Reduced NOx emissions and enhanced large scale turbulence from a precessing jet burner

Here the premixed Conditional Moment Closure (CMC) method is used to model the recent PIV and Raman turbulent, enclosed reacting methane jet data from DLR Stuttgart [1]. The experimental data has a rectangular test section at atmospheric pressure and temperature with a single inlet jet. A jet velocity of 90 m/s is used with an adiabatic flame temperature of 2,064 K. Contours of major species, temperature and velocities along with velocity rms values are provided. The conditional moment closure model has been shown to provide the capability to model turbulent, premixed methane flames with detailed chemistry and reasonable runtimes [2]. The simplified CMC model used here falls into the class of table lookup turbulent combustion models where the chemical kinetics are solved offline over a range of conditions and stored in a table that is accessed by the CFD code. Most table lookup models are based on the laminar 1-D flamelet equations, which assume the small scale turbulence does not affect the reaction rates, only the large scale turbulence has an effect on the reaction rates. The CMC model is derived from first principles to account for the effects of small scale turbulence on the reaction rates, as well as the effects of the large scale mixing, making it more versatile than other models. This is accomplished by conditioning the scalars with the reaction progress variable. By conditioning the scalars and accounting for the small scale mixing, the effects of turbulent fluctuations of the temperature on the reaction rates are more accurately modeled. The scalar dissipation is used to account for the effects of the small scale mixing on the reaction rates. The original premixed CMC model used a constant value of scalar dissipation, here the scalar dissipation is conditioned by the reaction progress variable. The steady RANS 3-D version of the open source CFD code OpenFOAM is used. Velocity, temperature and species are compared to the experimental data. Once validated, this CFD turbulent combustion model will have great utility for designing lean premixed gas turbine combustors.

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A Novel Turbulent Aggregation Device for Flue Gas

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.955-959.2425 ◽

2014 ◽

Vol 955-959 ◽

pp. 2425-2429 ◽

Cited By ~ 2

Author(s):

Yun Fei Li ◽

Jian Guo Yang ◽

Yan Yan Wang ◽

Xiao Guo Wang

Keyword(s):

Size Distribution ◽

Flue Gas ◽

Large Scale ◽

Balance Model ◽

Small Scale ◽

Multiphase Model ◽

Specific Performance ◽

Particles Size Distribution ◽

Scale Turbulence ◽

Eulerian Multiphase Model

The purpose of this study is to construct a turbulent aggregation device which has specific performance for fine particle aggregation in flue gas. The device consists of two cylindrical pipes and an array of vanes. The pipes extending fully and normal to the gas stream induce large scale turbulence in the form of vortices, while the vanes downstream a certain distance from the pipes induce small one. The process of turbulent aggregation was numerically simulated by coupling the Eulerian multiphase model and population balance model together with a proposed aggregation kernel function taking the size and inertia of particles into account, and based on data of particles’ size distribution measured from the flue of one power plant. The results show that the large scale turbulence generated by pipes favours the aggregation of smaller particles (smaller than 1μm) notably, while the small scale turbulence benefits the aggregation of bigger particles (larger than 1μm) notably and enhances the uniformity of particle size distribution among different particle groups.

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An overview of the effect of large-scale inhomogeneities on small-scale turbulence

Physics of Fluids ◽

10.1063/1.1476300 ◽

2002 ◽

Vol 14 (7) ◽

pp. 2475 ◽

Cited By ~ 25

Author(s):

L. Danaila ◽

F. Anselmet ◽

R. A. Antonia

Keyword(s):

Large Scale ◽

Small Scale ◽

Scale Turbulence

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Modeling the regional impact of ship emissions on NO<sub>x</sub> and ozone levels over the Eastern Atlantic and Western Europe using ship plume parameterization

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-6645-2010 ◽

2010 ◽

Vol 10 (14) ◽

pp. 6645-6660 ◽

Cited By ~ 44

Author(s):

P. Huszar ◽

D. Cariolle ◽

R. Paoli ◽

T. Halenka ◽

M. Belda ◽

...

Keyword(s):

Large Scale ◽

Western Europe ◽

Surface Ozone ◽

Chemical Species ◽

Nitrogen Monoxide ◽

Ozone Production ◽

Nox Emissions ◽

Ship Emissions ◽

Concentrated Source ◽

The Impact

Abstract. In general, regional and global chemistry transport models apply instantaneous mixing of emissions into the model's finest resolved scale. In case of a concentrated source, this could result in erroneous calculation of the evolution of both primary and secondary chemical species. Several studies discussed this issue in connection with emissions from ships and aircraft. In this study, we present an approach to deal with the non-linear effects during dispersion of NOx emissions from ships. It represents an adaptation of the original approach developed for aircraft NOx emissions, which uses an exhaust tracer to trace the amount of the emitted species in the plume and applies an effective reaction rate for the ozone production/destruction during the plume's dilution into the background air. In accordance with previous studies examining the impact of international shipping on the composition of the troposphere, we found that the contribution of ship induced surface NOx to the total reaches 90% over remote ocean and makes 10–30% near coastal regions. Due to ship emissions, surface ozone increases by up to 4–6 ppbv making 10% contribution to the surface ozone budget. When applying the ship plume parameterization, we show that the large scale NOx decreases and the ship NOx contribution is reduced by up to 20–25%. A similar decrease was found in the case of O3. The plume parameterization suppressed the ship induced ozone production by 15–30% over large areas of the studied region. To evaluate the presented parameterization, nitrogen monoxide measurements over the English Channel were compared with modeled values and it was found that after activating the parameterization the model accuracy increases.

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Observations of Turbulence in Free Atmosphere by Balloon-Borne Sensors

Sensors ◽

10.3390/s18103273 ◽

2018 ◽

Vol 18 (10) ◽

pp. 3273

Author(s):

Lesong Zhou ◽

Zheng Sheng ◽

Qixiang Liao

Keyword(s):

Large Scale ◽

Turbulent Energy ◽

Energy Dissipation Rate ◽

Sensor Data ◽

Free Atmosphere ◽

Height Range ◽

High Latitude Region ◽

Thorpe Scale ◽

Scale Turbulence ◽

Turbulence Parameters

In recent years, Thorpe analysis has been used to retrieve the characteristics of turbulence in free atmosphere from balloon-borne sensor data. However, previous studies have mainly focused on the mid-high latitude region, and this method is still rarely applied at heights above 30 km, especially above 35 km. Therefore, seven sets of upper air (>35 km) sounding data from the Changsha Sounding Station (28°12′ N, 113°05′ E), China are analyzed with Thorpe analysis in this article. It is noted that, in the troposphere, Thorpe analysis can better retrieve the turbulence distribution and the corresponding turbulence parameters. Also, because of the thicker troposphere at low latitudes, the values of the Thorpe scale L T and turbulent energy dissipation rate ε remain greater in a larger height range. In the stratosphere below the height of 35 km, the obtained ε is higher, and Thorpe analysis can only be used to analyze the characteristics of large-scale turbulence. In the stratosphere at a height of 35–40 km, because of the interference of sensor noise, Thorpe analysis can only help to retrieve the rough distribution position of large-scale turbulence, while it can hardly help with the calculation of the turbulence parameters.

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Large Scale Turbulence Suppression Control for Direct Reduction of Aero-Optical Aberrations

38th Plasmadynamics and Lasers Conference ◽

10.2514/6.2007-4008 ◽

2007 ◽

Cited By ~ 4

Author(s):

Fazlul Zubair ◽

Aaron Freeman ◽

Siarhei Piatrovich ◽

Jennifer Shockro ◽

Youssef Ibrahim ◽

...

Keyword(s):

Large Scale ◽

Direct Reduction ◽

Optical Aberrations ◽

Turbulence Suppression ◽

Scale Turbulence

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Carbon and air pollutant emissions from China's cement industry 1990–2015: trends, evolution of technologies and drivers

10.5194/acp-2020-631 ◽

2020 ◽

Author(s):

Jun Liu ◽

Dan Tong ◽

Yixuan Zheng ◽

Jing Cheng ◽

Xinying Qin ◽

...

Keyword(s):

Carbon Dioxide ◽

Large Scale ◽

Air Pollutant ◽

Cement Industry ◽

Pollutant Emissions ◽

Pollutant Emission ◽

Climate Mitigation ◽

Nox Emissions ◽

Cement Production ◽

Control Technologies

Abstract. China is the largest cement producer and consumer in the world. Cement manufacturing is highly energy-intensive, and is one of the major contributors to carbon dioxide (CO2) and air pollutant emissions, which threatens climate mitigation and air quality improvement. In this study, we investigated the decadal changes of carbon dioxide and air pollutant emissions for the period of 1990–2015, based on intensive unit-based information on activity rates, production capacity, operation status, and control technologies, which improved the accuracy of the cement emissions in China. We found that, from 1990 to 2015, accompanied by a 10.9-fold increase in cement production, CO2, SO2, and NOx emissions from China's cement industry increased by 626 %, 59 %, and 658 %, whereas CO, PM2.5 and PM10 emissions decreased by 9 %, 66 %, and 63 %, respectively. In the 1990s, driven by the rapid growth of cement production, CO2 and air pollutant emissions increased constantly. Then, the production technology innovation of replacing traditional shaft kilns with the new precalciner kilns in the 2000s markedly reduced SO2, CO and PM emissions from the cement industry. Since 2010, the growing trend of emissions has been further curbed by a combination of measures, including promoting large-scale precalciner production lines and phasing out small ones, upgrading emission standards, installing low-NOx burners (LNB) and selective noncatalytic reduction (SNCR) to reduce NOx emissions, as well as adopting more advanced particulate matter control technologies. Our study highlighted the effectiveness of advanced technologies on air pollutant emission control, however, CO2 emissions from China's cement industry kept growing throughout the period, posing challenges to future carbon emission mitigation in China.

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High-resolution large-eddy simulations of sub-kilometer-scale turbulence in the upper troposphere lower stratosphere

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-31891-2013 ◽

2013 ◽

Vol 13 (12) ◽

pp. 31891-31932 ◽

Cited By ~ 4

Author(s):

R. Paoli ◽

O. Thouron ◽

J. Escobar ◽

J. Picot ◽

D. Cariolle

Keyword(s):

Large Scale ◽

Lower Stratosphere ◽

Atmospheric Model ◽

Large Eddy Simulations ◽

Stratified Flows ◽

Flow Topology ◽

Upper Troposphere ◽

Large Eddy ◽

Scale Turbulence ◽

The Impact

Abstract. Large-eddy simulations of sub-kilometer-scale turbulence in the upper troposphere lower stratosphere (UTLS) are carried out and analyzed using the mesoscale atmospheric model Méso-NH. Different levels of turbulence are generated using a large-scale stochastic forcing technique that was especially devised to treat atmospheric stratified flows. The study focuses on the analysis of turbulence statistics, including mean quantities and energy spectra, as well as on a detailed description of flow topology. The impact of resolution is also discussed by decreasing the grid spacing to 2 m and increasing the number of grid points to 8×109. Because of atmospheric stratification, turbulence is substantially anisotropic, and large elongated structures form in the horizontal directions, in accordance with theoretical analysis and spectral direct numerical simulations of stably stratified flows. It is also found that the inertial range of horizontal kinetic energy spectrum, generally observed at scales larger than a few kilometers, is prolonged into the sub-kilometric range, down to the Ozmidov scales that obey isotropic Kolmorogov turbulence. The results are in line with observational analysis based on in situ measurements from existing campaigns.

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