Turbulence-combustion Interaction Research Articles

Development and Validation of a Compressible Reacting Gas-Dynamic Flow Solver for Supersonic Combustion

An approach based on the OpenFOAM library has been developed to solve a high-speed, multicomponent mixture of a reacting, compressible flow. This work presents comprehensive validation of the newly developed solver, called compressibleCentralReactingFoam, with different supersonic flows, including shocks, expansion waves, and turbulence–combustion interaction. The comparisons of the simulation results with experimental and computational data confirm the fidelity of this solver for problems involving multicomponent high-speed reactive flows. The gas dynamics of turbulence–chemistry interaction are modeled using a partially stirred reactor formulation and provide promising results to better understand the complex physics involved in supersonic combustors. A time-scale analysis based on local Damköhler numbers reveals different regimes of turbulent combustion. In the core of the jet flow, the Damköhler number is relatively high, indicating that the reaction time scale is smaller than the turbulent mixing time scale. This means that the combustion is controlled by turbulent mixing. In the shear layer, where the heat release rate and the scalar dissipation rate have the highest value, the flame is stabilized due to finite rate chemistry with small Damköhler numbers and a limited fraction of fine structure. This solver allows three-dimensional gas dynamic simulation of high-speed multicomponent reactive flows relevant to practical combustion applications.

Assessment of a hydrogen-fueled swirling trapped-vortex combustor using large-eddy simulation

In recent years, the study of hydrogen combustion has gained significant interest due to its exceptional lean blow-out (LBO) performance, high efficiencies, and almost negligible greenhouse gas emissions. The present study combines the advantages of hydrogen combustion with the beneficial characteristics of trapped-vortex combustion (TVC) and swirling flows. Large-eddy simulation (LES) is conducted to evaluate the performance of a swirling trapped-vortex combustor. LES sub-gird terms are described using k-equation subgrid model, while, turbulence-combustion interaction is modelled employing the PaSR (Partially Stirred Reactor) closure with a detailed 23-step chemical reaction mechanism for hydrogen/air. A radial vane swirler is incorporated to supply an annular mainstream and generate a wake region in front of the cavity leading edge to enhance cavity flow entrainment. To evaluate the performance of a hydrogen-fueled TVC under non-swirl and swirling conditions with varying swirl numbers (0.1–0.6), several flow and combustion characteristics are analyzed. These includes temperature distribution, vortical structure, combustion efficiency, NO emission, and flame shape. The results show that a large recirculation zone dominates the cavity for the all swirl numbers resulting in a strong fuel–air mixing and high combustion efficiency. It is demonstrated that the swirling motion effectively mitigates the negative impacts of pressure fluctuations arising from the interaction of combustion with cavity oscillations. A stable flame is observed inside the cavity and in the shear layer at the cavity lip in all cases, merging to form a distinctive C-shaped flame. Increasing the swirl number causes the second part of the flame to move to the wake region before the leading edge, enhancing combustion stability and efficiency. Combustion efficiency exceeds 98.5% for all cases, reaching 99.8% for a swirl number of 0.6. The temperature distribution is nearly uniform inside the cavity, with an improved distribution at the TVC’s outlet for higher swirl numbers. Under non-swirling conditions, the corrected NO concentration is below 5 ppm. Increasing the swirl number escalates the outlet NO emission, nevertheless, a maximum NO concentration of 19 ppm is observed for the swirling cases. Comparing these findings with existing data suggests that the swirling TVC offers advantages over other hydrogen-fired TVC’s.

Entropy: An Inspiring Tool for Characterizing Turbulence-Combustion Interaction in Swirling Flames via Direct Numerical Simulations of Non-Premixed and Premixed Flames.

This article focuses on entropy generation in the combustion field, which serves as a useful indicator to quantify the interaction between turbulence and combustion. The study is performed on the direct numerical simulations (DNS) of high pressure non-premixed and premixed swirling flames. By analyzing the entropy generation in thermal transport, mass transport, and chemical reactions, it is found that the thermal transport, driven by the temperature gradient, plays a dominant role. The enstrophy transport analysis reveals that the responses of individual terms to combustion can be measured by the entropy: the vortex stretching and the dissipation terms increase monotonically with the increasing entropy. In high entropy regions, the turbulence behaves as the "cigar shaped" state in the non-premixed flame, while as the axisymmetric state in the premixed flame. A substantial increase in the normal Reynolds stress with the entropy is observed. This is due to the competition between two terms promoted by the entropy, i.e., the velocity-pressure gradient correlation term and the shear production term. As a result, the velocity-pressure gradient correlation tends to isotropize turbulence by transferring energy increasingly from the largest streamwise component to the other smaller normal components of Reynolds stress and is dominated by the fluctuating pressure gradient that increases along the entropy. The shear production term increases with the entropy due to the upgrading alignment of the eigenvectors of strain rate and Reynolds stress tensors.

Numerical Investigation of a Coupled Blow-Off/Flashback Process in a High-Pressure Lean-Burn Combustor

Abstract Large eddy simulation is used to investigate the flashback mechanism caused by the combustion-induced vortex breakdown (CIVB) in a high-pressure lean-burn annular combustor with lean direct injection of kerosene. A single sector of the geometry, including a central pilot flame surrounded by a main flame, is simulated at takeoff conditions. A previously developed flamelet-based approach is used to model turbulence–combustion interactions due to its relatively low cost, allowing to simulate a sufficiently long time window. In stable operations, the flame stabilizes in an M-shape configuration and a periodic movement of the pilot jet, with the corresponding formation of a small recirculation bubble, is observed. Flashback is then observed, with the flame accelerating upstream toward the injector as already described in other studies. This large eddy simulation (LES), however, reveals a precursor partial blow-out of the main flame induced by a cluster of vortices appearing in the outer recirculation region. The combined effect of vortices and sudden quenching alters the mixing level close to the injector, causing first the main, then the pilot flame, to accelerate upstream, and initiate the CIVB cycle before the quenched region can re-ignite. Main and pilot flames partly extinguish as they cross their respective fuel injection point, and re-ignition follows due to the remnants of the reaction in the pilot stream. The process is investigated in detail, discussing the causes of CIVB-driven flashback in realistic lean-burn systems.

PeleLM-FDF large eddy simulator of turbulent reacting flows

A new computational methodology, termed ‘PeleLM-FDF’ is developed and utilised for high fidelity large eddy simulation (LES) of complex turbulent combustion systems. This methodology is constructed via a hybrid scheme combining the Eulerian PeleLM base flow solver with the Lagrangian Monte Carlo simulator of the filtered density function (FDF) for the subgrid scale reactive scalars. The resulting methodology is capable of simulating some of the most intricate physics of complex turbulence-combustion interactions. This is demonstrated by LES of a non-premixed CO/H temporally evolving jet flame. The chemistry is modelled via a skeletal kinetics model, and the results are appraised via a posteriori comparisons against direct numerical simulation (DNS) data of the same flame. Excellent agreements are observed for the time evolution of various statistics of the thermo-chemical quantities, including the manifolds of the multi-scalar mixing. The new methodology is capable of capturing the complex phenomena of flame-extinction and re-ignition at a 1/512 of the computational cost of the DNS. The high fidelity and the computational affordability of the new PeleLM-FDF solver warrants its consideration for LES of practical turbulent combustion systems.

Three-Dimensional Numerical Analysis of Longitudinal Thermoacoustic Instability in a Single-Element Rocket Combustor

This study numerically investigated the thermoacoustic combustion instability characteristics of a scaled rocket combustor based on a hybrid of the Reynolds-averaged Navier–Stokes and large–eddy simulation method. The turbulence–combustion interactions were treated using flamelet generated manifold approach. An unstable case was simulated with detailed reaction mechanisms (GRI-Mech 3.0). The obtained results agree well with experiment data from Purdue University, in terms of pressure oscillations frequency and power spectral density spectrum. The combustion instability mode was identified to be coupled with the first longitudinal acoustic mode of the combustion chamber by dynamic model decomposition method. According to Rayleigh index analysis, the unstable driving source was found to be located near the combustor step, which was further confirmed by time-averaged flow fields. Detailed three-dimensional vortex ring shedding evolutions at the combustor step were tracked with fine time resolution. Results indicate that the combustion instability arises from periodic vortex ring shedding at the combustor step and interacting with the chamber wall. The unburnt reactants were rolled up by the shedding vortex ring, which would not break up until impact with the chamber wall. Therefore, the mixing performance was significantly enhanced, leading to sudden heat release. Consequently, the thermal energy is added to the acoustic field, and the first longitudinal mode is thus reinforced, giving rise to large amplitude axial velocity oscillations which prompt the generation of the new vortex ring. The results of the present investigation will support the design and development of high-performance rocket engines.

A Study on turbulence-combustion interaction and Sub-grid Scale model in the simulation of Methane pool fire using LES

In this paper, the effect of the combustion and turbulence sub-grid scale (SGS) model on the simulation of pool fire turbulence field has been studied in open source CFD software, OpenFOAM. Two combustion models of Eddy Dissipation Model (EDM) and infinite fast chemistry, with the one-equation and Smagorinsky SGS model, is evaluated for a large-scale pool fire. In general, fast kinetic-based combustion models predict excessive heat release rate. The mean squared of the velocity fluctuations is over-predicted. In this simulation, the turbulence models have no significant effect on the results. In fact, the effect of the combustion model is dominant. The EDM combustion model is more compatible when used with the one-equation SGS model and improves the results compared to other cases. In addition, the infinite fast chemistry combustion model is not a suitable model for fire simulation.

Flame behaviour and flame location in large-eddy simulation of the turbulent premixed combustion

The lean premixed flame of a fuel mixture in a jet flow combustor was computationally investigated, and results were compared with experimental data at a constant thermal load of 9 kW and constant equivalence ratio of 0.588. Three variables, namely, the amplitude of pulsation, frequency (f), and the mass flow rate ratio (MFRR) of the inlet region, were considered to describe the turbulent effect and investigate the topology and location of the flame that represent the characteristics of sinusoidal wave inlet velocity. Results showed that flame topology strongly depended on varying the turbulence parameters examined, especially f and MFRR. The V-shaped flame with corrugated wings formed in the vicinity of the flame holder reflected the turbulence–combustion interaction in all test cases. The suggested large-eddy simulation (LES) model was suitable in predicting the flame location and flame topology associated with pulsating jet flow.

EGR Dilution and Fuel Property Effects on High-Efficiency Spark-Ignition Flames

<div class="section abstract"><div class="htmlview paragraph">Modern spark ignition internal combustion engines rely on fast combustion rates and high dilution to achieve high brake thermal efficiencies. To accomplish this, new engine designs have moved towards increased tumble ratios and stroke-to-bore ratios. Increased tumble ratios correlate positively with increases in turbulent kinetic energy and improved fuel and residual gas mixing, all of which favor faster and more efficient combustion. Longer stroke-to-bore ratios allow higher geometric compression ratios and use of late intake valve closing to control peak compression pressures and temperatures. The addition of dilution to improve efficiency is limited by the resulting increase in combustion instabilities manifested by cycle-to-cycle variability. A number of effects - preferential diffusion, turbulence-combustion interactions, stochastic flow patterns, laminar-turbulent flame kernel transitions, and relative length and velocity scales between flame and turbulence - are believed to be responsible for the increase in cycle-to-cycle variations, where their contributions are likely interlinked. Several studies have shown the influence of stochastic flow characteristics on the nature of combustion instabilities, such as velocity patterns on flame kernel formation and cycle-to-cycle variations in residual gas. However, few have focused on the specific effects of fuel properties. The objective of this work is to contrast the effects of dilution on propane stoichiometric combustion against gasoline. Dilution tolerance experiments were conducted in a purpose-built high stroke-to-bore ratio single cylinder engine with both gasoline and LPG. Three-dimensional full cycle computational fluid dynamics (CFD) simulations employing a level-set combustion approach and Reynolds averaged Navier-Stokes (RANS) turbulence modeling was used to qualitatively assess the changes in length and velocity scales for turbulence and the flame. The experimental results showed that LPG can tolerate higher exhaust gas recirculation (EGR) dilution under a variety of conditions. Analysis of CFD simulations showed that propane flames are likely less sensitive to influences from the flow field due to less thickening of the flame and higher effective flame speeds.</div></div>

Turbulence topology evolution in weakly turbulent premixed flames

In turbulent premixed flames, not only the isotropy of velocity fluctuations is altered by the thermal expansion effect but also the dissipative structure of the turbulent flow field and the flow topology are also deeply influenced by the flame. Considering the joint probability density function of the second and third invariants of the velocity gradient tensor (VGT)—or its traceless counterpart—is a classical way to deduce the topology of turbulent flows at these smallest scales. These quantities are analyzed by considering direct numerical simulation databases of premixed flame kernel growth in homogeneous isotropic turbulence. Two conditions of turbulence–combustion interaction are considered, which correspond to two distinct values of the Bray number. The analysis of the VGT shows that the propagating premixed flame and its associated density variations significantly modify the turbulence structure and flow topology. To understand this behavior as the flow interacts with the flame front, Lagrangian dynamics of the VGT and its invariants are studied by considering the conditional mean rate of change vectors. Special emphasis is thus placed on the Lagrangian evolution equations of these invariants. To the best of authors' knowledge, this is first time that such budgets are scrutinized under premixed combustion conditions. The pressure Hessian contribution to the VGT invariant transport equations is shown to be one of the leading-order terms in this evolution, making it critically important to the flow dynamics and turbulence structure.

Turbulence–Combustion Interactions in Premixed and Non-premixed Flames Generated by Hot Active Turbulent Jets

Direct numerical simulations of turbulent jet ignition (TJI)-assisted combustion of lean hydrogen–air mixtures are performed in a three-dimensional planar jet configuration for various thermo-chemical conditions. TJI is a novel ignition enhancement method which facilitates the combustion of lean and ultra-lean fuel–air mixtures by rapidly and continuously exposing them to high temperature combustion products. Fully compressible gas dynamics and species equations are solved with high order finite difference methods. The hydrogen–air reaction is simulated by a detailed chemical kinetics mechanism. Turbulence–combustion interactions in TJI systems are studied here for different conditions using the flame heat release, temperature, species concentrations, and a newly defined progress variable. Important phenomena such as localized flame extinction/re-ignition and simultaneous existence of premixed/non-premixed flames in TJI-assisted combustion are also investigated.

Coupling RSM with soot model for the study of soot formation in a momentum-dominated strained jet flames

This paper presents a comparison between the numerically determined soot volume fraction (SVF) in a momentum-dominated turbulent diffusion strained jet flames burning ethylene/hydrogen/nitrogen mixture in air with experimental results. The soot inception model used is based on the formation rate of two or three ring poly aromatic hydrocarbon with C6H6 as the soot precursor. Second-moment closure Reynolds stress method turbulent model is used in conjunction with the governing equation of mass, momentum and energy. The turbulent combustion kinetic chemistry interaction is modeled by choosing a chemical equilibrium non-premixed combustion model along with the species inlet diffusion probability density function (PDF). Soot radiation source term like P-1 radiation model is also included along with the turbulent combustion model. The soot turbulence interaction invoked uses single-variable PDF based on the temperature and mixture fraction (Z) for measurement of flame lift-off height, flame length and radiative heat loss. Equilibrium-based Lee soot oxidation model is chosen to estimate the hydroxyl (OH) and O2 species for the oxidation of soot particles. The numerical solutions for each of the experimental configurations are proposed by Mahmoud and co-workers for three different strained flames (4000 s−1, 7300 s−1, and 12,900 s−1). In each discretized finite volume cell, using a quadratic upstream interpolation for convective kinematics algorithm in spatial coordinate and time-bounded second-order accurate in temporal coordinate solution is obtained. All the above turbulence combustion interaction models are iterated with unit Courant–Friedrichs–Lewy condition. It is noted that the mixture fraction (Z) PDF used is very sensitive to the chosen turbulence combustion soot interaction models. Also, it is observed that the simulated outputs are in good agreement with the measured experimental data in terms of SVF, temperature both axially and radially. SVF increases with a decrease in the flame strain rate and shows the reverse trend in radially integrated soot volume reaction. In agreement with experiments, soot productivity shows a linear relationship in momentum-dominated flame with an increase in the strain rates for soot productivity, maximum mean SVF, exit Froude number, exit C2H4 flow rate.

A Reduced Order Model based on Large Eddy Simulation of Turbulent Combustion in the Hybrid Rocket Engine

A combined method of large eddy simulations for non-premixed combustion in a turbulent boundary layer coupled with proper orthogonal decomposition of instantaneous velocity, pressure and temperature fields is developed in order to obtain a reduced order model. First, we investigate a channel turbulent reacting flow using Large Eddy Simulations (LES) technique. Polypropylene/O2 has been considered as fuel/oxidant pair. The turbulence-combustion interaction is based on a combination of finite rate/eddy dissipation model applied to a reduced chemical mechanism with four reactions. The LES numerical results are analyzed with respect to RANS simulations and with other reference data. The second part of the paper refers to the derivation of a Reduced Order Model (ROM) based on proper orthogonal decomposition (POD) technique for the unsteady flow field. In order to achieve that, the eigenmodes of the flow are computed from several snapshots of the instantaneous fields uniformly spaced and the most energetic ones are used to set up the Reduced Order Model. Constant regression rate of the fuel grain is considered. The flow and thermal fields obtained with ROMs are compared with the ones obtained from the full simulation and an analysis on the number of modes required to achieve the desired accuracy is presented.

Large eddy simulation of turbulence-combustion interactions in a stagnation point reverse flow combustor

This study focuses on the interaction between turbulence and combustion in a stagnation point reverse flow (SPRF) combustor. Turbulent activities have been examined with large eddy simulation (LES) technique including k-equation subgrid turbulence modeling. The non-premixed and premixed combustion cases are modeled by using partially stirred reactor (PaSR) combustion model with one-step global reaction chemistry. In the non-premixed operation, a lifted flame is located about the two-thirds of the combustor, while an attached flame is observed for the premixed operation. Results of the complex flow field and combustion dynamics showed that SPRF combustor can operate at low emission conditions. The existence of the shear layer between the coaxial jets resulted with intense mixing, which further increases the efficiency of the combustor. Exhaust gas re-circulation prevented high temperature levels, hence high NOx levels within the combustor. The preliminary thermo-acoustic study showed that noise levels are highly affected by the turbulent production and heat release generation mechanisms. The contribution of the combustion noise to the total noise level is higher in the non-premixed operation as compared to the premixed one.

The effects of pressure treatment on the flamelet modeling of supersonic combustion

The flamelet method has been used extensively as an affordable turbulence-combustion interaction model that obviates the need to solve the evolution equations for the species mass fractions during a large-eddy or Reynolds-averaged Navier–Stokes calculation of a reactive flow field, leading to substantial savings in the simulation time and enabling modeling with relatively complex kinetic mechanisms. The canonical problem analyzed and stored in a look-up array in the flamelet procedure usually assumes some baseline fields; in particular, the pressure is often specified at a fixed value that is characteristic of the examined configuration. However, pressure in supersonic combustion has significant dynamical roles, unlike in low-Mach number or incompressible flows, and a constant pressure field will not be adequate for the former. To remedy this problem, reaction rate in the combustor is often assumed to scale squarely with pressure. This approach, which is probably acceptable for low-speed, high pressure combustors, is not suitable for dealing with the variable pressure conditions in supersonic combustion. This paper focuses on the assessment of the aforementioned scaling, in absolute sense, and also relative to an approach where pressure is added as a control parameter in the flamelet library. To achieve this, three classes of reactive systems with different levels of modeling complexities are investigated to show that representative chemical variables do not scale squarely with pressure. For the case of supersonic combustion, the scaling treatment in general leads to over-prediction of pressure and combustion and also tends to stabilize the flame. To the knowledge of the authors, no previous studies have reported on the issues addressed in the present paper.

Characterisation of the eddy dissipation model for the analysis of hydrogen-fuelled scramjets

ABSTRACTThe eddy dissipation model (EDM) is analysed with respect to the ability to address the turbulence–combustion interaction process inside hydrogen-fuelled scramjet engines designed to operate at high Mach numbers (≈7–12). The aim is to identify the most appropriate strategy for the use of the model and the calibration of the modelling constants for future design purposes. To this end, three hydrogen-fuelled experimental scramjet configurations with different fuel injection approaches are studied numerically. The first case consists of parallel fuel injection and it is shown that relying on estimates of ignition delay from a 1D kinetics program can greatly improve the effectiveness of the EDM. This was achieved through a proposed zonal approach. The second case considers fuel injection behind a strut. Here the EDM predicts two reacting layers along the domain which is in agreement with experimental temperature profiles close to the point of injection but not the case any more at the downstream end of the test section. The first two scramjet test cases demonstrated that the kinetic limit, which can be applied to the EDM, does not improve the predictions in comparison to experimental data. The last case considered a transverse injection of hydrogen and the EDM approach provided overall good agreement with experimental pressure traces except in the vicinity of the injection location. The EDM appears to be a suitable tool for scramjet combustor analysis incorporating different fuel injection mechanisms with hydrogen. More specifically, the considered test cases demonstrate that the model provides reasonable predictions of pressure, velocity, temperature and composition.

Dynamics and kinematics of the reactive scalar gradient in weakly turbulent premixed flames

In turbulent flames, chemical species mixing rates are controlled to a large extent by the geometric alignment of the species composition gradients with the local velocity gradients. This alignment indeed characterizes the turbulence–scalar interaction (TSI), which is one of the leading-order source terms in the scalar dissipation rate (SDR) evolution. In situations featuring density variations, which may be relevant either to (i) non-reactive but multiphase or compressible flows, or to (ii) reactive flows such as those considered herein, it should be acknowledged that there is still some controversy about the role of dilatational effects and its connection with the rotation of the strain-rate tensor principal axes. These two issues are analyzed by considering direct numerical simulation databases of flame kernel growth in homogeneous isotropic turbulence (HIT). Two distinct conditions of turbulence–combustion interaction (TCI) are considered: the first is a quasi-laminar reference case while the second displays some local thickening of the preheating zone. Special emphasis is placed on the kinematics of the scalar gradient orientation, which is studied through the direct inspection of the reactive scalar gradient orientation budget. To the best of the authors’ knowledge, this is first time that such a budget is scrutinized in premixed combustion conditions. The analysis shows that, for the flow conditions that are presently investigated, the role associated to the rotation of the strain-rate eigenframe is of paramount importance: it is the leading-order term in the scalar gradient orientation budget. This study also confirms that, in the vicinity of the flame, the resulting evolution opposes the rise of the reactive scalar gradient norm (i.e., the rise of the SDR) but the corresponding effects are lessened as the normalized root mean square (RMS) of the velocity fluctuations is increased.

Improved Flamelet Modeling of Supersonic Combustion

This paper has the objective of addressing a few basic issues pertaining to the use of the laminar flamelet method to model turbulence-combustion interactions in supersonic combustion. Specifically, this paper documents the way in which the use of Troe’s pressure-reaction-rate model affects the laminar flame solutions that are used in the generation of the flamelet library for supersonic combustion. For the opposed-jet model of nonpremixed flames, this study also investigates how the laminar-flamelet results obtained using the flamelet equations differ from those obtained from the canonical equations for opposed-jet flame (OJF). The differential results obtained for supersonic combustion predictions in two models of the scramjet isolator/combustor when pressure, in several formulations, is included as an independent variable of the flamelet table are also presented. Lastly, this study investigates the manner in which the use of various interpolations of the reaction progress variable from the S-curve affects turbulent supersonic combustion results. The overall goal of the various studies is to provide an improved flamelet modeling of supersonic combustion. Simulations based on linear progress variable interpolation coupled with the seven-level pressure field in the base flamelet library, using the OJF equations, appear to yield the best results.

Investigation of a turbulent premixed combustion flame in a backward-facing step combustor; effect of equivalence ratio

In the present study, LES (large-eddy simulation) is utilized to analyze lean-premixed propane-air flame stability in a backward-step combustor over a range of equivalence ratio. The artificially thickened flame approach coupled with a reduced reaction mechanism is incorporated for modeling the turbulence–combustion interactions at small scales. Simulation results are compared to high-speed PIV (particle image velocimetry) measurements for validation. The results show that the numerical framework captures different topological flow features effectively and with reasonable accuracy, for stable flame configurations, but some quantitative differences exist. The RZ (recirculation zone) is formed of a primary eddy and a secondary eddy and its overall size is significantly impacted by the equivalence ratio. The temperature distribution inside the recirculation zone is highly non-uniform, with much lower values observed close to the backward step and the bottom wall. The mixture distribution inside the RZ is also non-uniform because of mixing with reactants and heat loss to the walls. The flame is stabilized closer to the backward step as the equivalence ratio increases. At lower fuel fractions, the flame lifts off the step starting at equivalence ratio of 0.63 and the lift off distance is increased while the equivalence ratio is lowered.

A numerical investigation on heat transfer and emissions characteristics of impinging radial jet reattachment combustion (RJRC) flame

Radial Jet Reattachment combustion (RJRC) flame jet is used in applications where the impingement surface is delicate and demands low impingement pressure. In the present study, a two dimensional axisymmetric computational fluid dynamics (CFD) simulation is carried out. The turbulence–combustion interaction in the flame field is modeled in a k−ε/EDM framework. The distribution of heat flux, pressure coefficient and emissions is presented for varying Reynolds number (Re = 1000 to 30,000) and different non-dimensional nozzle tip to plate spacing (X/R = 0.5 to 3). It is found that the peak heat flux increases and pressure coefficient reduces significantly with the increase in Reynolds number. However, with the increase in the nozzle tip to plate spacing the peak heat flux and the pressure coefficient decrease. Furthermore, the concentrations of NOx and CO emissions increase with the increase in Reynolds number and the distance of the location of the nozzle tip from the impingement plate.