scholarly journals Field Testing Two Flux Footprint Models

2021 ◽  
Author(s):  
Trevor W. Coates ◽  
Monzurul Alam ◽  
Thomas K. Flesch ◽  
Guillermo Hernandez-Ramirez
Keyword(s):  
Field Study ◽  
Surface Area ◽  
Analytical Model ◽  
Release Rate ◽  
Emission Rate ◽  
Dispersion Model ◽  
Field Testing ◽  
Gas Emission ◽  
Flux Footprint ◽  
Area Source

Abstract. A field study was undertaken to investigate the accuracy of two micrometeorological flux footprint models when calculating the gas emission rate from a 10 × 10 m synthetic surface area source, based on the vertical flux of gas measured 15 to 50 m downwind of the source. Calculations were made with an easy-to-use tool based on the Kormann-Meixner analytical model and with a more sophisticated Lagrangian stochastic dispersion model. A total of 323 10 minute observation periods were measured over 9 days. On average, each of the two models calculated the emission rate to within 10 % of the actual release rate. No clear differences were observed between the two models in terms of overall accuracy.

scholarly journals Field testing two flux footprint models

2021 ◽  
Vol 14 (11) ◽  
pp. 7147-7152
Author(s):  
Trevor W. Coates ◽  
Monzurul Alam ◽  
Thomas K. Flesch ◽  
Guillermo Hernandez-Ramirez
Keyword(s):  
Field Study ◽  
Release Rate ◽  
Emission Rate ◽  
Dispersion Model ◽  
Field Testing ◽  
Gas Emission ◽  
Flux Footprint ◽  
Model Calculations ◽  
Area Source ◽  
Large Period

Abstract. A field study was undertaken to investigate the accuracy of two micrometeorological flux footprint models for calculating the gas emission rate from a synthetic 10 × 10 m surface area source, based on the vertical flux of gas measured at fetches of 15 to 50 m downwind of the source. Calculations were made with an easy-to-use tool based on the Kormann–Meixner analytical model and with a more sophisticated Lagrangian stochastic dispersion model. A total of 59 testable 10 min observation periods were measured over 9 d. On average, both models underestimated the actual release rate by approximately 30 %, mostly due to large underestimates at the larger fetches. The accuracy of the model calculations had large period-to-period variability, and no statistical differences were observed between the two models in terms of overall accuracy.

scholarly journals Deducing Ground-to-Air Emissions from Observed Trace Gas Concentrations: A Field Trial with Wind Disturbance

2005 ◽  
Vol 44 (4) ◽  
pp. 475-484 ◽  
Author(s):  
T. K. Flesch ◽  
J. D. Wilson ◽  
L. A. Harper
Keyword(s):  
Emission Rate ◽  
Similarity Theory ◽  
Dispersion Model ◽  
Trace Gas ◽  
Air Concentration ◽  
Area Source ◽  
Inverse Dispersion ◽  
Wind Measurements ◽  
The Mean ◽  
Dispersion Technique

Abstract Inverse-dispersion techniques allow inference of a gas emission rate Q from measured air concentration. In “ideal surface layer problems,” where Monin–Obukhov similarity theory (MOST) describes the winds transporting the gas, the application of the technique can be straightforward. This study examines the accuracy of an ideal MOST-based inference, but in a nonideal setting. From a 6 m × 6 m synthetic area source surrounded by a 20 m × 20 m square border of a windbreak fence (1.25 m tall), Q is estimated. Open-path lasers gave line-averaged concentration CL at positions downwind of the source, and an idealized backward Lagrangian stochastic (bLS) dispersion model was used to infer QbLS. Despite the disturbance of the mean wind and turbulence caused by the fence, the QbLS estimates were accurate when ambient winds (measured upwind of the plot) were assumed in the bLS model. In the worst cases, with CL measured adjacent to a plot fence, QbLS overestimated Q by an average of 50%. However, if these near-fence locations are eliminated, QbLS averaged within 2% of the true Q over 61 fifteen-minute observations (with a standard deviation σQ/Q = 0.20). Poorer accuracy occurred when in-plot wind measurements were used in the bLS model. The results show that when an inverse-dispersion technique is applied to disturbed flows without accounting for the disturbance, the outcome may still be of acceptable accuracy if judgment is applied in the placement of the concentration detector.

scholarly journals Influence of the variability of the odour emission rate on its impact range: a case study of the selected industrial source

2019 ◽  
Vol 100 ◽  
pp. 00070 ◽  
Author(s):  
Elżbieta Romanik ◽  
Yaroslav Bezyk ◽  
Marcin Pawnuk ◽  
Urszula Miller ◽  
Agnieszka Grzelka
Keyword(s):  
Emission Rate ◽  
Dispersion Model ◽  
Grid Size ◽  
Model Calculations ◽  
Gas Treatment ◽  
Industrial Source ◽  
Odour Concentration ◽  
Made In ◽  
Dynamic Olfactometry

Odour concentration measurements in a chosen industrial source were made in this study using the method of dynamic olfactometry. The two different scenarios considered the variation of the odour emission rate as input for the dispersion model were compared for the period 2017 (before installation of the equipment for gas treatment) and 2018 (after implementation of purifying technologies). In this paper the odour impact range was determined by applying model calculations conducted in the Polish reference dispersion model – OPERAT FB software for the grid size 2 x 2 km. The conducted research shows a significant improvement in the odour impact range of chosen industrial source in year 2018 compared to 2017.

scholarly journals Study on Gas Emission Rate Prediction Based on Chaos Analysis

2011 ◽  
Vol 24 ◽  
pp. 106-110 ◽  
Author(s):  
Liu Yang ◽  
Shi Qingjun ◽  
Li Jing ◽  
Ma Huibin ◽  
Liu Desheng
Keyword(s):  
Emission Rate ◽  
Gas Emission ◽  
Chaos Analysis ◽  
Rate Prediction

4D Measurements and Analysis of Heat Release Rate in a Model Gas Turbine Combustor

2020 ◽  
Author(s):  
Rongxiao Dong ◽  
Qingchun Lei ◽  
Yeqing Chi ◽  
Qun Zhang ◽  
Wei Fan
Keyword(s):  
Heat Release ◽  
Gas Turbine ◽  
Surface Area ◽  
Heat Release Rate ◽  
Release Rate ◽  
Flame Surface ◽  
Global Instability ◽  
Gas Turbine Combustor ◽  
Model Gas Turbine Combustor ◽  
Edge Contours

Abstract Time-resolved volumetric measurements (4D measurements) were performed to study the heat release rate characteristics in a model gas turbine combustor at 10 kHz. For this purpose, a high-speed camera combined with an image intensifier and a set of customized fiber probes were employed to continuously capture the CH* chemiluminescence signals from nine different viewing angles. Based on the measurements, the computed tomography program was performed to reconstruct the shot-to-shot 3D distributions of the CH* signals. Specific focuses have been made to demonstrate the capabilities of the current tomographic technique in applications of a realistic combustor, in which the full optical access was usually not available for every viewing angle. The results showed that the 3D reconstruction can successfully retrieval the flame edge contours rather than the signal intensity. The flame surface area was then calculated based on the reconstructed flame edge contours and used to infer the heat release rate. The fluctuation of global/local flame surface area indicated that there existed distinct difference between the global instability and local instabilities at various locations in the non-symmetric combustor. The global instability appears to be an integration of those local instabilities.

Experimental Study of Gas Dispersion over Complex Terrain

2016 ◽  
Vol 821 ◽  
pp. 85-90 ◽  
Author(s):  
Petr Michálek ◽  
David Zacho
Keyword(s):  
Experimental Study ◽  
Complex Terrain ◽  
Dispersion Model ◽  
Concentration Field ◽  
Ground Level ◽  
Gas Emission ◽  
Gas Dispersion ◽  
Terrain Model ◽  
Flame Ionization ◽  
Ionization Detectors

Experimental study of gas dispersion over complex terrain model was performed in VZLU Prague. A complex terrain model was mounted into a boundary layer wind tunnel and equipped with ground-level gas emission source. Concentration field of the emitted gas was measured using comb suction probe and flame ionization detectors. The results will serve for verification and validation of a new computational dispersion model.

Behaviour of Micropollutants in Soils Amended with River Cleaning out Sludge in Northern France

1992 ◽  
Vol 25 (11) ◽  
pp. 433-440
Author(s):  
V. Gandais ◽  
P. Marchandise
Keyword(s):  
Heavy Metals ◽  
Field Study ◽  
Surface Area ◽  
Joint Project ◽  
Northern France ◽  
Hydrocarbons In Soils

Thisstudyis aimed at determining the fate of some heavy metals and hydrocarbons in soils amended with sludge from river cleaning out. Northern France has been chosen for the experiment because it is a heavily industrialized region where contamination by micropollutants has been very acute for many years. Several French laboratories are associated in this joint project which is partly sponsored by the Ministry of Environment and Artois-Picardie Water Agency. The parcel of land studied has a surface area of 100m2. It has been instrumented with Chamberland candles in order to get water for micropollutants analysis, tensiometers and a neutronic probe so as to collect informations on the hydric state of the soil. Once instrumented the parcel has been spread with sludge from river cleaning out. The main objective is to obtain an estimation of the fluxes of micropollutants and to evaluate the respective proportions of infiltration and drainage. A lab study based on lysimeters is carried out together with the field study. The field study will last at least 2 years while the lab study will be going on for a year.

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