共查询到20条相似文献，搜索用时 265 毫秒
1.
《实验室研究与探索》2016,(9)
对基材钢(1Cr12Mo、X20Cr13、2Cr12Ni Mo1W1V)、C1(长城1号)涂层、表面处理工艺(6 min与12 min钢丸强化)三类6种不同气轮机叶片材质在200~600℃的不同冲角条件下的冲蚀率进行了冲蚀实验。结果表明:叶片因冲蚀的失重均随冲蚀颗粒质量呈线性变化;15°~25°冲角冲蚀率最大,90°冲蚀率最小;实验基材的冲蚀率随实验温度提高呈先下降后升高趋势;2Cr12Ni Mo1W1V在200℃与300℃的冲蚀率高于另两种材质,耐冲蚀性差,但在400℃实验温度且冲角40°状态下冲蚀率低于另两种材质;钢丸强化表面处理工艺对于提升实验材质抗冲蚀特性无明显优势;C1涂层的冲蚀率随温度升高呈先升高后降低趋势,在高温条件下具有良好的抗冲蚀特性。 相似文献
2.
3.
4.
《实验室研究与探索》2016,(3):64-69
设计并实现了一种用于实验研究透平叶片冲蚀成因、冲蚀行为和规律的中高温、低马赫数(Ma0.3)负压风洞实验系统。采用引风机提供负压环境,空气电加热器对气流进行可变温加热,翅片管式换热器对二相流降温,袋式除尘器回收冲蚀颗粒,并使用监控PC机通过DIGATTOT串口服务器进行实验数据采集和试验系统监控。经测试,系统最高温度可达750℃,气固两相流颗粒浓度可调,冲蚀速度可调,可0°~90°任意冲角调节。系统通过了温度、速度稳定性测试以及换热器性能测试。 相似文献
5.
烟气轮机动叶片在烟气中催化剂的粒度和浓度超标时会被严重冲蚀破坏.分析了冲蚀破坏受催化剂颗粒的流动速度、粒度、浓度、冲击角度及叶片涂层性能等因素的影响,从而在烟气轮机结构设计上采取了有效的防冲蚀设计. 相似文献
6.
《实验室研究与探索》2019,(11)
深水气井出砂,气流携砂快,筛管冲蚀更严重,极易造成防砂失效,加剧后期修井成本。为准确掌控深水气井防砂筛管冲蚀磨损情况,采用耗时短、成本低的仿真模拟实验开展研究,相较于室内实验研究更具实用和教学价值。构建了防砂筛管的整体物理模型和局部筛孔物理模型,并采用分阶段修正以匹配筛网冲蚀的孔径变化,建立离散颗粒广角度筛管冲蚀模型,引入气固耦合流动模型,采用亚松弛迭代计算两相流场分布和冲蚀磨损情况,形成筛管冲蚀仿真模拟方法,应用于XX井进行冲蚀磨损分析。提出的筛管冲蚀磨损模拟方法为深水气井防砂筛管优选和冲蚀磨损量计算提供了一种研究方法和理论依据,对保障海洋油气资源的安全高效开发具有重要意义。 相似文献
7.
《绵阳师范学院学报》2018,(11):93-99
为了解南方农牧交错带内,不同地形因子影响下植被净初级生产力(NPP)的分布情况.采用DEM数据和MOD17A3H遥感数据,利用Arc GIS空间分析工具,对南方农牧交错带内不同海拔、坡度、坡向下的植被生产力分布情况进行了分析.结果表明:(1)从研究区域整体来看植被NPP随海拔的增加而减小;(2)研究区域内南坡NPP最大,东坡NPP最小;(3)在大于35°的坡面,所分布的植被NPP值最大;(4)从海拔分级来看,在小于3 400 m的海拔范围内,NPP较高的坡面多分布于北坡和东北坡;而在大于4 000 m的海拔范围内NPP较高的坡面则多分布于西南坡.(5)在小于4 600m的海拔范围内10°35°的坡面植被NPP值较大,海拔高于4 600 m时,0°35°的坡面植被NPP值较大,海拔高于4 600 m时,0°3°的坡面植被NPP值最大. 相似文献
8.
管孝瑞 《实验室研究与探索》2019,(5):36-41
基于Euler-Eulerian两相流模型,采用CFD软件对低含液输气管道内不同粒径分布的液滴群空间分布以及随时间的变化规律进行了研究。利用边界层网格与增强壁面函数得到了近壁面处边界层内的速度分布:水平管内液滴群主要集中在管路底部区域;弯头内二次流促使液滴群向弯头外侧运动;上弯头后的竖直管内二次流依然存在,液滴群主要集中在迎流侧;液滴群的波动随着时间具有周期性。 相似文献
9.
当前,多采用垂直式压差预冷对果蔬进行冷却．建立了苹果压差预冷的周期性边界模型,通过数值分析,研究了不同送风角度对苹果冷却效果的影响．研究发现,不同送风角度会导致苹果摆放区域气流流动方向和流速发生变化,随着送风角度的增大,流域内气流最大速度呈先增后减趋势变化;送风角度为0°、15°和30°时,不同深度苹果内部温度差别不大,预冷效果均较好,但当送风角度为45°时,预冷效果要较其他送风角度略差．15°为最佳送风温度,推测其原因在于,略微偏斜的送风角度使得气流在流经苹果摆放区域时产生了更多旋流,这些旋流进一步提高了苹果的冷却效果．在冷库压差预冷苹果时,让送风角度保持在0°―30°,可以达到更好的冷却效果． 相似文献
10.
《浙江大学学报(A卷英文版)》2017,(3)
目的:90°弯管广泛应用于工业中的流体输送,但是流体在经过弯头时会由于离心力的作用而导致弯头下游管道内出现流体分布不均的现象,从而影响后续的生产过程。本文将实验和计算流体力学(CFD)模拟的方法结合研究缩径管对经过弯头后的流体整流作用并分析原因,以期为缩径管在工业中的应用提供一定的参考。创新点:1.提出在弯头后的管路中增加缩径管来调整流体的方法;2.在冷模实验数据验证模拟结果的正确性的基础上,根据CFD模拟得到的管道内的压力、流体速度、相分布及湍动能分布详细分析了缩径管能起整流作用的原因。方法:1.通过冷模实验所得的压力数据与模拟值进行对比,证明模拟所采用模型的正确性;2.通过对不同流体入口条件模拟结果的比较,找到缩径管的作用规律;3.通过CFD模拟得到管道内的压力、流体速度、相分布及湍动能,分析缩径管的整流原理。结论:1.模拟所采用的模型可较好地反映管道内的流体流动情况;2.缩径管能起到很好的整流效果;3.缩径管可使流体加速,促进流体的快速混合,因此能够使不稳定的流体快速达到稳定状态。 相似文献
11.
A droplet undergoes spreading,rebounding or splashing when it impacts solid boundary,which is a typical phenomenon of free surface flow that exists widely in modern industry.Smoothed particle hydrodynamics（SPH）method is applied to numerically study the dynamical behaviors of the droplet impacting solid boundary,and both the spreading and rebounding phenomena of the droplet are reproduced in the simulation.The droplet deformation,flow fields and pressure fields inside the droplet at different moments are analyzed.Two important factors,the initial velocity and diameter,are discussed in determining the maximum spreading factor,revealing that the maximum spreading factor increases with the increase of the impact velocity and droplet diameter respectively. 相似文献
12.
The scaling and similarity of wall bounded turbulent flow were studied. The properties of such flows and the relationship between a power law and a logarithmic type of velocity distribution were investigated. Based on the physical mechanism involved, our results show that the power law and the logarithmic distribution are only different forms with the same hypothesis and hold only in the outer flow zone. Thus, a universal explanation for various empirical formulae of velocity distribution was obtained. Manning＇s formula was studied to explain theoretically the experiential result that the roughness coefficient is only a comprehensive parameter of the whole system without a corresponding physical factor. The physical mechanism of the velocity distribution of parallel to wall bounded flow was explored, the results show that the parameters in the formula of velocity distribution are indices of the system responding to flowing environmental factors to represent general case of boundary roughness and the flowing state, corresponding physical mechanism is vortex motion. 相似文献
13.
A cold-model vertical multi-tube circulating fluidized bed evaporator was designed and built to conduct a visualization study on the pressure drop of a liquid-solid two-phase flow and the corresponding particle distribution.Water and polyformaldehyde particle (POM) were used as the liquid and solid phases,respectively.The effects of operating parameters such as the amount of added particles,circulating flow rate,and particle size were systematically investigated.The results showed that the addition of the particles increased the pressure drop in the vertical tube bundle.The maximum pressure drop ratios were18.65%,21.15%,18.00%,and 21.15%within the experimental range of the amount of added particles for POM1,POM2,POM3,and POM4,respectively.The pressure drop ratio basically decreased with the increase in the circulating flow rate but fluctuated with the increase in the amount of added particles and particle size.The difference in pressure drop ratio decreased with the increase in the circulating flow rate.As the amount of added particles increased,the difference in pressure drop ratio fluctuated at low circulating flow rate but basically decreased at high circulating flow rate.The pressure drop in the vertical tube bundle accounted for about 70%of the overall pressure drop in the up-flow heating chamber and was the main component of the overall pressure within the experimental range.Three-dimensional phase diagrams were established to display the variation ranges of the pressure drop and pressure drop ratio in the vertical tube bundle corresponding to the operating parameters.The research results can provide some reference for the application of the fluidized bed heat transfer technology in the industry. 相似文献
14.
INTRODUCTION Measurement technology for gas-solid two phase flow has important applications in fields such as process measurement, forecast and control in in- dustry (Teng et al., 2002). At present, most optical measurement methods, such as LDV (Laser Doppler Velocimetry), Laser Dust Particles Measurement Device, use an optical sensor probe that only yields information on a single point or a partial area in the flow field and cannot yield instantaneous multi-ori- entation flow states.… 相似文献
15.
基于有限体积方法,对嵌入式行星螺杆挤出机内流场进行了三维等温数值模拟。通过简化的物理模型来模拟螺杆的几何结构,使用用户自定义程序设定了行星螺杆运动的边界条件。分析了挤出机螺槽内压力和速度的分布;使用粒子追踪技术观察了螺杆内流体运动轨迹和粒子分布规律;对粒子在螺杆内的停留时间分布进行了统计。结果表明行星螺杆对流体运动产生了周期性扰动。初始位置在一起的两个粒子,终点位置却相距很远。示踪粒子的具有对初始敏感的混沌特性,粒子的运动轨迹具有无序性,说明流体存在着混沌效应。 相似文献
16.
宋安利 《杨凌职业技术学院学报》2010,9(2):14-16
河床冲刷是一种常见而极为复杂的客观现象,尤其是高含沙河流河床冲刷变化更为复杂。本文利用实测资料对刘家河水文站测验断面冲刷变化进行分析,建立了洪峰流量和断面深泓点冲刷深度之间关系,为粗估深泓点冲刷深度提供了依据。 相似文献
17.
NomenclatureV-Relative velocity vectorV′-Absolute velocity vectorω-Relative vorticity vectorω′-Absolute vorticity vectorR-Pipe radiusa-Radius of cylinder for helical vortex filament2πl-Pitch of i mage helical vortex filamentQ-Flowrate in pipe with an arbitrary cross-sectionΓ-Circulation of each helical vortex filamentV0-Constant transferal velocity of vortex filaments along thez-axisΩ-Constant angular velocity of vortex filaments around thez-axis(a,χ1) ,(a,χ2) -Relative helical … 相似文献
18.
针对激光选区熔化成形倾斜薄壁件尺寸精度低、成形质量差等问题,应用响应曲面法研究工艺参数及倾斜角度对薄壁件壁厚的影响,建立倾斜角度、工艺参数与壁厚相对误差关系模型。结果表明:倾斜角度对壁厚的影响最大,激光功率次之。由于倾斜角度改变,薄壁件悬垂面粉末支撑区域不同,导热效果存在差异,激光功率与扫描间距对于不同倾斜角度的薄壁件壁厚影响不同。其中,激光功率对45°倾斜薄壁件壁厚的影响最大,当激光功率选择150~350W时,壁厚相对误差最大差值为24%而扫描间距对90°倾斜薄壁件壁厚的影响最大,当扫描间距选择0.1~0.2mm时,壁厚相对误差最大差值为9.5%,合理的工艺参数能够有效降低壁厚相对误差。 相似文献
19.
Xue-cheng Wu Qin-hui Wang Chen Tian Zhong-yang Luo Meng-xiang Fang Ke-fa Cen 《浙江大学学报(A卷英文版)》2008,9(7):922-931
Particle rotation plays an important role in gas-solid flows. This paper presents an experimental investigation on the spatial distribution of average rotation speed for glass beads in the upper dilute zone of a cold circulating fluidized bed （CFB） riser. It is shown that in the horizontal direction, the average rotation speed in the near-wall area is larger than that in the center area, while in the vertical direction, it decreases as the height increases. The reason resulting in this distribution is analyzed by considering several factors including particle size, particle shape, particle number density, particle collision behavior, and the surrounding flow field, etc. The effects of CFB operation conditions on the spatial distribution of average rotation speed are also studied. The results show that the increasing superficial gas velocity increases the average rotation speed of particles in the near wall area but takes nearly no effect on that in the center area. The external solids mass flux, however, takes the opposite effect. It is found that the average rotation speeds of particles in both areas are increased as the total amount of bed material increases. 相似文献
20.
以ASTER GDEM 30m DEM为基础数据提取贵州省六盘水市地表坡度、坡向、地形起伏度、地表切割深度等地形特征要素,并结合特征统计分析对该地区地貌特征进行定量分析。结果表明六盘水地区坡度在0°～88°范围内都有分布,但相对集中在5°～25;°南北坡坡向面积相差不多,分布相对均衡;中部地区地形起伏度较大,最大处达到922m,地形切割深度最大值为627m。上述结论为研究区的农业规划、水土流失、土壤侵蚀、地质灾害、生态保护等研究提供了新的空间信息平台。 相似文献