Oscillatory Flows of Rectangular Hypersonic Inlet Unstart Caused by Downstream Mass-Flow Choking

2009 ◽  
Vol 25 (1) ◽  
pp. 138-147 ◽  
Author(s):  
Hui-Jun Tan ◽  
Shu Sun ◽  
Zhi-Long Yin
Keyword(s):  
Mass Flow ◽  
Oscillatory Flows ◽  
Flow Choking ◽  
Hypersonic Inlet ◽  
Inlet Unstart

A CFD assessment of classifications for hypersonic inlet start/unstart phenomena

2009 ◽  
Vol 113 (1142) ◽  
pp. 263-271 ◽  
Author(s):  
J. Chang ◽  
D. Yu ◽  
W. Bao ◽  
Z. Xie ◽  
Y. Fan
Keyword(s):  
Support Vector Machine ◽  
Classification Accuracy ◽  
Support Vector ◽  
Flight Tests ◽  
Multiple Classifiers ◽  
Hypersonic Inlet ◽  
Multiple Classifiers Fusion ◽  
Inlet Unstart ◽  
The Membership Function ◽  
Hypersonic Inlets

Abstract Inlet start/unstart detection is one of the most important issues of hypersonic inlets and is also the foundation of protection controls of scramjets. In ground and flight tests, it is inevitably to introduce the sensor noises to the measurement system. How to overcome or weaken the influence of the sensor noises and the outer disturbances is an important issue to the control system of the engine. To solve this problem, the 2D inner steady flow of hypersonic inlets was numerically simulated in different freestream conditions and backpressures, and two different inlet unstart phenomena were analysed. The membership function for hypersonic inlet start/unstart can be obtained by using probabilistic output support vector machine, and the algorithm of multiple classifiers fusion is introduced. The variations of the classification accuracy with the intensity of the sensor noises and the number of the classifier were discussed respectively. In conclusion, it is useful to introduce the algorithm of support vector machine and multiple classifiers fusion to overcome or weaken the influence of the sensor noises on the classification accuracy of hypersonic inlet start/unstart. The number of the practical fusion classifiers needs a tradeoff between the fusion classification accuracy and the complexity of the classification system.

scholarly journals Unstart Coupling Mechanism Analysis of Multiple-Modules Hypersonic Inlet

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Jichao Hu ◽  
Juntao Chang ◽  
Lei Wang ◽  
Shibin Cao ◽  
Wen Bao
Keyword(s):  
Oscillatory Flow ◽  
Coupling Effect ◽  
The Other ◽  
Coupling Mechanism ◽  
Mechanism Analysis ◽  
Reversed Flow ◽  
Hypersonic Inlet ◽  
Scramjet Engine ◽  
Coupling Characteristic ◽  
Inlet Unstart

The combination of multiplemodules in parallel manner is an important way to achieve the much higher thrust of scramjet engine. For the multiple-modules scramjet engine, when inlet unstarted oscillatory flow appears in a single-module engine due to high backpressure, how to interact with each module by massflow spillage, and whether inlet unstart occurs in other modules are important issues. The unstarted flowfield and coupling characteristic for a three-module hypersonic inlet caused by center module II and side module III were, conducted respectively. The results indicate that the other two hypersonic inlets are forced into unstarted flow when unstarted phenomenon appears on a single-module hypersonic inlet due to high backpressure, and the reversed flow in the isolator dominates the formation, expansion, shrinkage, and disappearance of the vortexes, and thus, it is the major factor of unstart coupling of multiple-modules hypersonic inlet. The coupling effect among multiple modules makes hypersonic inlet be more likely unstarted.

Tests of Hypersonic Inlet Oscillatory Flows in a Shock Tunnel

2015 ◽  
pp. 587-592
Author(s):  
Zhufei Li ◽  
Wenzhi Gao ◽  
Hongliang Jiang ◽  
Jiming Yang
Keyword(s):  
Shock Tunnel ◽  
Oscillatory Flows ◽  
Hypersonic Inlet

scholarly journals Alleviation of lateral spillage of two-dimensional hypersonic inlet using waverider-configuration chines

2020 ◽  
Vol 34 (14n16) ◽  
pp. 2040074
Author(s):  
Jian Zhai ◽  
Chen-An Zhang ◽  
Fa-Min Wang ◽  
Wei-Wei Zhang
Keyword(s):  
Mass Flow ◽  
Design Method ◽  
Three Dimensional ◽  
Major Type ◽  
Two Dimensional ◽  
Flow Ratio ◽  
Flow Uniformity ◽  
External Compression ◽  
Hypersonic Inlet ◽  
Mass Flow Ratio

Hypersonic inlet is an important part of the propulsion system of hypersonic air-breathing vehicles. However, the performance of the two-dimensional hypersonic inlet, a major type of hypersonic inlets, is considerably deteriorated for lateral spillage. In this study, waverider-configuration chines mounted on the lateral sides of a two-dimensional three-staged external-compression hypersonic inlet for a Mach number of 6.0 are investigated to determine their ability to alleviate the lateral spillage. The chines are built by using a waverider design method. The numerical results suggest that a severe flow spillage induced by three-dimensional effect shows up near the lateral edge of the inlet without chines, which degrades the mass-flow ratio and flow uniformity. In contrast, the waverider-configuration chines effectively alleviate the lateral spillage. Consequently, the mass-flow ratio and the flow uniformity are both improved significantly.

Dimensionless analysis of the unstart boundary for 2D mixed hypersonic inlets

2008 ◽  
Vol 112 (1135) ◽  
pp. 547-555 ◽  
Author(s):  
J. Chang ◽  
D. Yu ◽  
W. Bao ◽  
L. Qu
Keyword(s):  
Experimental Data ◽  
Pressure Ratio ◽  
Major Effect ◽  
Navier Stokes ◽  
Analysis Method ◽  
External Compression ◽  
Dimensionless Analysis ◽  
Hypersonic Inlet ◽  
Dimensional Analysis Method ◽  
Inlet Unstart

Abstract Inlet unstart boundary is one of the most important issues of the hypersonic inlet and is also the foundation of the protection control of a scramjet. To solve this problem, the 2D internal steady flow of a 2D mixed internal/external compression hypersonic inlet was numerically simulated at different freestream conditions and backpressures with a RANS (Reynolds-Averaged Navier-Stokes) solver using a RNG (Renormalisation Group) k-ε turbulence model, and two different inlet unstart phenomena were analysed. The dimensional analysis method was introduced to find the essence variables describing the inlet unstart boundary based on “numerical experimental” data in this paper. The dimensionless pressure ratios of the forebody and isolator were analysed respectively. The results show that the unstart boundary of the 2D mixed hypersonic inlet is determined by M0, α and Re0. Pressure ratio π increases with M0 increasing, and it increases firstly and decreases then with α increasing. Pressure ratio π increases with Re0 increasing. Re0 (Re0 < 2 × 107) has a major effect on π and Re0 (Re0 > 2×107) has little effect on π.

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