Effects of multiple rows and noncircular orifices on dilution jet mixing

Holdeman, J. D.; Srinivasan, Ram; Coleman, E.; Meyers, G. D.; White, C.

doi:10.2514/3.22977

Cited by 31 publications

(4 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1). In contrast to previous jet mixing studies [Kamotani and Greber, 1974, Holdeman, 1990, Holdeman and Walker, 1977, Holdeman et al, 1987 this investigation concentrates on the fast and homogeneous jet mixing due to the RQL-application. Jet trajectories and temperature profile development were of minor importance.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Multiple Jets Mixing With a Confined Crossflow

Doerr

Blomeyer

Hennecke

1995

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

View full text Add to dashboard Cite

An experimental investigation of a non-reacting multiple jet mixing with a confined crossflow has been conducted. Flow and geometric conditions were varied in order to examine favourable parameters for mixing. The requirement for a rapid and intense mixing process originates from combustion applications, especially the RQL-combustion concept. Thus, the jets were perpendicularly injected out of one opposed row of circular orifices into a heated crossflow in a rectangular duct. Spacing and hole size were varied within the ranges referring to combustor applications. The results presented are restricted to an inline orientation of opposed jet axis. Temperature distribution, mixing rate and standard deviation were determined at discrete downstream locations. Best i.e. uniform mixing can be observed strongly depending on momentum flux ratio. For all geometries investigated an optimum momentum flux ratio yields to a homogeneous temperature distribution in the flowfield downstream of the injection plane. Too high ratios deteriorate the mixing process due to the mutual impact of the opposed entraining jets along with a thermal stratification of the flowfield. Correlations are introduced describing the dependency of optimum momentum flux ratio on mixing hole geometry. They allow the optimization of jet-in-crossflow mixing processes in respect to uniform mixing.

show abstract

Section: Introductionmentioning

confidence: 99%

Optimization of Multiple Jets Mixing With a Confined Crossflow

Doerr

Blomeyer

Hennecke

1995

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

View full text Add to dashboard Cite

show abstract

“…These investigations have demonstrated that the primary factors defining jet penetration and the rate of mixing are the ratio between the jet and cross-flow momentum fluxes and the hole spacing-to-duct height ratio. Algebraic correlations for the cross-flow temperature distributions of a number of geometries have been determined and the degree of mixing predicted by these relationships has been shown to be strongly sensitive to the cross-flow temperature distribution (Holdeman et al, 1987). It is therefore necessary to be able to accurately define the temperature distribution before the jets.…”

Section: Introductionmentioning

confidence: 99%

Mixing of Multiple Jets in a Can Combustor

Ebbinghaus

Swithenbank

1995

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

View full text Add to dashboard Cite

Computational fluid dynamics and experiments have been used to study the mixing of multiple jets in a can combustor. An existing configuration having a poor exit temperature profile was chosen as the baseline case. In the computations, the air split and axial location of the primary, secondary and dilution jets were held constant while the number of jets at each location were varied parametrically to determine their effect on the exit temperature profile. As a result of these studies, two configurations were selected for experimental verification of the anticipated improved performance. The modified design was found to have a more uniform exit temperature profile than the baseline case. Thus the experimental results generally confirmed the predictions and demonstrated the potential utility of CFD as a design tool.

show abstract

“…Many workers have undertaken research related to this specific application, investigating the relative significance of the large number of aerodynamic and geometric variables involved in defining the dilution process. A comprehensive study of the mixing of air jets injected into a rectangular duct has been conducted by Holdeman et al (1977Holdeman et al ( to 1987, in which jet diameter and spacing, mixing duct geometry and velocity and temperature ratios were varied. It was concluded that the most important parameter influencing the mixing process is the jet to cross-flow momentum flux ratio, this being confirmed independently by the results of Sridhari (1970) when investigating the mixing of air jets injected into a circular duct.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Dilution Hole Geometry on Jet Mixing

Carrotte

Stevens

1989

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications

View full text Add to dashboard Cite

Measurements have been made on a fully annular test facility, downstream of a row of heated dilution jets injected normally into a confined cross-flow at a momentum flux ratio of 4. The investigation concentrated on the consistency of mixing between the jets, as indicated by the regularity of the temperature pattern around the cross-flow annulus. When the heated air was supplied from a representative feed annulus, the exit velocity profile across each plunged hole was significantly altered and caused a distortion of the temperature distribution in the ensuing jet. The degree of distortion varies in a random manner, so that each jet has its own mixing characteristics thereby producing irregularity of the temperature pattern around the annulus. With the same approach and operating conditions some of the plunged dilution holes were modified, and tests on this modified sector indicated a significant improvement in the circumferential regularity of the temperature pattern. Further tests showed these modifications to the dilution holes had a negligible effect on the values of the discharge coefficients.

show abstract

Effects of multiple rows and noncircular orifices on dilution jet mixing

Cited by 31 publications

References 7 publications

Optimization of Multiple Jets Mixing With a Confined Crossflow

Optimization of Multiple Jets Mixing With a Confined Crossflow

Mixing of Multiple Jets in a Can Combustor

The Influence of Dilution Hole Geometry on Jet Mixing

Contact Info

Product

Resources

About