Impinging Sweeping Jet Heat Transfer

Agricola, Lucas; Prenter, Robin; Lundgreen, Ryan; Hossain, Mohammad A.; Ameri, Ali; Gregory, J.N.; Bons, Jeffrey P.

doi:10.2514/6.2017-4974

Cited by 18 publications

(7 citation statements)

References 14 publications

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“…A similar analysis could be carried out on a series of sweeping jet impingement work, where the cooling performance is compared with a geometrically similar circular jet. Hossain et al [88] investigated sweeping jets under different configurations using Infrared thermography and computational fluid dynamics to understand the heat transfer and fluid flow characteristics. The authors employed the sweeping jet under both flat and concave [89] targets applicable to the context of a turbine vane [90].…”

Section: Thermal-hydraulic Performance Of Shaped Jetsmentioning

confidence: 99%

Opportunities in Jet-Impingement Cooling for Gas-Turbine Engines

Dutta

Singh

2021

Energies

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Impingement heat transfer is considered one of the most effective cooling technologies that yield high localized convective heat transfer coefficients. This paper studies different configurable parameters involved in jet impingement cooling such as, exit orifice shape, crossflow regulation, target surface modification, spent air reuse, impingement channel modification, jet pulsation, and other techniques to understand which of them are critical and how these heat-transfer-enhancement concepts work. The aim of this paper is to excite the thermal sciences community of this efficient cooling technique and instill some thoughts for future innovations. New orifice shapes are becoming feasible due to innovative 3D printing technologies. However, the orifice shape variations show that it is hard to beat a sharp-edged round orifice in heat transfer coefficient, but it comes with a higher pressure drop across the orifice. Any attempt to streamline the hole shape indicated a drop in the Nusselt number, thus giving the designer some control over thermal budgeting of a component. Reduction in crossflow has been attempted with channel modifications. The use of high-porosity conductive foam in the impingement space has shown marked improvement in heat transfer performance. A list of possible research topics based on this discussion is provided in the conclusion.

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Section: Thermal-hydraulic Performance Of Shaped Jetsmentioning

confidence: 99%

Opportunities in Jet-Impingement Cooling for Gas-Turbine Engines

Dutta

Singh

2021

Energies

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“…A self-oscillating flapping flow has demonstrated heat transfer coefficient enhancements ranging from 20 % to 70 % in the range of 20-100 Hz [14]. Another periodic unsteady flow device that created a self-oscillating sweeping flow has shown improvements in the uniformity of heat transfer at the impingement plate [15]. This study considers self-excited fluidic devices as a means of providing pulsating flow for heat transfer enhancement at frequencies greater than 100 Hz.…”

Section: Introductionmentioning

confidence: 99%

Self-Excited Fluidic Oscillators for Gas Turbines Cooling Enhancement: Experimental and Computational Study

Ten

Povey

2019

Journal of Thermophysics and Heat Transfer

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Pulsed flow has been shown to enhance heat transfer coefficients of impinging jets. This paper considers the use of pulsed impinging jets, derived from a self-excited fluidic oscillator, for gas turbine cooling. Self-excited oscillatory behavior was demonstrated in simulations over a wide range of inlet to outlet pressure ratios from ⁄ = 1.0025 to ⁄ = 2.18 for a device with a nozzle throat to splitter length of 10.4 mm. Heat transfer simulations at two test points (460 Hz and 769 Hz) resulted in Nu enhancement of 13% and 15% over corresponding cases with non-periodic flow at the same time mean mass flow rate. Increased oscillation frequency was found to increase Nu enhancement. In the range

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“…In a configuration with multiple jets, neighboring jets often collide in the space between them, hindering local heat transfer. A novel fluidic actuator generating a strongly periodic sweeping jet would thus be a very favorable mechanism to broaden the wall coverage of the jet (Agricola et al, 2017 andPark et al, 2018), while multiple sweeping jets with phase synchronization have great potential to bring flow phase-resolved on into the convective heat transfer due to the in-phase oscillation. As a first attempt at creating phase-synchronized dual sweeping impinging jets, flow dynamics and the resulting spatial distribution of the impingement along a flat wall are the focus of the current study.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, sweeping jets issued from a fluidic oscillator have shown increasing potential in applications of impingement (Camci and Herr, 2002;Tesař, 2009;Lundgreen et al, 2017;Agricola et al, 2017;and Park et al, 2018). Unlike other unsteady jet actuators, the fluidic oscillator requires no moving parts and relies only on internal flow dynamics to produce a transverse sweeping jet.…”

Section: Introductionmentioning

confidence: 99%

“…This superior capability of sweeping jets was also confirmed by a more recent study by Park et al (2018) using hot air within a range of 3.6 × 10 3 < Re < 15.3 × 10 3 . In an air thermal chamber, Agricola et al (2017) found that sweeping jets can also provide a more uniform impingement than a circular steady jet. To the best of the authors' knowledge, most previous efforts have been concentrated on a single sweeping jet.…”

Section: Introductionmentioning

confidence: 99%

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Interaction of dual sweeping impinging jets at different Reynolds numbers

Wen

Zhou

2018

Physics of Fluids

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Dual sweeping impinging jets emerging from a synchronized pair of fluidic oscillators were experimentally measured using time-resolved particle image velocimetry in a water tank. Interestingly, distinct behaviors of the dual jets were observed at three different Reynolds numbers. At the lowest Reynolds number Re = 1.8 × 10 3 , the dual jets can be generally treated as two isolated jets with a good in-phase sweeping motion and a relatively stable jet velocity. One pair of wall vortices develops and interacts in a trade-off manner in the middle region between the two jets. In the time-averaged flow fields close to the wall, each jet generates one major peak value of streamwise velocity and one pair of peak values (positive and negative) of transverse velocity laterally along the wall. The turbulence fluctuations in both directions also have peak values laterally. In the transverse direction, the velocity also has high turbulence fluctuations in the middle region between the two jets caused by the wall vortices. At the highest Reynolds number Re = 9.2 × 10 3 , the dual jets experience significantly distorted oscillation patterns and strong variations in their jet velocity during one actuation cycle. The dynamic behavior, the induced wall vortices, and the resulting time-averaged impingement of the dual jets are, in essence, very similar to the sweeping jet that would be produced from a single, but bigger, oscillator. At the intermediate Reynolds number Re = 5.5 × 10 3 , the performance of the dual sweeping jets is at the transition stage.

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Impinging Sweeping Jet Heat Transfer

Cited by 18 publications

References 14 publications

Opportunities in Jet-Impingement Cooling for Gas-Turbine Engines

Opportunities in Jet-Impingement Cooling for Gas-Turbine Engines

Self-Excited Fluidic Oscillators for Gas Turbines Cooling Enhancement: Experimental and Computational Study

Interaction of dual sweeping impinging jets at different Reynolds numbers

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