Advanced design and simulation study of a centripetal turbine for efficient recovery of residual gas pressure

The transportation of natural gas offers significant opportunities for the recovery of residual pressure, a resource often underutilized due to valve regulations. Efficiently harnessing this residual pressure can markedly reduce the costs associated with gas transport, facilitating a more comprehensive use of energy resources. Central to this study is the development of a 90 mm micro-turbine, the pivotal element in the residual pressure recovery system. The research, supported by a custom-built turbine power generation test bench and guided by orthogonal experimental design, meticulously examines the impact of variables such as blade wrap angle, guide vane angle, and volute cross-section on the power generation capacity of the turbine. Employing a detailed entropy production rate model, the investigation delves into both the turbine's flow dynamics and entropy production distribution via sophisticated numerical simulations. Key findings reveal an optimized turbine design featuring a rectangular volute, a 10° guide vane exit angle, and a 50° blade wrap angle, achieving an impressive power output of 354.03 W under test conditions. The study identifies turbulence dissipation and wall entropy production as primary contributors to increased turbine entropy, with minimal effects from temperature-related entropy and time-averaged entropy production. It is demonstrated that augmenting the blade wrap angle promotes flow field development within the turbine, leading to enhanced turbulence dissipation entropy production. Conversely, reducing the guide vane angle boosts airflow velocity, aiding impeller work and subsequently increasing turbulence dissipation entropy production. Comparative analysis of various volute designs highlights the superior efficiency of the rectangular volute in energy conversion, reduced entropy production, and minimal velocity loss. This comprehensive research offers invaluable insights for understanding of power generation capacities, flow characteristics, and entropy production mechanisms in micro-centripetal turbines.