前直段长度对回流脉冲爆震燃烧室起爆特性影响研究

Initiation Characteristics of Reverse Flow PDC Affected by Length of Front-Straight Segment

针对脉冲爆震涡轮发动机(PDTE)回流脉冲爆震燃烧室的起爆特性建立了数值仿真模型并进行了实验验证,使用校验过的模型对比分析了不同回流脉冲爆震燃烧室前直段长度对爆震波生成的影响规律。结果表明,本文建立的仿真模型和方法能够正确预测试验条件下回流脉冲爆震燃烧室内的爆震燃烧传播过程,数值模拟结果与试验基本相符。仿真结果显示,当前直段长度小于4倍管径时,弯管内高温区与高压区发生分离,燃烧波未转变成爆震波。当前直段大于6倍管径时,随着前直段的加长,爆震波生成位置距离弯段出口越近,但总的起爆距离加长。在设计回流脉冲爆震燃烧室时,可通过增加前直段长度来缩短压气机和涡轮间的轴向距离,但会增加爆震室总长度。

A numerical simulation model was developed and experimentally validated for the detonation characteristics of the reverse flow pulse detonation combustion chamber of a pulse detonation turbine engine(PDTE),and the effects of different reverse flow pulse detonation combustion chamber front straight section lengths on detonation wave generation were compared and analyzed using the calibrated model.The results show that the simulation model and method established in this paper can correctly predict the propagation process of detonation combustion in the reverse flow detonation combustion chamber under test conditions,and the numeri-cal simulation results show that when the length of the front straight section is less than 4 times the diameter of the tube,the high-temperature region in the bending tube is separated from the high-pressure region,and the com-bustion wave does not turn into the shock wave.When the front straight section is greater than 6 times the diame-ter of the tube,with the front straight section longer,the location of the generation of detonate waves closer to the exit of the bend,but the total detonation distance increases.In the design of the reverse flow pulse detonation combustion chamber,increasing the length of the front straight section could shorten the axial distance between the compressor and turbine,but it will increase the total length of the detonation chamber.