Investigation of geometry and dimensionless parameters effects on the flow field and heat transfer of impingement synthetic jets

Hatami, M.; Bazdidi–Tehrani, Farzad; Abouata, Ahmad; Mohammadi-Ahmar, Akbar

doi:10.1016/j.ijthermalsci.2018.01.011

Cited by 50 publications

(17 citation statements)

References 40 publications

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“…Thus, it is common to employ dimensionless parameters to determine an actuator's response, some of the most well-known are Reynolds Number (Re) and the Stroke Length, which is the column of fluid displaced during the blowing phase [3]. This parameter is related to the Strouhal number (Sr) as it is equal to its inverse; therefore, in many studies, the Stroke Length is employed as a dimensionless frequency rather than a dimensionless amplitude [9]. Jabbal et al [10] in their experimental study of a round SJ in quiescent flow discussed the role of these dimensionless numbers on the jet's behavior.…”

Section: Introductionmentioning

confidence: 99%

Towards Accurate Boundary Conditions for CFD Models of Synthetic Jets in Quiescent Flow

Matiz-Chicacausa

Mejia

2020

Energies

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In this paper, an accurate model to simulate the dynamics of the flow of synthetic jets (SJ) in quiescent flow is proposed. Computational modeling is an effective approach to understand the physics involved in these devices, commonly used in active flow control for several reasons. For example, SJ actuators are small; hence, it is difficult to experimentally measure pressure changes within the cavity. Although computational modeling is an advantageous approach, experiments are still the main technique employed in the study of SJs due to the lack of accurate computational models. The same aspect that represents an advantage over other techniques also represents a challenge for the computational simulations, such as capturing the unsteady phenomena, localized compressible effects, and boundary layer formation characteristic of this complex flow. One of the main challenges in the simulation of SJs is related to the fact that the spatial and temporal scales of the actuator and the corresponding flow control application differed in several orders of magnitude. Hence, in this study we focus on the use of Computational Fluid Dynamics (CFD) and Reduced Order Models (ROM) to develop an accurate yet low-cost model to capture the complexities of the flow of a SJ in quiescent flow. Numerical results show two possible paths for SJ modeling; (1) to obtain a boundary condition to predict velocity profile and jet formation from experimental data of diaphragm’s deformation; and, (2) to predict peak velocity at the jet’s outlet with a ROM approach and to use the physical details of the actuator to develop an accurate boundary condition for CFD. Both approaches are validated through experimental data available in the literature; good agreement between results from CFD, Lumped Element Model (LEM), and experimental data are achieved. Finally, it was concluded that the coupling between LEM and CFD is a novel and accurate approach, which improves CFD due to the advantages of LEM closing the gap between LEM’s lack of flow detail and CFD’s lack of geometrical/physical information of the actuator.

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Section: Introductionmentioning

confidence: 99%

Towards Accurate Boundary Conditions for CFD Models of Synthetic Jets in Quiescent Flow

Matiz-Chicacausa

Mejia

2020

Energies

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“…1. The air is considered to be an ideal gas with constant thermophysical properties [15,31]. The pressure-based transient solver is adopted.…”

Section: Introductionmentioning

confidence: 99%

“…In view of the axisymmetric configuration, only a half of the region on the meridian plane is selected as the computational domain, which has been repeatedly adopted to capture the main flow and heat transfer characteristics of impinging synthetic jets in the literature [36,37]. Further, Hatami et al [31] and Miró et al [32]…”

Section: Introductionmentioning

confidence: 99%

“…without any time-consuming manufacturing[31][32][33], a full-domain numerical model of heat transfer is established to capture the flow and heat transfer characteristics of impingement synthetic jets in confined spaces. The drawback of the flow structure and the cooling performance at a small nozzle-to-surface for a conventional impingement synthetic jet are first explored as a baseline for comparison.…”

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confidence: 99%

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Cooling performance improvement of impingement hybrid synthetic jets in a confined space with the aid of a fluid diode

Mei

Bai

et al. 2019

Applied Thermal Engineering

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Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.

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“…Basic parameters such as Reynolds number and jet-to-surface spacing significantly influence flow fields and heat transfer performances [2][3][4]. What's more, the further heat transfer enhancement of impinging jets can be obtained by combining other active or passive methods, which has been widely investigated by many scholars [5][6][7][8]. For example, single jet/jet arrays impinging onto dimpled target surface are numerically investigated [9].…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer and Flow Structures of Laminar Confined Slot Impingement Jet with Power-Law Non-Newtonian Fluid

Qiang

Wei

Luo³

et al. 2018

Entropy

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Heat transfer performances and flow structures of laminar impinging slot jets with power-law non-Newtonian fluids and corresponding typical industrial fluids (Carboxyl Methyl Cellulose (CMC) solutions and Xanthangum (XG) solutions) have been studied in this work. Investigations are performed for Reynolds number Re less than 200, power-law index n ranging from 0.5 to 1.5 and consistency index K varying from 0.001 to 0.5 to explore heat transfer and flow structure of shear-thinning fluid and shear-thickening fluid. Results indicate that with the increase of n, K for a given Re, wall Nusselt number increases mainly attributing to the increase of inlet velocity U. For a given inlet velocity, wall Nusselt number decreases with the increase of n and K, which mainly attributes to the increase of apparent viscosity and the reduction of momentum diffusion. For the same Re, U and Pr, wall Nusselt number decreases with the increase of n. Among the study of industrial power-law shear-thinning fluid, CMC solution with 100 ppm shows the best heat transfer performance at a given velocity. Moreover, new correlation of Nusselt number about industrial fluid is proposed. In general, for the heat transfer of laminar confined impinging jet, it is best to use the working fluid with low viscosity.

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Investigation of geometry and dimensionless parameters effects on the flow field and heat transfer of impingement synthetic jets

Cited by 50 publications

References 40 publications

Towards Accurate Boundary Conditions for CFD Models of Synthetic Jets in Quiescent Flow

Towards Accurate Boundary Conditions for CFD Models of Synthetic Jets in Quiescent Flow

Cooling performance improvement of impingement hybrid synthetic jets in a confined space with the aid of a fluid diode

Heat Transfer and Flow Structures of Laminar Confined Slot Impingement Jet with Power-Law Non-Newtonian Fluid

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