scholarly journals Erratum to “impact of burner plenum acoustics on the sound emission of a turbulent lean premixed open flame”

2020 ◽  
Vol 12 ◽  
pp. 175682772095690
Author(s):  
S Herff ◽  
K Pausch ◽  
H Nawroth ◽  
S Schlimpert ◽  
CO Paschereit ◽  
...  

The acoustic field of a turbulent lean cpremixed open flame is numerically investigated by a hybrid method solving the Navier-Stokes equations in a large-eddy simulation formulation and the acoustic perturbation equations. The interaction of acoustic modes of a burner plenum and the turbulent flame is analyzed with respect to the sound emission of the flame. It is investigated if a simplified computation yields a good broadband agreement of the sound pressure spectrum with experimental measurements. The results of two numerical setups, i.e., the first configuration consists of the burner plus the plenum geometry while in the second configuration the plenum is neglected, which is often done in technical applications due to computational efficiency reasons, are compared with experimental findings. It can be concluded that the plenum has a pronounced impact on the dynamics and combustion noise of the open flame. To be more precise, the comparative juxtaposition of the numerical and experimental results shows a good agreement only for the full burner-plenum computation since the interaction of the acoustic quarter-wave modes of the burner plenum with the jet flow has to be captured. The interaction of these quarter-wave modes with the flow is analyzed and the acoustic response to heat release fluctuations of the flame of the full burner-plenum computation is compared to that of the simplified burner computation, in which the plenum acoustics is neglected. Due to the excitation by the plenum acoustics, the jet flow of the full burner plenum contains higher turbulent kinetic energy and the flame is excited at several additional frequencies which result in distinct peaks in the acoustic spectrum and a higher overall sound pressure level.


Author(s):  
Stephan Schlimpert ◽  
Seong Ryong Koh ◽  
Antje Feldhusen ◽  
Benedikt Roidl ◽  
Matthias H. Meinke ◽  
...  

2021 ◽  
Vol 35 (8) ◽  
pp. 6776-6784
Author(s):  
Truc Huu Nguyen ◽  
Jungkyu Park ◽  
Changhun Sin ◽  
Seungchai Jung ◽  
Shaun Kim

Computation ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 43
Author(s):  
Shokri Amzin ◽  
Mohd Fairus Mohd Yasin

As emission legislation becomes more stringent, the modelling of turbulent lean premixed combustion is becoming an essential tool for designing efficient and environmentally friendly combustion systems. However, to predict emissions, reliable predictive models are required. Among the promising methods capable of predicting pollutant emissions with a long chemical time scale, such as nitrogen oxides (NOx), is conditional moment closure (CMC). However, the practical application of this method to turbulent premixed flames depends on the precision of the conditional scalar dissipation rate,. In this study, an alternative closure for this term is implemented in the RANS-CMC method. The method is validated against the velocity, temperature, and gas composition measurements of lean premixed flames close to blow-off, within the limit of computational fluid dynamic (CFD) capability. Acceptable agreement is achieved between the predicted and measured values near the burner, with an average error of 15%. The model reproduces the flame characteristics; some discrepancies are found within the recirculation region due to significant turbulence intensity.


Author(s):  
Neil E. Coughlan ◽  
Ross N. Cuthbert ◽  
Eoghan M. Cunningham ◽  
Stephen Potts ◽  
Diarmuid McSweeney ◽  
...  

AbstractSuppression of established populations of invasive alien species can be a complex and expensive process, which is frequently unsuccessful. The Asian clam, Corbicula fluminea (Müller, 1774), is considered a high impact invader that can adversely alter freshwater ecosystems and decrease their socioeconomic value. To date, C. fluminea continues to spread and persist within freshwater environments worldwide, despite repeated management attempts to prevent dispersal and suppress established populations. As extensive C. fluminea beds can often become exposed during low-water conditions, the direct application of hot or cold thermal shock treatments has been proposed as suitable mechanism for their control. Further, mechanical substrate disturbance may enhance the efficacy of thermal shock treatments by facilitating exposures to multiple layers of buried clams. In the present study, we advanced these methods by assessing combined applications of both hot and cold thermal shock treatments for control of C. fluminea, using steam spray (≥100 °C; 350 kPa), low- or high-intensity open-flame burns (~1000 °C) and dry ice (−78 °C). In a direct comparison of raking combined with hot thermal shock applications, both steam and high-intensity open-flame treatments tended to be most effective, especially following multiple applications. In addition, when hot thermal treatments are followed by a final cold shock (i.e. dry ice), steam treatments tended to be most effective. Further, when dry ice was applied either alone or prior to an application of a hot shock treatment, substantial if not complete C. fluminea mortality was observed. Overall, this study demonstrated that combined applications of hot and cold thermal shock treatments, applied following the disruption of the substrate, can substantially increase C. fluminea mortality compared to separate hot or cold treatments.


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