Effect of Integrating Metal Wire Mesh with Spray Injection for Liquid Piston Gas Compression

Abstract

Heat transfer enhancement techniques used in liquid piston gas compression can contribute to improving the efficiency of compressed air energy storage systems by achieving a near-isothermal compression process. This work examines the effectiveness of a simultaneous use of two proven heat transfer enhancement techniques, metal wire mesh inserts and spray injection methods, in liquid piston gas compression. By varying the dimension of the inserts and the pressure of the spray, a comparative study was performed to explore the plausibility of additional improvement. The addition of an insert can help abating the temperature rise when the insert does not take much space or when the spray flowrate is low. At higher pressure, however, the addition of spacious inserts can lead to less efficient temperature abatement. This is because inserts can distract the free-fall of droplets and hinder their speed. In order to analytically account for the compromised cooling effects of droplets, Reynolds number, Nusselt number, and heat transfer coefficients of droplets are estimated under the test conditions. Reynolds number of a free-falling droplet can be more than 1000 times that of a stationary droplet, which results in 3.95 to 4.22 times differences in heat transfer coefficients.

Various methodologies to improve the energy efficiency of a compressed air energy storage system

“…It has been found that the isothermal efficiency of the liquid piston compression process is about 88% to 90% instead of the base same efficiency of 82% to 84%. For further improvement of liquid piston thermal efficiency, recently, Ahn et al 104 integrated two already established methods of heat transfer enhancement in liquid piston gas compression that is, spray injection and use of metal wire mesh insert. The experimental results showed a significant change on Reynolds number for free‐falling droplets over stationary droplets, and hence heat transfer co‐efficient has changed from 3.95 to 4.22 103 .…”

Compressed Air Energy Storage as a Battery Energy Storage System for Various Application Domains: A Review

“…A comprehensive analysis was performed in other types of inserts; in [115], comprehensive study of metal foam inserts was carried out. In [116], wire mesh spirals of copper and aluminum were used, while in [117], the same wire mesh spiral was combined with a spray. In [118], thin copper tubes in honeycomb inserts were used to create contact between the pneumatic and hydraulic domains.…”

Experimental and numerical investigation on the flow and heat transfer behaviors during a compression–cooling–expansion cycle using a liquid piston for compressed air energy storage

“…Some studies [15,16,17,18] investigated the influences of operating conditions on the compression/expansion efficiency of the LP by thermodynamic analysis. Others [19,20,21,22] proposed and implemented different heat transfer enhancement measures for better thermal management, in order to approach the isothermal cycle. The average temperature and pressure of the gas phase are usually monitored and analysed in experimental studies.…”