Design and Experimental Study of an Over-Under TBCC Exhaust System.
Design and Experimental Study of an Over-Under TBCC Exhaust System.
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DOI：
10.1115/1.4025314
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
J. Mo;Jinglei Xu;Liuhuan Zhang
中科院分区：
文献类型：
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作者：
J. Mo;Jinglei Xu;Liuhuan Zhang
基于涡轮的联合循环 (TBCC) 推进系统已成为研究主题，作为更高效地超音速和高超音速飞行的手段。本研究的重点是在涡轮排气关闭和冲压喷气发动机排气增加的过渡模式期间 TBCC 排气系统中复杂流动的基本物理原理。使用特性方法 (MOC) 设计了 TBCC 排气系统，并进行了实验和计算研究。研究的主要目的是：（1）确定过渡模式阶段两个排气射流之间的相互作用及其对整个流场结构的影响； (2)确定并验证上下式TBCC排气喷管的气动性能； (3)根据实验条件验证计算流体力学(CFD)软件的模拟能力。采用静压口和纹影装置来获得壁面压力分布和流场结构。在涡轮流道分别半关闭和完全打开的六个不同位置对冲压喷气发动机喷嘴罩进行了稳态测试。 CFD 方法用于模拟排气流，它们通过提供对流场细节的更深入了解以及验证实验结果的方法来补充实验研究。结果表明，在排气系统模式转换过程中，两股排气射流相互作用，导致流动结构复杂。在此过程中排气系统推力系数从0.9288变化到0.9657。 CFD模拟结果与实验数据吻合良好，表明CFD方法能够有效评估TBCC排气系统在模式转换过程中的气动性能。
Turbine-based combined-cycle (TBCC) propulsion systems have been a topic of research as a means for more efficient flight at supersonic and hypersonic speeds. The present study focuses on the fundamental physics of the complex flow in the TBCC exhaust system during the transition mode as the turbine exhaust is shut off and the ramjet exhaust is increased. A TBCC exhaust system was designed using methods of characteristics (MOC) and subjected to experimental and computational study. The main objectives of the study were: (1) to identify the interactions between the two exhaust jet streams during the transition mode phase and their effects on the whole flow-field structure; (2) to determine and verify the aerodynamic performance of the over-under TBCC exhaust nozzle; and (3) to validate the simulation ability of the computational fluid dynamics (CFD) software according to the experimental conditions. Static pressure taps and Schlieren apparatus were employed to obtain the wall pressure distributions and flow-field structures. Steady-state tests were performed with the ramjet nozzle cowl at six different positions at which the turbine flow path were half closed and fully opened, respectively. Methods of CFD were used to simulate the exhaust flow and they complemented the experimental study by providing greater insight into the details of the flow field and a means of verifying the experimental results. Results indicated that the flow structure was complicated because the two exhaust jet streams interacted with each other during the exhaust system mode transition. The exhaust system thrust coefficient varied from 0.9288 to 0.9657 during the process. The CFD simulation results agree well with the experimental data, which demonstrated that the CFD methods were effective in evaluating the aerodynamic performance of the TBCC exhaust system during the mode transition.