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

Ogawa, H.; Kodera, Masatoshi

doi:10.2514/1.b35638

Cited by 21 publications

(4 citation statements)

References 20 publications

(25 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The numerical investigation of the hyper mixer with a row of alternating wedges having central fuel injection as shown in fig. 2 (Ogawa and Kodera 2015) shows the favorable efficient fuel/air mixing in narrow spanwise spacing which creates strong streamwise vortex but does not improve the fuel/air mixing.…”

Section: Review Of Literaturementioning

confidence: 98%

See 1 more Smart Citation

A Review of hyper mixers to enhance combustion efficiency in supersonic combustor

Ananthan¹,

Sekar²

2020

AJMT

View full text Add to dashboard Cite

Supersonic mixing and combustion enhancement is primarily focused to increase the efficiency of scramjet engine. The research on a fuel injection system performance is widely developing today. In scramjet engine, the air and fuel mixing is improper due to the supersonic flow inside the combustor. The flame instabilization occurs due to less resident time of air which tends to affect the output efficiency and it leads to loss of fuel energy. Hence apart from the modern research studies on various fuel injection techniques inside the supersonic combustor, this study provides the idea of various alternating wedge designs to enhance the air and fuel mixture. Also reducing the consumption of fuel in the combustor gives a great impact in usage of fuel energy efficiently in the aviation field.

show abstract

Section: Review Of Literaturementioning

confidence: 98%

“…The higher fuel/air mixing is achieved by greater vertical height and augments streamwise vortex circulation with the help of steeper ramp angle (Ogawa and Kodera 2015). The streamwise vortex interaction across the symmetry plans plays a vital role in convective mixing of fuel air.…”

Section: Fig 5: the Schematic Of Cavity Shaped Combustormentioning

confidence: 99%

A Review of hyper mixers to enhance combustion efficiency in supersonic combustor

Ananthan¹,

Sekar²

2020

AJMT

View full text Add to dashboard Cite

show abstract

“…For supersonic combustion, typical solutions for mixing intensification are based on vorticity generation such as by struts (hypermixers), cavities, shock wave impinging the fuel jet, etc. [117][118][119][120]. Plasma-based mixing is still considered an exotic approach.…”

Section: Mixing Enhancement By Electric Dischargesmentioning

confidence: 99%

Electrically Driven Supersonic Combustion

Leonov

2018

Energies

View full text Add to dashboard Cite

This manuscript reviews published works related to plasma assistance in supersonic combustion; focusing on mixing enhancement, ignition and flameholding. A special attention is paid for studies, which the author participated in person. The Introduction discusses general trends in plasma-assisted combustion and, specifically, work involving supersonic conditions. In Section 2, the emphasis is placed on different approaches to plasma application for fuel ignition and flame stabilization. Several schemes of plasma-based actuators for supersonic combustion have been tested for flameholding purposes at flow conditions where self-ignition of the fuel/air mixture is not realizable due to low air temperatures. Comparing schemes indicates an obvious benefit of plasma generation in-situ, in the mixing layer of air and fuel. In Section 3, the problem of mixing enhancement using a plasma-based technique is considered. The mechanisms of interaction are discussed from the viewpoint of triggering gasdynamic instabilities promoting the kinematic stretching of the fuel-air interface. Section 4 is related to the description of transitional processes and combustion instabilities observed in plasma-assisted high-speed combustion. The dynamics of ignition and flame extinction are explored. It is shown that the characteristic time for reignition can be as short as 10 ms. Two types of flame instability were described which are related to the evolution of a separation zone and thermoacoustic oscillations, with characteristic times 10 ms and 1 ms correspondingly.

show abstract

“…It was found that the alternating wedge strut gives better mixing and robust turbulent structures inducing streamwise vortices. The numerical study with alternating wedge strut was conducted by Ogawa and Kodera (2015). The authors conducted a parametric study of the alternating wedge strut by varying the ramp angle of the trailing wedge and the width of the wedge.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of the effect of strut geometries on the flow characteristics in a model combustor

Nair,

P.S.,

A.B.

2023

AEAT

View full text Add to dashboard Cite

Purpose The mixing of fuel and air plays a pivotal role in enhancing combustion in supersonic regime. Proper mixing stabilizes the flame and prevents blow-off. Blow-off is due to the shorter residence time of fuel and air in the combustor, as the flow is in supersonic regime. The flame is initiated in the local subsonic region created using a flameholder within the supersonic combustor. This study aims to design an effective flameholder which increases the residence time of fuel in the combustor allowing proper combustion preventing blow-off and other instabilities. Design/methodology/approach The geometry of the strut-based flameholder is altered in the present study to induce a streamwise motion of the fluid downstream of the strut. The streamwise motion of the fluid is initiated by the ramps and grooves of the strut geometry. The numerical simulations were carried out using ANSYS Fluent and are validated against the available experimental and numerical results of cold flow with hydrogen injection using plain strut as the flameholder. In the present study, numerical investigations are performed to analyse the effect on hydrogen injection in strut-based flameholders with ramps and converging grooves using Reynolds-averaged Navier–Stokes equation coupled with Menter’s shear stress transport k-ω turbulence model. The analysis is done to determine the effect of geometrical parameters and flow parameter on the flow structures near the base of the strut where thorough mixing takes place. The geometrical parameters under consideration include the ramp length, groove convergence angle, depth of the groove, groove compression angle and the Mach number. Two different strut configurations, namely, symmetric and asymmetric struts were also studied. Findings Higher turbulence and complex flow structures are visible in asymmetric strut configuration which develops better mixing of hydrogen and air compared to symmetric strut configuration. The variation in the geometric parameters develop changes in the fluid motion downstream of the strut. The fluid passing through the converging grooves gets decelerated thereby reducing the Mach number by 20% near the base of the strut compared to the straight grooved strut. The shorter ramps are found to be more effective, as the pressure variation in lateral direction is carried along the strut walls downstream of the strut increasing the streamwise motion of the fluid. The decrease in the depth of the groove increases the recirculation zone downstream of the strut. Moreover, the increase in the groove compression angle also increases the turbulence near the base of the strut where the fuel is injected. Variation in the injection port location increases the mixing performance of the combustor by 25%. The turbulence of the fuel jet stream is considerably changed by the increase in the injection velocity. However, the change in the flow field properties within the flow domain is marginal. The increase in fuel mass flow rate brings about considerable change in the flow field inducing stronger shock structures. Originality/value The present study identifies the optimum geometry of the strut-based flameholder with ramps and converging grooves. The reaction flow modelling may be performed on the strut geometry incorporating the design features obtained in the present study.

show abstract

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

Cited by 21 publications

References 20 publications

A Review of hyper mixers to enhance combustion efficiency in supersonic combustor

A Review of hyper mixers to enhance combustion efficiency in supersonic combustor

Electrically Driven Supersonic Combustion

Numerical investigation of the effect of strut geometries on the flow characteristics in a model combustor

Contact Info

Product

Resources

About