部分覆盖构型对凹腔冷态和燃烧流场的影响

Effects of Partly Covered Shape on an Isothermal and Exothermic Cavity Flowfield

关键词:  凹腔  部分覆盖  前壁面喷注  超声速燃烧

Key words:  Cavity  Partly-covered  Front wall injection  Supersonic combustion

摘要:

为了研究凹腔部分覆盖构型对燃烧室流场的影响，采用SST k - ε 湍流模型和有限化学速率/涡破碎模型，对部分覆盖型凹腔的冷态和燃烧的二维流场进行了数值仿真。比较了贫燃和富燃条件下，覆盖板对凹腔燃料分布、流场温度和燃烧效率的影响。研究发现贫燃下，覆盖板有利于凹腔内燃料的积累，提高了凹腔的火焰稳定性，同时由于点火适宜的当量比区域位于凹腔内低速区，增强了凹腔点火能力；富燃下，覆盖板使凹腔内富燃环境进一步恶化，降低了凹腔的火焰稳定性和燃烧效率，主要燃烧区部分向下游转移。

Abstract:

Aimed at investigating the effects of partly-covered shape on the flowfield of combustor，SST k - ε turbulent model and finite-rate/eddy-dissipation model were used to simulate both the isothermal and exothermic 2-D flowfiled of a partly-covered cavity. The effects of cover-plane on fuel distribution，static temperature distribution and combustion efficiency were checked on both lean and rich fuel condition. In the lean fuel flowfield，the cover-plane is helpful in accumlating the fuel in cavity，and the flameholding stability can be improved. In the flowfield with a partly-covered cavity，the region with feasible ignition equivalence ratio is located inside the cavity with low-speed. So the ignition capability of the partly-coved cavity is also improved. In the rich fuel flowfield，the cover-plane makes the rich condition worsen inside cavity. The flameholdering stability and combsution efficiency are both reduced. A part of main combustion region moves downstream.