Effects of internal flue gas recirculation rate on the NO  emission in a methane/air premixed flame

Shi, Baolu; Hu, Jie; Peng, Hao; Ishizuka, Satoru

doi:10.1016/j.combustflame.2017.09.043

Cited by 53 publications

(22 citation statements)

References 39 publications

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“…In CH 4 lean-premixed combustor, the thermal NO will increase dramatically with flame temperature and mask the contributions of the other chemical pathways. 35 The flame temperature in Figure 12 rises with equivalence ratio; the thermal NO x would increase dramatically with temperature growing. When the flame temperature is increasing, the amount of thermal NO x gradually takes the main component in the combustion chamber.…”

Section: No X Emission Propertiesmentioning

confidence: 97%

“…1 The increasingly strict regulation for pollutant emissions has recently led gas turbine manufacturers to develop lean-premixed combustors. [34][35][36] In lean-premixed combustion, the combustion zone is operated with excess air to reduce the flame global temperature. Consequently, thermal NO x is virtually eliminated.…”

Section: No X Emission Propertiesmentioning

confidence: 99%

“…When the flame temperature is increasing, the amount of thermal NO x gradually takes the main component in the combustion chamber. [35][36][37] Since the fuel NO x pathway is not exist in CH 4 combustion chamber, the thermal NO x pathway must be taken into consideration for most practical lean-premixed combustion systems operating at high inlet pressures and temperatures. 1 Prompt NO x does not generally form in any significant quantity in the post flame regions because the concentration of hydrocarbon radicals is quite small away from the flame front.…”

Section: No X Emission Propertiesmentioning

confidence: 99%

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Macrostructure and NO_x emission evolution characteristics of lean‐premixed flames under combustion instability

Tao

Zhou

2020

Asia-Pacific J Chem Eng

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Effects of combustion instability on flame macrostructures and NO x emissions were conducted experimentally in a model gas turbine combustor. Two variables of the CH 4 flame were investigated-the flow rate and the equivalence ratio. Results indicate that flame macrostructure changes when the equivalence ratio increases from 0.50 to 1.00, the average total length of flame front firstly decreases from 105 to 75 mm, and then increases to 110 mm. While the average length of flame root decreases from 25 to 5 mm. The appearance of the flame front evolves from a "M" shape to a reversed "V" shape, but the appearance of the flame root changes from elongated V shape to a flatted V shape. The envelop diagram of different combustion instability signifies that there are mode shifting of flame-acoustic interactions in the combustion chamber. Under instability conditions, the temperature and velocity distribution of the flame front or flame root affects the NO x emissions. Along the radial direction, the peak temperature in the inner recirculation region and the outer recirculation region drops. This article explored the dynamic characteristics of lean-premixed flames under combustion instability, which could be instructive to the designing of stable and clean combustors in industrial gas turbines.

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Section: No X Emission Propertiesmentioning

confidence: 97%

Section: No X Emission Propertiesmentioning

confidence: 99%

Section: No X Emission Propertiesmentioning

confidence: 99%

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Macrostructure and NO_x emission evolution characteristics of lean‐premixed flames under combustion instability

Tao

Zhou

2020

Asia-Pacific J Chem Eng

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“…Shi et al proposed a self‐sustained burning‐heating‐evaporating system to directly burn liquid ethanol without a spray system. Shi et al also put forward a internal flue gas recirculation technique to reduce the NO x emission. Zhao et al investigated the effects of N 2 and CO 2 dilution on the combustion characteristics of C 3 H 8 /O 2 in a swirl tubular flame burner.…”

Section: Introductionmentioning

confidence: 99%

An exploration of stabilization mechanisms in a novel vortex‐tube combustor with localized stratified peculiarity

Ren

2020

Int J Energy Res

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Experimental and numerical (via ANSYS FLUENT) studies have been conducted on the combustion stability and stabilization mechanisms in a localized stratified vortex-tube combustor (LSVC) under lean conditions. The stability limit and flame configuration were obtained under different combustion conditions. Combined with the flow field distribution, the formation mechanisms of the local stratification of species and the resultant flame configuration were analyzed. Results show that the local stratification peculiarity is responsible for the dual flame appearance. On the basis of the local stratification of species, the local equivalence ratio is close to stoichiometry in the vicinity of the flame front, while it is above 1.0 in the interior, enabling the achievement of stable combustion at a global equivalence ratio as low as 0.12 in the LSVC. The flow field can help the transport of the reactive species and yields an intensified combustion and a large density gradient. The peak heat release rate (HRR) of 0.5 W/mm 3 in the LSVC is much higher than that of 0.1 W/mm 3 in the rapidly mixed vortex-tube combustor (RMVC) at the global equivalence ratio of 0.6 and the maximum tangential velocity of 26.44 m/s. The flame-vortex interaction theory provides a new perspective to interpret the rapid flame propagation in vortex-tube combustors. Based on the pressure jump theory, the flame speed was obtained via a specific formula closely related to the density gradient and the injection velocity. It turns out that the flame speed in the LSVC is remarkably higher than that in the RMVC at a certain same combustion condition. Moreover, the decrease of local flow velocity resulted from the strong swirl provides a favorable guarantee for the balance with the local flame speed. K E Y W O R D S localized stratification, stability limit, stabilization mechanism, vortex bursting, vortex-tube combustor

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“…A model for tangential injection has also been developed to examine the tubular flame characteristics [9]. A variety of configurations from micro-combustor to large size (12 inch) tubular flame burner [10] have been developed to meet industrial demands, including power generation [11][12][13], emissions reduction [14,15], flame stabilization [4] and flame synthesis [16].…”

Section: Introductionmentioning

confidence: 99%

Response of lean premixed swirl tubular flame to acoustic perturbations

Zhao

et al. 2020

Experimental Thermal and Fluid Science

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This study experimentally examined the response of a lean premixed methane/air swirl tubular flame to the longitudinal acoustic perturbations. Experiments were conducted by varying the acoustic frequency (f0), acoustic power (P0) and inlet air flow rate (QA) to systematically study the acoustic-excited flame dynamics, including the flame stability, flame structure, heat release rate and acoustic pressure fluctuations. The results demonstrated that the lean tubular flame was much sensitive to longitudinal perturbations below 210 Hz. Even at low power of P0, the flame was forced to oscillate intensively when the perturbation was operated in two discontinuous frequency ranges of f0 = 150-200 and f0 = 50-100 Hz, while a weakened oscillation regime was observed in the middle range of f0 =100-150 Hz; a lower frequency (less than 50 Hz) would extinguish the flame. An increase in P0 intensified the flame oscillation under the perturbations of 50-100 Hz, and even resulted in flame lift-off and blow off with f0 between 150 and 200 Hz. In comparison to f0 and P0, the effects of air flow rate (QA) seemed to be weaker. The proper orthogonal decomposition (POD) analysis was performed to interpret the contributions from the mean mode and fluctuating axial and circumferential modes that led to combustion instability. It was found that as the energy fraction of the axial mode exceeded 5.0%, the flame lift-off appeared in the lean swirl tubular configuration.

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Effects of internal flue gas recirculation rate on the NO emission in a methane/air premixed flame

Cited by 53 publications

References 39 publications

Macrostructure and NO_x emission evolution characteristics of lean‐premixed flames under combustion instability

Macrostructure and NO_x emission evolution characteristics of lean‐premixed flames under combustion instability

An exploration of stabilization mechanisms in a novel vortex‐tube combustor with localized stratified peculiarity

Response of lean premixed swirl tubular flame to acoustic perturbations

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Effects of internal flue gas recirculation rate on the NO emission in a methane/air premixed flame

Cited by 53 publications

References 39 publications

Macrostructure and NOx emission evolution characteristics of lean‐premixed flames under combustion instability

Macrostructure and NOx emission evolution characteristics of lean‐premixed flames under combustion instability

An exploration of stabilization mechanisms in a novel vortex‐tube combustor with localized stratified peculiarity

Response of lean premixed swirl tubular flame to acoustic perturbations

Contact Info

Product

Resources

About

Macrostructure and NO_x emission evolution characteristics of lean‐premixed flames under combustion instability

Macrostructure and NO_x emission evolution characteristics of lean‐premixed flames under combustion instability