This paper reports a numerical investigation of an atmospheric lean-premixed swirl-stabilized burner. The focus on the flow behavior and flame stability is done at various swirl intensity to better understand the propane turbulent premixed flames. The numerical simulation is carried out using RANS technique with three turbulence closer models Standard k-ε, Realizable k-ε and SST k-ω. This in order to evaluate the performance of these models in the prediction of confined turbulent swirling flows. The turbulence-chemistry interaction scheme is modelled using Finite Rate-Eddy Dissipation model with three step global reaction mechanism. The combustor is operated with air and propane mixture under an atmospheric pressure at a global equivalence ratio of Φ = 0.5. The investigation is done using five different swirl numbers Sn = (0, 0.35, 0.75, 1.05, 1.4), including a validation with the available experimental data. Good agreement is found between RANS results and experimental data, in particular axial and radial velocity profiles, temperature and propane concentration profiles. Results indicate the presence of outer recirculation zone (ORZ) in the inlet burner corner, irrespective of the swirl number. When the swirl number reaches a critical value Sn = 0.75, an inner recirculation zone (IRZ) appears in the center of the burner inlet as a result of vortex-breakdown. Increasing swirl number to an excessive value leads to the propagation of the IRZ upstream the combustion chamber, and consequently the appearance of the flame flashback.
We report the development of a
single-pass
electrochemical
Birch reduction carried out in a small footprint electrochemical Taylor
vortex reactor with projected productivities of >80 g day
–1
(based on 32.2 mmol h
–1
), using a modified version
of our previously reported reactor [
Org. Process Res. Dev.
2021
,
25
, 7, 1619–1627], consisting
of a static outer electrode and a rapidly rotating cylindrical inner
electrode. In this study, we used an aluminum tube as the sacrificial
outer electrode and stainless steel as the rotating inner electrode.
We have established the viability of using a sacrificial aluminum
anode for the electrochemical reduction of naphthalene, and by varying
the current, we can switch between high selectivity (>90%) for
either
the single ring reduction or double ring reduction with >80 g day
–1
projected productivity for either product. The concentration
of LiBr in solution changes the fluid dynamics of the reaction mixture
investigated by computational fluid dynamics, and this affects equilibration
time, monitored using Fourier transform infrared spectroscopy. We
show that the concentrations of electrolyte (LiBr) and proton source
(dimethylurea) can be reduced while maintaining high reaction efficiency.
We also report the reduction of 1-aminonaphthalene, which has been
used as a precursor to the API Ropinirole. We find that our methodology
produces the corresponding dihydronaphthalene with excellent selectivity
and 88% isolated yield in an uninterrupted run of >8 h with a projected
productivity of >100 g day
–1
.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.