International Journal of Rotating Machinery最新文献

{"title":"Research on Meshing Stiffness and Vibration Response of Pitting Fault Gears with Different Degrees","authors":"Jie Liu, Chengye Wang, Wenchao Wu","doi":"10.1155/2020/4176430","DOIUrl":"https://doi.org/10.1155/2020/4176430","url":null,"abstract":"In order to study the influence of pitting on meshing stiffness, the normal distribution function is used to simulate the pitting location of pitting gear, and the potential energy method is used to analyze the influence of pitting on meshing stiffness. At the same time, the meshing stiffness of pitting gears with different degrees is analyzed by finite element method, and the validity of the calculation results with potential energy method is verified. On the basis of meshing stiffness, the dynamic model of gear system is established, and the vibration response of pitting gear system with different degrees is analyzed. The results show that with the increase of pitting area, the meshing stiffness decreases; the closer the meshing area of the driving wheel is to the pitting line, the more the meshing stiffness decreases, resulting in the intensification of vibration response and periodic impact; and in the time history diagram, there is a small spurious frequencies near the meshing frequency; in the phase diagrams and the Poincare diagram, trajectory and discrete point aggregation area is gradually increased.","PeriodicalId":46335,"journal":{"name":"International Journal of Rotating Machinery","volume":"20 1","pages":"1-7"},"PeriodicalIF":0.9,"publicationDate":"2020-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2020/4176430","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64751031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of Axis Orbit Image Optimization in Fault Diagnosis for Rotor System","authors":"Xinyu Pang, Jie Shao, Xuanyi Xue, W. Jiang","doi":"10.1155/2020/9540791","DOIUrl":"https://doi.org/10.1155/2020/9540791","url":null,"abstract":"The shape characteristic of the axis orbit plays an important role in the fault diagnosis of rotating machinery. However, the original signal is typically messy, and this affects the identification accuracy and identification speed. In order to improve the identification effect, an effective fault identification method for a rotor system based on the axis orbit is proposed. The method is a combination of ensemble empirical mode decomposition (EEMD), morphological image processing, Hu invariant moment feature vector, and back propagation (BP) neural network. Experiments of four fault forms are performed in single-span rotor and double-span rotor test rigs. Vibration displacement signals in the and directions of the rotor are processed via EEMD filtering to eliminate the high-frequency noise. The mathematical morphology is used to optimize the axis orbit including the dilation and skeleton operation. After image processing, Hu invariant moments of the skeleton axis orbits are calculated as the feature vector. Finally, the BP neural network is trained to identify the faults of the rotor system. The experimental results indicate that the time of identification of the tested axis orbits via morphological processing corresponds to 13.05 s, and the identification accuracy rate ranges to 95%. Both exceed that without mathematical morphology. The proposed method is reliable and effective for the identification of the axis orbit and aids in online monitoring and automatic identification of rotor system faults.","PeriodicalId":46335,"journal":{"name":"International Journal of Rotating Machinery","volume":"2020 1","pages":"1-13"},"PeriodicalIF":0.9,"publicationDate":"2020-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2020/9540791","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64754881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on Thermal Unstable Vibration of Rotor under Journal Whirl with Large Amplitude in Journal Bearing","authors":"Qilong Hu, Minjie Zhu, Jiangang Yang","doi":"10.1155/2020/1980759","DOIUrl":"https://doi.org/10.1155/2020/1980759","url":null,"abstract":"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.","PeriodicalId":46335,"journal":{"name":"International Journal of Rotating Machinery","volume":"2020 1","pages":"1-12"},"PeriodicalIF":0.9,"publicationDate":"2020-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2020/1980759","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42471808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combined Influence of Noncondensable Gas Mass Fraction and Mathematical Model on Cavitation Performance of Bearing","authors":"Li-li Wang, Zengkai Liu, Guo-teng Yuan, Yu-liang Wei","doi":"10.1155/2020/8409231","DOIUrl":"https://doi.org/10.1155/2020/8409231","url":null,"abstract":"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.","PeriodicalId":46335,"journal":{"name":"International Journal of Rotating Machinery","volume":"2020 1","pages":"1-7"},"PeriodicalIF":0.9,"publicationDate":"2020-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2020/8409231","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45114609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Introductory Chapter: Rotating Machinery","authors":"G. Hailu","doi":"10.5772/intechopen.89276","DOIUrl":"https://doi.org/10.5772/intechopen.89276","url":null,"abstract":"Rotating machinery or turbomachinery is a machine with a rotating component that transfers energy to a fluid or vice versa. Consequently, in a turbomachine there is energy transfer between the fluid and the rotor through dynamic interaction. Generally, if the energy transfer is from the rotor to the fluid, it is either a pump or fan. If the energy transfer is from the fluid to the rotor, then the machine is called turbine. We come across a turbomachine in everyday life. In fact, we come to use a turbomachine at least once in a day. When we dry our hair with a hair dryer, we are using a turbomachine. A hair dryer blows room temperature air over nichrome (alloy of nickel, chromium, and often iron) hot coils speeding up water evaporation. The important component of the hair dryer is the one that blows air (aka fan). This component is a turbomachine. Another commonly used household machine is the clothes washer. The washing machines need to drain the used dirty water and replace it with fresh water. To do so an important component of a washing machine is a pump that is used to remove the dirty water and supply fresh water. This pump is a turbomachine. If you own a car, you know how important it is to maintain an optimum operating temperature of your car. A water pump (hydrodynamic pump) is essential to your car’s operation. The pump ensures that the coolant keeps circulating through the engine block, hoses, and radiator and maintains an optimum operating temperature. Another everyday example is a kitchen vent. Fans inside the kitchen vent that pull the fumes in and push them via ductwork to the outside or through filters (that remove odors) and vent them back into the room are turbomachines. Besides a washing machine, a dishwasher, or a kitchen vent, when we are writing on our laptop/desktop, when we turn on the bathroom vent, and when we turn on a desktop fan or a ceiling fan, we are using turbomachines. All these components, the little fan in our computer which helps maintain the temperature of our computer or the ceiling fan which provides the thermal comfort needed in summer times, have certain types of geometry and shapes. You have probably noticed the difference in shapes and the number of blades between a windmill and modern wind turbine. These shapes and numbers are a result of careful analysis of fluid flow or air flow through these machines.","PeriodicalId":46335,"journal":{"name":"International Journal of Rotating Machinery","volume":"493 ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2020-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72437888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advance Measurement Techniques in Turbomachines","authors":"Fangyuan Lou","doi":"10.5772/intechopen.85910","DOIUrl":"https://doi.org/10.5772/intechopen.85910","url":null,"abstract":"This chapter focuses on advanced measurement techniques that have been used in applications of turbomachines including temperature measurements, pressure measurements, velocity measurements, and strain/stress measurements. Though the measurement techniques are fundamentally the same as those used in other applications, the unique features associated with turbomachines place challenges in implementing these techniques. This chapter covers the fundamental working principles of individual measurement technique as well as the highlights of its application in turbomachines.","PeriodicalId":46335,"journal":{"name":"International Journal of Rotating Machinery","volume":"9 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2020-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74634558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CD4+ cell count stratification to guide tuberculosis preventive therapy for people living with HIV.","authors":"Lelia H Chaisson, Valeria Saraceni, Silvia Cohn, Dena Seabrook, Solange C Cavalcante, Richard E Chaisson, Jonathan E Golub, Betina Durovni","doi":"10.1097/QAD.0000000000002398","DOIUrl":"10.1097/QAD.0000000000002398","url":null,"abstract":"<p><strong>Objectives: </strong>In 2018, Brazilian guidelines changed to recommend tuberculosis (TB) preventive therapy for all people with HIV and a CD4 cell count 350 cells/μl or less, but only for those with a positive tuberculin skin test (TST) if CD4 cell count is than 350 cells/μl. We determined the potential effectiveness of CD4-based guidelines for TB testing and preventive therapy.</p><p><strong>Design: </strong>Secondary analysis of the stepped-wedge, cluster-randomized THRio trial for isoniazid preventive therapy (IPT).</p><p><strong>Methods: </strong>We analyzed data from 4114 newly registered patients with HIV in 29 clinics followed until TB diagnosis, death, or administrative censoring. We compared incidence rates of TB and TB/death between CD4, TST, IPT, and antiretroviral therapy categories.</p><p><strong>Results: </strong>Initial CD4 cell count was 350 cells/μl or less in 2138 (52%) and more than 350 cells/μl in 1976 (48%) patients. TST was performed for 2922 (71%), of whom 657 (16%) were TST-positive [278 (13%) CD4 ≤ 350 vs. 379 (19%) CD4 > 350]. A total of 619 (15%) received IPT and 2806 (68%) received antiretroviral therapy. For patients with CD4 cell count 350 cells/μl or less who did not receive IPT, the incidence rate of TB was 1.79/100 person-years (pys) and TB/death was 3.89/100 pys. For patients with CD4 cell count more than 350 who did not receive IPT, the incidence rates of TB and TB/death were 0.57/100 and 1.49/100 pys for TST-negatives, and 1.05/100 and 1.64/100 pys for TST-unknowns.</p><p><strong>Conclusion: </strong>TB incidence was high among all patients who did not receive IPT, including those with CD4 cell count more than 350 cells/μl and negative or unknown TST results. TB preventive therapy should be provided to all people living with HIV in medium burden settings, regardless of CD4 cell count and TST status.</p>","PeriodicalId":46335,"journal":{"name":"International Journal of Rotating Machinery","volume":"8 1","pages":"139-147"},"PeriodicalIF":3.4,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7112158/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86219127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Uncertainty Analysis Techniques Applied to Rotating Machines","authors":"F. A. Lara-Molina, A. Dourado, A. Cavalini, V. Steffen","doi":"10.5772/intechopen.83828","DOIUrl":"https://doi.org/10.5772/intechopen.83828","url":null,"abstract":"This chapter presents the modeling procedure, numerical application, and experimental validation of uncertain quantification techniques applied to flexible rotor systems. The uncertainty modeling is based both on the stochastic and fuzzy approaches. The stochastic approach creates a representative model for the flexible rotor system by using the stochastic finite element method. In this case, the uncertain parameters of the rotating machine are characterized by homogeneous Gaussian random fields expressed in a spectral form by using the Karhunen-Loève (KL) expansion. The fuzzy approach uses the fuzzy finite element method, which is based on the α -level optimization. A comparative study regarding the numerical and experimental results obtained from a flexible rotor test rig is analyzed for the stochastic and fuzzy approaches.","PeriodicalId":46335,"journal":{"name":"International Journal of Rotating Machinery","volume":"25 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2019-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79682664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Methodology for Abrasive Wear Evaluation in Elevator Stage Centrifugal Pump Impellers","authors":"R. O. P. Serrano, J. G. Moreira, A. L. P. D. Castro, M. A. Pinto, Edna M. de F. Viana, C. B. Martinez","doi":"10.5772/intechopen.83794","DOIUrl":"https://doi.org/10.5772/intechopen.83794","url":null,"abstract":"The abrasion resistance of the impellers depends on the characteristics of the materials used in their manufacture. In this work, a methodology is proposed for the evaluation of the abrasive wear of the plates of the centrifugal pump impellers, used in the gross water infrastructure station (GWIS) of sedimentary rivers, due to the sediment load variation and the river fluviometric dimension. In order to determine the wear mode and the relationship of the material-specific wear coefficient (K), due to the sediment concentration, a rotating ball abrasometer test was performed on SAE 8620, gray cast iron (GCI), and nodular cast iron (NCI), used in the manufacture of impellers. As an abrasive suspension, the concentrations of 1, 2, 3, 5, and 10 g L (cid:1) 1 of sediment were used in distilled water. The wear volume as a function of the relative velocity of the mixture in relation to the impeller blades was estimated mathematically. The results show that: i) The abrasive capacity of the sediments in different concentrations; ii) SAE 8620 steel was more resistant to abrasive wear; and iii) the rotational control of the pump as a function of sediment concentration and river level showed the possibility of reducing wear by 30%.","PeriodicalId":46335,"journal":{"name":"International Journal of Rotating Machinery","volume":"5 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2019-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75653463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and Production of Innovative Turbomachinery Components via Topology Optimization and Additive Manufacturing","authors":"E. Meli, A. Rindi, A. Ridolfi, R. Furferi, F. Buonamici, G. Iurisci, S. Corbò, F. Cangioli","doi":"10.1155/2019/9546831","DOIUrl":"https://doi.org/10.1155/2019/9546831","url":null,"abstract":"The present paper proposes a methodology to design and manufacture optimized turbomachinery components by leveraging the potential of Topology Optimization (TO) and Additive Manufacturing (AM). The method envisages the use of TO to define the best configuration of the rotoric components in terms of both static and dynamic behavior with a resultant reduction of overall weight. Eventually, the topology-optimized component is manufactured by using appropriate materials that can guarantee valid mechanical performances. The proposed strategy has been applied to a 2D impeller used for centrifugal compressors to prove the effectiveness of a TO+AM-based approach. Although this approach has never been extensively used before to centrifugal compressors and expanders, its application on rotor and stator components might unlock several benefits: tuning the natural frequencies, a reduction in the stress level, and a lighter weight of the rotating part. These objectives can be reached alone or in combination, performing a single analysis or a multiple analyses optimization. Finally, the introduction of AM technologies as standard manufacturing resources could bring sensible benefits with respect to the time to production and availability of components. Such aspects are essential in the Oil and Gas context, when dealing with new projects but also for service operations.","PeriodicalId":46335,"journal":{"name":"International Journal of Rotating Machinery","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2019-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2019/9546831","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44228332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}