Computational Analysis of Non-Premixed Combustion in a Scramjet Combustor With a Wedge Shaped Strut Injector

2021 ◽  
Author(s):  
Sajal Katare ◽  
Nagendra P. Yadav
Keyword(s):  
Computational Analysis ◽  
Static Pressure ◽  
Computational Study ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Reaction Model ◽  
Premixed Combustion ◽  
Cold Flow ◽  
Flame Holder ◽  
Scramjet Combustor

Abstract This paper focuses the computational study of non-premixed combustion in a scramjet combustor. The wedge shaped strut injector was used in the combustion process. In order to investigate the flame holding mechanism of the wedge shaped strut in supersonic flow, the two-dimensional coupled implicit RANS equations, the standard k-ε turbulence model and the finite-rate/eddy-dissipation reaction model are introduced to simulate the flow field of the hydrogen fueled scramjet combustor with a strut flame holder under different conditions. The static pressure of the case under the engine ignition condition is much higher than that of the case under the cold flow condition. The reflection of shock waves improves the mixing of hydrogen with the stream of inlet air and thus increases combustion efficiency. The mass flow rate of air is optimized for the best performance of engine.

Computational Analysis of Hydrogen-Fueled Scramjet Combustor Using Cavities in Tandem Flame Holder

2015 ◽  
Vol 772 ◽  
pp. 130-135 ◽  
Author(s):  
Sukanta Roga ◽  
Krishna Murari Pandey
Keyword(s):  
Mach Number ◽  
Computational Analysis ◽  
Static Pressure ◽  
Combustion Efficiency ◽  
Recirculation Region ◽  
Stagnation Temperature ◽  
Computational Results ◽  
Species Transport ◽  
Flame Holder ◽  
Scramjet Combustor

This work presents the computational analysis of scramjet combustor using cavities in tandem flame holder by means of 3D. The fuel used by scramjet combustor with cavities in tandem flame holder is hydrogen, the fluid flow and the work is based on the species transport combustion with standard k-ε viscous model. The Mach number at inlet is 2.47 and stagnation temperature and static pressure for vitiated air are 1000K and 100kPa respectively. These computational analysis is mainly aimed to study the flow structure and combustion efficiency. The computational results are compared qualitatively and quantitatively with experimental results and these are agreed as well. Due to the combustion, the recirculation region behind the cavity injector becomes larger as compared to mixing case which acts as a flame holder. From the analysis, the maximum Mach number of 2.33 is observed in the recirculation areas.

Non-Premixed CH4 Combustion in a Porous Medium

2009 ◽  
Author(s):  
A. Tarokh ◽  
A. A. Mohamad ◽  
L. Jiang
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Combustion Zone ◽  
Combustion Process ◽  
Fiber Material ◽  
Combustion Efficiency ◽  
Premixed Combustion ◽  
Maximum Temperature ◽  
Wall Functions ◽  
Ch4 Combustion

Combustion process is the major contributor to the air pollution, such as CO, unburned hydrocarbon, soot and NOx, etc. Porous media can be a good candidate for improving the combustion efficiency and reducing pollution formation. Premixed combustion has been extensively investigated in the literature, experimentally and computationally. However, investigation of non-premixed combustion in porous media is limited in the open literature, which is the topic of this paper. The present work deals with the numerical modeling of methane/air non-premixed combustion in porous media. Physical problem that is considered here is fuel jet which is injected to the air in free flame case and injected into a porous medium, in the porous medium combustion case. The flow is assumed turbulent and standard k-ε model with standard wall functions is used in the simulation. The solid porous structure is assumed to be composed of alumina fiber material with temperature dependent heat conductivity. Discrete Ordinate method is used to solve radiative transport equations. The governing equations are solved using finite volume method. The results show that the combustion in porous media has superior combustion efficiency and significantly lower NOx and CO emissions compare to the free flame. This is due to the lower maximum temperature in porous media combustion. In comparison with the free flame case where the combustion zone is narrow and long, the results shows the combustion zone in porous media is shorter in axial and wider in radial direction.

Numerical Investigation on the Cold Flow Field of a Typical Cavity-based Scramjet Combustor with Double Ramp Entry

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
S. Periyasamy ◽  
S. Ragul ◽  
K. Sundararaj ◽  
P. S. Premkumar
Keyword(s):  
Flow Field ◽  
Static Pressure ◽  
Wave Structure ◽  
Back Pressure ◽  
Pressure Waves ◽  
Shock Train ◽  
Shock Wave Structure ◽  
Cold Flow ◽  
Scramjet Combustor ◽  
Inlet Conditions

AbstractThe effects of back pressure and cavity L/D ratio on the shock wave structure in the cold flow field of a typical cavity-based scramjet combustor with combined inlet and isolator is investigated numerically in the selected scramjet models. The scramjet with a throat ratio of TR 0.0 and cavity L/D 6.04 was analyzed. To perform such analysis, steady, 2-D RANS was used with SST k-ω. From the analysis, the value of static pressure along the cowl surface, contours of Mach number and pressure were obtained. The scramjet was modeled with different TR 0.1, 0.2, 0.25 and 0.3 with the same cavity L/D 6.04 and different cavity L/D 4.04, 9.04 and 12.04 with the same TR 0.25. All the models were analyzed with the same inlet conditions and the results were obtained. From the analysis, it was observed that the increase in back pressure moves the shock train towards the inlet of the isolator which leads to ‘engine unstart’ after the throat ratio of TR 0.1. Also, it is observed that there is an optimal L/D ratio of the cavity L/D 9.04 which restricts the propagation of high-pressure waves obtained in the combustor.

A Study on Performance Comparison of Integrated Aerodynamic-Ramp-Injector/ Gas-Portfire Flame Holder with Cavity

2013 ◽  
Vol 390 ◽  
pp. 8-11
Author(s):  
Bao Xi Wei ◽  
Qiang Gang ◽  
Yan Zhang ◽  
Rong Jian Liu ◽  
Liang Tian ◽  
...  
Keyword(s):  
Experimental Study ◽  
Mach Number ◽  
Supersonic Flow ◽  
Specific Impulse ◽  
Combustion Efficiency ◽  
Performance Comparison ◽  
Test Facility ◽  
Flame Holder ◽  
Scramjet Combustor ◽  
Total Temperature

Experimental study of an integrated aerodynamic-ramp-injector /gas-portfire (aero-ramp/G-P) has been conducted in a hydrogen-fueled scramjet combustor. The aero-ramp injectors consisted of four flush-walled holes, arranged to induce vorticular motion and enhance mixing. For comparison, a recessed cavity with four low downstream-angled circular injector holes was also examined. The combustor models were investigated experimentally using the scramjet direct connected test facility at the Beihang University. The facility can deliver a continuous supersonic flow of Mach number 2 with a total temperature of 1200K. The hot experimental results showed that the combustion efficiency and air specific impulse of aero-ramp/G-P are 85% and 35s while the corresponding values of cavity are 92% and 34s. These results justify the feasibility of aero-ramp/G-P flame holder.

Experimental Method for Combustion Efficiency Calculation in a Reheat Duct

1988 ◽  
Vol 110 (4) ◽  
pp. 690-694 ◽  
Author(s):  
A. Cadiou
Keyword(s):  
Cross Section ◽  
Static Pressure ◽  
Flow Characteristics ◽  
Combustion Efficiency ◽  
Pressure Measurements ◽  
Two Dimensional ◽  
Combustion Chambers ◽  
Outlet Cross Section ◽  
Gas Sampling ◽  
Flame Holder

An efficient method for the experimental measurement of the combustion efficiency in a reheat duct has been developed at ONERA. Such a method is useful because numerous reheat tests are necessary to study the effect of geometry and flow characteristics on reheat performances. Static pressure measurements along the duct and gas sampling in its outlet cross section are the basis of this downstream-to-upstream method. Experimental results with a tri-annular V-gutter flame holder are presented. These results are also used for comparison with theoretical two-dimensional calculations applied to reheat ducts that ultimately may reduce the number of experiments necessary for the development of reheat combustion chambers.

scholarly journals Experimental investigation of V-gutter flameholders

2017 ◽  
Vol 21 (2) ◽  
pp. 1011-1019 ◽  
Author(s):  
Dias Umyshev ◽  
Abay Dostiyarov ◽  
Musagul Tumanov ◽  
Quiwang Wang
Keyword(s):  
Bluff Body ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Bluff Bodies ◽  
Nox Emissions ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Flame Holder ◽  
Efficiency Increase ◽  
Exhaust Gas Temperature

Combustion characteristics and NOx emissions of propane and air mixture in a channel with a bluff body were investigated experimentally. Effects of the angle and type of the flameholder on the NOx emissions, blow-off limit, combustion efficiency, and exhaust gas temperature were examined. The results show that the NOx emissions are dependent on flameholder type and angle. Also it was observed that the perforated V-gutters considerably increases the blow-off performance. Moreover, the blow-off limit decreases as the geometrical size of flame-holder is increased. In addition, the combustion efficiency increase first and then decrease with the increase of the angle. The physics of the combustion process behind V-gutter flameholdes has been discussed. On the basis of experiment authors presented a modified version of the formula for calculation of lean blow-off limits when using bluff bodies, such as V-gutter flameholders.

scholarly journals Effect of added struts and intake velocity on flame stabilization in supersonic combustors

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Akram Mohammad ◽  
Keyword(s):  
Mole Fraction ◽  
Computational Study ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Single Step ◽  
Flame Stabilization ◽  
Reacting Flow ◽  
Mach Numbers ◽  
German Aerospace ◽  
The Impact

In the present computational study, the impact of strut positions and the effect of inlet Mach numbers on the combustion efficiency are investigated in a strut-based supersonic combustor. An experimentally investigated model combustor developed at the German Aerospace Center (DLR) is simulated and validated. Then, a model combustor with three struts placed at different positions is investigated. Two-dimensional, compressible, reacting-flow governing equations are solved along with single-step chemistry reaction and k-ω SST turbulence model using a commercial CFD code FLUENT. The oblique shock from the struts has a profound influence on the mixing and combustion process. The H2O mole fraction, H2 mole fraction contours, and combustion efficiency of various configurations are compared for finding better mixing and flame stabilization. The combustion efficiency reduces when the two struts are located in farther downstream or placed at the same downstream location. At higher Mach numbers, the combustion is delayed, and the mixing of fuel with the supersonic mainstream is incomplete.

CFD Analysis of Scramjet Combustor Using Strut With Circular and Planer Injector

2011 ◽  
Author(s):  
K. M. Pandey ◽  
Sivasakthivel Thangavel
Keyword(s):  
Mach Number ◽  
Research Work ◽  
Combustion Efficiency ◽  
Reaction Model ◽  
Reactive Flow ◽  
Mixing Efficiency ◽  
Cfd Analysis ◽  
Scramjet Combustor ◽  
Temperature And Pressure ◽  
Solid Walls

The simulation of a supersonic reactive flow is an important tool for the investigation and development of Scramjet engines. Numerical investigations have become less expensive than experiments. In this research work mixing and combustion for different type of strut injector is studied especially for strut with circular injector and strut with planer injector, in this work DLR scramjet combustor model is used, it having length of 340mm, width of 40mm, inlet entry height of 50mm and exit height of the combustor is 62mm. In this combustor strut is placed at the distance of 77mm from the inlet. Total length of the strut is 32mm. Air entry Mach number is 2, temperature and pressure of the air is 340k and 1 bar, at the base of the strut hydrogen will be injected at a Mach number of 1, temperature and pressure of the Hydrogen is 250k and 1 bar. Combustion will be initiated using pre burning of small amount of hydrogen and oxygen. In this CFD analysis two-dimensional coupled implicit NS equation, the standard k-ε turbulence model and the finite-rate/eddy-dissipation reaction model have been applied to numerically simulate the flow field of the hydrogen fuelled scramjet combustor. From analysis it is found that strut with planer injector giving good mixing efficiency, combustion efficiency and total pressure loss is less as compared to strut with circular injector. In both cases subsonic regions at the channel symmetry axis are responsible for flame holding. If the combustor geometry is chosen in a favourable way these subsonic zones may be kept small. Moreover, the flames are away from solid walls thus minimizing the wall heat load.

CFD Analysis of Hypersonic Combustion of H2-Fueled Scramjet Combustor with Cavity Based Fuel Injector at Flight Mach 6

2014 ◽  
Vol 656 ◽  
pp. 53-63 ◽  
Author(s):  
Krishna Murari Pandey ◽  
Sukanta Roga
Keyword(s):  
Flow Structure ◽  
Combustion Process ◽  
Wave Pattern ◽  
Combustion Efficiency ◽  
Fuel Injector ◽  
Recirculation Flow ◽  
Scramjet Combustor ◽  
Supersonic Mixing ◽  
Stable Flame ◽  
Scramjet Engine

This paper presents a numerical analysis of the inlet-combustor interaction and flow structure through a scramjet engine at a flight Mach 6 with cavity based injection. Fuel is injected at supersonic speed of Mach 2 through a cavity based injector. These numerical simulations are aimed to study the flow structure, supersonic mixing and combustion for cavity based injection. For the reacting cases, the shock wave pattern is modified which is due to the strong heat release during combustion process. The shock structure and combustion phenomenon are not only affected by the geometry but also by the flight Mach number and the trajectory. The inlet-combustor interaction is studied with a fix location of cavity based injection. Cavity is of interest because recirculation flow in cavity would provide a stable flame holding while enhancing the rate of mixing or combustion. The cavity effect is discussed from a view point of mixing and combustion efficiency.

scholarly journals Combustion Optimization for Coal Fired Power Plant Boilers Based on Improved Distributed ELM and Distributed PSO

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1036 ◽  
Author(s):  
Xinying Xu ◽  
Qi Chen ◽  
Mifeng Ren ◽  
Lan Cheng ◽  
Jun Xie
Keyword(s):  
Power Plant ◽  
Combustion Process ◽  
Optimization Method ◽  
Combustion Efficiency ◽  
Pollutant Emissions ◽  
Combustion Model ◽  
Nox Emissions ◽  
Coupling Characteristics ◽  
Learning Machine ◽  
Combustion Optimization

Increasing the combustion efficiency of power plant boilers and reducing pollutant emissions are important for energy conservation and environmental protection. The power plant boiler combustion process is a complex multi-input/multi-output system, with a high degree of nonlinearity and strong coupling characteristics. It is necessary to optimize the boiler combustion model by means of artificial intelligence methods. However, the traditional intelligent algorithms cannot deal effectively with the massive and high dimensional power station data. In this paper, a distributed combustion optimization method for boilers is proposed. The MapReduce programming framework is used to parallelize the proposed algorithm model and improve its ability to deal with big data. An improved distributed extreme learning machine is used to establish the combustion system model aiming at boiler combustion efficiency and NOx emission. The distributed particle swarm optimization algorithm based on MapReduce is used to optimize the input parameters of boiler combustion model, and weighted coefficient method is used to solve the multi-objective optimization problem (boiler combustion efficiency and NOx emissions). According to the experimental analysis, the results show that the method can optimize the boiler combustion efficiency and NOx emissions by combining different weight coefficients as needed.

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