孔壁面的磨蚀量有所增加;交点位置由上至下的变化对喷孔壁面磨蚀量的影响较小,但是喷孔入口处磨蚀量有所增加。     

PFBC-CC燃气透平叶片防护涂层热态筛选试验研究

ＰＦＢＣ－ＣＣ燃气透平叶片工作条件恶劣，通过施加防护涂层可有效地防止叶片腐蚀和磨蚀。本文叙述了１５ＭＷＰＦＢＣ－ＣＣ中试燃气透平叶片防护涂层动态筛选试验的情况。试验在一台材料腐蚀（磨蚀）试验装置上进行，分高、低温两个试验段，选择了３种工艺、１４种配方的涂层参加试验。运用ＳＥＭ、ＴＥＭ、ＸＲＤ、ＥＤＡＸ、ＡＥＳ等现代分析手段和腐蚀（磨蚀）机理对试验结果进行了详细的分析，筛选出的优秀涂层为：高温区ＣＲ１涂层，低温区ＣＲ９涂层。这些涂层已用于中试燃气透平叶片上。强化试验的腐蚀（磨蚀）机理为：腐蚀（磨蚀）交互作用，高温区为磨蚀增强的腐蚀过程，低温区为腐蚀增强的磨蚀过程。     

不同叶型对喷嘴叶栅内粒子运动轨迹及磨蚀特性的影响

应用PIV激光测速仪对3套调节级喷嘴叶栅(73A,Self,mith)进行了气固两相流场测量,以研究不同叶栅几何参数对喷嘴叶栅内粒子运动轨迹及磨蚀特性的影响。实验结果表明:3套喷嘴叶栅耐磨蚀性能因叶型的几何参数不同而有差异,较大的前缘圆直径、缓慢变化的型线曲率以及较小的相对节距能提高叶栅的抗磨性。3套喷嘴叶栅的耐磨蚀性能由强至弱排序为Self、mith、73A。     

水轮机磨蚀防护技术研究进展

磨损、空蚀及其他破坏耦合作用是水轮机常见的破坏形式,在过流部位进行涂层防护是提高抗磨蚀能力的有效方法之一.简述了过流部件磨蚀等破坏的机理及其影响因素,并综述了过流部件耐磨蚀涂层技术的研究进展,评述了不同类型涂层的技术特点,通过金属熔覆技术、抗撕裂聚氨酯材料以及综合防护措施的应用案例阐述了该领域取得的进展,并展望了未来的...     

流化床煤燃烧室浸管磨蚀的冷模研究

本文在以宽筛分的硅砂和溢流渣为床料，截面为０．４ｍ×０．４ｍ的常压流化床试验台上对Ｕ型水平浸管的磨蚀特性进行了冷模试验研究，获得了在鼓泡流化区，浸管的磨蚀速率随流化速度、床料粒径和物性的变化规律；初步揭示了管束的结构与布置方式对磨蚀强度及其分布的影响。     

T型三通道横向射流流动与传热实验研究

对不同射流与主流流速比下T型三通管中横向射流的流动与传热进行了实验研究，得到了流动的基本特性以及不同流速比下局部点的温度波动特性，测量了几个关键处的局部传热系数。     

Performance of a thermal trap solar collector/storage system

This paper presents an analysis of a novel solar collector/storage system consisting of a network of pipes buried in a mass of sand; the sand is covered with a glazed thermal trap. The heat can be extracted by flow of fluid in the pipes at a constant flow rate. An expression has been derived for the periodic rate at which useful heat can be collected, keeping the flow rate constant. Numerical calculations for a typical cold day in Delhi predict that the collection efficiency of the system is about 50% for flow rate of 10 kg/h. The efficiency increases with thermal trap thickness and with flow rate.     

某工程引水系统引水防沙设计与试验验证

针对原引水系统引水保证率低、防沙能力弱的问题,在已建成的无坝引水系统位于凸岸下端增设拦河闸,设计独特的拦、排沙设施(S型导墙、阶梯式拦沙坎、下宽上窄的弧形冲沙槽)。试验验证表明,拦河闸位置选择合理,泄流和排沙能力强;S型导墙能缩短冲沙前缘长度,束窄河床,抬高水位,提高有压引水口的引水能力;阶梯式拦沙坎满足冲沙比降的要求,提高了进水闸的防沙能力;冲沙槽按"下宽上窄"布置,束窄了冲沙槽上游端水流,从而提高了冲沙槽的流速,其在平面上呈弧形,加强了底流的横向环流作用;冲沙槽中螺旋流的存在,提高了冲沙槽的冲沙能力。     

上游洲滩与橡胶坝之间相互影响关系的试验研究

鉴于江心洲或边滩在河道中具有塑造河槽、约束水流的作用,试验模拟了江心洲与橡胶坝（全坝和开口坝）的相互作用在不同流量下对坝址上游水位和流速的影响,并分析了含江心洲的河道中不同坝型在洪水期对泄流量的影响。结果表明,全坝与江心洲同时存在时对水力特性的影响比开口坝与江心洲同时存在时明显,在洪水期开口坝与江心洲同时存在时的泄流量大于全坝与江心洲同时存在时的泄流量。为此在河道整治过程中可充分利用橡胶坝与洲滩的相互影响,以达到防洪和生态兼顾的效果。     

铸造型砂处理工部电控系统的技术改造

介绍铸工车间砂处理生产自动线电控系统及控制流程,因其具备较高的自动化程度,大大降低了工人劳动强度,改善劳动环境,提高生产效率.     

西部环境下内燃机活塞下区气流场数值研究

运用商用软件ANSYS,模拟了典型西部环境恶劣因素沙尘对活塞下区气流场的影响,分析了沙尘颗粒的速度、直径、浓度和密度对活塞下区气缸壁压力和气流速度的影响。研究表明：存在影响活塞下区气缸壁压力和气流速度场的临界沙尘颗粒直径和临界速度,较大的沙尘颗粒直径和速度是导致缸壁应力和变形增加的主要因素;沙尘颗粒的存在会使其周围的流场产生负压;随着沙尘颗粒的密度和浓度的增加,活塞下区气缸壁所受最大压力会相应增大,且气流入口处压力增加较快。     

含砂水对混流泵过流部件磨损的数值模拟

为了分析含砂水介质通过混流泵时的流场特性及叶片磨损情况,基于UG软件对混流泵进行建模并利用ICEM软件对其进行网格划分,使用CFX软件对含砂水两相流介质通过混流泵时的内部流场进行模拟分析。结果表明:混流泵磨损主要集中在叶轮叶片和空间导叶处,而且在叶片进口处容易出现磨蚀现象;混流泵扬程随流量增大而减小,效率随流量先增大后减小,且混流泵输送含砂水效率低于输送清水效率。     

Numerical simulation of sand erosion phenomena in rotor/stator interaction of compressor

Sand erosion is a phenomenon where solid particles impinging to a wall cause serious mechanical damages to the wall surface. This phenomenon is a typical gas-particle two-phase turbulent flow and a multi-physics problem where the flow field, particle trajectory and wall deformation interact with each other. On the other hand, aircraft engines operating in a particulate environment are subjected to the performance and lifetime deterioration due to sand erosion. Especially, the compressor of the aircraft engines is severely damaged. The flow fields of the compressor have strongly three dimensional and unsteady natures. In order to estimate the deterioration due to sand erosion, the sand erosion simulation for a compressor is required under the consideration of the rotor-stator interaction. In the present study, we apply our three dimensional sand erosion prediction code to a single stage axial flow compressor. We numerically investigate the change of the flow field, the particle trajectories, and the eroded wall shape in the compressor, to clarify the effects of sand erosion in the compressor.     

风力机叶片涂层风沙冲蚀磨损特性的风洞试验研究

传统的挟沙冲蚀试验台与风沙风洞难以构建均匀风沙流场,难以准确反映风力机叶片的风沙磨损特性。因此,在改造的风沙风洞中,通过对风力机叶片平板试样开展涂层冲蚀磨损试验,探究不同冲击速度、冲击角度及有效截面质量流率对风力机叶片涂层材料冲蚀特性的影响规律。试验结果表明：有效颗粒质量流率一定时,在相同冲击速度与冲击时间内,磨损量在冲击角度约为30°时达到最大。小于30°时,磨损量随冲击角度的增大而快速增加,大于30°时磨损量随冲击角度的增大而逐渐降低;磨损量随冲击速度的增大而增大;磨损量随有效颗粒质量流率的增大而呈线性增大趋势;切削磨损量与总磨损量有相同趋势,冲击磨损量随着冲击角度的增大而逐渐增大。     

Experimental investigation of the plugging mechanisms of non-consolidated prepacked gravel screens

Sand production is one of the most common problems in exploiting poorly consolidated sands reservoirs in general. It can cause numerous production obstacles, such as plugging of surface processing equipment, eroding downhole and surface production equipment, sand filling up the wellbore, impairing of well productivity, and so on. Hence, sand control is required for sand production in oil and gas wells. Mechanical sand control screen is the most commonly used method of sand control, but it is easy to be plugged during production, leading to reduced production or even unexpected shutdown of oil wells. Gravel packing sand control method is the most effective sand control method, but the operation risk is high, the cycle is long, and the cost is high. So far, no suitable sand control method has been found. In this study, a non-consolidated prepacked gravel screen (NCPPGS) was introduced to replace the gravel packing sand control method for reducing cost and risk of gravel packing sand control method, and effectively preventing plugging of mechanical sand control screen. To achieve the goal, the plugging mechanisms and progress of NCPPGS were systematically studied through a series of experiments. A new sand retention testing (SRT) method was employed in this study. Impacts of the structural, formation, and production parameters on the plugging of NCPPGS were experimentally investigated. Results show that the anti-plugging ability of the NCPPGS is affected by the packing density and gravel size simultaneously. With increasing pack density, gravel size should be appropriately enlarged to maintain the original flow capacity. Obviously, the sand retaining precision of NCPPGS differs in the gravel packing sand control method. In addition, results present that montmorillonite can cause more serious plugging of screens due to the strong fluid–solid coupling effect compared with illite and kaolinite. Based on the above research results, designing low production rates at the beginning of the production can further help control screen plugging.     

Effect of a thermal trap on the performance of a solar sand collector

The effects of different parameters—e.g. the thickness of the trap material, the flow rate of the water and the depth of the heat-retrieval plane—on the water temperature have been investigated. A comparison of the present system with a conventional solar sand collector was also made.