摘要：

In gas turbines, compared to gaseous ammonia, the utilization of liquid ammonia can reduce energy loss and startup time. However, the flash boiling phenomenon and the high latent heat of liquid ammonia makes the spray flame difficult to stabilize. Increasing the preheated air temperature or adding small amount of hydrogen as a piloted fuel are considered as effective methods to enhance the stability. To understand the flame topological structure, simultaneous Mie scattering and planar laser-induced fluorescence of OH (OH-PLIF) techniques are used to visualize the liquid ammonia spray structure and flame region information. Results show that the liquid ammonia swirl spray flame exhibits the flame topological structure of distinct zoning characteristics without overlap, including the droplet zone, the mixing zone, and the flame zone. Increasing the preheated air temperature accelerates the evaporation of liquid ammonia, leading to an increase in the local equivalence ratio and radial flame splitting. At lower air temperature conditions, increasing the hydrogen blending ratio has minimal impact on the flame topological structure. However, at higher temperature conditions, hydrogen blending significantly promotes reactionintensity upstream and reduces the flame lift-off height, which makes the mixing zone smaller. In general, to achieve better flame stability effect, the two factors need to be reasonably matched, which has important reference value for the development of liquid ammonia direct injection gas turbine combustor.