Sudan

The combustion of hydrogen increases the water content of the combustion products affecting the aerodynamic performance of turbines using hydrogen as a fuel. This study aims to design a radial turbine using the differential evolution (DE) algorithm to improve its characteristics and optimize its aerodynamic performance through an orthogonal experiment and analysis of means (ANOM). The effects of varying water content in combustion products ranging from 12% to 22% on the performance of the radial turbine are also investigated. After optimization the total–static efficiency of the radial turbine increased to 89.12% which was 1.59% higher than the preliminary design. The study found that flow loss in the impeller primarily occurred at the leading edge trailing edge and the inlet of the suction surface tip and outlet. With a 10% increase in water content the enthalpy dropped Mach number increased and turbine power increased by 4.64% 1.71% and 2.41% respectively. However the total static efficiency and mass flow rate decreased by 0.71% and 2.13% respectively. These findings indicate that higher water content in hydrogen combustion products enhances the turbine’s output power while reducing the combustion products’ mass flow rate.

The thermal protection of rocket engine combustion chambers presents a critical challenge in supersonic flight applications. This study numerically investigates the enhancement of heat transfer and coolant flow characteristics in regenerative cooling channels through cylindrical rib integration employing ANSYS Fluent with SST k-ω turbulence modeling to evaluate single- and double-row configurations (0.75–1.25 mm diameter) under supercritical hydrogen conditions (3 MPa 300 K inlet). Results demonstrate that rib-induced turbulence disrupts thermal boundary layers with a 1.25 mm single-row design achieving a 13.67 % reduction in peak wall temperature compared to smooth channels while double-row arrangements show diminishing returns due to increased flow resistance. The thermal performance factor (η = (Nu/Nu₀)/(f/f₀) 1/3) reveals Case 3′s superiority (21.88 % improvement over the smooth channel configuration) in balancing heat transfer enhancement against pressure drop penalties (9.23–20.93 % for single-row 8.26–18.7 % for double-row). Notably density-driven flow acceleration near heated walls mitigates pressure losses through localized viscosity reduction. Furthermore cylindrical ribs reduce thermal stratification by up to 30 % in single-row configurations with double-row designs providing additional temperature homogenization at the cost of increased flow resistance. These findings offer critical insights for optimizing rib-enhanced cooling systems in high-performance rocket engines achieving simultaneous thermal efficiency and hydraulic performance improvements.

This work provides a detailed evaluation of a novel biomass-fueled multigeneration system conceived to contribute to the growing emphasis on sustainable energy solutions. The architecture comprises a biomass gasifier an innovative cascaded organic Rankine cycle (CORC) incorporating a high-temperature mixture in the top cycle a proton exchange membrane electrolyzer (PEME) a Brayton cycle and waste heat utilization units all operating together to deliver electricity hydrogen (H2) and thermal output. A comprehensive thermodynamic modeling framework is established to evaluate the system’s performance across various operational scenarios. The framework emphasizes critical metrics including exergy efficiency levelized total emissions (LTE) and payback period (PP). These indicators ensure a holistic assessment of energy exergy economic and environmental considerations. Parametric studies demonstrate that enhancements in biomass mass flow rate and combustion chamber temperature significantly increase power output and H2 production while reducing the payback period underscoring the system’s flexibility and economic feasibility. Furthermore the study employs sophisticated machine learning optimization methods combining artificial neural networks (ANNs) with genetic algorithms (GA) to determine optimal operating conditions with minimal computational effort and maximum efficiency. When evaluated at nominal parameters the system records an exergy efficiency of 23.72 % achieves a PP of 5.61 years and yields an LTE value of 0.34 ton/GJ. However under optimized conditions these values improve to 35.01 % 3.78 years and 0.241 ton/GJ respectively.