Comparison of single-phase and two-phase flow dynamics in the HLTP for microalgae culture

Abstract

This paper aims to show dynamic behavior of microalgae suspension in a Horizontal Loop Tubular Photobioreactor (HLTP). Two models of a single-phase flow and a two-phase flow have been proposed taking into account the light irradiance. The governing equations describing a single-phase flow are the continuity equation and the Navier-Stokes equation. The viscosity of the microalgae suspension is a function of microalgae cell concentration which varies in time. Using the governing equations of a single-phase flow together with the Cahn-Hiliard mass conservation equation, we can describe the dynamic behavior of a two-phase flow. The results obtained from both models are compared. It is noted that both results are significantly different. In the two-phase flow model, the mass transfer rate and the shear rate are higher than those obtained from the single-phase model.