THE THEORETICAL METHOD TO INCREASE THE THRUST OF HIGH MACH NUMBER SCRAMJETS
-
摘要: 斜爆轰发动机和激波诱导燃烧冲压发动机在高马赫数吸气式发动机中具有重要应用前景, 但是斜爆轰发动机是否具有足够大的净推力, 还是一个未知的问题, 因此需要对高马赫数冲压发动机的推进性能以及提高推力的方法进行理论研究. 本文主要分为3部分. 第1部分理论研究了超燃冲压发动机中的爆燃波和爆轰波的传播特性. 保证发动机稳定燃烧是提高推力的前提. 通过对爆燃波和爆轰波传播特性研究, 得到了影响发动机燃烧稳定性的关键参数和物理规律. 第2部分研究了发动机处于热壅塞临界状态下的燃烧规律和推力特性. 在临界状态下, 燃烧室入口气流速度正好等于爆轰波传播速度, 二者处于平衡状态, 这是发动机推进性能的理论上限. 第3部分研究了提高高马赫数超燃冲压发动机推力的理论方法. 对于高马赫数冲压发动机, 燃烧室入口气流速度远远大于爆轰波的传播速度, 这部分速度差就是提高推力的理论空间. 对于马赫数Ma ≥ 12的超燃冲压发动机, 理论上燃烧产生的爆燃波或激波不会引起发动机不起动, 因此可以通过进一步添加燃料和氧化剂的方法来提高其推力. 理论分析结果表明, 对于高马赫数超燃冲压发动机, 不但燃烧流场是容易稳定的, 而且可以有很多方法来进一步提高推力.
-
关键词:
- 高马赫数超燃冲压发动机 /
- 斜爆轰发动机 /
- 激波诱导燃烧冲压发动机 /
- 超声速燃烧 /
- 提高推力的方法
Abstract: The oblique detonation engines and shock-induced combustion ramjets have been proved to be practicable for high flight Mach number air-breathing engines in recent years. However, whether the oblique detonation engines and shock-induced combustion ramjets have enough thrust or not is unknown yet. In this paper, the combustion characteristics and propulsive performance of scramjets are discussed theoretically. Firstly, the mechanism of engine unstart of scramjets is discussed from the point of view of shock/shock interaction and deflagration-to-detonation transition. The results show that engine unstart process is very similar to the deflagration-to-detonation transition process. In the combustor of scramjets, the maximum velocity of the deflagration wave is very close to the detonation velocity. Therefore, the C-J detonation velocity is defined as the stable operation boundary of scramjets. Secondly, the formula of thrust produced by the divergent nozzle is put forth and key parameters influencing thrust are obtained. According to the thrust formula, supersonic combustion is beneficial for increasing the thrust. The main way to increase the thrust is to increase the pressure of combustion products. The propulsive performance of scramjets is theoretically analyzed by using C-J detonation theory, which is the critical condition when the engine is thermally choked. Finally, the theoretical method to increase the thrust is discussed. For high flight Mach number scramjets Ma ≥ 12, the velocity in the isolator is much faster than the C-J detonation velocity in the combustor and the problem of engine unstart disappears. Therefore, extra fuel and oxidizer can be injected into the combustor to increase the thrust further as long as the shock wave generated by the high pressure combustion products is slower than the air velocity in the isolator. The theoretical results agree well with the existing experimental and numerical results, which can be used as a baseline for the development of high Mach number scramjets. -
表 1 国内外超燃冲压发动机试验结果汇总
Table 1. Summary of some typical scramjets experimental results
表 2 不同飞行马赫数下斜爆轰发动机参数
Table 2. Parameters of oblique detonation under different flight Mach numbers
Ma∞ Ma1 T1/K p2/p1 Ma2 βODW/(°) 9 4.41 618.1 8.16 1.86 47.6 10 4.68 683.3 7.94 2.15 41.9 11 4.93 752.9 7.86 2.38 37.8 12 5.52 826.6 7.87 2.61 34.8 表 3 不同飞行马赫数等熵压缩后的参数
Table 3. Parameters behind isentropic compression for different flight Mach numbers
Ma∞ T∞/K T1/K Ma1 8 225 1250 2.69 9 225 1250 3.22 10 225 1250 3.68 11 225 1250 4.12 12 225 1250 4.63 -
[1] Ferri A. Review of problems in application of supersonic combustion. The Aeronautical Journal, 1964, 68(645): 575-597 [2] Curran ET. Scramjet engines: the first forty years. Journal of Propulsion and Power, 2001, 17(6): 1138-1148 doi: 10.2514/2.5875 [3] 俞刚, 范学军. 超声速燃烧与高超声速推进. 力学进展, 2013, 43(5): 449-471 (Yu G, Fan Xuejun. Supersonic combustion and hypersonic propulsion. Advances in Mechanics, 2013, 43(5): 449-471 (in Chinese) [4] Preller D, Smart MK. Reusable launch of small satellites using scramjets. Journal of Spacecraft and Rockets, 2017, 54(6): 1317-1329 doi: 10.2514/1.A33610 [5] Zhang TT, Wang ZG, Huang W, et al. An analysis tool of the rocket-based combined cycle engine and its application in the two-stage-to-orbit mission. Energy, 2020, 193: 116709 doi: 10.1016/j.energy.2019.116709 [6] 王兵, 谢峤峰, 闻浩诚等. 爆震发动机研究进展. 推进技术, 2021, 42(4): 721-737 (Wang Bing, Xie Qiaofeng, Wen Haocheng, et al. Research progress of detonation engines. Journal of Propulsion Technology, 2021, 42(4): 721-737 (in Chinese) [7] Laurence SL, Karl S, Schramm JM, et al. Transient fluid combustion phenomena in a model scramjet. Journal of Fluid Mechanics, 2013, 722: 85-120 doi: 10.1017/jfm.2013.56 [8] Laurence SL, Lieber D, Schramm JM, et al. Incipient thermal choking and stable shock-train formation in the heat-release region of a scramjet combustor. Part I: shock-tunnel experiments. Combustion and Flame, 2015, 162(4): 921-931 doi: 10.1016/j.combustflame.2014.09.016 [9] Larsson J, Laurence SJ, Moreno IB, et al. Incipient thermal choking and stable shock-train formation in the heat-release region of a scramjet combustor. Part II: large eddy simulations. Combustion and Flame, 2015, 162(4): 907-920 [10] Nordin-Bates K, Fureby C, Karl S, et al. Understanding scramjet combustion using LES of the HyShot II combustor. Proceedings of the Combustion Institute, 2017, 36: 2893-2900 doi: 10.1016/j.proci.2016.07.118 [11] Tian Y, Yang SH, Le JL, et al. Investigation of combustion and flame stabilization modes in a hydrogen fueled scramjet combustor. International Journal of Hydrogen Energy, 2016, 41: 19218-19230 doi: 10.1016/j.ijhydene.2016.07.219 [12] Tian Y, Yang SH, Le JL. Study on the effect of air throttling on flame stabilization of an ethylene fueled scramjet Combustor. International Journal of Aerospace Engineering, 2015, 2015: 504684 [13] Deng WX, Le JL, Yang SH, et al. Ethylene fueled scramjet combustion experiments. Modern Applied Science, 2013, 7(5): 51-59 [14] Mitani T, Tani K, Miyajima H. Flow choking by drag and combustion in supersonic engine testing. Journal of Propulsion and Power, 2007, 23(6): 1177-1184 doi: 10.2514/1.30264 [15] Lin KC, Ma FH, Yang V. Acoustic characterization of an ethylene-fueled scramjet combustor with a cavity flame holder. Journal of Propulsion and Power, 2010, 26(6): 1161-1169 doi: 10.2514/1.43338 [16] Li J, Zhang LW, Choi JY, et al. Ignition transients in a scramjet engine with air throttling. Part II: reacting flow. Journal of Propulsion and Power, 2015, 31(1): 79-88 doi: 10.2514/1.B35269 [17] Crump JE, Schadow KC, Culick FEC, et al. Longitudinal combustion instabilities in ramjet engines: identification of acoustic modes. Journal of Propulsion and Power, 1986, 2(2): 105-109 doi: 10.2514/3.22852 [18] Choi JY, Ma FH, Yang V. Combustion oscillations in a scramjet engine combustor with transverse fuel injection. Proceedings of the Combustion Institute, 2005, 30(2): 2851-2858 doi: 10.1016/j.proci.2004.08.250 [19] Sun MB, Cui XD, Wang HB, et al. Flame flashback in a supersonic combustor fueled by ethylene with cavity flameholder. Journal of Propulsion and Power, 2015, 31(3): 976-980 doi: 10.2514/1.B35580 [20] Chan WYK, Razzaqi SA, Turner JC, et al. Freejet testing of the HIFiRE 7 Scramjet flowpath at Mach 7.5. Journal of Propulsion and Power, 2018, 34(4): 844-853 doi: 10.2514/1.B36652 [21] Denman ZJ, Chan WYK, Brieschenk S, et al. Ignition experiments of hydrocarbons in a Mach 8 shape-transitioning scramjet engine. Journal of Propulsion and Power, 2016, 32(6): 1462-1471 doi: 10.2514/1.B36099 [22] Doherty LJ, Smart MK, Mee DJ. Experimental testing of an airframe-integrated three-dimensional scramjet at Mach 10. AIAA Journal, 2015, 53(11): 3196-3207 doi: 10.2514/1.J053785 [23] Landsberg WO, Wheatley VO, Smart MK, et al. Performance of high Mach number scramjets-tunnel vs. flight. Acta Astronautica, 2018, 146: 103-110 doi: 10.1016/j.actaastro.2018.02.031 [24] Urzay J. Supersonic combustion in air-breathing propulsion systems for hypersonic flight. Annual Review of Fluid Mechanics, 2018, 50: 593-627 doi: 10.1146/annurev-fluid-122316-045217 [25] Chang J, Li N, Xu K, et al. Recent research progress on unstart mechanism, detection and control of hypersonic inlet. Progress in Aerospace Sciences, 2017, 89: 1-22 doi: 10.1016/j.paerosci.2016.12.001 [26] Im SK, Do H. Unstart phenomena induced by flow choking in scramjet inlet-isolators. Progress in Aerospace Sciences, 2018, 97: 1-21 doi: 10.1016/j.paerosci.2017.12.001 [27] Ganguli S. Linear stability analysis of a normal shock train in a constant area isolator of a hypersonic scramjet. 2019, arXiv: 1907.08568 v2 [28] Laderman AJ, Urtiew PA, Oppenheim AK. On the generation of a shock wave by flame in an explosive gas. Proceedings of the Combustion Institute, 1963, 9: 265-274 doi: 10.1016/S0082-0784(63)80033-8 [29] Chue RS, Clarke JF, Lee JHS. Chapman-Jouguet deflagrations. Proceedings of the Royal Society of London A, 1993, 441: 607-623 [30] Zhu YJ, Chao J, Lee JHS. Propagation mechanism of critical deflagration waves that lead to detonation. Proceedings of the Combustion Institute, 2007, 31: 2455-2462 doi: 10.1016/j.proci.2006.07.209 [31] Saif M, Wang WT, Pekalski A, et al. Chapman-Jouguet deflagrations and their transition to detonation. Proceedings of the Combustion Institute, 2017, 36: 2771-2779 doi: 10.1016/j.proci.2016.07.122 [32] Goodwin GB, Houim RW, Oran ES. Shock transition to detonation in channels with obstacles. Proceedings of the Combustion Institute, 2017, 36: 2717-2724 doi: 10.1016/j.proci.2016.06.160 [33] Poludnenko AY, Chambers J, Ahmed K, et al. A unified mechanism for unconfined deflagration-to-detonation transition in terrestrial chemical systems and Type IA supernovae. Science, 2019, 366: eaau7365 doi: 10.1126/science.aau7365 [34] Liu YF, Shen H, Zhang DL, et al. Theoretical analysis on deflagration to detonation transition. Chinese Physics B, 2018, 27(8): 084703 doi: 10.1088/1674-1056/27/8/084703 [35] Bychkov V, Valiev D, Akkerman V, et al. Gas compression moderates flame acceleration in deflagration-to-detonation transition. Combustion Science and Technology, 2012, 184(7-8): 1066-1079 doi: 10.1080/00102202.2012.663995 [36] Valiev DM, Bychkov V, Akkerman V, et al. Different stages of flame acceleration from slow burning to Chapman-Jouguet deflagration. Physical Review E: Statistical, Nonlinear, and Soft Matter Physics, 2009, 80(3): 036317 doi: 10.1103/PhysRevE.80.036317 [37] Liu YF, Jiang ZL. Reconsideration on the role of the specific heat ratio in Arrhenius law applications. Acta Mechanica Sinica, 2008, 24: 261-266 doi: 10.1007/s10409-008-0137-2 [38] 刘云峰, 姜宗林. 详细化学反应模型中温度修正项特性研究. 中国科学: 物理学 力学 天文学, 2011, 41: 1-11 (Liu Yunfeng, Jiang Zonglin. Study on the chemical reaction kinetics of detonation models. Science China Physics,Mechanics &Astronomy, 2011, 41: 1-11 (in Chinese) [39] 刘云峰, 姜宗林. 分裂算法对准爆轰波数值模拟的影响. 中国科学: 物理学 力学 天文学, 2014, 44: 1213-1219 (Liu Yunfeng, Jiang Zonglin. Influence of operator-splitting algorithm on numerical simulation of quasi-detonation. Science China Physics,Mechanics &Astronomy, 2014, 44: 1213-1219 (in Chinese) [40] 韩信, 张子健, 马凯夫等. 超燃冲压发动机喷管推力性能理论预测. 气体物理, 2021, doi: 10.19527/j.cnki.2096-1642.0888Han Xin, Zhang Zijian, Ma Kaifu, et al. Theoretical prediction on the nozzle thrust of scramjets. Physics of Gases, 2021, doi: 10.19527/j.cnki.2096-1642.0888 (in Chinese) [41] Ma KF, Zhang ZJ, Liu YF, et al. Aerodynamic principles of shock-induced combustion ramjet engines. Aerospace Science and Technology, 2020, 103: 105901 doi: 10.1016/j.ast.2020.105901 [42] Zhang ZJ, Ma KF, Zhang WS, et al. Numerical investigation of a Mach 9 oblique detonation engine with fuel pre-injection. Aerospace Science and Technology, 2020, 105: 106054 doi: 10.1016/j.ast.2020.106054 [43] Zhang ZJ, Wen CY, Zhang WS, et al. Formation of stabilized oblique detonation waves in a combustor. Combustion and Flame, 2021, 223: 423-436 [44] 张子健, 韩信, 马凯夫等. 斜爆轰发动机燃烧机理试验研究. 推进技术, 2021, 42(4): 786-794 (Zhang Zijian, Han Xin, Ma Kaifu, et al. Experimental research on combustion mechanism of oblique detonation engines. Journal of Propulsion Technology, 2021, 42(4): 786-794 (in Chinese) [45] 沈欢, 张子健, 刘云峰等. 超燃冲压发动机推进性能理论分析. 气体物理, 2018, 3(1): 12-19 (Shen Huan, Zhang Zijian, Liu Yunfeng, et al. Analysis on the propulsion performance of scramjets. Physics of Gases, 2018, 3(1): 12-19 (in Chinese) [46] 马凯夫, 张子健, 刘云峰等. 斜爆轰发动机流动机理分析. 气体物理, 2019, 4(3): 1-10 (Ma Kaifu, Zhang Zijian, Liu Yunfeng, et al. Flow mechanism of oblique detonation engines. Physics of Gases, 2019, 4(3): 1-10 (in Chinese) [47] 韩信, 张文硕, 张子健等. 鼓包诱导斜爆震波的数值研究. 推进技术, 2021, doi: 10.13675/j.cnki.tjjs.200853Han Xin, Zhang Wenshuo, Zhang Zijian, et al. Numerical study of oblique detonation waves induced by a bump. Journal of Propulsion Technology, 2021, doi: 10.13675/j.cnki.tjjs.200853 (in Chinese) -