Flow field features of chevron impinging synthetic jets at short nozzle-to-plate distance

Crispo, Cuono Massimo; Greco, Carlo Salvatore; Cardone, Gennaro

doi:10.1016/j.expthermflusci.2019.04.020

Cited by 14 publications

(10 citation statements)

References 45 publications

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“…The chevron SJ topology affects the distribution of the Nusselt number on the cooling plate in the case of impinging SJ application. In effect, the chevron synthetic jet shows better heat transfer characteristics than the circular synthetic jet [27]. The impact of the chevron orifice on the heat transfer enhancement was also confirmed by Lyu et al [25].…”

Section: Introductionmentioning

confidence: 63%

“…The time mean-reaction method allows measuring only the primary flow parameters of the SJ. The flow visualization of the chevron SJ was made by Crispo et al [26,27] for the actuator with a chevron nozzle. Therefore, it should be considered whether the SJ generated by the investigated actuators will be similar to those presented by Crispo et all [26,27].…”

Section: Flow Parametersmentioning

confidence: 99%

“…The synthetic jet actuator (SJA) can move the fluid using a loudspeaker [1], piezoelectric transducer [2], piston [3], or plasma [4]. The SJA with the chevron nozzle was investigated by Crispo et al [26][27][28]. They investigated mainly the difference in flow organization in the case of SJ generated by the actuator with the circular nozzle and the chevron nozzle.…”

Section: Introductionmentioning

confidence: 99%

“…Crispo et al [27] showed that except for the noncircular vortex ring the chevron SJA generated also the counter-rotating streamwise vortices in cutouts of the orifice. These structures have a significant impact on heat transfer enhancement.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Sharp and Rounded Cutouts in a Chevron Orifice and Them Impact on the Acoustic and Flow Parameters of Synthetic Jet

Smyk

2021

Applied Sciences

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The application of a synthetic jet actuator in workplaces entails the necessity of noise reduction, which they generate. One of the methods to achieve this is the use of the chevron orifice or nozzle. Therefore, the impact of different numbers of chevrons and rounding of cutouts in the orifice on the actuator efficiency and the sound pressure level was tested. The chevron orifices were compared to the circular orifice. The time-mean reaction force method was used to measured efficiency and flow parameters, and the noise was measured according to the ISO 3746:2010. The rounded cutouts had an advantageous impact on the actuator efficiency at the power P >1 W, while the efficiency of the actuator with classic chevron orifice was smaller than with circular orifice. The noise generated by the actuator with the chevron orifice was smaller from 0.6 to 1.6 dB than by the actuator with the circular orifice, at the number of chevrons equal to 7 or more. The rounding of cutouts in the chevron orifice can advantageously impact the parameters of synthetic jet actuators.

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Section: Introductionmentioning

confidence: 63%

Section: Flow Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Sharp and Rounded Cutouts in a Chevron Orifice and Them Impact on the Acoustic and Flow Parameters of Synthetic Jet

Smyk

2021

Applied Sciences

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“…There are many studies and research projects treating the jet noise reduction [5,6], but the simplest technique is to manufacture chevrons on the nozzle without having high loss of the propulsion force [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Impact of Using Chevrons Nozzle on the Acoustics and Performances of a Micro Turbojet Engine

Cican

Deaconu

2021

Applied Sciences

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This paper presents a study regarding the noise reduction of the turbojet engine, in particular the jet noise of a micro turbojet engine. The results of the measurement campaign are presented followed by a performances analysis which is based on the measured data by the test bench. Within the tests, beside the baseline nozzle other two nozzles with chevrons were tested and evaluated. First type of nozzle is foreseen with eight triangular chevrons, the length of the chevrons being L = 10 percentages from the equivalent diameter and an immersion angle of I = 0 deg. For the second nozzle the length and the immersion angle were maintained, only the chevrons number were increased at 16. The micro turbojet engine has been tested at four different regimes of speed. The engine performances were monitored by measuring the fuel flow, the temperature in front of the turbine, the intake air flow, the compression ratio, the propulsion force and the temperature before the compressor. In addition, during the testing, the vibrations were measured on axial and radial direction which indicate a normal functioning of the engine during the chevron nozzles testing. Regarding the noise, it was concluded that at low regimes the noise doesn’t presents any reduction when using the chevron nozzles, while at high regimes an overall noise reduction of 2–3 dB(A) was achieved. Regarding the engine performances, a decrease in the temperature in front of the turbine, compression ratio and the intake air and fuel flow was achieved and also a drop of few percent of the propulsion force.

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Experimental study on heat transfer enhancement of square-array jet impingement by using an integrated synthetic jet actuator

Tan,

Lyu,

Zhang

et al. 2023

Sci. China Technol. Sci.

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Flow field features of chevron impinging synthetic jets at short nozzle-to-plate distance

Cited by 14 publications

References 45 publications

Sharp and Rounded Cutouts in a Chevron Orifice and Them Impact on the Acoustic and Flow Parameters of Synthetic Jet

Sharp and Rounded Cutouts in a Chevron Orifice and Them Impact on the Acoustic and Flow Parameters of Synthetic Jet

Impact of Using Chevrons Nozzle on the Acoustics and Performances of a Micro Turbojet Engine

Experimental study on heat transfer enhancement of square-array jet impingement by using an integrated synthetic jet actuator

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