A gas–thermal–solid coupling study of leakage flow and heat transfer characteristics in honeycomb labyrinth seal: Effects of leakage rate and Reynolds number

• Unveils complex gas–thermal–solid interactions in honeycomb labyrinth seals. • Demonstrates leakage flow-induced vortex structures affecting heat transfer. • Identifies turbulence-driven variations in enthalpy and Nusselt number distribution. • Quantifies leakage rate and Reynolds number effects on thermal performance. • Provides insights for optimizing sealing efficiency in turbine systems. Turbine systems are pivotal in energy conversion, with efficiency directly influencing energy utilization and carbon emissions. This study examines leakage flow and heat transfer in multi-stage honeycomb labyrinth seals (HLS) under dynamic operating conditions, aiming to inform optimized seal design. A novel gas–thermal–solid coupling framework, validated against experimental data from the literature, is employed to resolve coupled fluid, thermal, and structural interactions over a range of leakage rates and Reynolds numbers. Leakage, driven by geometric periodicity and pressure differentials, induces periodic vortices and pressure pulsations that modulate turbulence intensity and local heat exchange. Total temperature fields reveal downstream cooling counteracted by compression heating at high leakage rates, while enthalpy oscillations correspond closely to vortex structures. Peak average Nusselt numbers rise by 44.96% on the rotor and 53.06% on the stator, with distinct Reynolds-number-dependent heat-transfer responses. Energy-consumption analysis shows that combined pressure work and heat losses increase by approximately 223.53% with pressure ratio, underscoring the economic and operational importance of balancing leakage control and turbulence management. These findings deliver experimentally grounded, quantitative insights for HLS optimization, contributing to improved turbine efficiency and sustainable, low-carbon energy production.