A review of the research on complex erosion by wind and water

Complex erosion by wind and water, which is also called aeolian-fluvial interactions, is an important erosion process and landscape in arid and semiarid regions. The effectiveness of links between wind and water process, spatial environmental transitions and temporal environmental change are the three main driving forces determining the geomorphologic significance of aeolian-fluvial interactions. As a complex interrelating and intercoupling system, complex erosion by wind and water has spatial- temporal variation features. The process of complex erosion by wind and water can be divided into palaeoenvironmental process and contemporary process. Early work in drylands has often been attributed to one of two schools advocating either an ＇aeolianist＇ or a ＇fluvialist＇ perspective, so it was not until the 1930s that the research on complex erosion by wind and water had been conducted. There are two obstacles restricting the research of complex erosion by wind and water. Firstly, how to transform in different temporal and spatial scales is still unsettled; and secondly, the research methodology is still immature. In the future, the mechanism and control of erosion, the complex soil erodibility in wind and water erosion will be the focus of research on complex erosion by wind and water.

Two-flow model for piping erosion based on liquid-solid coupling

Previous studies have indicated that piping erosion greatly threatens the safe operation of various hydraulic structures. However, few mathematical models are available to perfectly describe the erosion process due to the complexity of piping. The focus of the present work is to propose a new fluid solid coupling model to eliminate the shortcomings of existing work. A 'pseudo-liquid' assumption is suggested to simulate the particle movement in the erosion process. Then, based on the mass and momentum conservations of the moving particles and flowing water, a new two-flow model is established by using the continuity equations and motion equations. In the model, the erosion rate of soil is determined with a particle erosion law derived from tests results of STERPI. And ERGUN's empirical equation is used to determine the interaction forces between the liquid and the solid. A numerical approach is proposed to solve the model with the finite volume method and SIMPLE algorithm. The new model is validated with the tests results of STERPI. And the soil erosion principles in piping are also explored.

Influences of sand cover on erosion processes of loess slopes based on rainfall simulation experiments

Aeolian-fluvial interplay erosion regions are subject to intense soil erosion and are of particular concern in loess areas of northwestern China. Understanding the composition, distribution, and transport processes of eroded sediments in these regions is of considerable scientific significance for controlling soil erosion. In this study, based on laboratory rainfall simulation experiments, we analyzed rainfall-induced erosion processes on sand-covered loess slopes （SS） with different sand cover patterns （including length and thickness） and uncovered loess slopes （LS） to investigate the influences of sand cover on erosion processes of loess slopes in case regions of aeolian-fluvial erosion. The grain-size curves of eroded sediments were fitted using the Weibull function. Compositions of eroded sediments under different sand cover patterns and rainfall intensities were analyzed to explore sediment transport modes of SS. The influences of sand cover amount and pattern on erosion processes of loess slopes were also discussed. The results show that sand cover on loess slopes influences the proportion of loess erosion and that the compositions of eroded sediments vary between SS and LS. Sand cover on loess slopes transforms silt erosion into sand erosion by reducing splash erosion and changing the rainfall-induced erosion processes. The percentage of eroded sand from SS in the early stage of runoff and sediment generation is always higher than that in the late stage. Sand cover on loess slopes aggravates loess erosion, not only by adding sand as additional eroded sediments but also by increasing the amount of eroded loess, compared with the loess slopes without sand cover. The influence of sand cover pattern on runoff yield and the amount of eroded sediments is larger than that of sand cover amount. Furthermore, given the same sand cover pattern, a thicker sand cover could increase sand erosion while a thinner sand cover could aggravate loess erosion. This difference explains the existence of intense erosion on slopes that are thinly covered with sand in regions where aeolian erosion and fluvial erosion interact.

Erosion-Induced Inflammation on Coronary Plaque Stress/Strain and Flow Shear Stress Calculations Using OCT-Based FSI Computational Model

Plaque erosion,together with plaque rupture,is a common cause for acute coronary syndrome(ACS).Plaque erosion alone is responsible for about one third of the patients with ACS.Eroded plaque is defined as thrombosed,endothelium-absent and non-ruptured but often-inflamed plaques based on histological findings.Even though there is efficient imaging technologies to detect the eroded plaque in vivo and tailored treatment strategy has also been developed for ACScaused by erosion in clinics,the pathogenesis mechanisms that cause plaque erosion are not fully understood.It is widely postulated that thrombus formation and endothelial apoptosis(the precursors of plaque erosion)have closed association with biomechanical conditions in the coronary vessel.Revealing of the mechanical conditions in the eroded plaque could advance our knowledge in understanding the formation of plaque erosion.To this end,patient-specific OCT-based fluid-structure interaction(FSI)models were developed to investigate the plaque biomechanical conditions and investigate the impact of erosioninduced inflammation on biomechanical conditions.In vivo OCTand Biplane X-ray angiographic data of eroded coronary plaque were acquired from one male patient(age:64). OCT images were segmented manually with external elastic membrane contour and the trailing edge of the lipid-rich necrotic core(lipid)assumed to have positive remodeling ratio 1.1.Locations with luminal surface having direct contact with intraluminal thrombus on OCT images were identified erosion sites.Fusion of OCT and biplane X-ray angiographic data were performed to obtain the 3D coronary geometry.OCT-based FSI models with pre-shrink-stretch process and anisotropic material properties were constructed following previously established procedures.To reflect tissue weakening caused by erosion-induced inflammation,the material stiffness of plaque intima at the erosion site was adjust to one tenth of un-eroded fibrous plaque tissue.Three FSI models were constructed to investigate the impacts of inflammation and lipid component on plaque biomechanics:M1,without erosion(this means plaque intima at the erosion sites were not softened)and without inclusion of lipid component;M2,with erosion but no lipid;M3,with erosion and inclusion of lipid.FSI models were solved by ADINA to obtain the biomechanical conditions at peak blood pressure including plaque wall stress/strain(PWS/PWSn)and flow wall shear stress(WSS).The average values of three biomechanical conditions at the erosion sites and at the fibrous cap overlaying lipid component were calculated from three models for analysis.The results of M1 and M2 were compared to investigate the impact of erosion-induced inflammation on plaque biomechanics.Mean PWS value decreases from 49.98 kPa to 18.83 kPa(62.32%decrease)while Mean PWSn value increases from 0.123 1 to 0.138 4(12%increase)as the material stiffness becomes 10times soft.Comparing M2 and M3 at the cap sites,M3(with inclusion of lipid)will elevates mean PWS and PWSn values by48.59%and 16.09%,respectively.The impacts of erosion and lipid on flow shear stress were limited(<2%).To conclude,erosion-induced inflammation would lead to lower stress distribution but larger strain distribution,while lipid would elevate both stress and strain conditions.This shows the influence of erosion and lipid component has impacts on stress/strain cal-culations which are closely related to plaque assessment.

An experimental study on the influences of wind erosion on water erosion

In semi-arid regions, complex erosion resulted from a combination of wind and water actions has led to a massive soil loss and a comprehensive understanding of its mechanism is the first step toward prevention of the erosion. However, the mutual influences between wind erosion and water erosion have not been fully understood. This research used a wind tunnel and two rainfall simulators and simulated two rounds of alternations between wind erosion and water erosion（i.e., 1^（st） wind erosion–1^（st） water erosion and 2^（nd） wind erosion–2^（nd） water erosion） on three slopes（5°, 10°, and 15°） with six wind speeds（0, 9, 11, 13, 15, and 20 m/s） and five rainfall intensities（0, 30, 45, 60, and 75 mm/h）. The objective was to analyze the influences of wind erosion on succeeding water erosion. Results showed that the effects of wind erosion on water erosion were not the same in the two rounds of tests. In the 1^（st） round of tests, wind erosion first restrained and then intensified water erosion mostly because the blocking effect of wind-sculpted micro-topography on surface flow was weakened with the increase in slope. In the 2^（nd） round of tests, wind erosion intensified water erosion on beds with no rills at gentle slopes and low rainfall intensities or with large-size rills at steep slopes and high rainfall intensities. Wind erosion restrained water erosion on beds with small rills at moderate slopes and moderate rainfall intensities. The effects were mainly related to the fine grain layer, rills and slope of the original bed in the 2^（nd） round of tests. The findings can deepen our understanding of complex erosion resulted from a combination of wind and water actions and provide scientific references to regional soil and water conservation.

Distinct Aeolian-fluvial Interbedded Landscapes in Three Watersheds of the Northern China

Due to the complex dynamic of aeolian and fluvial interacted processes behind the landform development,most of previous works started from classifying the types of landscape characterized by various aeolian and fluvial features.Such classifications are usually generalized based on large geomorphic data set abstracted from satellite images without field verification and dynamic field data.In this study,we identified river banks in deserts as a unique geographical unit dominated by aeolian-fluvial processes.Three distinct locations have been identified as representative study cases,which are in the Keriya River Basin in the west,the Mu Bulag River Basin in the middle and the Xar Moron River Basin in the east of the northern China.The aeolian-fluvial interaction types were quantified based on site observation and measurement,topographic mapping and remote-sensing image analysis.Dimensional morphological relationship between river channel and adjacent sand dunes areas were explored.We concluded that different channels are often associated with different distributions of riparian dunes.The quantitative data enabled us to distinguish statistically four different types of landscape in aeolian-fluvial dominant environment,namely riverside dunes-straight channel,symmetrical interleaving dunes-meandering channel,river-island dunes-braiding channel,and grid-like dunes-anastomosing channel,aiming to provide compensational information to current aeolian-fluvial interaction studies.The angle of interaction between aeolian and fluvial systems,the windward and leeward sites of the bank,vegetation coverage and underlying landform determines the distribution,morphology,scale and direction of extension of the riparian dunes.The results of the work study can provide a reference for study of aeolian-fluvial interactions at different spatial scales in arid region.

黑土长缓坡地形与横垄对土壤有机碳空间分异的交互作用

横坡垄作对坡耕地土壤有机碳(soil organic carbon,SOC)流失有一定的阻控作用,但黑土区特有长而缓的地形与横垄对坡耕地SOC空间分异会产生交互作用,而这种交互作用引发的SOC流失风险没引起足够的重视。该研究以典型黑土区黑龙江省黑河市北安分局红星农场为研究区域,2022年在横坡垄作与顺坡水线方向上共布设25个采样点,采用地理探测器模型、单因素方差分析(one-way ANOVA)和Pearson相关性分析,探讨土壤有机碳的空间分异及其交互作用。结果表明,横坡垄作方向上垄沟土壤有机碳含量从坡顶到水线呈现逐渐增大的变化趋势;在垄台从坡顶到水线呈现先增大后减小的变化趋势。顺坡水线方向,土壤有机碳含量在垄沟呈现从上坡到下坡增大的变化趋势;在垄台呈现先增大后减小的变化趋势。由于断垄产生水线,顺坡土壤有机碳含量上坡与下坡仍有显著差异(P<0.05)。Pearson相关性分析表明,有机碳与可蚀性K因子呈显著负相关(垄沟和垄台相关系数分别为–0.228和–0.238,P<0.05),与碳循环相关的β-葡萄糖苷酶和微生物生物量碳在垄沟呈极显著正相关(相关系数为0.398和0.676,P<0.01)。地理探测器分析表明,顺坡水线对土壤有机碳空间分异的影响最大,其对垄沟和垄台SOC的解释力分别达到61%和52%以上;顺坡水线与其他因子的交互作用共同增强了对土壤有机碳的解释力,尤其是顺坡水线与高程的交互作用最为明显。黑土区坡耕地土壤有机碳空间分异主要受顺坡水线与高程的交互作用,横坡垄作虽然能够拦截径流,但由于长缓坡地形影响产生的断垄会加剧土壤侵蚀诱发的有机碳流失。因此,黑土坡耕地治理需要同时考虑横垄与地形的共同影响,从而实现防蚀的优化效果。

沿海氯盐环境下地铁车站结构地震响应规律

地铁车站结构抗震分析中,通常只对完好结构进行地震响应规律分析,然而,沿海城市地铁车站结构埋置于地下,易遭受氯离子侵蚀,导致材料性能退化。为此,针对沿海氯盐环境下不同锈蚀程度的地铁车站结构,建立相应的非线性土-结构相互作用有限元模型。采用整体式静力推覆分析,研究氯离子侵蚀对土-结构柔度比的影响,并基于非线性时程分析,研究氯离子侵蚀下地铁车站结构的地震响应规律。数值模拟结果表明:相对完好状态,10%和20%锈蚀率的车站结构土-结构柔度比分别下降6%和18%,然而,由于地下结构受到周围土体的约束,在相同地震作用下,底层中柱的最大层间位移角没有显著变化;底层中柱作为抗震薄弱环节,钢筋锈蚀造成中柱变形能力及承载能力的下降,导致地铁车站结构的安全系数下降10%和20%左右;锈蚀后结构中柱最大层间位移角增幅与场地响应有关,低频成分丰富的地震作用下,土体将产生大的剪切变形,使得中柱纤维截面中钢筋承担更多的剪力,此时钢筋锈蚀将对中柱层间位移角产生较大影响。

气候变化与土壤侵蚀相互作用研究进展

气候变化和土壤侵蚀是当前全球变化研究重点关注的两个自然过程,二者之间的相互作用是地表过程的重要研究内容之一。本文从土壤侵蚀对气候变化的响应、碳循环过程对土壤侵蚀的反馈两个方面综述了气候变化与土壤侵蚀相互作用研究进展。分析认为:理想的地质载体是深刻理解地质历史时期土壤侵蚀对气候变化响应特征的关键;土壤侵蚀预测模型的适用条件和范围以及降雨侵蚀力估算方法缺乏标准化是造成土壤侵蚀量估算结果存在差异的主要因素;侵蚀作用下土壤有机碳矿化的生物学过程与机制是科学评估土壤侵蚀是碳源或碳汇的关键环节。建议未来在以下三个方向开展工作:(1)以湖泊沉积物为地质载体研究历史时期气候变化与土壤侵蚀有着巨大发展和应用潜力,建议利用AMS 14C、137Cs和210Pb等多种定年手段,使用环境指示意义明确的代用指标,建立近千年高分辨率流域气候与侵蚀序列,研究十年至百年尺度气候变化与土壤侵蚀之间的关系;(2)流域版水蚀预报模型(WEPP)可能更适合小流域预测研究,在其实践应用过程中除规范标准小区的坡度和坡长之外,还应通过长期观测和试验确定不同气候区侵蚀性降雨阙值以计算降雨侵蚀力;(3)可以尝试采用定量稳定同位素探针技术(qSIP)研究微生物对土壤有机碳库的分解和转化的驱动机制,因为qSIP不仅能量化土壤微生物的生长速率,还能同步测定土壤有机碳的矿化速率。

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.

油田集输管道多相流冲刷腐蚀机理与影响因素研究进展

冲刷腐蚀是油田集输管道壁厚减薄失效的主要形式之一,多相流冲刷腐蚀日益成为影响油田集输安全的重要因素。首先,针对多相流作用下油田集输管道的冲刷腐蚀问题,介绍了冲刷腐蚀机理、冲刷腐蚀理论模型以及冲刷与腐蚀的相互协同效应;其次,结合国内外冲刷腐蚀研究成果,综合分析了影响冲刷腐蚀的主要因素,重点阐述了流体力学因素、固体粒子性质、流体介质属性和温度对冲刷腐蚀的影响机制;最后,在总结现有研究存在问题的基础上,对集输管道多相流冲刷腐蚀未来研究方向进行了展望。

全风化花岗岩管沟回填土坡面侵蚀影响因素及交互作用

为了查明全风化花岗岩地区输油气管道作业边坡坡面水土流失问题,通过野外典型边坡边界条件测量、坡面侵蚀特征冲沟沟深、冲沟截面积数据采集、岩土体取样测试,并结合室内模型降雨试验等方法。结果表明:降雨、坡长、坡度、汇水面积、岩土体特性5种因素均影响全风化花岗岩管沟回填土坡面侵蚀。产沙率和产流率随着降雨强度的增大而增大。坡长、坡度、汇水面积与冲沟沟深和冲沟截面积呈正相关关系,且随着坡长、坡度、汇水面积的增大,冲沟沟深和冲沟截面积也在增大。通过取样测试发现,原状土与回填土的颗粒组成相对含量具有较大差异,初始回填土粒度级配为良好土。降雨冲刷初期回填土坡面径流主要携带粉粒和黏粒。5年回填土相对于原状土,孔隙率增加到原来的1.13倍,土体渗透系数增大1个数量级,饱和状态下黏聚力降低为原状土的67.6%,内摩擦角降低为原状土的87.5%。通过查明全风化花岗岩管沟回填土坡面侵蚀影响因素及其作用,为后续的边坡治理提供依据。

基于流固耦合的燃气冲刷烧蚀内膛特性分析

火炮发射时,火药燃气与身管间发生剧烈的传热传质作用是导致身管烧蚀的重要因素。为了研究某155 mm火炮中高温高压高速的燃气流对身管的烧蚀特性,采用CFD流固耦合方法,建立了发射过程中的身管非稳态流动传热模型,并根据炮钢在不同温度下的烧蚀特点,将烧蚀过程分为热化学烧蚀和熔化烧蚀,建立了分段烧蚀模型。计算结果表明,身管内壁温度随时间的增加先迅速增大,随后逐渐降低。整体上,内壁温度随身管轴向距离的增大而逐渐降低。身管膛线起始区域的壁面温度最高,其烧蚀是熔化和热化学烧蚀共同导致的,而线膛部的大部分区域仅发生了热化学烧蚀。总烧蚀量随着身管轴向距离的增大而逐渐降低,膛线起始部的烧蚀最为严重,单发总烧蚀量(常温)为5.06μm。同时分析了不同工况对身管烧蚀特性的影响,发现最大烧蚀量与初始壁面温度呈现很强的正相关性,温度的升高会加剧身管的烧蚀。

喀斯特区土壤侵蚀与石漠化协同演变及交互关系

为探究喀斯特地区土壤侵蚀、石漠化协同演变规律、驱动因子及主要驱动因子下二者交互关系。采用优化后的RUSLE模型估算贵州省喀斯特地区2005—2015年土壤侵蚀,并利用贵州省全国石漠化普查数据库计算同期石漠化状况,运用地理探测器探究驱动因子以及主要驱动因子下二者交互关系。结果表明:2005—2015年贵州省喀斯特地区土壤侵蚀与石漠化均以中度及以下为主,其中土壤侵蚀中度及以下占比58%以上,而中度及以下石漠化占比达80%以上;时间上二者存在发生时间的异同性,但研究期间,二者均不同程度地趋于好转;中度及以下石漠化中土壤侵蚀发生率较大,中度以上中占比极少,其中无石漠化中土壤侵蚀发生率达70%以上;土壤侵蚀驱动因子解释力大小依次为土地利用>坡度>年降雨量>海拔>岩石裸露率>植被盖度>岩性>土层厚度,石漠化驱动因子解释力大小依次为岩石裸露率>土层厚度>年降雨量>海拔>岩性>土地利用>植被盖度>坡度。因子组合(交互)对土壤流失及石漠化的解释力均较单因子有所增强,其中土壤侵蚀的主导因子为土地利用,石漠化的主导因子为岩石裸露率;主要驱动因子下二者交互关系结果表明,土壤侵蚀与石漠化存在因果关系且土壤侵蚀先于石漠化发生发展,但简单线性关系并不能解释二者关系,而是分阶段呈正相关或负相关的复杂关系。研究结果可为喀斯特地区土壤侵蚀与石漠化防治提供理论参考。

围填海对渤海湾泥沙冲淤的影响

基于FVCOM(finite-volume coastal ocean model)-SWAN(simulating waves nearshore)耦合模型进一步建立三维泥沙模型,对渤海湾围填前后泥沙输运进行模拟,分析了围填海对渤海湾泥沙冲淤的影响。结果表明:围填海对围填海区附近海域泥沙输运的影响较为显著,而对远离其海域的影响较小。涨急、落急时,月均垂向平均含沙量在曹妃甸三港池口门、天津南港工业区附近海域和黄骅港部分海域增加,在其他主要围填海区减少。渤海湾主要泥沙输运方向没有明显变化,为由东向西的向岸输运。同时,曹妃甸三港池口门附近冲淤发生变化,内部其他水域淤积减少。天津港围填外边界附近海域淤积增加,而临港经济区口门、南港工业区的口门及其围填外边界东南转角附近海域冲刷增加。紧邻黄骅港附近海域冲淤变化幅度较小。此外还研究了波浪对泥沙的影响。波流共同作用与不考虑波浪作用的情况相比,总体上渤海湾沿岸海域的含沙量增加,单宽悬沙通量变化较明显,床面冲淤幅度差别显著。

内蒙古砒砂岩地区风蚀、水蚀及重力侵蚀交互作用研究

内蒙古砒砂岩地区是黄河重要的粗沙来源区 ,具有水蚀、风蚀及重力侵蚀交互的特点。利用 3个试验流域1983～ 1997年的天然观测资料 ,分析得到了砒砂岩侵蚀交互作用的时空分布规律 ;通过对砒砂岩的理化性质及侵蚀产沙特性的分析表明 ,砒砂岩的产流和产沙能力均高于当地的黄土和风沙土。建立了砒砂岩地区的水蚀模型 。

土壤复合侵蚀研究进展与展望

土壤复合侵蚀是在两种或多种以上侵蚀营力交互作用或耦合作用下发生的侵蚀现象,也是最难治理的生态环境问题之一。近年来,在复合侵蚀发生机理、复合侵蚀对土壤退化作用及多动力侵蚀交互作用的模拟技术等方面取得了明显进展。该文基于前人研究成果,系统总结了复合侵蚀类型与特征、复合侵蚀发生机理、复合侵蚀研究方法等若干方面的研究进展,分析了研究中存在的主要问题,提出了今后在复合侵蚀规律与模拟试验方法等研究中需要重点解决的若干关键科学问题,以及应关注的基于多源数据融合的降雨-风洞-冻融等多动力交替循环试验模拟技术、复合侵蚀系统中驱动因子作用的定量评估技术与方法、多动力不同耦合状态下产沙过程辨识及量化等研究方向,以期为开展相关研究提供参考。

弯曲荷载与氯盐侵蚀共同作用下的预应力混凝土梁耐久性能研究

当前在进行海工混凝土结构受氯盐侵蚀的耐久性研究时往往忽略了混凝土力学损伤的影响,这可能会导致高估结构的耐久性能。该文提出了在数值分析中引入损伤因子实现综合考虑结构损伤影响及氯盐侵蚀共同作用的分析方法,通过干湿循环的氯盐侵蚀试验与数值模拟分析,研究遭受氯盐腐蚀且受到长期荷载作用的预应力混凝土梁的耐久性能。结果表明,数值分析结果和试验结果吻合良好。参数分析结果表明:0.2mm宏观裂缝的出现对氯离子浓度有着较为显著的影响,未出现宏观裂缝时,拉应力对氯离子输运的影响较为有限;荷载比的大小影响结构的损伤范围和程度,进而影响氯离子在混凝土内的传输;梁构件施加预应力后,在15%和30%两种低荷载比状态下延缓其力学损伤(裂缝)的开展,减小荷载作用对氯离子扩散系数的增大效应,有效提高构件的抗氯盐侵蚀性能,当荷载比增加到45%以上,普通钢筋混凝土梁相对于预应力梁的氯离子浓度增比降至10%以内,这表明较高应力比下预应力对梁抗氯盐侵蚀能力的影响减弱。

冲蚀磨损与冲蚀、空蚀交互磨损的对比研究

基于计算流体力学(computational fluid dynamics,CFD)方法,数值对比研究了在模拟水轮机工况中不同转速时,冲蚀与冲蚀、空蚀交互作用时,转盘表面的流场(压力场、流体浓度分布),然后在转盘式磨损装置上,进行了汽液固三相冲蚀与空蚀交互磨损试验.结果表明:对于冲蚀磨损来说,随着转速增加,压力增大,在冲蚀作用下加入空蚀磨损,压力增高,磨损加剧;而对于交互磨损来说,随着转速增加,转盘表面的空蚀磨损区域从空化孔附近开始沿着转盘旋转的反方向偏移,并且磨损程度加剧;数值计算的气泡较多且压力梯度较高区域和试验转盘磨损区域基本一致,数值计算结果和试验结果吻合得较好.

动态与静态纯腐蚀对定量研究材料冲刷腐蚀交互作用的影响

分别测定了不锈钢和碳钢静态与动态纯腐蚀失重率、冲刷腐蚀失重率及其电化学行为,研究了静态与动态纯腐蚀失重率对材料冲刷腐蚀交互作用失重率的影响,实验表明:(1)动态纯腐蚀比静态纯腐蚀更能反映材料在液固两相流中冲刷腐蚀交互作用的本质:(2)本实验条件下．T8钢动态纯腐蚀失重率是静态纯腐蚀失重率的2倍以上．18-8不锈钢动态纯腐蚀失重率竟是静态纯腐蚀失重率200倍以上．静态交互作用失重率是动态交互作用失重率的2倍以上,可见静态与动态纯腐蚀对定量研究材料冲刷腐蚀交互作用会产生很大的差异:(3)在腐蚀性浆料中．首先要保证材料具有一定的耐蚀性,其次再考虑提高材料的硬度和耐磨性．这样才能有效地提高材料的耐冲刷腐蚀性能,对不同的工况,必须同时兼顾材料的耐蚀性和耐磨性。