Computational investigation on nitrogen displacement process in a thermal environment simulation chamber

Abstract

The computational fluid dynamics method is used to study the transient nitrogen displacement process of acquiring ultra-low dew point temperature during thermal environment simulation. A three-dimensional numerical simulation of the nitrogen displacement process is analyzed based on the species transport model. The effects of inlet flow velocity, inlet temperature, as well as inlet direction on the displacement efficiency are discussed in detail. Increasing inlet velocity can decrease displacement time and nitrogen consumption while increasing displacement efficiency monotonously. On the other hand, increasing inlet temperature can decrease the displacement time and nitrogen consumption, and increase the displacement efficiency monotonously. In comparison to increasing the inlet temperature, the displacement efficiency is significantly improved by increasing inlet velocity. The influence of the inlet direction on the displacement efficiency is mainly determined by the entrance area, without consideration of temperature effect, which is nearly proportional to the entrance area. The use of high-temperature nitrogen to displace moist air in different inlet directions is unfeasible, except for –Y direction.