Abstract In the present study, numerical analysis on the effect of steam dilution and high pressure on liquid fuel swirl combustion is carried out using a turbulent non-premixed combustion model. Tangential air injection scheme is adopted in a conical combustor. High recirculation is achieved inside the combustor due to the swirl pattern produced by the tangential air inlets. n-Dodecane, which is a major component of kerosene and Jet-A fuel, is selected as fuel in the present study. The thermal intensity of 5.37 MW/m3 with 21.1 kW thermal input is considered for the computational study. The chamber pressure is varied from 1 to 20 atm, keeping the momentum of inlet airflow constant. Steam added in the oxidizer as a diluent is varied from 0 to 20% by mass. Computational Fluid Dynamics (CFD) analysis using RANS (Reynolds Averaged Navier-Stokes) equations is performed to understand the flow characteristics and study the effect of steam dilution and pressure on NO formation. Realizable k- e turbulence model is used in the present study to capture the flow behavior due to the swirling motion. Spray characteristics are modelled using the Discrete Phase Model. The chemical representation is realized using scalar conservation concept with β -PDF model. Detailed chemical kinetic analysis with ignition delay characteristics, rate of species production, reaction behavior and sensitivity analysis is carried out. It is observed that the ignition delay decreases rapidly with pressure and very slowly with steam dilution. Effect of pressure and dilution on the OH concentration and olefins are discussed. Peak flame temperature and NO formation decreased with the steam addition. Emission characteristics are presented in the paper.

中文翻译：

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评估蒸汽稀释和压力对旋流环境中正十二烷燃烧影响的数值和化学动力学分析

摘要 本研究采用湍流非预混燃烧模型对蒸汽稀释和高压对液体燃料旋流燃烧的影响进行数值分析。锥形燃烧室采用切向空气喷射方案。由于切向空气入口产生的涡流模式，在燃烧器内部实现了高再循环。正十二烷是煤油和 Jet-A 燃料的主要成分，在本研究中被选为燃料。计算研究考虑了 5.37 MW/m3 的热强度和 21.1 kW 的热输入。腔室压力从 1 到 20 个大气压不等，保持入口气流的动量恒定。添加到氧化剂中作为稀释剂的蒸汽在 0 到 20 质量％之间变化。使用 RANS（雷诺平均纳维-斯托克斯）方程进行计算流体动力学 (CFD) 分析，以了解流动特性并研究蒸汽稀释和压力对 NO 形成的影响。在本研究中使用可实现的 k-e 湍流模型来捕获由于涡流运动引起的流动行为。喷雾特性使用离散相模型进行建模。化学表示是使用标量守恒概念和 β-PDF 模型实现的。进行了详细的化学动力学分析，包括点火延迟特性、物种产生率、反应行为和敏感性分析。观察到点火延迟随压力迅速下降，而随着蒸汽稀释非常缓慢。讨论了压力和稀释对 OH 浓度和烯烃的影响。峰值火焰温度和 NO 的形成随着蒸汽的加入而降低。论文中介绍了排放特性。