Turbulent flame characteristics of ethane and blends with hydrogen

Ethane, a critical component of natural gas and a significant fuel source, presents a notable knowledge gap regarding its turbulent flame characteristics. This study employs the Leeds MK-II fan-stirred, spherical combustion vessel to explore the impact of pressure, temperature, turbulence intensity and hydrogen additions on ethane/air premixed flames. Experimental measurements span a broad range, encompassing equivalence ratios from 0.8 to 1.2, rms turbulent velocity at 1, 3, and 5 m/s, pressures of 0.1 and 0.5 MPa, temperatures at 300 and 360 K, and hydrogen additions varying from 25 % to 100 % by volume fraction. This study’s measurements are plotted on Peters-Borghi turbulent combustion diagram, covering the wrinkled flamelets, corrugated flamelets, and distributed reaction zones. Results show that both turbulent flame propagation speeds and turbulent burning velocities increase with root-mean-square turbulent velocity (uʹ), hydrogen additions, temperature, and pressure. A revised U-K turbulent burning velocity correlation is proposed by incorporating pressure explicitly as a key variable. This refinement enables separate expressions for different pressure levels and significantly improves predictive accuracy. This advancement allows for a distinct expression for each pressure level, enhancing the accuracy compared to the previous approach that used strain rate Markstein number. A comparison with previous measurements under V-shaped flame configurations shows that, despite differing setups, the relationship between normalized turbulent burning velocity (utr/uʹ) and the Karlovitz stretch factor (K) remains consistent, confirming the general validity of the proposed correlation.