Investigation on gas–liquid two-phase flow in the mixer of a liquid metal magneto-hydro-dynamic system and wavelet-based analysis

Abstract

In this paper, turbulent elements are introduced into the mixer of a two-phase magneto-hydro-dynamic power generation system, effectively addressing the challenges of transporting high-density and high-viscosity liquid metals and inhomogeneous gas–liquid mixing. The effects of different types and numbers of turbulent elements on the gas–liquid two-phase flow pattern and phase change heat transfer are investigated using numerical simulation and wavelet multiscale analysis methods. A comprehensive evaluation index for the mixer is established, considering performance indicators such as gas–liquid mixing uniformity, friction coefficient, volumetric heat transfer coefficient, and velocity. The results indicate that the turbulent elements significantly enhance heat transfer performance, liquid metal transport velocity, and mixing uniformity. However, an increase in the number of turbulent elements also leads to an increase in the friction coefficient, particularly in the SX type mixer, where it is approximately 20% higher than that in the SK type mixer. A comprehensive analysis reveals that the overall performance of the SX mixer surpasses that of the SK mixer, with the optimal number of turbulent elements being 3 for the SX mixer and 1 for the SK mixer. Additionally, there is a clear gravity-induced stratified flow in the empty pipe mixer. The flow pattern in the SK type mixer is primarily influenced by the ratio of gravity to centrifugal force, while that in the SX type mixer is predominantly determined by gravity and the number of turbulent elements. Wavelet multiscale analysis demonstrates that the pressure fluctuations in the mixer are primarily influenced by gas–liquid interface deformation and bubble collision frequency.