A PLIF and PIV study of liquid mixing enhanced by a lateral synthetic jet pair

Xia, Qingfeng; Zhong, Shan

doi:10.1016/j.ijheatfluidflow.2012.04.010

Cited by 28 publications

(13 citation statements)

References 21 publications

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“…The tested data exhibit an excellent linearity relationship between fluorescence intensity with Rhodamine B concentration up to 0.3 mg/L. The similar phenomenon was also found by Xia and Zhong [21]. Using the linear relationship, the instantaneous concentration distribution was displayed in Fig.…”

Section: Fig 7 Schematic Diagram Of Experimental Systemsupporting

confidence: 81%

Combined Influence of Surface Deposition and Hole-Blockage on Film-Cooling Performances

Wang

Yuan

et al. 2016

Volume 5C: Heat Transfer

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Commercial aero-engines may operate in dust-laden environments, such as taking off and landing on desert ground or flying through volcano dust cloud, and foreign particles frequently deposit at hot surface and film hole-exits, which results in partial blockage of film holes, clog of cooling air, reduction in cooling effect, and could induce catastrophic damage. This problem has not been well solved up to now. This paper presents an experimental investigation on two surface deposition models (deposition limited to upstream of hole with a peak height of 1.5 diameter of hole called D1.5, and downstream forming a trench with a peak height of 1.0 diameter of hole, called D1) and two blockage models (leading edge of hole LB, and trailing edge TB), as well as two combined models D1.5-LB, and D1-TB. The experiments are conducted in a low speed water tunnel using Planar Laser Induced Fluorescence (PLIF) technique. Through this experiment, the following interesting phenomena, which were not reported in previous literatures, are reveled: 1) The effect of blockage ratio at leading edge on cooling performance of combined D1.5-LB is opposite to individual LB, i.e. in the case of combined D1.5-LB, a higher blockage ratio corresponds to a lower cooling effectiveness; whereas, for individual LB, the cooling effectiveness increases with the blockage ratios in the tested range. 2) At all blowing ratios, the cooling performances of combined D1.5-LB are better than that of perfect model D0-B0 (without deposition and blockage). At all blockage ratios tested in this experiment, in the case of combined D1.5-LB, a higher blowing ratio corresponds to a higher cooling effectiveness and a lager film coverage length. 3) At lower blockage ratios of 0.1 and 0.3, the overall-averaged cooling effectiveness of combined D1-TB is higher than that of perfect model D0-B0. At large blockage ratio 0.5, the blockage effect is dominant, and the averaged cooling effectiveness of combined model D1-TB is lower than that of D0-B0. In the case of individual deposition model D1-B0, although the lateral-averaged film cooling effectiveness is augmented, the area of film cooling is reduced.

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Section: Fig 7 Schematic Diagram Of Experimental Systemsupporting

confidence: 81%

Combined Influence of Surface Deposition and Hole-Blockage on Film-Cooling Performances

Wang

Yuan

et al. 2016

Volume 5C: Heat Transfer

View full text Add to dashboard Cite

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“…A typical microscale problem that can be effectively resolved using SJs is the cooling of highly loaded electronic components in microchannels (Timchenko et al 2007;Lee et al 2012a, b;Trávníček et al 2012b). A closely related problem was studied experimentally by means of PLIF and PIV by Xia and Zhong (2012b), in which fluid mixing between two laminar water streams in a channel was enhanced by a pair of lateral SJs.…”

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confidence: 99%

Visualization study of hybrid synthetic jets

Broučková

Trávníček

2014

J Vis

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A synthetic jet (SJ) is a fluid flow that is created from an oscillatory process of suction and blowing. A hybrid synthetic jet (HSJ) combines this principle with fluidic pumping through a valveless pump. The present study addresses round HSJs issuing into quiescent surroundings from an actuator orifice 8 mm in diameter. For comparison purposes, a common (zero-net-mass-flux) SJ is used. The working fluid is air, and the maximum Reynolds numbers are 11,000 and 9,000 for HSJs and SJs, respectively. The following five experimental methods are employed: flow visualization using a smoke wire technique, velocity measurements using a hot-wire anemometer, velocity measurements using a Pitot tube, impedance measurements of the actuators, and measurements of the jet momentum using precision scales. Flow visualization demonstrates phase-locked flow fields. The first resonance frequencies are theoretically derived to be 79 and 98 Hz for an SJ and HSJ, respectively. These values are confirmed by all of the experimental methods used. The results demonstrate the advantages of HSJs. The tested HSJ achieves a 24 % higher pumped volume flow rate in comparison to the SJ at a maximum volumetric efficiency of 33 %. Moreover, the overall energy efficiency of the HSJ actuator is 1.8 times higher than that of the SJ actuator. These promising HSJ features, including significantly higher efficiencies, can be useful for various heat transfer applications such as the cooling of highly loaded electronic devices.

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“…The potential applications have been found especially in boundary-layer separation control [3][4][5][6][7][8][9][10], jet vectoring [11][12][13][14][15][16], heat transfer enhancement [17][18][19][20][21][22], and mixing [23][24][25]. A variant of the SJ, namely a non-zero-net-mass-flux jet (or hybrid SJ), has been investigated more recently [26-28, 21, 29-31].…”

Section: Introductionmentioning

confidence: 99%

Comparison of synthetic jet actuators based on sharp-edged and round-edged nozzles

Kordík

Trávníček

2017

EPJ Web Conf.

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Abstract. Axisymmetric synthetic jet actuators based on a loudspeaker and on two types of flanged nozzles were tested and compared experimentally. The first type of the nozzle was a sharp-edged circular hole. The second one had a special design with fillets at inner and outer nozzle exit and with a small step in the middle of the nozzle. The function of the step was to prevent the flow reattachment during the extrusion stroke. The actuators with the two types of nozzles were operated at resonance and were compared first qualitatively using a simple phase locked flow visualization. Then the hot-wire anemometer was used to measure velocity distributions along nozzle axis and velocity profiles at the nozzle exit. Comparison of the nozzles was based on evaluation of the characteristic velocity and integral quantities (volumetric, momentum, and kinetic energy fluxes). It was found out that these quantities, which were evaluated at the nozzle exit, differ substantially for both nozzles. On the other hand the velocity flow field in farther distances from the nozzle exit area did not exhibit such prominent differences.

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A PLIF and PIV study of liquid mixing enhanced by a lateral synthetic jet pair

Cited by 28 publications

References 21 publications

Combined Influence of Surface Deposition and Hole-Blockage on Film-Cooling Performances

Combined Influence of Surface Deposition and Hole-Blockage on Film-Cooling Performances

Visualization study of hybrid synthetic jets

Comparison of synthetic jet actuators based on sharp-edged and round-edged nozzles

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