Premixed Combustion Characteristics Research Articles

Premixed Combustion Characteristics of Hydrogen/Air in a Micro-Cylindrical Combustor with Double Ribs

Premixed Combustion Characteristics of Hydrogen/Air in a Micro-Cylindrical Combustor with Double Ribs

Deflagration dynamics of ammonia-syngas-air premixed flames in T-type tube

In the context of carbon peak carbon neutrality, the carbon-free emission of NH3 combustion has received increasing attention within the field of combustion, but due to the low activity of NH3, research has generally been carried out through NH3 blending with other more active hydrocarbon fuels. In this work, a combination of experimental and simulation approach was used to study the premixed flame combustion characteristics of ammonia-syngas-air mixture. Two fuels, NH3 and H2 (one of the main components of syngas), were used as the main body of the mixture and their volume fractions were set to vary from 0 to 1, respectively. Then comparative analyses were performed on the flame base combustion characteristics. The results of the study showed that an increase in the volume fraction of NH3 decreases the flame propagation speed, while H2 has the opposite effect. For example, when both NH3 and H2 volume fractions were 0.6, the time required for the premixed flame to travel from the combustion chamber bifurcation to rush out of the pipe was 15 ms and 3.5 ms, respectively. The stability of the flame also decreased with the increase of NH3 content, the fold area of the flame tip increased, and the flame tip structure became cellular at 81 ms when the NH3 volume fraction was 0.6. With the increase of NH3 volume fraction, Lewis gradually decreases, and the decrease rate of Lewis is basically the same, linearly decreasing. The Lewis of pure ammonia combustion is less than the critical value of 1, and the flame is unconditionally unstable. The stability of the flame of the gas mixture with H2 as the main fuel is with the increase of the volume fraction of H2 first rise and then fall, the most stable is X(H2) = 0.7, Lev = 1.16495, when the volume fraction of CO and NH3 in the fuel are both 0.15. Meanwhile, the main reaction paths in the combustion reaction process are similar for both fuel bodies, but the rate of each reaction path in the NOx formation process is faster when H2 is the fuel body.

Investigation of Split Diesel Injections in Methanol/Diesel Dual-Fuel Combustion in an Optical Engine

Methanol is a promising alternative fuel due to its wide availability of raw materials, mature production processes, and low production cost. However, because of the low cetane number, methanol must include a more reactive fuel to assist with combustion when used in compression ignition (CI) engines. In this study, based on the optical CI engine platform, methanol is injected into the intake port, and diesel is directly injected into the cylinder to achieve dual-fuel combustion. The effects of the methanol energy ratios and diesel split injection strategies on combustion are investigated. The results show that the premixed blue flame was mainly concentrated in the near wall region, whereas the yellow flame produced by diesel combustion tended to concentrate in the central region as the methanol energy ratio increased. When the methanol energy ratio exceeded 50%, the ignition delay was significantly prolonged, while the flame area was greatly reduced. Meanwhile, the peak values for the cylinder pressure and heat release rate decreased significantly, indicating a significant deterioration in combustion. At the earlier diesel pre-injection timing at −58°, the overall dual-fuel combustion at each main injection timing exhibited low-temperature premixed combustion characteristics, with a lower peak exothermic rate and flame brightness. At the later pre-injection timing at −33°, the spray flame at all main injection timings could be observed, with higher peak heat release rates and indications of thermal efficiency. Combustion at later main injection timings was characterized by diffusion combustion, and the main injection timing could effectively regulate the combustion process through phase adjustment.

Numerical simulation of premixed n-heptane/air combustion in micro tube with internal channel optimization

In military and aerospace fields, petrol and aviation kerosene are the preferred fuels for micro power systems due to their reduced carrying load and convenient fuel source. Therefore, n-heptane, an alternative to petrol and aviation paraffin, was chosen as the fuel. A micro quartz glass tube was used as the combustor, and the premixed combustion characteristics of n-heptane/air were investigated using numerical simulations. The method used to improve the internal flow channel includes a built-in cross baffle and scaled backward-facing step. The resulting optimized combustion characteristics, such as internal flow line, wall temperature, CO emission, and wall radiation, have been analyzed. The results indicate that, with a fixed equivalence ratio of 1.0 and a n-heptane mass flow rate of 2.70 mg/s, the built-in cross baffle concentrates and stabilizes the high temperature zone of the flame, resulting in a significant increase in wall temperature. Conversely, the use of the micro tube with scaled backward-facing step creates a reflux zone due to the sudden expansion of the inlet cross-section, which promotes better fuel mixing and flame anchoring. Furthermore, after comparing the output efficiencies of micro tube with different internal structures, it was discovered that enhancing the internal channel of the micro tube is crucial for increasing the wall radiation efficiency.

Numerical investigation of CH4/H2/air micro-mixing combustion flow in a micro gas turbine combustor with different head-end structures

In order to investigate the premixed combustion characteristics of CH4/H2/air in a micro-mixing combustor, the effects of different micro-mixing head-ends (HE1, HE2, HE3) and hydrogen mixing ratios on the temperature distribution, heat transfer process, emission characteristic, flames shape are analyzed. The results show that compared with swirl head-end combustion, the micro-mixing combustion performance is better. Among the three head-ends, HE3 has the best combustion characteristics and stable flames. The temperature distribution in the high-temperature zone is uniform, and low-temperature zone is concentrated near the jet, which can suppress the flashback. The velocity and temperature gradient near the central axis of jet streams show a strong synergistic effect. The flames are plume shaped and flames stability is mainly influenced by the H2 combustion process. Increasing the jet diameter, decreasing the jet spacing and increasing the hydrogen mixing ratio all contribute to the flames stability, but these three methods can stabilize the flames by affecting fluid Reynolds number, interaction between small flames and combustion rate, respectively. Moreover, small jet diameter and high hydrogen mixing ratio can reduce OTDF, which contributes to improve outlet temperature uniformity.

Study of CH4-H2-CO-Air premixed combustion characteristics based on fractal dimension and flame crack method

The laminar combustion characteristics of CH4-H2-CO-Air are studied in a constant volume combustion chamber with different hydrogen content ratios and the initial conditions of 300 K and 0.2 MPa by schlieren technology. The influence laws of flame instability are analyzed through the influence laws of hydrogen content ratio and equivalence ratio (Φ) on the fractal dimensions of the flame contour and the ratio of the total flame face cracks' lengths to the flame radius (L/R), as well as the influence laws of hydrodynamic instability and thermal-diffusive instabilities on the flames. The results show that L/R is more sensitive to flame instabilities than flame front fractal dimensions due to a wider sampling range. After R exceeds a certain value, for lean and rich combustion conditions with the same distance from the stoichiometric ratio, the L/R is greater during lean combustion, and as the equivalence ratio gradually increases from 0.6 to 1.4, the effect of increasing hydrogen content (Hydrogen mole fraction ranges from 60% to 66.67%) on flame instability gradually shifts from promotion to suppression. This study has certain reference value for the combustion application of biomass synthesis gas.

Optical diagnostics and chemical kinetic analysis on partially premixed combustion characteristics fueled with methanol and various cetane improvers

The need for decarbonization has inspired the utilization of methanol in transportation industry. Via both experimental and modeling frameworks, this study, for the first time, reveals the ignition, heat release and flame development characteristics of methanol mixed with different cetane improvers, i.e., 2-ethylhexyl nitrate (EHN) and di-tertiary‑butyl peroxide (DTBP), under practical, advanced engine conditions. Particularly, a detailed chemical kinetic model is newly developed for methanol/EHN/DTBP mixtures, incorporating the most updated sub-chemistries for relevant fuel components and critical intermediates, to assist in further analysis on the effects of EHN and DTBP on ignition and emission formation under engine thermodynamic environments derived from recorded in-cylinder pressure histories. Results show that stable combustion of methanol/EHN mixtures can be realized under low direct injection (DI) pressure, high in-cylinder thermodynamic condition, featuring the lowest coefficient of variation of indicated mean effective pressure (COVIMEP) of 1.46 %. Throughout the combustion process, the yellow and white flame dominates. At the same DI timing, methanol/EHN mixtures present shorter ignition delay, faster heat release rate (HRR) and more advanced combustion phasing compared with methanol/DTBP mixtures. At similar combustion phasing, the peak flame/OH* natural luminosity intensity of methanol/EHN mixtures is higher. KL factor, which is utilized to evaluate soot concentration, also shows similar trend, indicating higher sooting tendency of methanol/EHN mixtures. Flux analysis further highlights higher production of soot precursor (i.e., C2H2) with EHN than DTBP, primarily via the pathway of C2H4→ C2H3→C2H2. The active atmosphere created by the decomposition of EHN or DTBP has significant effects on decreasing methanol ignition delay in the early stage of their exothermic process, while the active atmosphere of EHN remains impactful whereas that of DTBP diminishes at later stages. The thermal atmosphere shows greater effects on methanol ignition at later stages of the exothermic process of EHN or DTBP decomposition than the early stages.

Numerical analysis for optimizing combustion strategy in an ammonia-diesel dual-fuel engine

Due to the stringent environmental regulations, the use of ammonia, a carbon-free fuel, as a fuel for internal combustion engines is attracting attention. It is necessary to understand the characteristics of engines using ammonia to replace diesel engines. Therefore, in this study, the combustion characteristics of an ammonia-diesel dual-fuel engine were investigated through numerical simulation to optimize the combustion strategy. A reaction mechanism was constructed for the simulation. Ammonia energy fractions ranging from 40 to 90% and diesel injection timings from −80 to −15 crank angle degrees (CAD) were considered. When the diesel injection timing was advanced, the combustion period was shortened, and the premixed combustion characteristics were shown. An increase of the efficiency of up to 11.0% compared to diesel combustion was obtained under advanced injection timing and high ammonia energy fraction. This is because the slow flame propagation of ammonia was compensated for by the effect of premixed combustion. Therefore, the advance of the injection timing resulted in a reduction in unburned ammonia emissions. Also, the combustion temperature increased due to the premixed combustion effect. So, the nitrous oxide emission was greatly reduced by thermal decomposition. And carbon dioxide emission was proportional to diesel quantity. As a result, greenhouse gases were reduced by up to 80.6% compared to diesel combustion in advanced injection timing and high ammonia energy fraction. However, nitric oxide emissions increased as the ammonia energy fraction increased and injection timing advanced under the influence of fuel and thermal nitrogen oxides. It was significant compared to diesel engines.

Numerical simulation of lean premixed combustion characteristics and emissions of natural gas-ammonia dual-fuel marine engine with the pre-chamber ignition system

As an efficient hydrogen carrier, ammonia (NH3) has great potential to realize the target of carbon neutralization. In this paper, a natural gas-ammonia dual-fuel engine model has been established to evaluate the feasibility of ammonia application in a high-pressure medium-speed four-stroke natural gas marine engine. In order to achieve the efficient and clean combustion of ammonia, a method combining the pre-chamber ignition system with lean-burn combustion technology was proposed. In addition, a CH4/NH3 combustion mechanism with reasonable accuracy was developed to simulate the combustion process of the engine. Moreover, the effect of using various ammonia concentration in the fuel on jet flame formation, thermal efficiency, unburned ammonia, and NOx and N2O emissions were compared. The results showed that the pyrolysis of ammonia mixtures in the pre-combustion chamber promoted the formation of jet flame, which had a “chain effect” on the turbulent kinetic energy in the main combustion chamber and further enhanced the flame propagation in lean conditions. In addition, NOx emission showed a decreasing function of the split ratio of ammonia, which was caused by the NO reduction by unburned NH3. However, the low-temperature generation characteristics of N2O emissions led to the opposite trend. Furthermore, the application of ammonia increased N2O emissions by 0.18–0.49 g/kWh, which is about 0.06%–0.1% of nitrogen in ammonia fuel, resulting in a partial offset of CO2 emission reduction effect.

Uncertainty quantification of the premixed combustion characteristics of NH3/H2/N2 fuel blends

Green ammonia is a candidate fuel to decarbonise shipping and other industries. However, ammonia features a lower reactivity compared to conventional fuels and is therefore difficult to burn. To resolve this issue, thermo-catalytic cracking of ammonia using waste heat is often employed to produce NH3/H2/N2 blends as fuel. However, on-site operational variations in this process can become sources of uncertainty in the fuel composition, causing randomness of the flame's physicochemical properties and challenging flame stability. In the present work, a surrogate model is built using the polynomial chaos expansion (PCE) method to investigate the impact of fuel composition variability on combustion characteristics at different operating conditions. Impacts of 1.5% deviation in the fuel composition on the flame properties for different initial pressures (Pi) and unburnt fuel temperatures (Tu) are investigated for a wide range of equivalence ratios covering lean and rich mixtures. The uncertainty effects defined by the coefficient of variation (COV) fluctuate for equivalence ratios greater than 1.1, while no fluctuation is observed in COV for near stoichiometric combustion conditions. It is shown that H2 variation in the fuel blend has the strongest effect (over 80%) on the uncertainty of all investigated physicochemical properties of the flame. The least affected property is the adiabatic flame temperature with variations of about 2.5% in richer fuel conditions. The results further show that preheating of the reactants can significantly reduce the COV of laminar flame speed. The consequences of these uncertainties upon different combustion technologies are then discussed and it is argued that moderate and intense low oxygen dilution (MILD) and colourless distributed combustion (CDC) technology may remain resilient.

Experimental and numerical study on laminar burning velocity and premixed combustion characteristics of NH3/C3H8/air mixtures

Propane (C3H8) is the major component of liquefied petroleum gas, the combustion of C3H8 and ammonia (NH3) should be concerned. However, there is a scarcity of experimental data on NH3/C3H8/air mixtures to validate the kinetic models, especially at elevated pressures. This work aims to provide some new laminar burning velocity data and investigate the premixed combustion characteristics of NH3/C3H8/air mixtures in detail. The measurement was performed at various equivalence ratios (ϕ = 0.6–1.4), ammonia ratios (α = 20 %, 50 %, 80 %), and initial pressures (P0 = 0.1–0.5 MPa). Besides, five kinetic models were compared against the experimental data, the optimal performing model was used for numerical simulation. The results show that when the mole fraction of C3H8 in fuels is 50 %, the peak laminar burning velocity is about 28.5 cm/s. And the peak value decreases to 19.0 cm/s when the initial pressure rises to 0.5 MPa. The burned gas Markstein length decreases with the increase of equivalence ratio mainly due to the remarkable effect of the effective Lewis number, and it also decreases with the increase of initial pressure because of the decreasing flame thickness. C3H8 promotes the combustion intensity of NH3, which is reflected in the enhancement of flame temperature and radical pool, but C3H8 has no obvious effect on the mixture heating value of the NH3/C3H8/air mixtures. NH3 substituting can effectively reduce CO and CO2 emissions, and the reduction effect is more significant under high NH3 mole fraction conditions.

Experimental and numerical study on the effect of CO2 dilution on the laminar combustion characteristics of premixed CH4/H2/air flame

The effects of diluents on the characteristics of constant volume combustion and Chemkin-Pro laminar premixed combustion were investigated. The laminar combustion characteristics of the CH4/H2/CO2/N2 mixtures under different initial conditions were studied by using a chemical kinetic model. After experiment and comparison, the FFCM-1 mechanism works well. Based on the laminar burning velocity (LBV), a numerical decoupling method was used to separate the three effects of diluent CO2: the dilution effect, the thermal effect and the chemical effect, those show that three effects increased with the rising initial temperature while the elevated pressure reversed. The unit fuel, thermal parameters and active free radicals were gained by parameter analysis, sensitivity analysis, chemical path analysis and mole fraction analysis, which increased the LBV and caused the three effects to change. The R32 takes the leading role with initial temperature increased and the R54 and R84 play a key role in the chemical effect in rising initial pressure, respectively. The effect of CO2 on the combustion characteristics of CH4/H2 mixture was investigated under this work, which provided a theoretical reference for exhaust gas recirculation.

Combustion and emission characteristics of premixed biogas mixtures: An experimental study

In this study, effects of fuel composition, swirl number and hydrogen addition on combustion and emission characteristics of various biogas mixtures were experimentally investigated. To this end, a laboratory scale combustor and a swirl stabilized premixed burner were designed and manufactured. Later on, this combusting apparatus was equipped with flow, control, safety and measurement tools, hence entire test system was constituted. Combustion and emission characteristics of tested biogas mixtures were determined by measuring temperature and species (CO 2 , CO, O 2 and NO) distributions throughout the combustion chamber. Additionally, flame structures of tested biogas mixtures were evaluated by examining flame luminosity, visible flame length and flame thickness from instantaneous flame images. Results of this study showed that both radial and axial temperature distribution variations of tested biogas mixtures differently alter with hydrogen addition based on the gas composition. Although flame temperature increases with swirl number at burner outlet, it presents a non-monotonous dependence on swirl number outside the flame region because of the modified flow characteristics. This is also the case for emissions of CO 2 . • Premixed combustion characteristics of various biogas mixtures were investigated. • Gas composition, swirl number and hydrogen addition effects were examined. • Hydrogen addition differently altered temperature distribution based on the gas composition. • Flame temperature presented a non-monotonous dependence on swirl number.

Effect of background turbulent field on ion current characteristics of methane-air premixed combustion

Ion current detection technology has a broad application prospect in natural gas engines. The effect of background turbulent environment on ionic current characteristics of methane - air mixture premixed combustion needs further study. The premixed combustion of methane-air mixtures under different turbulence intensities was studied on the constant volume combustor with controllable turbulence intensities. The effects of turbulence intensity on flame image, combustion pressure and ion current signal during combustion were analyzed. The ion current calculation model was built by coupling Cantera chemical reaction calculation program in the MATLAB environment. The variation of the concentration of the main species under different conditions was analyzed and the ion current signals under different turbulent conditions were simulated. The results show that in turbulent environment, the flame front appears fold and cellular structure, which increases the flame front area and accelerates the combustion speed. With the increase of turbulence intensity, the peak of combustion pressure increases and the peak time is advanced. The ion current appeared earlier in turbulent environment, and the duration of ion current decreased with the increase of turbulence intensity. When the equivalent ratio is near 1, the species concentration change greatly due to the influence of incomplete combustion. The concentration of species except water and carbon dioxide increases with the increase of temperature. The ion current calculation model can predict the overall trend of ion current signal in turbulent premixed combustion, but the simulation results of ion current signal in the later stage of combustion are too large.

Experimental study on premixed combustion characteristics of methane-air under dual spark plug ignition strategy in a closed spherical chamber

Dual spark plug ignition technology can effectively improve the low heat release rate of engine caused by slow combustion of natural gas. However, the mechanism of flame stability and ion current in the combustion process of double flame are not clear. This study is based on a nearly spherical closed constant volume combustion chamber experimental platform. Experiments on premixed combustion characteristics of methane-air under different ignition strategies (single spark plug ignition, dual spark plug synchronous ignition and asynchronous ignition) were carried out. The cellular structure of flame front and the relationship between the stretch flame propagation velocity and stretch rate were analyzed. The effects of different ignition strategies on heat release rate and ion current signal were analyzed. The results show that the flame stability of single spark ignition and synchronous ignition is better than that of asynchronous ignition. Under the asynchronous ignition strategy, the flame front appears fold and cellular structure with the increase of ignition interval time. Markstein length is the smallest and flame stability is the weakest due to the action of opposite flame. The heat release rate and mean ion current of synchronous ignition are higher than those of single spark plug ignition, and are not different from those of asynchronous ignition. Dual spark ignition greatly shortens the main combustion duration and is conducive to rapid combustion. Synchronous ignition is a promising ignition strategy which can guarantee flame stability and increase combustion velocity.

Numerical Simulation of Lean Premixed Combustion Characteristics and Emissions of Natural Gas-Ammonia Dual-Fuel Marine Engine with the Pre-Chamber Ignition System

Numerical Simulation of Lean Premixed Combustion Characteristics and Emissions of Natural Gas-Ammonia Dual-Fuel Marine Engine with the Pre-Chamber Ignition System

Lewis number effects on lean premixed combustion characteristics of multi-component fuel blends

Variation in natural gas composition, alongside the potential for H2 enrichment, creates the potential for significant changes to premixed flame behaviour. To strengthen fundamental understanding of lean multi-component alternative fuel blends, an outwardly propagating spherical flame was employed to measure the flame speeds and Markstein lengths of C1C4 hydrocarbons, alongside precisely mixed blends of CH4/C2H6, CH4/C3H8 and CH4/H2. Theoretical relationships between Markstein length and Lewis Number are explored alongside effective Lewis number formulations. Under lean conditions, equal volumetric additions of H2 and C3H8 (30% vol.) to CH4 resulted in similar augmentation of burning velocity, however, opposite susceptibility to preferential diffusional instability was noted. At a fixed equivalence ratio of 0.65, limited changes in composition provide a marked change in the premixed flame response with the addition of C2H6 and C3H8 to CH4. For lean CH4/H2 mixtures, a diffusional based Lewis Number formulation yielded a favourable correlation, whilst a heat-release model resulted in better agreement for lean CH4/C3H8 blends. Modelling work suggests that measured enhancement of lean CH4 flames upon H2 or C3H8 is strongly correlated to changes in volumetric heat release rates and production of H radicals. Furthermore, a systematic analysis of the flame speed enhancement effects (thermal, kinetic, diffusive) of H2 and C3H8 addition to methane was undertaken. Augmented flame propagation of CH4/H2 and CH4/C3H8 was demonstrated to be principally an Arrhenius effect, predominantly through reduction of associated activation energy. Finally, plausible short-term variations in composition with hydrogen-enriched multi-component natural gas flames were investigated experimentally and numerically. At the leanest conditions, small variations in CH4:C3H8 content at a fixed H2 fraction resulted in discernible changes in stretch related behaviour, a reflection of the thermo-diffusive behaviour of each fuel's response.

Experimental and numerical study on premixed partially dissociated ammonia mixtures. Part II: Numerical study of premixed combustion characteristics

Adding dissociated ammonia (NH3) is an effective way to improve the combustion properties of NH3. Research on the laminar burning velocity of partially dissociated NH3 mixtures was shown in part I. In order to further explore the feasibility of enhancing ammonia combustion by adding dissociated ammonia, several essential combustion properties were numerically studied in part Ⅱ of this study. The burned gas Markstein length was obtained by the experiment and theoretical calculation, and the relevant combustion parameters such as adiabatic flame temperature, heat release rate and NO formation were calculated by planar flame simulation. Results show that the Markstein length increases with the increasing dissociating degree on the lean side, but decreases under rich conditions, which is mainly due to the determination of flame thickness, effective Lewis number and Zel’dovich number. The addition of dissociated NH3 increases the mixture heating value, but the combustion efficiency decreases slightly. The primary exothermic elementary reactions in the combustion are gradually replaced by the reactions in the H2 system, and the exothermic process shifts to a lower temperature with the increase of dissociating degree. NO is the main NOx emission, the formation of NO is determined by the concentration of the O/H radicals and NH3, its mole fraction first increases and then decreases with the increase of dissociating degree. Moreover, the NO emission on the rich side only decreases slightly under high dissociating degree conditions, which is different from the significant plummet under the low and medium dissociating degree conditions.

Numerical investigation of the effects of H2/CO/syngas additions on laminar premixed combustion characteristics of NH3/air flame

Co-firing NH3 with H2/CO/syngas (SYN) is a promising method to overcome the low reactivity of NH3/air flame. Hence, this study aims to systematically investigate the laminar premixed combustion characteristics of NH3/air flame with various H2/CO/SYN addition loadings (0–40%) using chemical kinetics simulation. The numerical results were obtained based on the Han mechanism which can provide accurate predictions of laminar burning velocities. Results showed that H2 has the greatest effects on increasing laminar burning velocities and net heat release rates of NH3/air flame, followed by SYN and CO. CO has the most significant effects on improving NH3/air adiabatic flame temperatures. The H2/CO/SYN additions can accelerate NH3 decomposition rates and promote the generation of H and NH2 radicals. Furthermore, there is an evident positive linear correlation between the laminar burning velocities and the peak mole fraction of H + NH2 radicals. The reaction NH2 + NH <=> N2H2 + H and NH2 + NO <=> NNH + OH have remarkable positive effects on NH3 combustion. The mole fraction of OH × NH2 radicals positively affects the net heat release rates. Finally, it was discovered that H radicals play an important role in the generation of NO. The H2/CO/SYN additions can reduce the hydrodynamic and diffusional-thermal instabilities of NH3/air flame. The NH3 reaction pathways for NH3–H2/CO/SYN-air flames can be categorized mainly into NH3–NH2–NH–N–N2, NH3–NH2–HNO–NO(−N2O)–N2 and NH3–NH2(−N2H2)–NNH–N2. CO has the greatest influence on the proportions of three NH3 reaction routes.

Premixed combustion of producer gas in a cyclonic flow combustion chamber under varying number of burners

ABSTRACT Producer gas derived from biomass gasification can be used as an alternative to fossil fuel for generating power. Low heating value and high CO content are main obstacles for using it via a combustion process, leading to require a special combustor design to achieve its efficient burning. This study aims to investigate premixed combustion characteristics of producer gas in a cyclonic flow combustion chamber under varying from single to four burners using 3D computational fluid dynamics simulation. Combustion process is operated at fixed thermal power input of about 90 kW with respect to injection of air-fuel mixture at the ambient condition. A 17 species skeletal reaction scheme with 73 chemical reversible reactions is used for chemical interactions. The numerical result is well agreed with the experimental data. Through all studied results it could be concluded that the peak combustion temperature, which is higher than 1600 K, is obtained for the case of multiple burners, except for the single burner case. The lowest CO formation is obtained for the case of four burners, which is approximately 243 ppm while lowest NO formation is obtained for the single burner case, which is approximately 17 ppm.