Dimensionless Characteristic Analysis of Indoor Gas–Liquid Humidification Jet Under Low Air Pressure on the Qinghai-Xizang Plateau

Abstract

Mastering the characteristics of gas–liquid humidification jets at low pressure is fundamental for creating indoor humidity environments on the Qinghai-Xizang Plateau. In this paper, we numerically simulate gas–liquid two-phase jets at 50.0–101.3 kPa and analyze their flow, mass transfer, and heat transfer properties based on relevant dimensionless numbers. The results show that, for Reynolds number (Re) = 1652–9914 at low pressure, the jet axis velocity decays more slowly, the entrainment between the jet boundary and ambient air is enhanced, and the momentum diffusion range is larger. Specifically, at Re = 1652, the average jet axis velocity of 50.0 kPa is 0.13 m/s higher than that of 101.3 kPa. The jet dimensionless velocity distribution of each radial section obeys the Voigt curve. Under low-pressure conditions, the humidity diffusion range of the jet expands, while the temperature diffusion range decreases. The jet flow trajectory and velocity distribution are highly dependent on Re and Froude number (Fr), and temperature distribution depends significantly on Prandtl number (Pr) and Re. The jet humidity distribution highly depends on Schmidt number (Sc) when Re = 1652 and Re = 4957–9914, while showing weaker dependence on Sc for Re = 1652–4957. This study is aimed at enhancing the theory of gas–liquid jet flow and providing theoretical guidance for developing indoor humidity environment construction techniques at low pressure, thereby improving the livability of plateau buildings.