Research on the piston precise electromagnetic centering of labyrinth-piston compressor

Cheng, Junming; Zhang, Meimei; Liu, Zhan; Feng, Qian; Zeng, Xiangjun

doi:10.1177/0957650916638195

Cited by 6 publications

(5 citation statements)

References 12 publications

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“…However, it is difficult for the piston to move along the axis of the cylinder under the changing gas force and the restriction guiding structure itself, and it is often in the eccentric operation state. 4 Based on this situation, an active electromagnetic control system is proposed to control the piston eccentricity to achieve accurate centering in the cylinder. The active electromagnetic control system mainly adopts the electromagnetic coil to apply electromagnetic attraction to the piston to achieve its stable levitation.…”

Section: Design Of the Active Electromagnetic Control Systemmentioning

confidence: 99%

Section: Design Of the Active Electromagnetic Control Systemmentioning

confidence: 99%

“…However, due to the influence of various factors such as changing gas force, reciprocating inertia force in the process of crankshaft rotation, piston rod bending, and vibration, it is difficult for the piston to keep good concentricity in cylinder. 4,5 And in most cases, the piston is in an eccentric state. Due to the piston eccentric movement in the cylinder, the labyrinth sealing clearance is constantly changing.…”

Section: Introductionmentioning

confidence: 99%

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Research on precise control of piston eccentricity by electromagnetic levitation in labyrinth piston compressor

Zhang

Pan

2023

Proceedings of the Institution of Mechanical Engineers, Part C:

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The piston in the Labyrinth piston compressor (LPC) usually runs eccentrically in the cylinder, which results in large internal leakage and low volumetric efficiency. An active electromagnetic control method based on the electromagnetic levitation theory was proposed in this paper to control the piston eccentricity, and a triple close-loop multi-factor coupled feedback control strategy composed of a current loop, a velocity loop, and a displacement loop was designed to realize the levitation control of the piston. The experimental research shows that there is serious piston eccentricity in the LPC, and the piston eccentricity is positively correlated with the increase of compressor pressure ratio and speed. By adopting the active electromagnetic control system proposed in this paper, the piston eccentricity is significantly reduced, and the maximum reduction is over 88%. Further research shows that the volume flow rate and volumetric efficiency of the LPC with control are maximum improved by about 45.6% and 44%, respectively. In conclusion, the piston eccentricity in the LPC could be effectively reduced by adopting the active electromagnetic control method proposed in this paper, thus improving its performance.

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Section: Design Of the Active Electromagnetic Control Systemmentioning

confidence: 99%

Section: Design Of the Active Electromagnetic Control Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Research on precise control of piston eccentricity by electromagnetic levitation in labyrinth piston compressor

Zhang

Pan

2023

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…In FPHS system, the final energy converter is linear generator. The linear motor is used as the starting motor in the system starting process, and as the generator in the electromagnetic 32 induction output. Different from the traditional rotary motor, linear generator 33,34 does reciprocate linear motion, but its working principle is the same.…”

Section: Dynamic Modelmentioning

confidence: 99%

The effect of electromagnetic load fluctuation on the gas exchange stability of a free-piston hybrid power system

Yuan

2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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The free-piston hybrid power system (FPHS) is affected by the dynamic coupling of combustion drive, power transmission, piston motion, excitation generation and gas exchange, and its operating state is very different from that of traditional engines. In this paper, the influence of the change of electromagnetic load on the ventilation stability of the whole system is studied by combining the method of system simulation and experimental validation. A dynamic-ventilation one-dimensional coupled gas exchange model was established, and the influence of the fluctuation of the electromagnetic load on the gas exchange is simulated by combining the thermodynamic model with the magnetic inductive load model. The results show that the scavenging efficiency is positively correlated with the load fluctuation, while the trapping efficiency changes with the opposite rule. Specifically, increasing the electromagnetic load properly will increase the time of gas exchange and obtain more fresh charge. The reduction of the electromagnetic load will make the compression process have higher gas pressure and temperature, which the mixture of oil and gas is more homogeneous and the combustion rate is faster after ignition. The stability of the ventilation performance of FPHS is very sensitive to electromagnetic fluctuations. The control of FPHS system can be achieved by adjusting the electromagnetic load.

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“…With respect to the labyrinth piston machine, Cheng et al [18,19] introduced a new electromagnetic centering system replacing the traditional supporting structure to precisely center the piston and proposed a new numerical method to study the piston's dynamic behavior. Tang et al [20] simulated the effect of the labyrinth seal characteristics, including tooth angle, sealing clearance, and cavity depth.…”

Section: Introductionmentioning

confidence: 99%

Leakage Characteristic Identification of Labyrinth Seals on Reciprocating Piston through Transient Simulations

Wang

Feng

Wang³

et al. 2019

Mathematical Problems in Engineering

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In the reciprocating labyrinth piston compressor, the characteristic of the internal leakage is crucial for the leakage management and performance improvement of the compressor. However, most of the published studies investigated the rotor-stator system, and those who study the reciprocating piston-cylinder system basically focus on the effects of the geometrical parameters. These conclusions could not directly be applied to predict the real-time leakage flow rate through the labyrinth seal because of the fast reciprocating motion of the piston, which will cause continually pressure change in two compression chambers, and then the pressure fluctuation will affect the flow through the labyrinth seal. A transient simulation model employing the multiscale dynamic mesh, which considers the effect of the reciprocating motion of the piston in the cylinder, is established to identify the characteristics of the internal leakage. This model was verified by a specially designed compressor, and the influence of various parameters was analyzed in detail. The sealing performance decreased linearly with the increase in the pressure ratio, and higher pressure inlet leads to higher leakage flow under the same pressure ratio. The labyrinth seal performance positively correlated to the increase of the rotational speed. Leakage characteristics of five working mediums were carried out, and the results indicated that the relative leakage decreased with an increase in the relative molecular mass. From this study, the realistic internal leakage flow rate under different operating parameters in the reciprocating labyrinth piston compressor could be predicated.

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Research on the piston precise electromagnetic centering of labyrinth-piston compressor

Cited by 6 publications

References 12 publications

Research on precise control of piston eccentricity by electromagnetic levitation in labyrinth piston compressor

Research on precise control of piston eccentricity by electromagnetic levitation in labyrinth piston compressor

The effect of electromagnetic load fluctuation on the gas exchange stability of a free-piston hybrid power system

Leakage Characteristic Identification of Labyrinth Seals on Reciprocating Piston through Transient Simulations

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