Numerical study on flow irreversibility and wear of elbow-reducer pipe connection with gas-solid two phase flow

The flow resistance and wear of the pipeline system are jointly influenced by pipe structure, fluid flow pattern, and fluid composition. When two local resistance components are connected, the upstream component will affect the fluid flow pattern into the downstream component. In other words, the interaction of two components will affect the flow resistance and wear of the pipeline system. In this study, numerical models for the flow and wear of the elbow-reducer pipe connection were developed and validated. When the elbow is directly connected with the reducer pipe, great flow resistance and large wear occur. The local entropy generation model of gas-solid flow was developed to evaluate the irreversible loss of the flow field. The existence of solid particles will affect the average entropy generation, turbulent entropy generation and wall entropy generation. The results may provide some guidance for the design and optimization of pipeline system.