Fluid dynamic analysis of liquefied natural gas flow through a cryogenic ball valve in liquefied natural gas receiving stations

Abstract

Cryogenic ball valves are one of the most important fluid control devices in liquefied natural gas (LNG) receiving stations. The dynamic flow characteristics of cryogenic ball valves directly affect the stability of a pipeline system. In this paper, the sliding mesh technology was adopted to simulate the dynamic flow characteristics inside the cryogenic ball valve. Firstly, the energy loss inside the cryogenic ball valve during the opening and closing process was analyzed. It is found that the energy loss is larger when the spool degree is less than 30°, while the fluid resistance is very small at the rest of the degree. Then, the dynamic flow characteristics of the cryogenic ball valve at different spool rotational speeds were investigated. It is found that the velocity value and the flow turbulence are gradually increased when the spool rotational speed increases from 1.25 deg/s to 10 deg/s. Finally, dynamic flow characteristics during the valve opening process with fluctuation of inlet velocity were analyzed. It is found that the distribution of velocity and pressure is approximately consistent, while the value of velocity and pressure is increased with the increase of inlet velocity. It is helpful for the design of cryogenic ball valves and the improvement of the whole LNG pipeline system.