Study on the heat transfer characteristics of a plate-fin-typed precooler considering cooling fluid phase change

Abstract

A quasi-two-dimensional calculation method has been proposed to design a plate-fin-typed precooler with high efficiency and low resistance. This method considers the variation of fluid properties during the heat transfer process, particularly for cryogenics with phase change. The precooler heat transfer characteristics are comprehensively investigated based on the proposed method and calculation models. The calculation results demonstrate that the proposed method effectively explores the fluid properties distribution, such as the temperature distribution and steam quality distribution inside the precooler. Besides, the hot fluid temperature drop exceeds 1200 K, while the pressure drop remains below 15% of the inlet pressure above all cases. Moreover, the heat transfer performance between cooling fluid and hot fluid is compared. It is worth noting that the cooling fluid heat transfer coefficient is10∼102 magnitude higher than that of the hot fluid, especially when the cooling fluid steam quality is below 0.60. Therefore, it is critical to improve the heat transfer performance of the hot fluid for the precooler. Additionally, the first heat exchanger inside the precooler plays a more important role in heat transfer than heat exchangers at other locations because the temperature drop and pressure drop inside the precooler account for the largest proportion, with a value up to 50%.

Keywords

• Precooler
• Heat transfer
• Calculation
• Phase change