Stability analysis of rigid rotors supported by gas foil bearings coupled with electromagnetic actuators

Basumatary, Kamal Kumar; Kumar, Gaurav; Kalita, Karuna; Kakoty, Sashindra Kumar

doi:10.1177/0954406219877903

Cited by 10 publications

(4 citation statements)

References 17 publications

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“…Jeong and Lee [31] used a control algorithm to reduce the sudden imbalance vibration amplitudes of a rigid rotor which was operated at up to 12,000rpm. Basumatary et al [32] presented a dynamic model that coupled dynamics of gas foil bearings and electromagnetic actuator to discusses the effect of electromagnetics actuators on the stability of a rotor supported on gas foil bearings. However, HFMBs design remains largely empirical, in spite of a small amount of successful applications.…”

Section: Introductionmentioning

confidence: 99%

“…It was experimentally verified that using the HFMB made sudden imbalance vibration control possible during rotor operation with an air foil bearing. Basumatary et al 39 presented a dynamic model that coupled dynamics of GFBs and electromagnetic actuator to discuss the effect of electromagnetic actuators on the stability of a rotor supported on GFBs. The sub-synchronous vibration present in case of GFBs is reduced and the stability band of the rotor is increased due to the implementation of electromagnetic actuator.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical investigation of hybrid foil-magnetic bearings on operation mode and load sharing strategy

Zhang

Yin

Guan

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part J:

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This paper presents a theoretical investigation on operation mode and load sharing strategy of hybrid foil-magnetic bearings (HFMBs). According to the inherent characteristics of gas foil bearings (GFBs) and active magnetic bearings (AMBs), six possible work scopes are discussed to understand the operation mode of HFMBs. A numerical model coupling the calculations of the film pressure in GFBs and the magnetic forces in AMBs is conducted to predict the operation performance of HFMBs. The accuracy of the model is proved by comparing the predicted and tested friction torques. Analysis on the static and dynamic performance of HFMBs within three representative cases is conducted by varying the load sharing ratio. The dynamic supporting stiffness and operation position of HFMBs can be obviously enhanced by adjusting the operating mode and load sharing strategy. Results show that the direct stiffness and dynamic damping of HFMBs adopting hybrid mode are significantly higher than those adopting AMB or GFB independent mode.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Theoretical investigation of hybrid foil-magnetic bearings on operation mode and load sharing strategy

Zhang

Yin

Guan

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…Experimental and numerical investigations have been carried out on several different configurations to study the dynamic performance of gas film, such as gas foil bearings (Basumatary et al, 2020;Zhang et al, 2018;Zywica et al, 2021), self-acting gas journal bearings (Feng et al, 2017;Zhang et al, 2014), and other externally pressurized gas bearing (Moore et al, 2011;Han et al, 2014;Ise et al, 2014). Although the pressure distribution of the gas film obtained numerically with standard Reynolds equation is approximately to determine the stiffness and damping, the thermally coupled analysis of the bearing may be impeded.…”

Section: Introductionmentioning

confidence: 99%

Thermal Management and Dynamic Performance of a Cooler Design for the Supercritical CO2 Turbine Shaft Cooling

Gurgenci

Guan

et al. 2022

Front. Energy Res.

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This paper presents the results of a numerical study on a supercritical CO2 (SCO2) turboshaft cooling device by considering heat transfer and hydrodynamics. A micro-cooling device with a radius clearance of 50 micron and a nozzle diameter of 4 mm was designed and used to investigate the heat transfer characteristics of a micro-spacing impinging and gas film dynamics. Sixteen nozzles (N = 16) are equally spaced around the shaft in single or double rows. Investigations include journal speed- and eccentricity-dependent forward and cross-coupled force coefficients, and the effects of nozzle layouts and mass flow rate on the heat transfer efficiency. Analysis of the correlation coefficient shows that the gas density in the radial clearance is the dominant factor affecting the convective heat transfer performance, while the fluid velocity is a secondary factor. And the cooling efficiency (mass flow utilization rate) at low cooling pressure (ps < 0.7 MPa) is significantly greater than that at high cooling pressure (ps > 0.7 MP). In addition, considering the structure alone, a dual-row cooler exhibits a higher average Nusselt number, also registers a higher mass flow rate at the same pressure. Once the shaft is heated only one end, the difference in effectiveness between single- and dual-row cooling is not significant, so coolers with a single-row configuration should be preferred. Then, experimental values for the temperature of the heated rotor are provided under specific cooling airflow conditions. Dynamic analysis results show that the force coefficient of the single-row configuration is more dependent on the journal rotation speed and eccentricity ratio, and exhibits a negative direct stiffness coefficient at higher inlet pressure and journal rotation speed. Moreover, cross-coupled terms (stiffness coefficient) generally have a more explicit variation tendency than direct terms, and are more sensitive to changes in shaft speed and eccentricity. Small clearance cooling is a relatively complex technology aimed to improve heat dissipation efficiency in gas cooling devices while minimizing the effect of hydrodynamic pressure. Comparing the gas force coefficients of different journal speeds reveals a drastic increase in the effect of hydrodynamic pressure when the journal is eccentric. The cooler may be considered for operation with compliant support (such as bump foil) to generate additional damping and appropriately compensate for the eccentricity of the rotor.

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Section: Introductionmentioning

confidence: 99%

A Theoretical Investigation of Hybrid Foil-Magnetic Bearings on Operation Mode and Load Sharing Strategy

Feng¹,

Zhang²,

Yin³

et al. 2020

Preprint

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To guide the conceptual design of hybrid foil-magnetic bearings (HFMBs), this paper presents a theoretical investigation on operation mode and load sharing strategy. According to the inherent characteristics of GFBs and AMBs, seven possible work scopes are discussed to understand the operation mode of HFMBs. A numerical model coupling the calculations of the film pressure in GFBs and the magnetic forces in AMBs is conducted to predict the performance of HFMBs. The deflection of top foil and bumps is also included in the prediction model. The analysis, which is conducted for static and dynamic performance of HFMBs within three representative work scopes by varying the load sharing, uncovers the effects of the operation mode and load sharing strategy on bearing behavior. Results show that HFMBs performance including the supporting stiffness and stability can be obviously enhanced by adjusting the operating mode and load sharing strategy.

show abstract

Stability analysis of rigid rotors supported by gas foil bearings coupled with electromagnetic actuators

Cited by 10 publications

References 17 publications

Theoretical investigation of hybrid foil-magnetic bearings on operation mode and load sharing strategy

Theoretical investigation of hybrid foil-magnetic bearings on operation mode and load sharing strategy

Thermal Management and Dynamic Performance of a Cooler Design for the Supercritical CO2 Turbine Shaft Cooling

A Theoretical Investigation of Hybrid Foil-Magnetic Bearings on Operation Mode and Load Sharing Strategy

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