Experimental and numerical investigation of the flow characteristics within a Solar Expanding-Vortex Particle Receiver-Reactor

Chinnici, Alfonso; Xue, Yunpeng; Lau, Timothy C. W.; Arjomandi, Maziar; Nathan, Graham J.

doi:10.1016/j.solener.2016.11.020

Cited by 21 publications

(12 citation statements)

References 38 publications

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“…For all radial profiles, the value of Uθ/Ue increases from 0 to 0.12 within 0 ≤ r/Dc ≤ 0.15 and then decreases to 0.07 for r/Dc > 0.15. This is qualitatively similar to the PIV data reported by Chinnici et al 29 for multiple swirling jets, which shows the presence of a forced vortex near to the central region, surrounded by a free vortex, i.e., a "Rankine" vortex (forced and free combined vortex). This vortex has also been widely documented for high-swirled jet configurations [41][42][43][44] .…”

Section: Results and Discussion A Mean Velocity Fieldssupporting

confidence: 91%

“…The results in Fig. 6(c) also show that Uθ/Ue in Regime III is around 20% higher than the data of Chinnici et al 29 . This indicates the presence of a highly-swirled flow for this regime.…”

Section: Results and Discussion A Mean Velocity Fieldssupporting

confidence: 46%

“…It can also be seen that a high velocity region (Uθ/Ue ≈ 0.12) occurs within the range -0.15 ≤ r/Dc ≤ 0.15 for all measured locations except the central point (r/Dc ≈ 0.15). This, in turn, suggests that a higher degree of swirl occurs close to the axis of the cylindrical chamber 29 , while this pronounced swirl region is not observed in the other two regimes. Hence, it can be concluded that the significance of the swirl within the central region tends to increase significantly as the dominant flow feature changes from the ERZ (Regime I) to the CRZ (Regime III).…”

Section: Results and Discussion A Mean Velocity Fieldsmentioning

confidence: 91%

“…Hence, there is a need for reliable, comprehensive and sufficient data under well-defined, consistent inflow and boundary conditions to fully characterize the swirl within the ERZ and CRZ that generated by a range of αj and θj. Flow unsteadiness has been widely investigated for swirling annular jets configurations 9,18,[24][25][26][27][28][29][30][31] . One of the key flow features is the precessing vortex core (PVC) within the recirculation zone, which has been identified for a wide range of vortex applications 27,29,30,32 .…”

Section: Introductionmentioning

confidence: 99%

“…Flow unsteadiness has been widely investigated for swirling annular jets configurations 9,18,[24][25][26][27][28][29][30][31] . One of the key flow features is the precessing vortex core (PVC) within the recirculation zone, which has been identified for a wide range of vortex applications 27,29,30,32 . The PVC is a largescale coherent and time-dependent flow structure embedded within a vortex, which is defined as the precession of the vortex-core relative to the geometric axis of an axisymmetric device, as described in the detailed review by Syred 9 .…”

Section: Introductionmentioning

confidence: 99%

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Characteristics of swirling and precessing flows generated by multiple confined jets

et al. 2019

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An experimental study is reported of the interaction between multiple iso-thermal jets within a cylindrical chamber under conditions relevant to a wide range of engineering applications, including the confined swirl combustors, industrial mixers and concentrated solar thermal devices. The Particle Image Velocimetry (PIV) technique was used to investigate the swirling and precessing flows generated with four rotationally-symmetric inlet pipes at a fixed nozzle Reynolds number of ReD = 10,500 for two configurations of swirl angle (5° and 15°) and two alternative tilt angles (25° and 45°). The measurements reveal three distinctive rotational flow patterns within the external recirculation zone (ERZ) and the central recirculation zone (CRZ) for these configurations. It was found that the mean and root-mean-square flow characteristics of the swirl within the chamber depend strongly on the relative significance of the ERZ and CRZ, with the swirling velocity being higher in the CRZ than that in the ERZ. A precessing vortex core (PVC) was identified for all experimental conditions considered here, although its significance was less for the cases with a dominant CRZ.

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