Nikola Stosic^**, Ian K. Smith, Ahmed Kovacevic

Frontiers in Heat and Mass Transfer, Vol.3, No.2, pp. 1-7, 2012, DOI:10.5098/hmt.v3.2.3003

Abstract Due to fast rotation of screw compressor rotors, temperature is uniform in the rotor cross section and temperature field is a function of the axial coordinate only. Apart of that the rotors in one cross section the rotors are simultaneously heated by hot gas on one side while cooled at another side by cold gas. As a result of identification of the main modes of heat transfer both in the rotors and between the rotors and their surroundings and the relative significance of each, a novel procedure is suggested to cool the rotors by injection of minute quantities of a… More >

Cheng-Yeh Li, Jui-Hsiang Kao^*

CMES-Computer Modeling in Engineering & Sciences, Vol.138, No.3, pp. 2277-2304, 2024, DOI:10.32604/cmes.2023.030215

Abstract The performance of a water jet propulsion system is related to the inlet duct, rotor, stator, and nozzle. Generally, the flow inlet design must fit the bottom line of the hull, and the design of the inlet duct is often limited by stern space. The entire section, from the rotor to the nozzle through the stator, must be designed based on system integration in that the individual performance of these three components will influence each other. Particularly, the section from the rotor to the nozzle significantly impacts the performance of a water jet propulsion system. This study focused on nozzle… More >

Chunxiu Ji¹, Dan Xie^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.25, No.3, pp. 1-1, 2023, DOI:10.32604/icces.2023.010329

Abstract Blade flutter is a complex phenomenon that can lead to serious damage or failure of turbomachinery systems. Predicting and mitigating blade flutter is therefore an important aspect of the design and analysis of these systems[1]. In this paper, we present a comparative study of two representative methods for blade flutter predictions: the energy method and the computational fluid dynamics/computational structural dynamics (CFD/CSD) coupled time-domain method. The energy method is a decoupled approach that uses a simplified model of the blade and fluid-structure interaction to calculate the stability boundaries of the system[2]. The time-domain method, on the other hand, is a… More >

Zhaolin Chen^1,*, Xiaohui Wei¹, Tianhang Xiao¹, Ning Qin²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.25, No.2, pp. 1-1, 2023, DOI:10.32604/icces.2023.09976

Abstract A computational study has been conducted on various airfoils to simulate flows at low Reynolds numbers 17,000 and 21,000 with Mach number changes from 0.25 to 0.85 to provide understanding and guidance for Mars rotory wing designs. The computational fluid dynamics tool used in this study is a Reynolds-averaged Navier–Stokes solver with a transition model (k-ω SST γ-Reθ). The airfoils investigated in this study include NACA airfoils (4, 5, and 6% camber), UltraThin airfoils, and thin cambered plates (3% camber, but various maximum camber locations). Airfoils were examined for lift and drag performance as well as surface pressure and flow… More >

Gang Liu¹, Xinqi Chen^2,3,*, Lijuan Bao¹, Linbo Xu^2,3, Chaochao Dai¹, Lei Yang^2,3, Chengmin Wang⁴

Structural Durability & Health Monitoring, Vol.17, No.4, pp. 337-351, 2023, DOI:10.32604/sdhm.2022.023583

Abstract Aiming at the fact that the rotor winding inter-turn weak faults can hardly be detected due to the strong electromagnetic coupling effect in the excitation system, an interval observer based on current residual is designed. Firstly, the mechanism of the inter-turn short circuit of the rotor winding in the excitation system is modeled under the premise of stable working conditions, and electromagnetic decoupling and system simplification are carried out through Park Transform. An interval observer is designed based on the current residual in the two-phase coordinate system, and the sensitive and stable conditions of the observer is preset. The fault… More >

Youping Lin¹, Huangbin Lin^2,*, Dezhi Wei¹

Intelligent Automation & Soft Computing, Vol.37, No.2, pp. 1363-1379, 2023, DOI:10.32604/iasc.2023.038601

Abstract The digital twin (DT) includes real-time data analytics based on the actual product or manufacturing processing parameters. Data from digital twins can predict asset maintenance requirements ahead of time. This saves money by decreasing operating expenses and asset downtime, which improves company efficiency. In this paper, a digital twin in braiding machinery based on IoT (DTBM-IoT) used to diagnose faults. When an imbalance fault occurs, the system gathers experimental data. After that, the information is sent into a digital win model of the rotor system to see whether it can quantify and locate imbalance for defect detection. It is possible… More >

Shengyang Lu^1,2, Tong Wang², Yuanqing Liang¹, Shanshan Cheng¹, Yupeng Cai², Haixin Wang¹, Junyou Yang^1,*, Yuqiu Sui^1,3, Luyu Yang²

CMES-Computer Modeling in Engineering & Sciences, Vol.135, No.3, pp. 2373-2386, 2023, DOI:10.32604/cmes.2023.024461

Abstract With the increasing integration of new energy generation into the power system and the massive withdrawal of traditional fossil fuel generation, the power system is faced with a large number of stability problems. The phenomenon of low-frequency oscillation caused by lack of damping and moment of inertia is worth studying. In recent years, virtual synchronous generator (VSG) technique has been developed rapidly because it can provide considerable damping and moment of inertia. While improving the stability of the system, it also inevitably causes the problem of active power oscillation, especially the low mutual damping between the VSG and the power… More >

Quanchun Yan^1,2,*, Chao Yuan¹, Wen Gu¹, Yanan Liu¹, Yiming Tang¹

Energy Engineering, Vol.120, No.1, pp. 49-68, 2023, DOI:10.32604/ee.2022.018555

Abstract In order to solve the problems of rotor overvoltage, overcurrent and DC side voltage rise caused by grid voltage drops, a coordinated control strategy based on symmetrical and asymmetrical low voltage ride through of rotor side converter of the doubly-fed generator is proposed. When the power grid voltage drops symmetrically, the generator approximate equation under steady-state conditions is no longer applicable. Considering the dynamic process of stator current excitation, according to the change of stator flux and the depth of voltage drop, the system can dynamically provide reactive power support for parallel nodes and suppress the rise of DC side… More >

Yanliang Qiu^1,2, Bin Xiong^1,2, Zhe Hou^1,2,*, Lin Luo³

Energy Engineering, Vol.119, No.6, pp. 2243-2254, 2022, DOI:10.32604/ee.2022.021322

Abstract The shrink fit retaining ring is currently the easiest to install and the most widely used end fixed for structure AC excitation variable speed generator-motor rotor end windings. However, the current research on the effect of high strength sealing on the ventilation and heat dissipation performance of the end is not enough. In this paper, based on the actual structural parameters and periodic symmetry simplification, the three-dimensional coupled calculation model of fluid field and temperature field is established. After solving the fluid and thermal equations, the influence of the length of rotor support block, the height of rotor support block,… More >

M. Li^1,2,*, D.H. Li³, Y. Rae¹, W. Sun¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.24, No.1, pp. 1-2, 2022, DOI:10.32604/icces.2022.08759

Abstract In order to better understand the physical process of deformation and cyclic softening a 12% Cr martensitic stainless steel FV566 has been cyclically tested at high temperature in strain control. Increase in temperature was found to increase the cyclic life, softening rate and viscous stress magnitude. An increase in the dwell time led to the acceleration of the material degradation. The microstructure changes and dominating deformation mechanisms were investigated by means of scanning electron microscopy, electron backscatter diffraction and transmission electron microscopy. The results have revealed a gradual sub-grain coarsening, transformation of lath structure into fine equiaxed sub-grains, and misorientation… More >