Theoretical and experimental studies on the hydrodynamic damping of elastic rotating propeller blades

Chen Hongyang,Tong Xiandong,Chen Yong,He Jingyi 대한조선학회 2022 International Journal of Naval Architecture and Oc Vol.14 No.1

The hydrodynamic damping characteristics of elastic rotating propeller blades are investigated theoretically and experimentally. Firstly, the modal hydrodynamic damping ratio of propeller blade rotating in water is theoretically predicted based on the cantilever plate theory. Then, a series of tests are designed to determine the mechanical, acoustic radiation and hydrodynamic damping of the first-order bending mode of the rotating blade. During the hydrodynamic damping test, the bending vibration of the blade is excited by the rotation-induced turbulence and measured by two strain gauges attached to the blade root. The results show that the theoretical prediction is in good agreement with the experimental results. The hydrodynamic damping increases linearly with the rotational speed of the propeller. Theoretical analysis also shows that the modal hydrodynamic damping ratio of the first-order bending mode is much larger than that of higher-order bending modes. The hydrodynamic damping decays exponentially with the increase of frequency ratio while increases slightly with the increase of propeller advance ratio which represents the ratio of free stream fluid speed to the propeller tip speed.

A Novel Double Layer Cantilevers Harvester for Vibration Energy

Chen Xiaojie,Qiu Chengjun,Qu Wei,Liu Yibo,Xia Hongyang 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.8

This paper reported a double layer cantilever harvester powered for vibration energy. A space layer between the PZT beam and the support silicon beam is existed, leading to the double layer cantilever structure. Such structure can allow the more strain generated by the piezoelectric layer due to the existing of space layer, and the output voltage is further increased. The formula of output voltage is then derived from the piezoelectric effect equation and vibration model. And the formula verifies the relationship of voltage and structure parameter. And the simulation in micrometer lever is used to discuss the relationship. Finally, the prototype is assembled and measured to verify the feature of the device. Experimentally, the 3.8V output voltage and 16.9uW output power is acquired.

Analysis on Temperature Distribution and Current-Carrying Capacity of GIL Filled with Fluoronitriles-CO₂ Gas Mixture

Chen, Geng,Tu, Youping,Wang, Cong,Cheng, Yi,Jiang, Han,Zhou, Hongyang,Jin, Hua The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.6

Fluoronitriles-$CO_2$ gas mixtures are promising alternatives to $SF_6$ in environmentally-friendly gas-insulated transmission lines (GILs). Insulating gas heat transfer characteristics are of major significance for the current-carrying capacity design and operational state monitoring of GILs. In this paper, a three-dimensional calculation model was established for a GIL using the thermal-fluid coupled finite element method. The calculated results showed close agreement with experimentally measured data. The temperature distribution of a GIL filled with the Fluoronitriles-$CO_2$ mixture was obtained and compared with those of GILs filled with $CO_2$ and $SF_6$. Furthermore, the effects of the mixture ratio of the component gases and the gas pressure on the temperature rise and current-carrying capacity of the GIL were analyzed. Results indicated that the heat transfer performance of the Fluoronitriles-$CO_2$ gas mixture was better than that of $CO_2$ but worse than that of $SF_6$. When compared with $SF_6$, use of the Fluoronitriles-$CO_2$ gas mixture caused a reduction in the GIL's current-carrying capacity. In addition, increasing the Fluoronitriles gas component ratio or increasing the pressure of the insulating gas mixture could improve the heat dissipation and current-carrying capacity of the GIL. These research results can be used to design environmentally-friendly GILs containing Fluoronitriles-$CO_2$ gas mixtures.

Motion Control of Autonomous Vehicles with Guaranteed Prescribed Performance

Hongyang Xia,Jiqing Chen,Fengchong Lan,Zhaolin Liu 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.6

In this paper, a novel motion control scheme with guaranteed prescribed performance is proposed for autonomous vehicles with consideration of couplings between lateral and longitudinal motions. Firstly, a prescribed performance transformation function is constructed to equivalently release the output error constraints. Then, a coordinated controller is designed to complete lateral and longitudinal motion control tasks simultaneously based on sliding-mode control. The designed coordinated controller can guarantee predefined trajectory tracking performance (e.g., minimum speed of convergence, maximum steady state error and overshoot), in presence of strongcoupled characteristics, model uncertainties and external disturbance. Finally, simulation results under different boundary constraints further validate the feasibility and good robustness of the controller.

Analysis on Temperature Distribution and Current-Carrying Capacity of GIL Filled with Fluoronitriles-CO₂ Gas Mixture

Geng Chen,Youping Tu,Cong Wang,Yi Cheng,Han Jiang,Hongyang Zhou,Hua Jin 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.6

Fluoronitriles-CO₂ gas mixtures are promising alternatives to SF6 in environmentallyfriendly gas-insulated transmission lines (GILs). Insulating gas heat transfer characteristics are of major significance for the current-carrying capacity design and operational state monitoring of GILs. In this paper, a three-dimensional calculation model was established for a GIL using the thermal-fluid coupled finite element method. The calculated results showed close agreement with experimentally measured data. The temperature distribution of a GIL filled with the Fluoronitriles-CO₂ mixture was obtained and compared with those of GILs filled with CO₂ and SF6. Furthermore, the effects of the mixture ratio of the component gases and the gas pressure on the temperature rise and current-carrying capacity of the GIL were analyzed. Results indicated that the heat transfer performance of the Fluoronitriles-CO₂ gas mixture was better than that of CO₂ but worse than that of SF₆. When compared with SF6, use of the Fluoronitriles-CO₂ gas mixture caused a reduction in the GIL’s current-carrying capacity. In addition, increasing the Fluoronitriles gas component ratio or increasing the pressure of the insulating gas mixture could improve the heat dissipation and current-carrying capacity of the GIL. These research results can be used to design environmentally-friendly GILs containing Fluoronitriles-CO₂ gas mixtures.

Design and torque calculation of permanent magnet eddy current coupling with sinusoidal torque output

Ke Chen,Hongyang Shi,Yajun Guo,Lei Yin,Ziwei Bao,Hongmei Zheng 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.4

Due to its unique characteristic of non-contact torque transmission between its permanent magnetic rotor and conductorrotor, permanent magnet eddy current coupling (PMECC) is preferable in transmitting torque from the outside to the insideof a sealed container, which can effectively avoid the tricky problem of dynamic seals. To mix non-uniform liquid solutionsor gas mixtures in sealed containers more effectively, a sinusoidal torque is also required. Thus, permanent magnet eddy current coupling with a slotted conductor is proposed in this paper, which can adaptively output sinusoidal torque under a real-time load when the input rotational speed is constant. Based on the equivalent magnetic circuit method, an analytical model for calculating torque is proposed. When establishing the equivalent magnetic circuit model of the PMECC, the radial magnetic flux leakage circuit is added to the equivalent magnetic circuit diagram, and the cross-sectional shape of the eddy current region is equivalent to an octagon, which simplifies the torque calculation process. The analytical model is verified by finite element method (FEM) simulation and experiments. According to a comparison, the peak and lowest values of output torque obtained by the experiments, the analytical model, and the FEM simulation are consistent. The output torque waveform obtained by the analytical model and FEM simulation are also consistent.

Quantitative characterization and magnetic separation of copper pyrometallurgical tailing for molybdenum and copper pre-concentration and cleaning of environmentally hazardous elements

Huihui Zhou,Guijian Liu,Chuncai Zhou,Yu Chen,Muhammad Arif,Mei Sun,Yuan Liu,Hongyang Wang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.122 No.-

The comprehensive and harmless utilization of copper slag flotation tailing (CSFT) is the key to a wastefreeand sustainable copper industry. Here, the mineralogy and molybdenum micro-dissemination inCSFT were quantified and characterized, and the feasibility of the comprehensive recovery of Mo, Cuand Fe resources from CSFT and hazardous elements fractionation behavior by magnetic separationwas discussed. To investigate the occurrence and abundance of Mo in each phase, CSFT was classified intofour types of phases, including magnetite/hematite (27.26%), silicate associations (43.37%), and metallicsulphides and oxides. Molybdenum distribution is closely related to magnetite/hematite-Fe and S. Themagnetic separation results indicated that Mo and Cu were enhanced in magnetic products by 34–41and 15–21%, respectively. Cleaner non-magnetic residues were found to decrease significantly by 37–44, 58–60, and 11–19% for Cu, As, and Cr, respectively. Mineral fractionation was observed instead ofchemical changes during magnetic separation. Despite a weak separation effect on magnetic and nonmagneticphases due to their close bonds and fine-disseminated minerals, the Fe-silicate associationswithout magnetic phases were well separated into non-magnetic residues. The enrichment of Ca, Mgand separation of an iron-silicate component in non-magnetic residues enhanced the cementitious propertyand allowed the development of more pathways of reutilization.