等离子体助燃下超燃支板燃烧室燃烧特性数值研究

Numerical Study on Combustion Characteristics of Supersonic Strut Combustor under Plasma-Assisted Combustion

关键词:  支板喷注器  等离子体射流  超声速燃烧  数值模拟  燃烧效率

Key words:  Strut injector  Plasma jet  Supersonic combustion  Numerical simulation  Combustion efficiency

摘要:

为了将支板喷注器与等离子体射流这两种促进超声速燃烧室燃烧的方式结合起来，设计了一种带有等离子体射流喷孔的支板燃烧室，并在超声速来流的条件下，针对燃料喷注总压、燃料喷注位置、等离子体射流介质、等离子体射流总压对燃烧室燃烧性能的影响进行了三维数值模拟。研究发现：增大燃料的喷注总压，燃烧室的燃烧范围明显增大，燃烧效率呈现出先增大后减小的趋势，在燃料喷注总压为2.0MPa时，燃烧效率达到最大值90.4%；不同的燃料喷注位置对燃烧室的燃烧范围影响较小；等离子体射流介质为O₂时，燃烧效率最高，燃烧范围最广；提高等离子体射流的喷注总压，能够提升凹腔剪切层高度，有效促进燃烧，但同时也带来了更高的总压损失。

Abstract:

In order to combine the two methods of promoting the combustion in a scramjet combustor, the strut injector and the plasma jet, a strut combustor with a plasma jet nozzle was designed. Under the condition of supersonic flow, the three-dimensional numerical simulation of the effects of fuel injection total pressure, fuel injection position, plasma jet medium and plasma jet total pressure on the combustion performance of the combustor was carried out. The obtained results show that: increasing the total fuel injection pressure, the combustion range of the combustor increased significantly, and the combustion efficiency increased first and then decreased, when the total fuel injection pressure is 2.0MPa, the combustion efficiency reaches a maximum of 90.4%; different fuel injection positions had less influence on the combustion range of the combustor; when the plasma jet medium is O₂, the combustion efficiency is the highest and the combustion range is the widest. Increasing total injection pressure of the plasma jet can increase the height of the shear layer of the cavity and effectively promote combustion, but also bring higher total pressure loss.