| Research Article |
|
|
|
|
|
Comparison of NOx numerical models for methane/air combustion simulations |
| SUN Jihao, LUO Shaowen, ZHAO Ningbo, YANG Huiling, ZHENG Hongtao |
| College of Power and Energy Engineering, Harbin Engineering University, Harbin 150001, China |
|
|
|
|
Abstract [Objective] Correct usage of models for NOx combustion simulations can considerably reduce the computational time compared to directly coupling the detailed chemical mechanisms. Several NOx models are available: the NOx postprocessing model, decoupled detailed mechanism model, and adding NOx transport equations in flamelet generated manifold (FGM) model. However, their differences and applicability remain unclear, so choosing a model for a particular work is challenging. Therefore, the differences and applicability of these models must be verified under different situations, particularly for diffusion combustion, premixed combustion, and real combustors (partly premixed combustion). [Methods] In this study, numerical simulations were performed on a diffusion jet flame (Sandia flame D), premixed swirl flame (Cambridge swirl flame SW3), and partly premixed flame (an industrial gas turbine combustor) to thoroughly understand the differences and applicability of these three models. The turbulence and combustion models were the realizable standard k-ε model and the flamelet-generated manifold model, respectively. The turbulence and combustion models were verified against the experimental results; furthermore, the NOx (including NO, NO2, and N2O) distribution and formation characteristics, as well as NOx emissions, were compared and discussed with the experimental results. For the NOx postprocessing model, O and OH radicals were treated as partial equilibrium consumption, and the turbulence-combustion interaction was modeled as β-PDF (β-probability density function, PDF) consumption. For the decoupled detailed mechanism model, the species (excluding NOx), pressure, velocity, and temperature distributions were obtained using numerical simulation and held constant, and then NOx chemistry was solved. For the added NOx transport equation model, the three NOx transport equations of NO, NO2, and N2O were added to the PDF table to calculate NOx (including NO, NO2, and N2O). During the computation of NOx transport equations, only NO, NO2, and N2O were solved, and the remaining species, such as O, OH, and CH, were directly read from the PDF table. [Results] (1) For diffusion combustion, premixed combustion, and the gas turbine combustor, NO accouned for more than 95.00% of the total NOx behind the flame (at the burned-out zone), the amount of N2O was relatively small, and the amount of NO2 was negligible. (2) The NOx postprocessing model could accurately simulate the NOx formation position near the flame (at the reacting zone) and the NOx generation rate behind the flame; however, this method underestimated the NOx concentration and NOx generation rate at the flame position. Moreover, the NOx postprocessing model couldn't reproduce the phenomenon of the initial increase in the N2O concentration near the flame and then its decrease. (3) The added NOx transport equation model showd the best accuracy for the NOx generation position, NOx concentration, and NOx formation rate near the flame, but it underestimated the NOx generation rate behind the flame. (4) The decoupled detailed mechanism model showd the worst accuracy in NOx simulation and couldn't correctly predict the NOx formation characteristics of the three studied cases. [Conclusions] The decoupled detailed mechanism model may not be suitable for NOx simulation under some conditions. To capture NOx formation and distribution characteristics, the postprocessing model and added NOx transport equation model can be used. However, the postprocessing model may not provide quantitative results, particularly in diffusion flames. The added NOx transport equation model may be suitable under most conditions.
|
| Keywords
NOx model
numerical simulation
diffusion jet flame
premixed swirl flame
combustor
|
|
Issue Date: 22 April 2023
|
|
|
[1] WANG L J, WANG J, TAN X D, et al. Analysis of NOx pollution characteristics in the atmospheric environment in Changchun city[J]. Atmosphere, 2020, 11(1):30.
[2] AHMAD N, NAIRUI L, TARIQ M, et al. NOx emission prediction analysis and comparison in gas turbine combustor utilizing CFD and CRN combined approach[C]//Proceedings of the Sixth International Conference on Aerospace Science and Engineering (ICASE). Islamabad, Pakistan:IEEE, 2019:1-9.
[3] YOUSEFIAN S, BOURQUE G, MONAGHAN R F D. Review of hybrid emissions prediction tools and uncertainty quantification methods for gas turbine combustion systems[C]//ASME Turbo Expo 2017:Turbomachinery Technical Conference and Exposition. Charlotte, USA:ASME, 2017:V04BT04A005.
[4] 母滨,雷福林,邵卫卫,等.贫预混燃烧室化学反应器网络模型建模及不确定性分析[J].航空动力学报, 2019, 34(10):2108-2119. MU B, LEI F L, SHAO W W, et al. Modeling and uncertainty analysis of chemical reactor network model in lean premixed combustion chamber[J]. Journal of Aerospace Power, 2019, 34(10):2108-2119.(in Chinese)
[5] GLARBORG P, MILLER J A, RUSCIC B, et al. Modeling nitrogen chemistry in combustion[J]. Progress in Energy and Combustion Science, 2018, 67:31-68.
[6] MATSSON J E. An Introduction to ANSYS Fluent 2022[M]. Kansas:Sdc Publications, 2022.
[7] KETELHEUN A, OLBRICHT C, HAHN F, et al. NO prediction in turbulent flames using LES/FGM with additional transport equations[J]. Proceedings of the Combustion Institute, 2011, 33(2):2975-2982.
[8] 唐军,宋文艳.基于FGM和附加输运方程的NO数值模拟方法研究[J].推进技术, 2017, 38(7):1523-1531. TANG J, SONG W Y. Numerical study of NO formation with FGM and an additional transport equation[J]. Journal of Propulsion Technology, 2017, 38(7):1523-1531.(in Chinese)
[9] VAN OIJEN J A, DE GOEY L P H. Predicting NO formation with Flamelet generated manifolds[C]//Proceedings of the 4th European Combustion Meeting. Vienna, Austria:TU Wien, 2009:810248.
[10] AN Z H, ZHANG M, ZHANG W J, et al. Emission prediction and analysis on CH4/NH3/air swirl flames with LES-FGM method[J]. Fuel, 2021, 304:121370.
[11] WESTENBERG A A. Kinetics of NO and CO in lean, premixed hydrocarbon-air flames[J]. Combustion Science and Technology, 1971, 4(1):59-64.
[12] WARNATZ J. NOx formation in high temperature processes[D]. Germany:University of Stuttgart, 2001.
[13] BAULCH D L, COBOS C J, COX R A, et al. Evaluated kinetic data for combustion modelling[J]. Journal of Physical and Chemical Reference Data, 1992, 21(3):411-734.
[14] DE SOETE G G. Overall reaction rates of NO and N2 formation from fuel nitrogen[J]. Symposium (international) on Combustion, 1975, 15(1):1093-1102.
[15] VAN OIJEN J A, DE GOEY L P H. Modelling of premixed laminar flames using flamelet-generated manifolds[J]. Combustion Science and Technology, 2000, 161(1):113-137.
[16] DONINI A, BASTIAANS R J M, VAN OIJEN J A, et al. A 5-D implementation of FGM for the large eddy simulation of a stratified swirled flame with heat loss in a gas turbine combustor[J]. Flow, Turbulence and Combustion, 2017, 98(3):887-922.
[17] 李威,张哲巅.某航空发动机燃烧室天然气湿燃烧数值模拟研究[J].热能动力工程, 2021, 36(5):126-133. LI W, ZHANG Z D. Numerical investigation on a jet-engine combustor fueled by humidified natural gas[J]. Journal of Engineering for Thermal Energy and Power, 2021, 36(5):126-133.(in Chinese)
[18] 刘富强,张栋芳,崔耀欣,等.某重型燃气轮机环形燃烧室的数值模拟[J].燃气轮机技术, 2011, 24(1):20-25. LIU F Q, ZHANG D F, CUI Y X, et al. Numerical simulation of combustion flow in the heavy gas turbine annular combustor[J]. Gas Turbine Technology, 2011, 24(1):20-25.(in Chinese)
[19] 党新宪,赵坚行,吉洪湖.双旋流器燃烧室NOx生成研究[J].航空动力学报, 2008, 23(3):430-435. DANG X X, ZHAO J X, JI H H. A study on NOx formation for double swirler combustor[J]. Journal of Aerospace Power, 2008, 23(3):430-435.(in Chinese)
[20] 康尧,林宇震,付镇柏,等.台阶高度对LESS燃烧室的影响研究[J].推进技术, 2014, 35(7):941-949. KANG Y, LIN Y Z, FU Z B, et al. Effects of step height on low emission stirred swirl combustor[J]. Journal of Propulsion Technology, 2014, 35(7):941-949.(in Chinese)
[21] MALLOUPPAS G, GOLDIN G, ZHANG Y Z, et al. Investigation of an industrial gas turbine combustor and pollutant formation using LES[C]//ASME Turbo Expo 2017:Turbomachinery Technical Conference and Exposition. Charlotte, USA:ASME, 2017:V04BT04A039.
[22] BARLOW R S, FRANK J H. Pilotes CH4/Air Flames C, D, E, and F:Release 2.1[R/OL].[2010-05-10]. http://www.sandia.gov/TNF/DataArch/FlameD.html.
[23] SWEENEY M S, HOCHGREB S, DUNN M J, et al. The structure of turbulent stratified and premixed methane/air flames Ⅱ:Swirling flows[J]. Combustion and Flame, 2012, 159(9):2912-2929.
[24] STOPPER U, AIGNER M, MEIER W, et al. Flow field and combustion characterization of premixed gas turbine flames by planar laser techniques[J]. Journal of Engineering for Gas Turbines and Power, 2009, 131(2):021504.
[25] STOPPER U, AIGNER M, AX H, et al. PIV, 2D-LIF and 1D-Raman measurements of flow field, composition and temperature in premixed gas turbine flames[J]. Experimental Thermal and Fluid Science, 2010, 34(3):396-403.
[26] BULAT G, JONES W P, MARQUIS A J. NO and CO formation in an industrial gas-turbine combustion chamber using LES with the Eulerian sub-grid PDF method[J]. Combustion and Flame, 2014, 161(7):1804-1825.
[27] LAUNDER B E, SPALDING D B. Lectures in mathematical models of turbulence[M]. London:Academic Press, 1972.
[28] SMITH G P, GOLDEN D M, FRENKLACH M, et al. GRI-MECH 3.0[EB/OL].(1999-08-06)[2022-12-21]. http://www.me.berkeley.edu/gri_mech/.
[29] 孙继昊.甲烷/空气机理简化及燃烧室污染物空间分布[D].哈尔滨:哈尔滨工程大学, 2020. SUN J H. Reduction of methane/air mechanism and spatial distribution of combustor pollutants[D]. Harbin:Harbin Engineering University, 2020.(in Chinese)
[30] TURNS S R. Introduction to combustion:Concepts and applications[M]. New York:McGraw-Hill Companies, 1996.
[31] 徐琛,孙继昊,赵宁波. O3对射流火焰燃烧特性影响的数值研究[J].燃气涡轮试验与研究, 2021, 34(1):27-33. XU C, SUN J H, ZHAO N B. Numerical study of the effect of O3 on combustion characteristics of jet flame[J]. Gas Turbine Experiment and Research, 2021, 34(1):27-33.(in Chinese)
[32] SUN J H, ZHANG Z H, LIU X, et al. Reduced methane combustion mechanism and verification, validation, and accreditation (VV&A) in CFD for NO emission prediction[J]. Journal of Thermal Science, 2021, 30(2):610-623.
[33] APELOIG J, GAUTIER P, SALAVN E, et al. PLIF measurements of nitric oxide and hydroxyl radicals distributions in swirled stratified premixed flames[C/OL]//Instituto Superior Técnico-Center for Innovation, Technology andPolicy Research.(2016-07-04)[2022-12-21]. https://www.repository.cam.ac.uk/handle/1810/262800. |
|
Viewed |
|
|
|
Full text
|
|
|
|
|
Abstract
|
|
|
|
|
Cited |
|
|
|
|
| |
Shared |
|
|
|
|
| |
Discussed |
|
|
|
|
2023,
Vol. 63
