Development of a Highly Reliable Helium Refrigeration System. R&amp;D of a Highly Reliable Helium Refrigeration System (Oil-free type).

Asakura, Hiroshi; Saji, Nobuyoshi; Yoshinaga, Seiichiro; Ishizawa, Takehiko; Ikeuchi, Masamitsu; Yanagi, Hideharu; Hirao, Yasuhiro; Kitagawa, Kazuhiro

doi:10.2221/jcsj.36.135

Cited by 4 publications

(3 citation statements)

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“…2,3 However, for the conventional oil-free twin-screw compressors, a pair of synchromesh gears are always designed in the compressor to transfer the torque to prevent two rotors from contacting each other due to the poor lubricity of water and working fluid. [4][5][6][7] Recently, it is a trend to eliminate synchromesh gears and also rely on the direct contact between two rotors for oil-free twin-screw compressors, especially on the condition of high-speed operation, due to much power consumed by gears. Thus, they are similar to the oil-injected twin-screw compressors structurally.…”

Section: Introductionmentioning

confidence: 99%

Theoretical research on the wear characteristics of rotors in a twin-screw compressor

Wang

Xing

Sun

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part E:

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Thanks to the development and application of coating technology and polymer rotor material, it is an inevitable trend to eliminate synchronous gear for water-injected and dry twin-screw compressors, especially running at a high speed, due to much power consumed by synchronous gears. However, it is not economical and reliable to rely only on coating or rotor material to enhance the wear resistance of rotor. This paper attempts to lighten the rotor wear in twin-screw compressors from the angle of setting driving belt. To achieve this goal, the contact analysis is carried out in this paper, taking the rotor profile of a developed water-lubricated twin-screw air compressor as an example. By the contact analysis, equivalent curvature radius, Hertz contact stress, sliding distance, the value of PH S, and the minimum film thickness of each mesh point on different tooth curve are calculated and discussed. The product of the Hertz contact stress and total sliding distance, PH S, and minimum film thickness are chosen as the evaluation indexes to estimate the wear resistance of all tooth curves. By comparing these indexes of each tooth curve, some suggestions about setting the driving belt are proposed.

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Section: Introductionmentioning

confidence: 99%

Theoretical research on the wear characteristics of rotors in a twin-screw compressor

Wang

Xing

Sun

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part E:

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“…The system works with 70 MW power consumption, 9320 h without failure, and 100 L/h liquefication rate 9 . The same study is investigated for oil‐free type compressors, and the result shows that the rate of liquefication increases to 160 L/h 10 . A Claudet cycle is integrated into another refrigerator, an internal turboexpander, and a piston turboexpander.…”

Section: Introductionmentioning

confidence: 99%

Investigation of a new energy‐efficient cryogenic process configuration for helium extraction and liquefaction

2021

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Summary This study's main focus is to simulate and design a novel cryogenic system that produces liquid helium. The novelty of this research has two main parts: first, this system is able to produce large amounts of liquid helium at atmospheric pressure, and second, from an energy consumption point of view, it performs better than other processes of liquid helium production. The first and second laws of thermodynamic are used to investigate this process. In this novel cryogenic process, liquid helium is produced at three stages; first, the mainstream contains some helium enter to helium upgrader to increase helium concentration. After that, the stream with high helium concentration enters to pressure swing adsorption process, and pure helium is obtained. Finally, pure helium enters to cryogenic process and is liquified in an expander. The network consumption in this system is equal to 18.66 MW, and the proposed system's exergy efficiency is obtained at 23.4%. Also, the results show that this system can produce 196.5 kg/h liquid helium. In this research, Aspen HYSYS V10 and MATLAB software are used to simulate this cryogenic process. Finally, numerical assessment is done on the key parameters that influence the performance of the process.

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“…However, in the case of air foil bearings, friction exists between the bearing and rotor at startup and shutdown, and solid lubrication is required [3]. Furthermore, the load capacity of air foil bearings is quite low, and they decrease the stability because they provide low damping [4]. On the other hand, magnetic bearings have several advantages.…”

Section: Introductionmentioning

confidence: 99%

Design of magnetic bearings for turbo refrigerant compressors

Park

Choi

Ham

2014

Mechanics & Industry

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Magnetic bearings are oil-free bearings that are widely employed in turbo machineries such as turbo refrigerant compressors in order to eliminate lubrication systems, avoid contamination, and increase efficiency. We have developed a 145 refrigerant ton (RT)-class turbo refrigerant compressor using homopolar-type radial hybrid magnetic bearings (HMBs) and thrust magnetic bearings. The thrust magnetic bearing comprises a thrust HMB and a permanent magnet that generate downward forces to overcome high upward thrust forces of 2000 N at 21 000 rpm. A test rig and controller for the compressor with magnetic bearings were fabricated, and rotordynamics such as the unbalance response and axial displacement were investigated. Rotordynamics analyses using the finite element method predicted that the 1st bending mode is located at a high frequency with sufficient margin from the operating speeds. Further, the zero-to-peak displacement caused by the unbalanced response was sufficiently small. The rotor was stably supported with few vibrations across the entire range of the operational speeds. Our results demonstrate that the advantages of oil-free bearings can be easily exploited in turbo machineries such as turbo refrigerant compressors by adopting HMBs.

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Development of a Highly Reliable Helium Refrigeration System. R&D of a Highly Reliable Helium Refrigeration System (Oil-free type).

Cited by 4 publications

References 0 publications

Theoretical research on the wear characteristics of rotors in a twin-screw compressor

Theoretical research on the wear characteristics of rotors in a twin-screw compressor

Investigation of a new energy‐efficient cryogenic process configuration for helium extraction and liquefaction

Design of magnetic bearings for turbo refrigerant compressors

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