Influences of distributed J-T effect on the performance of mixed-refrigerant Joule-Thomson refrigeration cycle

Abstract

In a mixed-refrigerant Joule-Thomson (MRJT) cycle, the working fluid usually produces a throttling effect in the expansion element. However, the high-pressure flow in the recuperator could also generate a throttling effect due to the narrow channels, i.e., the distributed Joule-Thomson effect (DJTE). Previously published studies indicated that the cooling performance of cryocoolers would be improved by DJTE accompanying the heat recovery process. However, most of the current research on this phenomenon is focused on the heat transfer characteristics of the cryocooler itself, with a lack of research on the effect of DJTE on the cycle performance in much detail.Therefore, a detailed investigation of the influence pattern of DJTE on the cycle performance is carried out by combining with the exergy analysis. The simulation is conducted under three quintessential conditions of the recuperator. The results indicate that it is possible to manipulate the DJTE to maintain satisfactory cycle performance under specific conditions. In addition, at a constant minimum temperature difference in the recuperator, the maximum achievable DJTE is closely related to the isothermal throttling effect of the mixed refrigerant. The conclusions of this paper clarify the effect and the application value of DJTE on the cycle efficiency, which provide a reference for determining reasonable operating conditions and ensuring the cycle efficiency in practical applications.