International Journal of Rotating Machinery

Literature research has shown that the high turbulent viscosity of original Reynolds‐averaged Navier–Stokes (RANS) models in the wake reduces the cavitation instability, resulting in an unreasonable performance prediction of the cavity generation, shedding, and collapse. Hence, a density‐corrected model (DCM) is utilized to improve the prediction capacity of the RNG k – ε model in the two‐phase flow simulation. Selected results are provided for two cases, namely, a two‐dimensional Clark‐Y hydrofoil and a Venturi geometry associated with the unsteady cavitating flows. We compare hydrodynamic coefficients, cavity characteristics, and time‐averaged velocity with available experimental results. This work is aimed at providing a better physical insight to describe the vortex dynamics and structures during the cavity evolution, explaining the mechanism of the transient cavitating flows by quantifying the force coefficients of the cavity and its surrounding turbulent structures, and revealing the promoting effect of the re‐entrant jet on the cavitation transition. In addition, vorticity transport equations are conducted to analyze the interaction of vortex and cavitation. The results demonstrate that the DCM has sufficient robustness to predict the periodic cavity evolution of generation, breakup, shedding, and collapse. An unsteady cavitation process contains the development of complex vortex structures. Re‐entrant jet near trailing of the attached cavity leads to distinct changes of velocity gradient, which has great influence on production and dissipation of vorticity. Intensive mass transfer between liquid and vapor phases may introduce the volume expansion or contraction as well as the baroclinic torque, which leads to unsteady distribution of vorticity.

Jing Li

Chunbao Liu

Cavitation Dynamics and Vorticity Analysis of a Clark‐Y Hydrofoil and a Venturi Geometry Based on the DCM

基于DCM的Clark‐Y水翼和文丘里几何结构的空化动力学与涡量分析

The rotary vector (RV) reducer, as a highly precise transmission mechanism, can lead to a series of consequential hazards when experiencing local faults. Conducting corresponding research on performance monitoring and fault diagnosis holds significant importance. In order to achieve higher diagnostic accuracy, better classification, prediction effect, and less use of sensors, this paper proposes a local fault diagnosis method of RV reducer based on Motor current signature analysis (MCSA). Firstly, the centre gear local fault electromechanical coupling model is created by combining the working principle of the servo motor, the working characteristics of the RV reducer, and the influencing factors of motor current. Then, according to the actual operating conditions of industrial robots (IRs), the corresponding experimental platform is designed and constructed, and current signals in four different modes are collected. Fast Fourier transform (FFT) is performed on the current signals to obtain frequency domain features, and the correctness of the local fault coupling model of the centre gear is experimentally verified. Finally, the time‐domain statistical features, time–frequency domain features, and CNN features of servo‐feedback current signals under different rotational speeds are extracted and used in the implementation of local fault diagnosis for the RV reducer, respectively. In this paper, it is confirmed that MCSA can be used for localized fault diagnosis of the RV reducer, and combined with a deep learning network, it can effectively predict the fault modes with an average accuracy of more than 96%.

Heng Li

Bing Zhao

Jingyang Li

Yueqi Qiao

Shen Zhang

Research on Local Fault Diagnosis of Rotary Vector Reducer Based on Motor Current Signature Analysis

基于电机电流特征分析的回转矢量减速器局部故障诊断研究

In industrial robot welding heat exchanger plate route planning, there are drawbacks to using the traditional ant colony algorithm (ACA), including poor search efficiency and a propensity to trend toward the local optimum. To address the above issues, first of all, the article introduces the improved pheromone volatilization factor, which is adjustable based on iteration times in the ACA. Secondly, it combines the new perturbation strategy and the cross‐mutation operation, proposes an improved genetic algorithm, and fuses it into the ACA, which increases the diversity of the ACA’s path searching and improves the ability of the local and global search. Finally, the improved ACA mechanism is verified by experiments and compared with six existing path planning algorithms (including three ACA variant algorithms and three mainstream algorithms). The experimental results show that the IACAG algorithm has excellent performance in welding heat exchanger path planning and can achieve lower calculation time and iteration times under the conditions of optimal solution and zero deviation, showing comprehensive advantages in solution quality, stability, and efficiency.

Xianlong Chu

Xinning Li

Hu Wu

Xianhai Yang

Liyong Yang

Path Optimization in Robotic Welding of Plate Heat Exchangers: An Improved Ant Colony Approach

板式换热器机器人焊接路径优化：一种改进的蚁群算法

The presence of cavitation in the oil film seriously affects the bearing lubrication performance and bearing capacity. Now the research of this phenomenon mostly focuses on the model of Reynolds equation (R-E equation) or Navier-Stokes equation (N-S), the influence of the two computation models is less analyzed, and the effect of noncondensable gas (NCG) mass fraction on the bearing performance is seldom studied. In the manuscript, the cavitation mechanism is studied using the mixed model of three-dimensional N-S equation and Jakobsson-Floberg-Olsson (JFO) condition of two dimensional Reynolds equation, and the influence of rotational speed and NCG mass fraction on the cavitationoil film pressure, and bearing capacity was studied. The results show that the change trend of cavitation with the rotational speed is basically consistent for N-S equation and R-E equation. The bearing capacity calculated by N-S equation is greater than that calculated by R-E equation. The peak pressure and bearing capacity of film can be improved by increasing the NCG mass fraction of lubricant and rotational speed.

Lili Wang

Zengkai Liu

Guoteng Yuan

Yuliang Wei

Combined Influence of Noncondensable Gas Mass Fraction and Mathematical Model on Cavitation Performance of Bearing

非冷凝气体质量分数与数学模型对轴承空化性能的联合影响

To investigate the thermal unstable vibration caused by journal whirls with large amplitude in journal bearing, an analysis model of lubricant film thickness is established. The journal surface temperature distribution is solved, and the reason for journal surface temperature difference appearance and its influence on rotor vibration are analyzed. Taking a turbogenerator as an example, the journal surface temperature difference and the induced rotor thermal bending under synchronous whirl in the bearing are calculated. Meanwhile, an engineering vibration fault with its treatment is presented. Results show that, the journal surface circumferential temperature difference is caused by viscous shearing within lubricant film under journal whirls with large amplitude in journal bearing. The direction of temperature difference is related to the direction of unbalanced force acting on journal. The temperature difference causes rotor thermal bending, which can be converted to a thermal unbalance on the rotor. The rotor vibration is caused by both thermal and initial unbalance. When the rotor is running below or at the critical speed, the vibration is on the increase until it leads to instability of the rotor eventually. When the rotor is running above the critical speed, the rotor vibration fluctuates periodically. Reducing the initial (mechanical) unbalances decreases the rotor vibration and the journal surface circumferential temperature difference.

Qilong Hu

Min Zhu

Jiangang Yang

Study on Thermal Unstable Vibration of Rotor under Journal Whirl with Large Amplitude in Journal Bearing

研究在滑动轴承中大振幅油膜涡动下转子热不稳定振动的研究

The flow capacity of the intake port has a great influence on the charging efficiency of the internal combustion engine, affecting the engine’s performance, so it is critical to improve the intake port flow capacity. In this paper, the intake port numerical model was established, and the influence of the inlet and outlet area ratio on intake port flow capacity was studied. The results show that, under the same condition of relative pressure difference, the intake port discharge coefficient increases sharply and then slowly with an increase in area ratio. Under the same condition of area ratio, the discharge coefficient is only determined by relative pressure difference and decreases with an increase of relative pressure difference when the inlet and outlet area <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1"><mtext>ratio</mtext><mo>&gt;</mo><mn>1</mn></math> . The optimal area ratio decreases and then converges with an increase in relative pressure difference. When the intake port is designed, the optimal area ratio under the working condition of a smaller relative pressure difference should be applied in order to ensure the discharge coefficient is optimal under all working conditions.

Jingmin Rui

Jiangjiang Li

Chenhong Feng

Zhongjie Shi

Dehai Li

Influence of Inlet and Outlet Area Ratio on Intake Port Flow Capacity

入口和出口面积比对进气道流量能力的影响

Gas transportation through the pipeline network requires high pressure; otherwise, movement will be impossible. Due to friction with the walls of the pipes, the gas loses both speed and pressure. Therefore, it is necessary to increase the pressure in the main pipeline, which can extend for thousands of kilometers. For this purpose, compressor stations are located along the main network, facilitating the gas transport process by raising it to the required pressure. Compressor stations mainly consume the transported gas, with approximately 5% expended on gas compression. This article presents a study on the fuel cost for compressor stations, using mathematical models to optimize the operation of gas compressor units. The objective is to minimize gas consumption as a fuel and provide an optimization method with control over blower revolutions and valve installations to ensure safe transportation. Mathematical modeling of the described process detected the technically unjustified fuel gas consumption during the operation of gas compressor units at a specific compressor station under consideration. The paper proposes a method for minimizing costs, which can serve as the basis for providing recommendations to engineers-dispatchers. Compressor stations of the type under study lack measuring instruments for mass flow; therefore, the methods such as PID controllers, MPC, or neural networks are not applicable here.

Dinara Zhussupova

Mukhtarbay Otelbaev

Saule Burgumbayeva

Modeling Gas Compressor Station Operation to Minimize Fuel Costs for Surge Zone Protection

模拟天然气压缩站运行以最小化喘振区保护的燃料成本

To give timely and accurate diagnosis in the early stage of demagnetization failure for effective control and treatment, based on wavelet packet analysis, principal component analysis (PCA) dimensionality reduction, and least squares support vector machine(LSSVM), the extraction of features and the classification of demagnetization faults are completed. Since it is difficult to collect real data sets of demagnetization faults in practice, a two-dimensional finite element simulation model of permanent magnet synchronous motor (PMSM) under uniform demagnetization and partial demagnetization faults is established based on the Maxwell simulation platform. The wavelet packet analysis is used to extract the demagnetization feature of the A-phase current of the PMSM. Based on PCA dimensionality reduction, the dimensionality reduction of fault features is realized. The LSSVM is used to identify the fault and complete the fault classification. The simulation results show that the method has a high classification accuracy rate for demagnetization faults.

Guo Ye

Yanbin Lu

Jinyong Ju

Lianchao Sheng

Research on Demagnetization Fault Diagnosis Method of Mine Cutting Permanent Magnet Synchronous Motor

矿用切割永磁同步电机退磁故障诊断方法研究

Abbreviation	Int. J. Rotating Mach.
Journal Impact	0.74
Quartiles(Global)	ENGINEERING, MECHANICAL(Q4)

ISSN	1023-621X, 1026-7115, 1542-3034
h-index	40

Publication Information	Publisher: Hindawi Publishing Corporation，Publishing cycle: ，Journal Type: journal，Open Access Journals: Yes
Basic data	Year of publication: 2006，Proportion of original research papers: 100.00%，Self Citation Rate:0.00%， Gold OA Rate: 100.00%
Journal Fees	$950Details
Average review cycle	网友分享经验：25 Weeks

International Journal of Rotating Machinery

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Cavitation Dynamics and Vorticity Analysis of a Clark‐Y Hydrofoil and a Venturi Geometry Based on the DCM

Research on Local Fault Diagnosis of Rotary Vector Reducer Based on Motor Current Signature Analysis

Path Optimization in Robotic Welding of Plate Heat Exchangers: An Improved Ant Colony Approach

Combined Influence of Noncondensable Gas Mass Fraction and Mathematical Model on Cavitation Performance of Bearing

Study on Thermal Unstable Vibration of Rotor under Journal Whirl with Large Amplitude in Journal Bearing

Influence of Inlet and Outlet Area Ratio on Intake Port Flow Capacity

Modeling Gas Compressor Station Operation to Minimize Fuel Costs for Surge Zone Protection

Research on Demagnetization Fault Diagnosis Method of Mine Cutting Permanent Magnet Synchronous Motor

Cavitation Dynamics and Vorticity Analysis of a Clark‐Y Hydrofoil and a Venturi Geometry Based on the DCM

Research on Local Fault Diagnosis of Rotary Vector Reducer Based on Motor Current Signature Analysis