Research on power consumption distribution characteristics of a water-lubricated twin-screw air compressor for fuel cell applications. (1st October 2022)

• Record Type: Journal Article
• Authors: Wang, Chuang; Liu, Mingkun; Wang, Bingqi; Xing, Ziwen; Shu, Yue
• Is Part Of: Energy. Volume 256(2022)
• Publication Date: 2022-10-01
• Subjects: Water lubrication -- Screw compressor -- Power consumption distribution -- Friction loss; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2022.124673
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: The water-lubricated twin-screw air compressor is very suitable for applications in high-pressure PEMFCs in distributed power generation, for it can provide absolutely oil-free air. Power consumption distribution is a significant characteristic for clarifying the influence mechanism of water injection and lubrication, which could provide the optimizing direction for performance enhancement. Hence, a mathematical model is constructed in this paper, aiming to analyze the power consumption distribution in different positions of the compressor at different rotating speed, including indicated power of dry air, water vapor and liquid water, friction power in the rotor chamber, friction power of radial journal bearings, thrust bearings and the lip seal. Results show that thrust bearings account for the largest amount of total power loss by over 52%, followed by indicated power of liquid water, radial journal bearings, while the indicated power of water vapor, friction powers in the rotor chamber and of the lip seal are minor power losses. This is very different from the common oil-injected twin-screw compressors, in which the friction power in the rotor chamber is also the dominant power loss. It illustrates the advantage of the low friction coefficient of water for sealing clearances in the water-lubricated twin-screw air compressor. Graphical abstract: Image 1 . Highlights: Introduce the WLTSAC into high-pressure PEMFCs for distributed power generation applications. The power consumption distribution characteristics of the WLTSAC are identified. Reducing friction loss of thrust bearings and indicated power of liquid water is the key to performance improvement. The mechanical efficiency of the WLTSAC keeps a nearly constant value of about 83% at different rotating speeds.