Numerical modeling of the hydraulic blade pitch actuator in a spar‐type floating wind turbine considering fault conditions and their effects on global dynamic responses

This paper deals with numerical modeling of the hydraulic blade pitch actuator and its effect on the dynamic responses of a floating spar‐type wind turbine under valve fault conditions. A spar‐type floating wind turbine concept is modeled and simulated using an aero‐hydro‐servo‐elastic simulation tool (Simo‐Riflex [SR]). Because the blade pitch system has the highest failure rate, a numerical model of the hydraulic blade pitch actuator with/without valve faults is developed and linked to SR to study the effects of faults on global responses of the spar‐type floating wind turbine for different faults, fault magnitudes, and environmental conditions. The consequence of valve faults in the pitch actuator is that the blade cannot be pitched to the desired angle, so there may be a delay in the response due to excessive friction and the wrong voltage, or slit lock may cause runaway blade pitch. A short circuit may cause the blade to get stuck at a particular pitch angle. These faults contribute to rotor imbalance, which result in different effects on the turbine structure and the platform motions. The proposed method for combining global and hydraulic actuator models is demonstrated in case studies with stochastic wind and wave conditions and different types of valve faults.     

二维碳粒床中阴燃传播的数值模拟

本文对内部有受迫气流经过的二维碳粒填充床的阴燃，从点火开始到稳态传播整个过程进行了数值模拟。计算采用控制容积法，用ＰＩＳＯ算法求解。主要研究新鲜空气流动速度与阴燃波的传播速度和反应温度之间的关系，也探讨了正向阴燃与反向阴燃之间的异同。其结果为：在受迫气流经过的阴燃床中点火，将产生反向阴燃，且气流速度越大，阴燃波的传播速度越快，阴燃温度越高。在条件相同的情况下，反向阴燃的传播速度比正向阴燃的传播速度大；而反向阴燃的反应温度比正向阴燃的反应温度低。     

己二酸生产中沸腾床干燥和气流干燥工艺性能比较

在目前己二酸生产中,用于固体物料干燥的代表性工艺是气流式及沸腾床式2种,对2种T艺在己二酸干燥中应用进行了综合性比较。     

高负荷条件下膜反应器污水处理实验研究

总结分析了在各种负荷条件下悬浮载体生物膜型反应器的试验结果.研究表明：悬浮生物膜反应器MBR应用于污水处理是完全可行的,它具有有机负荷高、处理效果优、耐冲击负荷能力强、占地面积少等优点;在悬浮填料投加率为30%时,对于CODcr≤2500mg/L的废水处理效果可达到废水回用标准.     

浮环密封和双端面干气密封在富气压缩机上的应用

详细阐述富气压缩机浮环密封和双端面干气密封的原理结构及优缺点,并对浮环密封存在的问题作了分析,最后在选择密封型式上提出建议。     

异步模拟移动床色谱的数值模拟

Asynchronous simulated moving bed chromatography (ASMBC), known also as the “VARICOL“ process, is more efficient and flexible than the well-known and traditional simulated moving bed chromatography (SMBC). A detailed model of ASMBC, taking account of non-linear competitive isotherms, mass transfer parameters, and complex port switching schedule parameters, was developed to simulate the complex dynamics of ASMBC.The simulated performance is in close agreement with the experimental data of chiral separation reported in the literature. The simulation results show that ASMBC can achieve the performance similar to SMBC with fewer columns and can achieve better performance than SMBC with the same total column number. All design and operation parameters can be chosen correctly by numerical simulation. This detailed ASMBC model and the numerical technique are useful for design, operation, optimization and scale-up of ASMBC.     

The selective hydrogenation of butyne-1,4-diol by supported palladiums: a comparative study on slurry, fixed bed, and monolith downflow bubble column reactors

The present study was carried out to asses performance of a Pd-monolith downflow bubble column (DBC) reactor, and compare it with that of the slurry and the fixed bed DBC. The selective hydrogenation of butyne-1,4-diol to cis-2-butene-1,4-diol over palladium catalyst was chosen as a model reaction. In principle, the monolith DBC allowed the reaction to take place under kinetic control regime. Comparison with DBC employing 5% Pd/C powder and 1% Pd-on-Raschig ring catalysts revealed a better performance of the monolith DBC (1% Pd loading) with advantage of smaller reaction volume and intensified reaction rate. In the monolith DBC, improved hydrogen transport was possible, as the interface between bubbles and the channel wall was very thin, thus, the length of the diffusion path was very short. In addition, the interfacial surface area at both gas–liquid and liquid–solid interface in the monolith was also very high. The reaction kinetics was well represented by the Langmuir–Hinshelwood mechanism. As an alternative to conventional three-phase reactors, the monolith DBC was simple due to its inherent characteristic operation and no specially designed device.     

Numerical Simulations of the Effect of Conical Dimension on the Hydrodynamic Behaviour in Spouted Beds

The flow behaviours of gas‐solids were predicted by means of a hydrodynamic model of dense gas‐solid flow in spouted beds. Constitutive equations describing the particulate solids pressure and viscosity were implemented into a hydrodynamic simulation computer program. The effect of operating conditions (inclined angle and gas spouting velocity) on particle velocity and concentration in the spout, annulus and fountain regions were numerical studied. Both vertical and horizontal particle velocities increased with increasing spouting gas velocity. The diameter of the spout increases with decreasing the inclination angle. As the inclination angle is set greater than 60°, the spout cross‐section starts becoming bottlenecked, limiting the upwards flow of solids.     

基于生态功能分区的平原河网生态校园景观水系水生态规划探讨

在"生态校园"概念的引导下,以生态优先为理念、生态学原理为指导、生态平衡为原则、生态构建为核心、水文化和水景观规划为补充,依据现场区域特点、水质状况等实际情况,结合水生态目标校核,设定不同生态功能分区,采取多种净化措施进行强化处理,以构建完整的生态校园景观水系水生态系统。文中以某学院智慧水利示范建设项目中的水生态系统构建为例,对生态校园景观水系规划进行简要探讨,以期为今后新建校园建设提供重要的参考。     

铁氧化物在流化床温度和CO气氛下的形态迁移及其对NO催化还原

利用小型固定床实验台实验研究了铁氧化物在典型流化床温度和CO还原性气氛下的形态迁移及其生成物对NO的催化还原作用,采用分级还原结合X射线衍射（XRD）表征分析,确定铁氧化物与CO和NO反应后生成物的价态及各种铁氧化物对NO的还原机制。结果表明,Fe₂O₃在实验条件下可依次被CO还原为Fe₃O₄、FeO和单质铁,反应过程中随着还原度的增加,还原速率逐级下降,从Fe₂O₃还原到Fe₃O₄的速率最高,FeO还原到Fe速率最低,在实验温度范围内,床温升高有利于提高Fe₂O₃到Fe₃O₄的还原速率和还原度。不同形态的铁氧化物对NO的催化还原特性不同,Fe₂O₃及其部分还原后生成的Fe₃O₄都不能直接与NO反应,Fe₂O₃对CO催化还原NO的效果很弱,而Fe₃O₄对CO还原NO的反应却有很强的催化作用,而进一步还原生成FeO与单质铁还可直接与NO反应。