Highly-resolved LES and PIV Analysis of Isothermal Turbulent Opposed Jets for Combustion Applications

Stein, Oliver T.; Böhm, Benjamin; Dreizler, Andreas; Kempf, Andreas

doi:10.1007/s10494-010-9310-3

Cited by 32 publications

(14 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The next region is dominated by strong jet-to-jet interactions and a decay in the jet velocity. In the final stages, individual jets can no longer be observed, and the turbulence decays (Böhm et al, 2010;Stein et al, 2011). While the general behavior is similar to the studies described above, the unconfined jets also showed a strong convergence along the side of the array.…”

Section: Multiple Jetssupporting

confidence: 74%

See 1 more Smart Citation

Near-Field Study of Multiple Interacting Jets : Confluent Jets

Ghahremanian¹

2015

View full text Add to dashboard Cite

Section: Multiple Jetssupporting

confidence: 74%

“…The experimental data and numerical simulations in Böhm et al (2010); Rieth et al (2014); Stein et al (2011) show three regions. An initial region with a constant jet velocity and low velocities between the jets is located near the nozzle plate.…”

Section: Multiple Jetsmentioning

confidence: 98%

Near-Field Study of Multiple Interacting Jets : Confluent Jets

Ghahremanian¹

2015

View full text Add to dashboard Cite

“…There have been many collaborations in the past involving experimental and numerical studies of the TCF configuration (e.g., [4,12,[18][19][20]). One of the underlying aspects in these studies is the choice of the computational domain.…”

Section: Choice Of Les Solution Domainmentioning

confidence: 99%

A Simple Approach for Specifying Velocity Inflow Boundary Conditions in Simulations of Turbulent Opposed-Jet Flows

Tirunagari

Pettit

Kempf³

et al. 2016

Flow Turbulence Combust

Self Cite

View full text Add to dashboard Cite

A new methodology is developed to specify inflow boundary conditions for the velocity field at the nozzle exit planes in turbulent counterflow simulations. The turbulent counterflow configuration consists of two coaxial opposed nozzles which emit highlyturbulent streams of varying species compositions depending on the mode considered. The specification of velocity inflow boundary conditions at the nozzle exits in the counterflow configuration is non-trivial because of the unique turbulence field generated by the turbulence generating plates (TGPs) upstream of the nozzle exits. In the method presented here, a single large-eddy simulation (LES) is performed in a large domain that spans the region between the TGPs of the nozzles, and the time series of the velocity fields at the nozzle exit planes are recorded. To provide inflow boundary conditions at the nozzle exit planes for simulations under other conditions (e.g., different stream compositions, bulk velocity, TGP location), transformations are performed on the recorded time series: the mean and r.m.s. (root-mean-square) quantities of velocity, as well as the longitudinal integral length scale on the centerline, at the nozzle exits in simulations are matched to those observed in experiments, thereby matching the turbulent Reynolds number Re t . The method is assessed by implementing it in coupled large-eddy simulation/probability density function (LES/PDF) simulations on a small cylindrical domain between the nozzle exit planes for three different modes of the counterflow configuration: N 2 vs. N 2 ; N 2 vs. hot combustion products; Ranjith R. Tirunagari Flow Turbulence Combust and CH 4 /N 2 vs. O 2 . The inflow method is found to be successful as the first and second moments of velocity from the LES/PDF simulations agree well with the experimental data on the centerline for all three modes. This simple yet effective inflow strategy can be applied to eliminate the computational cost required to simulate the flow field upstream of the nozzle exits. It is also emphasized that, in addition to the predicted time series data, the availability of experimental data close to the nozzle exit planes plays a key role in the success of this method.

show abstract

“…Closely spaced jets in an opposed jet burner issuing through turbulence-generating plates have been investigated experimentally by Böhm et al (2010) and computationally using LES by Stein et al (2011) and using both LES and DNS by Rieth et al (2014). In both CFD simulations and experiments three regions were found for the jets in the turbulent opposed burners.…”

Section: 3mentioning

confidence: 99%

“…The region that follows is dominated by strong jet-to-jet interactions and decay in jet velocity. Then, at the final stage, turbulence decays and individual jets can no longer be seen (Böhm et al, 2010;Stein et al, 2011).…”

Section: 3mentioning

confidence: 99%

Experimental and Numerical Investigations of Confluent Round Jets

Svensson¹

2015

View full text Add to dashboard Cite

Unconfined multiple interacting confluent round jets are interesting from a purely scientific point of view, as interaction between neighboring jets brings additional complexity to the flow field. Unconfined confluent round jets also exist in various engineering applications, such as ventilation supply devices, sewage disposal systems, combustion burners, chemical mixing or chimney stacks. Even so, little scientific attention has been paid to unconfined confluent round jets, and detailed investigations on the complete three-dimensional turbulent flow field of confluent jet configurations issuing into an unconfined stagnant environment are scarce.The present work uses both advanced measurement techniques and computational models to provide deeper understanding of the turbulent flow field development of unconfined confluent round jets. Both Laser Doppler Anemometry (LDA) and Particle Image Velocimetry (PIV) have been used to measure mean velocity and turbulence properties within two setups, consisting of a single row of 1×6 jets and a square in-line array of 6×6 confluent jets. LDA was used for measurements very close to the nozzle inlets and to verify the main findings made with PIV. A comparison between LDA and PIV results showed that the two measurement techniques produced results that are in good agreement with each other.Simulations using Computational Fluid Dynamics (CFD) of the 6×6 setup were conducted using three different Reynolds Averaged Navier-Stokes (RANS) turbulence models: the standard k-ε, the RNG k-ε and the Reynolds Stress Model (RSM). The results from the CFD simulations were compared with the experimental PIV data. The employed RANS turbulence models were all capable of accurately predicting mean velocities and turbulent properties in the investigated confluent jet array. In general the RSM and the standard k-ε model provided smaller deviations between numerical and experimental results than the RNG k-ε model. In terms of mean velocity the second-order closure model (RSM) was not found to be superior to the less complex standard k-ε model.The validated CFD results provide data at all locations in the solution domain and the computational results were used to further analyze the investigated confluent jet array. The validated CFD model was also employed in a parametrical investigation, including five independent variables: inlet velocity, nozzle diameter, nozzle edge-toedge spacing, nozzle height and the number of jets in the array. The parametrical investigations made use of statistical methods in the form of Response Surface Methodology and Box-Behnken Design of Experiments. The derived response surface models provided information on the principal influence and relative importance of the investigated parameters within the design limits.ii The positions of the jets within the array strongly influence both mean velocity and turbulence. In all investigated setups the jets experience merging and combining. Square arrays also include considerable jet convergence, which was not present in th...

show abstract

Highly-resolved LES and PIV Analysis of Isothermal Turbulent Opposed Jets for Combustion Applications

Cited by 32 publications

References 36 publications

Near-Field Study of Multiple Interacting Jets : Confluent Jets

Near-Field Study of Multiple Interacting Jets : Confluent Jets

A Simple Approach for Specifying Velocity Inflow Boundary Conditions in Simulations of Turbulent Opposed-Jet Flows

Experimental and Numerical Investigations of Confluent Round Jets

Contact Info

Product

Resources

About