Numerical Study on the Supersonic Mixing Enhancement Using Streamwise Vortices

Kodera, Masatoshi; Sunami, Tetsuji; Scheel, Frithjof

doi:10.2514/6.2002-5117

Cited by 23 publications

(8 citation statements)

References 4 publications

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“…In addition, mixing can also be enhanced using modified structures such as, ramps (10,11,12) and pylons (13,14) . The enhancement of mixing due to the stream-wise vortices introduced by modified structures has also been investigated (15,16,17) . However, strut based injection is reported to be the most promising strategy owing to the fact that the fuel can be injected at the middle of the combustor.…”

Section: Computational Methodologymentioning

confidence: 99%

Numerical investigation of the role of hyper-mixers in supersonic mixing

Desikan

Kumaran

Babu³

2010

Aeronaut. j.

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Hypersonic air-breathing engines are considered to be the most appropriate alternative device to rocket based propulsion systems in reusable space vehicles within the lower atmospheric regime. Supersonic combustion ramjet (scramjet) engine is the key enabling technology for such sustained hypersonic flights. In scramjet engines, since the residence time of the mixture is of the order of a millisecond (for flight Mach numbers from 6 to 8) owing to the short combustor length, generation of useful thrust over the vehicle drag through heat addition at such high speeds is a challenging task. This is due to the fact that the fuel has to mix and burn completely within the short combustor length. Consequently, this places a severe limitation on the mixing time scale. This emphasises the importance of fuel injectors and mixing enhancement devices in supersonic combustors. ABSTRACTIn this numerical study, the role of hyper-mixers on supersonic mixing is investigated for six different strut configurations. To this end, 3D, compressible, turbulent, non-reacting flow calculations with air as the secondary injectant have been carried out. A qualitative comparison of the predictions with experimental results is made through Schlieren and Mie scattering images. A quantitative evaluation of the predictions is made by comparison with experimentally measured exit stagnation pressure, wall static pressure and the degree of unmixedness. Based on these results, three strut configurations have been selected for carrying out simulations with hydrogen as the injectant. Results from the hydrogen simulations are compared with the predictions using air and also across the strut configurations. The results clearly demonstrate that castellated strut configurations are very effective in enhancing mixing in such high speed flows.

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Section: Computational Methodologymentioning

confidence: 99%

Numerical investigation of the role of hyper-mixers in supersonic mixing

Desikan

Kumaran

Babu³

2010

Aeronaut. j.

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“…However, the dierence in the extent of the fuel distributions becomes more pronounced at downstream stations, which may be attributed to increased turbulent eects at higher ramp angles of the strut [20].…”

Section: Computational Uid Dynamicsmentioning

confidence: 97%

Physical Insight into Fuel/Air Mixing with Hypermixer Injectors for Scramjet Engines

Ogawa

Kodera

2015

Journal of Propulsion and Power

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Ecient mixing of fuel and air is a major objective for the successful operation of scramjet engines, where the supersonic combustion process must occur within an extremely short time frame in the hypersonic ight. This paper presents the insights gained into the key design factors and underlying mechanism for fuel/air mixing enhancement with streamwise vortices introduced by alternating wedges called hypermixers. The results of a parametric numerical study and sensitivity analysis suggest that: Narrow spanwise intervals between the alternating wedges and large fuel/air equivalence ratios are benecial for eective mixing, while higher total pressure recovery is associated with shallower ramp angles and lower fuel/air equivalence ratios.Higher fuel penetration is achieved with steeper ramp angles and higher fuel/air equivalence ratios. Streamwise vortex circulation increases with wider spanwise spacing and steeper ramp angles, but eective mixing enhancement is observed only in the latter case.

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“…Vibrating splitter, Helmholtz resonators, piezoelectric actuators, and acoustic excitation are common devices for the active excitation [24]. Most of the measures' aim is to generate large scale structures and streamwise vortices attracted much attention [29][30][31][32][33][34][35]. Large-scale streamwise vortices are passively formed and the instability of mixing layer is excited, usually applying injections from struts of trailing ramp with different configurations.…”

Section: Introductionmentioning

confidence: 99%

A LES Study on Passive Mixing in Supersonic Shear Layer Flows Considering Effects of Baffle Configuration

Ren

Wang

2014

Advances in Mechanical Engineering

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Under the background of dual combustor ramjet (DCR), a numerical investigation of supersonic mixing layer was launched, focused on the mixing enhancement method of applying baffles with different geometric configurations. Large eddy simulation with high order schemes, containing a fifth-order hybrid WENO compact scheme for the convective flux and sixth-order compact one for the viscous flux, was utilized to numerically study the development of the supersonic mixing layer. The supersonic cavity flow was simulated and the cavity configuration could influence the mixing characteristics, since the impingement process of large scale structures formed inside the cavity could raise the vorticity and promote the mixing. The effect of baffle's configurations on the mixing process was analyzed by comparing the flow properties, mixing efficiency, and total pressure loss. The baffle could induce large scale vortexes, promote the mixing layer to lose its stability easily, and then lead to the mixing efficiency enhancement. However, the baffle could increase the total pressure loss. The present investigation could provide guidance for applying new passive mixing enhancement methods for the supersonic mixing.

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Numerical Study on the Supersonic Mixing Enhancement Using Streamwise Vortices

Cited by 23 publications

References 4 publications

Numerical investigation of the role of hyper-mixers in supersonic mixing

Numerical investigation of the role of hyper-mixers in supersonic mixing

Physical Insight into Fuel/Air Mixing with Hypermixer Injectors for Scramjet Engines

A LES Study on Passive Mixing in Supersonic Shear Layer Flows Considering Effects of Baffle Configuration

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