双管头部进气旋流-突扩燃烧室冷态流场研究

AN EXPERIMENTAL STUDY ON FLOWFIELDS IN A DUAL INLET SWIRL-DUMP COMBUSTOR

关键词:  冲压式喷气发动机  燃烧室  旋涡  速度分布

Key words:  Ramjet engine  Combustion chamber  Swirl  Velocity distribution

摘要:

本文对双管头部进气旋流-突扩燃烧室模型进行了冷态流场试验研究,以探索进气方式(全旋型或部分旋型)、旋流强度(旋流数S或旋流角(?))、旋流室出口扩张角2α、旋流室长径比l/d、内通道相对面积F等参数对燃烧室流场结构的影响规律.结果表明,适当选择燃烧室结构参数可以在燃烧室中形成稳定的中心回流区和头部旋涡回流区.当(?)=45°、α=15°、l/d=1.3、F=0.41时,除了形成旋流室回流区外,在其尾部还形成了一个较大的、切向分速较低的中心回流区,两者“联串”在一起.部分旋的中心回流区长度与相同旋流角全旋进气时的回流区长度几乎相等,但总压损失却降低63.4%.

Abstract:

In this paper, flowfields in a dual inlet swirl-dump combustor at cold state were studied experimentally to investigate the effects of flow entrance type (full-swirl or part-swirl), swirl strength (swirl number S or vane angle (?)), divergence angle of divergent nozzle of swirl chamber (2a), swirl chamber length to diameter ratio (l/d), inner channel to whole channel area ratio (F) on structures of combustor flowfields. The results of experimental studies show that stable central recirculation zones and head votex systems can be established in the combustor through properly selecting combustor geometric parameters. Moreover, it is found that, in addition to the swirl chamber recirculation zones, bigger central recirculation zones without tangential velocities are formed behind them when (?) = 45 degrees, a = 15 degrees, l/ d=1.3, F = 0.41. Both recirculation zones are connected with each other. The central recirculation zenes in length with part-swirl are nearly equal to that ones with full-swirl, but the former loss of total pressure in combustor is decreased about 63%.