Numerical analysis of transient gas-solid flow in a non-mechanical L-valve

The performance of non-mechanical valves is determined by the gas–solid interactions. This paper describes the transient gas–solid flow behaviors in a non-mechanical L-valve analyzed with computational fluid dynamics coupled with discrete element method. The simulated gas–solid flow in the downcomer and horizontal pipe agrees well with the theoretical and empirical correlations. It is found that the gas flow direction in the downcomer changes during the transient flow. A linear correlation between the dimensionless pressure drop and aeration rate is identified, enabling the construction of a phase diagram to characterize gas flow regimes in the downcomer. The gas flow direction is depicted as upward along the downcomer above the line. In contrast, the bottom area stands for the gas flowing downward from the downcomer into the horizontal pipe of the L-valve. This study provides an instructive guidance for the design and application of non-mechanical valve.