Characteristics of jet impingement in a side-dump combustor

Nosseir, N.; Behar, S.

doi:10.2514/3.9520

Cited by 35 publications

(11 citation statements)

References 6 publications

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“…It is seen that streamwise vortices are formed irregularly in space and have a tendency of clustering in groups, in the form of counter-rotating pairs. Comparing this picture with the one obtained by Nosseir and Behar (1986) at the similar streamwise location, we find that vortices appeared in the present pictures are more randomly spaced than those they observed. We suggest that this discrepancy is due to the difference in the Reynolds numbers of these two experiments performed.…”

Section: Resultscontrasting

confidence: 37%

“…Both Nosseir and Behar (1986) and Miau et al (1987) found that the formation of streamwise vortices in the stagnation region was directly associated with the velocity modulations in the inlet flows. Further, Miau et al (1987) postulated that the velocity modulations might be amplified by the hydrodynamic instability growth in the stagnation region, similar to that reported by Erickson and Olfe (1978).…”

Section: Resultsmentioning

confidence: 99%

“…Recently flow of such a configuration has attracted a number of researchers' attention, mainly due to the concerns of the turbulent flows developed in a ramjet side-dump combuster (Vanka et al 1983) and in a gas turbine combustor (Sivasgaram and Whitelaw 1986). To understand the fundamental aspects of turbulence generation due to impinging flows, Nosseir and Behar (1986) and Miau et al (1987) separately employed a water channel and a water tunnel facilities to study the impingement of the two counter-directional flows, which were two-dimensional basically. A major finding obtained from these studies is that impingement of flows leads to a flapping motion in the stagnation region, in which counter-rotating streamwise vortices are generated.…”

Section: Introductionmentioning

confidence: 99%

“…The purpose of this note is to present some of the recent visualization results obtained, in order to further clarify the physical picture depicted by Miau et al (1987) and Nosseir and Behar (1986). Particle-tracer visualization technique was employed.…”

Section: Introductionmentioning

confidence: 99%

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Streamwise vortices generated by impinging flows in a confined duct

Miau

Sun

Yao

1989

Experiments in Fluids

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Particle-tracer technique was employed for visualizing flow structures in a side-inlet square duct. The results obtained indicate that the streamwise vortices developed in the stagnation region of impinging flows are irregularly distributed. As the vortices convect downstream they are first stretched and merged, then squashed due to the non-zero pressure gradient effects caused by the flow separation regions existed along the side walls. The mechanism responsible for generating streamwise vortices in the stagnation region is suggested due to the hydrodynamic instability effect, similar to that previously found for three-dimensional disturbances growing in a two-dimensional stagnation flow.

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Section: Resultscontrasting

confidence: 37%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Streamwise vortices generated by impinging flows in a confined duct

Miau

Sun

Yao

1989

Experiments in Fluids

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“…Some preliminary investigations including flow visualization, mixing rates etc., have been performed by Beasley et al (1970), Smoot and Fort (1976), Nosseir and Behar (1986) and Nosseir et al (1987). Gowda et al (1987 a) have performed a parametric investigation in a dump combustor model by flow visualization in water, and in a subsequent investigation (Gowda et al 1987b), they have reported the pressure field characteristics.…”

Section: Introductionmentioning

confidence: 99%

Studies on the mixing of two non-axial plane jets in a confined passage: mean flow characteristics

Manjunath

Gowda

Natarajan

1991

Experiments in Fluids

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Abstract. The present study deals with the static pressure and mean velocity fields generated due to the mixing of two plane turbulent jets in a confined passage. Four different impingement angles, viz., 15, 30, 45 and 60 degrees, have been investigated. It is found that the inlet angle is the most important parameter governing the extent of the central recirculation zone, the wall recirculation zones, the position of the confluence point and the distance required for complete mixing. The rate of decay of the maximum velocity is very rapid for inlet angles exceeding 45 degrees.

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Self‐sustained oscillations in opposed impinging jets in an enclosure

Johnson

Wood

2000

Can J Chem Eng

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he flow field of opposed axisymmetric jets in a confined cavity has been examined for instabilities due to various geometrical and T fluid parameters. Practical examples where such configurations are used are the mix head for reaction injection molding (RIM) and the side dump combustor. RIM involves a rapid mixing process of two or more liquid pre-polymers in a mix chamber that flow into a mold to form a solid polymer part. For most RIM systems, mixing is carried out through directly opposed jet-to-jet impingement of the reactant streams.Stable efficient mixing is paramount to the quality of parts produced with RIM as poorly mixed materials will cause spatial variation in the physical properties and variation in the physical appearance of a finished molded part. Typically, mix chambers are cylindrical and 10 to 15 m m in diameter using nozzles with openings of 0.5 to 3 m m to form the jets near the closed end of the chamber (Figure 1). Fluid issues from the opposed nozzles and may create an impingement region in the mix chamber depending on the geometry and fluid parameters. The closed end is the face of the clean-out piston used to remove the polymer from the nozzle region after completion of the shot. The mixed fluid then leaves the open end of the chamber to the mold. A dimensionless group used to characterize the flow is the Reynolds number, Re,, which is based on the nozzle diameter d, the fluid kinematic viscosity and the volumetric flow rate Q through the nozzle (Q = xd2/4UOvg).Previous visualization studies have shown the existence of an oscillating flow field under some geometric and fluid configurations. They found steady impingement below Re, = 75 (D' = 10.67, D = 25.4 mm, $I = 180"), and a t values higher than this, an instability in the impingement surface began to grow and oscillate. Experimentally, above Red = 150 the jets would not directly impinge, although the computer simulations showed steady oscillations from Re, = 100 to 300. Our interest is in quantifying the range of oscillation parameters and to determine the effect on the stability or performance of the opposed jet mix head configuration. Visualizations of the flow patterns by Sandell et al. (1985) in a mix chamber ( D ' = 5.5, 0 = 30°, H' = 0.73) has shown an oscillating flow above Re, = 150. Generally, the flow became less steady when increasing the Re, or increasing the distance to the head region.In a similar study, Nosseir and Behar (1 986) used a rectangular model with opposed (@ = 180") rectangular jets at an average Re, of 3000 based on nozzle width to simulate the side dump combustor. Oscillations in the flow were detected when the dyed fluid interrupted a laser beam at aThe flow of jets in confining enclosures has significant application in many engineering processes. In particular, the impingement of axisymmetric jets in a confined space has been examined using flow visualization, laser Doppler anemometry, and numerical simulations. Several flow regions were found; stable steady, regular oscillatory, and irregular oscillatory...

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Characteristics of jet impingement in a side-dump combustor

Cited by 35 publications

References 6 publications

Streamwise vortices generated by impinging flows in a confined duct

Streamwise vortices generated by impinging flows in a confined duct

Studies on the mixing of two non-axial plane jets in a confined passage: mean flow characteristics

Self‐sustained oscillations in opposed impinging jets in an enclosure

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