Dynamics analysis of the pitch control reducer for MW wind turbine

An analytic dynamics model was presented for the three-stage planetary transmission in the pitch control reducer for MW wind turbine based on the lumped-parameter method. The mechanical characteristic of the contact components was analyzed using the stiffness factor method. All the stiffness sub-matrices were combined to form the overall stiffness matrix of the three-stage transmission. According to the analytic model and the parameters of the pitch control gearbox, the movement differential equations were solved to investigate the natural frequencies and the vibration modes. Then, the undamped and damping forced vibration response were studied. A test rig was set up to measure the vibration displacement of the ring at the second stage and the output shaft under the nominal load condition, the comparison of the analytic forced vibration response with the experimental results validates the effectiveness of the lumped-parameter dynamics model for the pitch control reducer. This paper provides a reference for the dynamics optimization of multistage planetary transmission

A Nonaqueous Approach to the Preparation of Iron Phosphide Nanowires

Previous preparation of iron phosphide nanowires usually employed toxic and unstable iron carbonyl compounds as precursor. In this study, we demonstrate that iron phosphide nanowires can be synthesized via a facile nonaqueous chemical route that utilizes a commonly available iron precursor, iron (III) acetylacetonate. In the synthesis, trioctylphosphine (TOP) and trioctylphosphine oxide (TOPO) have been used as surfactants, and oleylamine has been used as solvent. The crystalline structure and morphology of the as-synthesized products were characterized by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The obtained iron phosphide nanowires have a typical width of ~16 nm and a length of several hundred nanometers. Structural and compositional characterization reveals a hexagonal Fe2P crystalline phase. The morphology of as-synthesized products is greatly influenced by the ratio of TOP/TOPO. The presence of TOPO has been found to be essential for the growth of high-quality iron phosphide nanowires. Magnetic measurements reveal ferromagnetic characteristics, and hysteresis behaviors below the blocking temperature have been observed

FEM-DEM coupling simulations of the tool wear characteristics in prestressed machining superalloy

Due to the complicated contact loading at the tool-chip interface, ceramic tool wear in prestressed machining superalloy is rare difficult to evaluate only by experimental approaches. This study aims to develop a methodology to predict the tool wear evolution by using combined FEM and DEM numerical simulations. Firstly, a finite element model for prestressed cutting is established, subsequently a discrete element model to describe the tool-chip behaviour is established based on the obtained boundary conditions by FEM simulations, finally, simulated results are experimentally validated. The predicted tool wear results show nice agreement with experiments, the simulation indicates that, within a certain range, higher cutting speed effectively results in slighter wear of Sialon ceramic tools, and deeper depth of cut leads to more serious tool wear

A Comparative Study of Standard Carbon Capture Process and Advanced Flash Stripper Configuration Using MEA

The advanced flash stripper (AFS) is proven to have benefits in capital investment and energy saving for carbon capture plants using piperazine, whilst monoethanolamine is still the most used amine in the existing commercial carbon capture plants. The production and use of energy and material consumed during CO2 absorption and regeneration generate CO2. In this research, the 130-tonne daily CO2 capture plants with conventional configuration and AFS configuration are simulated in Aspen Plus. Their total annualized costs are estimated to be 3.33 million USD and 2.87 million USD, respectively. The life cycle assessment is conducted to evaluate the environmental impacts from the cradle and grave of energy and materials consumed during carbon capture, showing 58% equivalent CO2 in flue gas is generated

(3,5-Dimethyl-1H-pyrrol-2-yl)(phenyl)methanone

In the title molecule, C13H13NO, the dihedral angle between phenyl and pyrrole rings is 57.2 (1)°. In the crystal, N—H...O hydrogen bonds link the molecules, forming chains propagating along the b axis

A direct approach of design optimization for small horizontal axis wind turbine blades

The performance of a wind turbine rotor depends on the wind characteristics of the site and the aerodynamic shape of the blades. The blade geometry determines the torque and the power generated by the rotor. From aerodynamic point of view, an economic and efficient blade design is attained by the maximization of rotor power coefficient. For small wind turbine blade design, there are some factors different from large blade. Such as, the small ones experience much lower Reynolds number flow than the large ones, thus large wind turbine airfoils may perform very poorly in small applications. The small turbines are self-started at lower wind speed, thus the hub and tip parts are vital for the starting-up torque which should be able to conquer the resistance of the generator and the mechanical system. This paper presents a direct method for small wind turbine blade design and optimization. A unique aerodynamic mathematical model was developed to obtain the optimal blade chord and twist angle distributions along the blade span. The airfoil profile analysis was integrated in this approach. The Reynolds number effects, tip and hub effects, and drag effects were all considered in the design optimization. The optimal chords and twist angles were provided with series of splines and points and three-dimensional blade models. This approach integrates blade design and airfoil analysis process, and enables seamless link with computational fluid dynamics analysis and CNC manufacturing

FEM-DEM coupling simulations of the tool wear characteristics in prestressed machining superalloy

Due to the complicated contact loading at the tool-chip interface, ceramic tool wear in prestressed machining superalloy is rare difficult to evaluate only by experimental approaches. This study aims to develop a methodology to predict the tool wear evolution by using combined FEM and DEM numerical simulations. Firstly, a finite element model for prestressed cutting is established, subsequently a discrete element model to describe the tool-chip behaviour is established based on the obtained boundary conditions by FEM simulations, finally, simulated results are experimentally validated. The predicted tool wear results show nice agreement with experiments, the simulation indicates that, within a certain range, higher cutting speed effectively results in slighter wear of Sialon ceramic tools, and deeper depth of cut leads to more serious tool wear

INFLUENCE FACTORS OF CONTACT PRESSURE BETWEEN SHRINK-FIT TOOL HOLDER AND SHANK

To improve the contact state of shrink-fit tool holder and shank,the factors affecting the contact pressure distribution in matching surface are discussed. The shrink-fit tool holder and shank parametric model is established by ANSYS parametric design language commend stream. The pressure distribution on the matching surface is revealed by pressure sensitive films. Compared with the finite element analysis,the reliability of parametric model is verified. The contact pressure is calculated by getting the stress distribution of the matching surface on the holder. Calculations indicated that the average pressure,max pressure and uniformity on matching surface will decrease with the increase of holder thickness,inner diameter,length and angle of matching,but the trend and range of the pressure distribution are the same; increased the thickness of the shank and selecting the thickness of the shrink-fit tool holder properly is helpful to reduce the stress concentration