Flow and mixing characteristics of double-concentric jets pulsed at annular flow

Murugan, Sudharson; Huang, Rong Fung; Hsu, Ching Min

doi:10.1016/j.expthermflusci.2020.110039

Cited by 6 publications

(2 citation statements)

References 31 publications

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“…Although stationary mixing declined in the streamwise direction, the rate of relative mixing varied according to the mixing tendency of the regimes. Many studies [51][52][53][54] have shown that the Reynolds number or velocity ratio affects the mixing of flow regimes. Thus, the MR is defined as the ratio of the Reynolds number at the outlet to that at the inlet for each control volume.…”

Section: Inlet Egrmentioning

confidence: 99%

Entropy generation rate analysis of turbocharger radial flow compressor in range from surge to choke

Altafi,

Mojaddam,

Bastankhah

2023

Proceedings of the Institution of Mechanical Engineers, Part A:

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This study compares the local losses of a radial compressor in the range from surge to choke considering shock phenomena, boundary layer separation, and mixing mechanisms. For this purpose, formulation of the local entropy generation rate (EGR) is added to the computational fluid dynamics (CFD) solver, which models the turbulent flow field of the compressor through the RANS approach. For validation, the numerical pressure rise curve of the compressor is compared with the experimental data. The results indicate that at the design point, the impeller, diffuser, and the volute account for approximately 50.8%, 30.0%, and 12.3% of the EGR, respectively, with approximately 5% in the impeller backspace, 1% in the diffuser cavity, and less than 0.5% in the inlet duct. Approaching the surge condition, local losses due to mixing and shock waves decline while boundary layer losses increase. Based on comprehensive analysis of the leading-edge boundary layer, the largest dead-air zone is found at the design point, resulting in a lower diffusion entrance loss and a higher mixing loss. Furthermore, the EGR variation in the diffuser channel is investigated by shedding light on mixing dynamics and classification of the channel flow regime into three different zones based on mixing ratio (MR). The outcomes show that the flow regime tends to mix more quickly at a higher MR, resulting in a slight decrease in EGR, which benefits compressor performance. We demonstrate that the mixing rate of flow regimes decreases in both the leading-edge boundary layer and the radial diffuser approaching the surge margin.

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Section: Inlet Egrmentioning

confidence: 99%

Entropy generation rate analysis of turbocharger radial flow compressor in range from surge to choke

Altafi,

Mojaddam,

Bastankhah

2023

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…Coaxial jets, consisting of an inner round jet surrounded by a concentric outer jet (see Fig. 1a), are widely utilized in the field of energy conversion as an effective method to mix fuel and oxidant streams, e.g., pulverized coal gasification and combustion devices, turbofan and rocket engines [1][2][3]. To achieve the optimal mixing properties of coaxial jets, there is a cross angle or contraction angle (the angle between the inner/outer channel with the axis, see Figs.…”

Section: Introductionmentioning

confidence: 99%

Evolution and Dynamics of the Coherent Vortices in Contraction and Premix Coaxial Jets

Hao

et al. 2022

Chem Eng & Technol

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Contraction and premix coaxial jets are commonly employed in gasification and combustion systems. Understanding the spatial development of coherent structures is a prerequisite to improve the mixing and stability characteristics. The evolution and dynamics of coherent vortices under the contraction and premix coaxial jets are visualized and discussed using flow visualization technology. The contraction configuration increases the instability of the outer shear layer corresponding to an organized rolling up of the outer vortex rings. In the premixed configuration, the earlier interaction between the inner and outer shear layers induces the precocious development of the inner Kelvin-Helmholtz (K-H) vortices. Two empirical equations are proposed to predict the transition length towards a fully turbulent flow.

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Flow and mixing characteristics of dual parallel plane jets subject to acoustic excitation

Kumar

Huang

Hsu

2021

European Journal of Mechanics - B/Fluids

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Flow and mixing characteristics of double-concentric jets pulsed at annular flow

Cited by 6 publications

References 31 publications

Entropy generation rate analysis of turbocharger radial flow compressor in range from surge to choke

Entropy generation rate analysis of turbocharger radial flow compressor in range from surge to choke

Evolution and Dynamics of the Coherent Vortices in Contraction and Premix Coaxial Jets

Flow and mixing characteristics of dual parallel plane jets subject to acoustic excitation

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