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Yu Minghao,Lv Bo,Qiu Zeyang,Wang Zhe 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.80 No.3
In this study, a two-dimensional model of a medium-power inductively coupled plasma (ICP) torch was established to investigate the effects of different geometric parameters on the plasma properties, such as the temperature, velocity and electromagnetic field by performing multi-physical field-coupling simulations. The effects of the coil position, number of coil turns, input power and inductive current frequency on the plasma properties were studied and discussed in detail for a medium-power ICP torch. The results show that the coil position can affect the plasma uniformity, i.e., with increasing distance between the coil and the middle quartz tube, the plasma uniformity increases. When the number of coil turns is small, the electromagnetic field intensity is strong. In addition, when the input power and the current frequency are enhanced, the plasma temperature and volume both increase. Due to the effect of E–H mode conversion hysteresis, as the input power is increased, the temperature changes little, but the electromagnetic field intensity and the plasma velocity increase significantly.
Bowen Tian,Zeyang Yu,Liyang Xie,Yu Zhang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.2
In this paper, the stochastic dynamic analysis of a dual-rotor system with a local defect on the inner raceway of the inter-shaft bearing is presented. The dynamic model of the dual-rotor system is also proposed. The defect size and its uncertainty are considered. The non-intrusive polynomial chaos expansion model is utilized to deal with the uncertainty of the defect size, and the validity of the model is verified. The probability density distribution of vibration displacements for the dual-rotor system is obtained. Results indicate that the mean value (MV) and standard deviation (SD) of the defect edge length have extremely significant effects on the displacement distribution of high-pressure rotor. The coefficients of variation of the displacements along x 2 and φ x directions for high-pressure rotor increase by 6.56 and 7.06 times, respectively. When the MV of the defect edge length increases by three times, 3.46 times, and 3.69 times, its SD increases by five times. The increase of eccentricity has opposite effects on the vibration displacements of high- and low-pressure rotors. The variation of the radial clearance of the inter-shaft bearing has a complex influence on the dual-rotor system. As the radial clearance increases, the displacement dispersion of the low-pressure rotor along θ x direction is almost unchanged. However, that along x 1 direction is increased.