H2/Air连续旋转爆震发动机推力测试(II)-双波模态下的推力

Thrust Measurement of H2/Air Continuously Rotating Detonation Engine (II) - Thrust Under Dual Wave Mode

关键词:  连续旋转爆震模型发动机  H2/Air  双波模态  时频分析  推力测量  推力积分  比冲

Key words:  Continuously rotating detonation model engine  H2/Air  Dual-wave mode  Time-domain and frequency-domain analysis  Thrust measurement  Thrust integration  Specific impulse

摘要:

在环缝-喷孔对撞式喷射的H2/Air连续旋转爆震模型发动机上实现双波自持。详细分析了连续旋转爆震波以双波模态自持传播的典型波形特征和时域、频域特征。测量了模型发动机工作在双波形模态下所产生的一维推力，讨论了比冲等推力性能。时频特性和推力积分表明:出口背压为大气压时，在空气流量786.6g·s-1，氢气流量20g·s-1，当量比为0.8733的工况下，模型发动机以平均传播频率10.5809kHz，平均传播速度1578.9m·s-1的双波模态稳定工作超过650ms。产生可靠的有效推力约808.5N。以火箭模式计算，有效排气速度为1002.3m·s-1，总比冲为102.3s；以冲压模式计算，有效排气速度(氢气消耗率)为40425m·s-1，燃料比冲为4125s，所消耗氢气的单位面积质量流率为13404g·m-2·s-1，单位推力为1027.8m·s-1。相比于单波模态，双波模态使得燃烧室内压力更为均匀，高频推力曲线振荡幅值小。爆震波头个数增多有利于推力稳定。

Abstract:

A self-sustained dual-wave mode of continuously rotating detonation was achieved in a model engine in which H2/Air mixture via slit-orifice collision was injected. Typical waveform characteristic of the steadily self-sustained dual-wave mode，as well as its time-domain and frequency-domain characteristics，were analyzed in detail. Simultaneously，one dimensional thrust supplied by this model engine working in dual-wave mode was directly measured，and propulsive performance such as specific impulse was discussed. The time/frequency domain characteristics and thrust integration show that，supplying the operating condition of 1 atmosphere backpressure and 0.8733 equivalent ratio，that is，air injected 786.6g·s-1 and H2 injected 20g·s-1，the model engine steadily works in dual wave mode for more than 650ms，which has an average frequency of 10.5809kHz and an average velocity of 1578.9m·s-1. Therefore this model engine generates a reliable effective thrust of 808.5N. Calculated in rocket mode，the effective exhaust velocity is 1002.3m·s-1，and total specific impulse is 102.3s. Calculated in ramjet mode，the effective exhaust velocity (hydrogen consumption rate) is 40425m·s-1，fuel specific impulse is 4125s，the consumption of hydrogen mass flow rate per unit area is 13404g·m-2·s-1，and the unit thrust is 1027.8 m·s-1. Compared to single-wave mode，dual-wave mode leads to more uniform pressure in combustion combustor，therefore causing a high frequency thrust curve fluctuating within small amplitude. An increase in the number of detonation waves is in favor of a more stable thrust.