Spar式风力机平台设计及水动力影响因素研究

针对NREL5MW风力机设计Spar式风力机平台并采用频域分析方法对该平台的水动力性能进行分析,研究纵荡板、平台工作水深以及重心高度对其水动力性能的影响。研究表明,垂荡板可将Spar平台的垂荡响应峰值降低至无垂荡板时峰值的1/3。当水深大于设计吃水的4倍时,水深对垂荡运动影响很小,这说明Spar风力机平台适合工作在水深大于4倍平台设计吃水的海域。当加压载后,平台重心低于设计重心的距离在0!0.8倍的设计重浮心距离范围内时,Spar风力机平台实际重心位置的偏离对平台的水动力性能影响较小。分析结果将为海上浮式风力机支撑平台的设计以及水动力性能研究提供参考。     

郑庄东大井区煤层含气量主控地质因素

以郑庄区块东大井区为主要研究对象,综合运用实验测试数据、煤田钻孔及煤层气井资料,并结合沉积、构造和地下水动力的原理和方法,深入分析了该区煤层含气量分布和主控地质因素。研究结果表明:研究区煤层含气量较高,总体呈自东向西逐渐增大的趋势,且主要受煤层埋藏深度、地质构造和水动力条件三个因素控制。即煤层埋深对含气量分布具有较好的控制作用,总体上含气量高值区大都位于北部深埋区域;地质构造对含气量的影响主要表现为次级构造叠加在煤层埋深影响的总体背景之上导致含气量展布复杂化;北部地区水动力条件对煤层气的运移和富集具有显著的控制作用,是影响煤层含气量展布的主要因素;而南部地区则由于埋深和断层等因素的影响,从而导致水动力条件与煤层含气量的相关性不太明显。     

介质阻挡放电反应器降解邻二甲苯的特性研究

采用介质阻挡放电(DBD)降解常压下流动态的邻二甲苯模拟废气,系统地考察了放电极值电压,气体的初始质量浓度、停留时间以及相对湿度等工艺参数对邻二甲苯降解的影响,并初步探讨了邻二甲苯的降解产物.实验研究结果表明:在7.0kV的放电极间电压下,邻二甲苯的初始质量浓度为1 500mg/m3,停留时间为9s,其去除率可达到80%以上.降解产物主要为CO2、H2O以及苯甲酸、苯乙酸、苯乙醛等有机物,并且经降解后产物的生物可生化性得到提高,因而为后续的等离子-生物法联合处理VOCs提供了依据.     

动水压力作用下沥青路面水-孔隙结构应力分析

为了研究动水压力对沥青路面产生水损害的原因,对水-孔隙结构进行了应力分析,建立了沥青路面水-孔隙结构承受车辆荷载的模型,提出了沥青路面空隙率与孔隙水压力的关系,并讨论了沥青路面内部因孔隙水压力而致使孔壁在反复的荷载作用下发生的胀裂与抽吸和冲刷作用.     

船舶静水航行水动力模型的简化及其应用

针对现有船舶水动力模型考虑因素多、通用性差的缺点,通过简化船体线形、忽略波浪和风向等复杂因素的影响,对船舶水动力模型进行研究。推导静水面船体的迎流区域范围,计算水流作用在船体微小面元上的动压力,得出整船水流总阻力计算模型。在此基础上,给出船体航行动力学模型,分析船舶在静水面航行中动力、水阻力和运动状态之间的关系。将该水动力模型应用于船舶稳定航行控制,结果表明模型具有较好的实用性。     

Sand corrosion,thermal expansion,and ablation of medium- and high-entropy compositionally complex fluorite oxides

Sand corrosion, thermal expansion, and ablation properties of a new class of medium- and high-entropy compositionally complex fluorite oxides (CCFOs) are examined as potential protective coating materials. Five binary oxides were mixed and sintered into dense, single-phase CCFOs of the general formula: [Hf_(1-2x)/3Zr_(1-2x)/3Ce_(1-2x)/3Y_xYb_x]O_2-δ (x = 0.2, 0.074, and 0.029). These CCFOs exhibit decreased molten sand infiltration and interaction at intermediate temperatures (1200-1300°C) in comparison with a cubic yttria-stabilized zirconia (YSZ) reference; however, at higher temperatures, the trend is reversed due to the increased chemical reactivity. The equimolar high-entropy (Hf_0.2Zr_0.2Ce_0.2Y_0.2Yb_0.2)O_2-δ exhibits no grain boundary penetration by molten sand at all examined temperatures (1200°C-1500°C), although reaction and precipitation are significant. Moreover, these CCFOs exhibit higher intrinsic thermal expansion coefficients (CTE) than the YSZ reference, thereby being more compatible with Ni-based superalloys. The 8YSZ-like (Hf_0.284Zr_0.284Ce_0.284Y_0.074Yb_0.074)O_2-δ exhibits the highest CTE in this series of CCFOs due to oxygen clustering effects. Finally, these CCFOs also exhibit lower emissivities and form unique faceted microstructures in ablative environments.     

Nondestructive measurements of residual stress in air plasma-sprayed thermal barrier coatings

Premature spallation of thermal barrier coatings (TBCs) is a critical issue during the service of gas turbines, and nondestructive evaluation is crucial to address this problem. Herein, a novel approach that indicates delamination by measuring the residual stress evolution of thermally grown oxide (TGO) for air plasma spraying (APS) TBCs is proposed and verified via the combination of photoluminescence piezo-spectroscopy (PLPS) and X-ray computed tomography. A mineral-oil-impregnating approach and a cold-mount low-shrinkage epoxy-mounting approach are used to alleviate the signal attenuation by pores and microcracks in APS TBCs, improving the detectable PLPS signal and X-ray transmission for stress measurement and delamination characterization, respectively. We have nondestructively measured the TGO residual stress mapping in APS TBCs and its evolution with oxidation. Furthermore, the evolution of TGO morphology and critical microcracks are obtained by X-ray computed tomography. The synchronous evolution of TGO residual stress, TGO thickness, and critical microcracks as a function of oxidation time is obtained and correlated. The transition point, as experimentally identified, at which the TGO stress starts to drop, agrees well with the critical moment of microcrack coalescence. This directly verifies that the TBC delamination can be effectively indicated by residual stress evolution of TGO in APS TBCs.     

Tailorable thermal expansion in leucite-pollucite materials derived from geopolymers for environmental barrier coatings

The K[AlSi₂O₆]-Cs[AlSi₂O₆] pseudo-binary system was synthesized by geopolymer crystallization. The thermal expansion properties of these materials were studied by in situ high-temperature X-ray diffraction to characterize thermal expansion behavior for potential application as environmental barrier coatings. Tailorable thermal expansion through changing cation stoichiometry allowed reduced thermal expansion mismatch with SiC_f/SiC composites compared to rare-earth-based coatings.     

High-temperature Na2SO4 interaction with air plasma sprayed Yb2Si2O7 + Si EBC system: Topcoat behavior

The high-temperature interaction between ~2.5 mg/cm² of Na₂SO₄ and an atmospheric plasma sprayed (APS) Yb₂Si₂O₇ topcoat–Si bond coat system on SiC CMC substrates was studied for times up to 240 h at 1000°C–1316°C in a 0.1% SO₂–O₂ gaseous environment. Yb₂Si₂O₇ reacted with Na₂SO₄ to form Yb₂SiO₅ and an intergranular amorphous Na-silicate phase. Below 1200°C, the reaction was sluggish, needing days to cause morphological changes to the “splat microstructure” associated with APS coatings. The reaction was rapid at 1200°C and above, needing only a few hours for the entire topcoat to transform into a granulated microstructure consisting of Yb₂SiO₅ and Yb₂Si₂O₇ phases. Na₂SO₄ deposits infiltrated the Yb₂Si₂O₇ topcoat and transformed into an amorphous Na-silicate in less than 1 h at all exposure temperatures. Quantitative assessment of the Yb₂SiO₅ area fraction in the topcoat showed a linear decrease over time at 1316°C, attributed to reaction with the SiO₂ thermally grown oxide (TGO) formed on the Si bond coat and rapid transport through the interpenetrating amorphous Na-silicate grain boundary phase. It was predicted that nearly 2 weeks is needed for complete removal of Yb₂SiO₅ from the topcoat at 1316°C for a single applied loading of Na₂SO₄.     

无溶剂重防腐环氧涂料的制备与研究

采用中低相对分子质量树脂体系以及改性脂环胺固化剂,以化学、物理防锈颜料,体质填料为粉料体系制备无溶剂重防腐环氧涂料。通过 EIS、划线盐雾剥离、耐 3. 5% NaCl溶液和 10% NaOH溶液、混合溶液浸泡后的附着力,研究了涂层屏蔽性、耐碱性、湿态附着力。结果表明：铁钛粉、 绢云母粉、长石粉粉料体系涂层屏蔽性、耐碱性最佳;改性脂环胺固化剂屏蔽性好,湿态附着力性能优异;采用 EIS、划线盐雾剥离,耐 3. 5% NaCl溶液、 10% NaOH溶液浸泡以及混合溶液浸泡后附着力下降程度来评价涂层屏蔽性、耐碱性、湿态附着力性能具有一定的可参考性,研究结果与涂层耐阴极剥离实验性能正相关,可用于涂层耐阴极剥离性能的早期评价与判断。