Novel Oscillatory Patterns of Hypersonic Inlet Buzz

Chang, Juntao; Wang, Lei; Bao, Wen; Qin, Jiang; Niu, Jun; Xue, Wei

doi:10.2514/1.b34553

Cited by 66 publications

(15 citation statements)

References 11 publications

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“…The case of Mach 5.0 was also investigated and was described in Chang et al 15 Its experimental result is not presented in this paper due to the little number of plug position, which provides very little information about buzz. From these signals, the max backpressures (P max ) which the inlet can resist is obtained, and it is the critical backpressure.…”

Section: Resultsmentioning

confidence: 96%

“…For the two positions, x ¼ 104 and x ¼ 103, the buzz oscillations have no prominent dominant frequency though the inlet operates in unstart mode. This phenomenon is termed as the mixed oscillatory flow pattern in Chang et al, 15 and it is not considered in modeling. The frequencies corresponding to different x are listed in Table 2.…”

Section: Resultsmentioning

confidence: 98%

“…Air spillage at the entrance of the inlet is taken as the disturbance source and three communicating ways, namely, convection, shock train motion, and acoustic wave propagation, jointly establish the signal feedback loop. Chang et al 15 investigated experimentally the unstart process in a scramjet engine model at freestream Mach number of 4.5, 5, and 6, two extra unstart flow patterns were observed, namely, mixed oscillatory pattern and non-oscillatory violent pattern. In these oscillatory patterns, spillage plays an important role.…”

Section: Introductionmentioning

confidence: 96%

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Mathematical modeling and characteristic analysis of scramjet buzz

Chang

Wang

Bao

2014

Proceedings of the Institution of Mechanical Engineers, Part G:

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Buzz is an important issue for a scramjet engine. A mathematical model of buzz oscillations is necessary for control system design. Control-oriented models of hypersonic vehicle propulsion systems require a reduced-order model that is accurate to some extent but requires less than a few seconds of computational time. To achieve this goal, a reducedorder model of buzz oscillations for a scramjet engine is built by introducing the modeling idea of Moore-Greitzed model for compressors. The introduction of characteristic lines avoids the complex interactions in hypersonic inlet, such as shock-shock interactions and shock-boundary layer interaction. And the inlet characteristics are obtained from the pressure signal of combustor. Based on the established buzz model, we can predict the inlet performance, characterize the stability margin of inlet, reflect the oscillatory characteristics of inlet buzz including the dominant amplitude and frequency and describe the transition process of inlet buzz.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 96%

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Mathematical modeling and characteristic analysis of scramjet buzz

Chang

Wang

Bao

2014

Proceedings of the Institution of Mechanical Engineers, Part G:

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“…Twenty-five pressure transducers (labeled T1-T25), with the acquisition frequency is 5 kHz, were flush mounted in a row near the centerline of the compression surfaces and internal surface, to monitor the unsteady flow patterns of the inlet. The more detailed descriptions of testing model and measurements can be found in Chang et al 6 The test conditions are listed in Table 1. During each test, the plug was initially located in the downstream exit, so the inlet could start and the flow was stable.…”

Section: Experimental Setup and Resultsmentioning

confidence: 99%

“…Inlet experimental results [4][5][6] indicate that the shock train in an isolator moves upstream with the increase of backpressure, thus, the distance from shock train leading-edge to the most allowed upstream location can be used to character stable margin of hypersonic inlet. Many techniques 7,8 were developed to detect the location of shock train leading-edge, in order to character stable margin and prevent inlet unstart from occurring.…”

Section: Introductionmentioning

confidence: 97%

Real-time unstart prediction and detection of hypersonic inlet based on recursive Fourier transform

Chang

Wang

Qin

et al. 2014

Proceedings of the Institution of Mechanical Engineers, Part G:

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Unstart is an abnormal operation, and special care is devoted to this phenomenon for a hypersonic inlet. The process of a two-dimensional hypersonic inlet from start to unstart is experimentally demonstrated by recording the corresponding time history of the wall static pressure. By analyzing the pressure signals, it can be found that the oscillation of shock train flow can be used to characterize the location of shock train leading-edge. The register of shock train leading-edge at T14 located close to inlet throat is a good precursor for unstart prediction. T8 located in the upstream of last ramp compression shock is the optimum transducer for unstart detection because its pressure just goes through steady flow and unstart flow. Based on the differences in frequency domain among steady flow, shock train flow and unstart flow, recursive Fourier transform for unstart prediction and detection is introduced. The algorithm description, algorithm application, and parameters influence of the detection method are discussed, and the results show the validity of the detection method.

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Tests of Hypersonic Inlet Oscillatory Flows in a Shock Tunnel

Gao

Jiang

et al. 2015

29th International Symposium on Shock Waves 1

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Novel Oscillatory Patterns of Hypersonic Inlet Buzz

Cited by 66 publications

References 11 publications

Mathematical modeling and characteristic analysis of scramjet buzz

Mathematical modeling and characteristic analysis of scramjet buzz

Real-time unstart prediction and detection of hypersonic inlet based on recursive Fourier transform

Tests of Hypersonic Inlet Oscillatory Flows in a Shock Tunnel

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