Experimental investigation of combustion instability and NOx emissions control by adjustable swirl jet in lean premixed flames

Hu, Liubin; Zhou, Hao

doi:10.1016/j.joei.2022.11.009

Cited by 8 publications

(4 citation statements)

References 44 publications

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“…Finally, grid search is used to determine the optimal results for the three hyperparameters: time step of the feature matrix, number of input features, and number of neurons in hidden layer. Set the search range of the time step to [1,30] and the step distance to 1; Set the search range of number of input features to [1,12] and the step distance to 1; Set the search range of number of neurons in the hidden layer to [150, 800] and the step distance to 25.…”

Section: Feature Reconstruction Based On Mutual Information Theorymentioning

confidence: 99%

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NOx emissions estimation of boiler based on mutual information feature reconstruction and optimization of extreme learning machine

Jiang

Dong

Sun

et al. 2023

Meas. Sci. Technol.

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The measurement of NOx emissions in the selective catalytic reduction (SCR) system of boiler has problems with poor real-time performance and abnormal measurement during purging. It is necessary to accurately estimate NOx emissions. For this reason, the NOx emissions prediction method of boiler based on mutual information feature reconstruction and optimization of extreme learning machine (ELM) is proposed: Firstly, delay estimation and data space reconstruction of input features are performed based on mutual information; Then the conditional mutual information based on greedy selection strategy is adopted to rank and choose the input features; Finally, the hybrid quantum sparrow search algorithm (QSSA) was proposed by combining Lévy flight strategy and quantum strategy in the sparrow search algorithm (SSA), and QSSA is used to optimize the weights and biases of the ELM. Taking the operation data of the SCR system of a 1000MW thermal power unit as an example for verification. The results show that the proposed method can effectively improve the accuracy and generalization ability of the ELM, and provide a new method for NOx emissions estimation of boiler.

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Section: Feature Reconstruction Based On Mutual Information Theorymentioning

confidence: 99%

“…NOx generated by the combustion of power plant boilers is one of the main harmful substances in atmospheric pollution [1]. A large number of nitrogen elements are discharged into the * Author to whom any correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

NOx emissions estimation of boiler based on mutual information feature reconstruction and optimization of extreme learning machine

Jiang

Dong

Sun

et al. 2023

Meas. Sci. Technol.

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“…The strong non-linear interaction between turbulence and combustion is one of the remarkable features of swirling flames. Swirling structures have been shown to intensify the heat release [ 3 ], short the ignition delay [ 4 ], influence the extinction [ 5 ], and control the emissions [ 6 ] of the flames. Good understanding of the turbulent dynamic interaction with intense combustion is desirable to enable improved design of efficiency.…”

Section: Introductionmentioning

confidence: 99%

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

Su,

Liu,

Xiao

et al. 2023

Entropy

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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.

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“…からその特性が分析されている (Shtork et al, 2007). また，微粉炭燃焼バーナーに設置された二つの同一方向のスワールと逆方向のスワールのそれぞれを用いて，管状渦の影響に関する実験的が行われた (Kim et al, 2020) (Ogawa et al, 2011)．また，燃焼の不安定性と NOx の排出特性を制御するために，旋回噴流に使用するガスの種類，その噴流角度，および噴流の流量をパラメータとして，その影響について議論および分析を行っている (Hu and Zhou, 2023) ．一方で， (Durox et al, 2013, Guiberti et al, 2015は，角度調整可能な旋回羽根をもつ円筒型ノズルを新たに開発し，燃焼器内に形成される予混合火炎の構造とその挙動を分析している．また，旋回羽根の位置を軸方向に変更可能として，その混合距離が変化した場合の燃焼の安定性を検討している (Xu et al, 2022) ．一方で，我々はギア機構による時間可変角度の旋回羽根を開発し (Ichikawa et al, 2015)…”

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時間可変旋回羽根による予混合火炎挙動の安定化

KOMIYAMA,

MIZUNO,

NISHIDA

2023

Transactions of the JSME (In Japanese)

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In this study, we aimed to stabilize premixed flame behaviors in a circular pipe with swirling flow. We constructed a system that automatically changes swirl vane angles according to the flame tip positions keeping the air ratio and flow rate. In addition, we tried to stabilize the flame behavior using this system, and simultaneously employed time-series PIV measurements in the flow fields in the circular pipe. The findings obtained in this study are shown below. (1) Under this experimental condition, it was shown that there was a positive and strong correlation between the flame tip positions and the integrated scattering intensity of tracer particles in a circular pipe with swirling flow. (2) Using the integrated scattering intensity of tracer particles as an index, the change of the flame tip positions was judged, and the swirl vane angle could be changed according to the behavior of the premixed flame.It was shown that keeping the flame tip positions within the circular pipe was possible. (3) While operating the flame position stabilization system, time-series PIV measurements simultaneously measured the flow fields near the flame tip. From the results, when the swirl vane angle was changed in the positive direction, an upstream-direction velocity region appeared by increasing the swirl intensity. After that, the flame propagated upstream along the formed upstream-direction velocity region.

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Experimental investigation of combustion instability and NOx emissions control by adjustable swirl jet in lean premixed flames

Cited by 8 publications

References 44 publications

NOx emissions estimation of boiler based on mutual information feature reconstruction and optimization of extreme learning machine

NOx emissions estimation of boiler based on mutual information feature reconstruction and optimization of extreme learning machine

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

時間可変旋回羽根による予混合火炎挙動の安定化

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