超燃冲压发动机壁板振动对燃烧室性能的影响

Effects of Panel Vibration on Performance of Combustor for Scramjet

关键词:  超燃冲压发动机  超声速燃烧  壁板振动  燃烧效率  总压损失系数

Key words:  Scramjet  Supersonic combustion  Panel vibration  Combustion efficiency  Total pressure loss ratio

摘要:

为了研究超燃冲压发动机壁板振动对燃烧室性能的影响，以改进后的JNAL模型为研究对象，分别对上游壁板和下游壁板施加强迫振动，研究振动幅值、频率、波长对燃烧效率和总压损失系数的影响。对于本文的计算模型，结果表明:(1)壁板振动对燃烧室性能产生明显的影响，提高燃烧效率的同时也提高了总压损失系数；(2)对于上游和下游壁板振动而言，振幅和波长对燃烧性能的影响规律基本相同，燃烧效率和总压损失系数随振幅的增加而增加，最大增加幅度分别达到了40.52%和55.74%，随波长的减小而增加，且波长较小时，燃烧室性能变化较敏感；(3)对于上游壁板振动而言，随频率的增加，燃烧效率和总压损失系数先略有下降，后单调增加，但是，对下游壁板振动而言，随频率的增加，燃烧效率和总压损失系数先增加后减小，且当振动频率与下游流场压力脉动的主频率接近时，壁板振动对燃烧室性能的影响达到最大，燃烧效率和总压损失系数增加的幅度分别达到了75.42%和65.68%。

Abstract:

In order to investigate the effects of panel vibration on the performance of combustor for scramjet，based on the improved JNAL model，through applying forced vibration respectively on upstream panel and downstream panel，the effects of vibration amplitude，frequency and wavelength on the combustion efficiency and total pressure loss ratio are studied. For the model in this paper，the calculation results show that: (1)The panel vibration has a significant influence on the performance of combustor，improving the combustion efficiency while the total pressure loss ratio increases.(2)For the panel vibration of upstream and downstream，the effects of amplitude and wavelength on the combustion performance are similar，combustion efficiency and total pressure loss ratio increase with the increase of the amplitude，the amplitude increment is about 40.52% and 55.74%，respectively. They increase with the decrease of the wavelength，and the combustion performance is sensitive for the relative small wavelength.(3)For the upstream panel vibration，with the increase of frequency，the combustion efficiency and total pressure loss ratio slightly decrease at first，and then increase monotonously. But for the downstream panel vibration，with the increase of frequency，the combustion efficiency and total pressure loss ratio decrease at first，and then increase，when the vibration frequency is close to the dominant frequency of pressure pulsation in the downstream flow field，the effects of panel vibration on the performance of the combustion chamber reach maximum，the increase amplitude of combustion efficiency and total pressure loss ratio is about 75.42% and 65.68%，respectively.