The manipulation of an unstarting supersonic flow by plasma actuator

Im, Seong Kyun; Do, Hyungrok; Cappelli, Mark A.

doi:10.1088/0022-3727/45/48/485202

Cited by 35 publications

(7 citation statements)

References 34 publications

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“…where P xy is the cross-power spectral density of the two signals,x and y; see Eqs. (1) and (2). P xx and P yy are the power spectral densities of x and y.…”

Section: Discussionmentioning

confidence: 99%

“…M ETHODS of supersonic and hypersonic boundary-layer (BL) flow control by electrical discharges have previously been studied extensively [1][2][3][4], showing a plausible controlling effect due to a nonuniform localized heating of the near-surface gas layer. Of a particular interest to this study is the effect of a pulsed plasma actuator on the flow oscillations along a flat plate leading up to a compression ramp with a separation zone in hypersonic flow.…”

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confidence: 99%

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Measurement of Flow Perturbation Spectra in Mach 4.5 Corner Separation Zone

et al. 2018

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Characterization of the M 4.5 flow over a flat-plate model with a 30 deg compression ramp was performed with low-enthalpy (T 0 300 K) and high-enthalpy (T 0 800-1250 K) flow conditions for a wide range of unit Reynolds numbers (Re l 4 ⋅ 10 5 − 1 ⋅ 10 7 m −1). Three measurement techniques were employed to measure the frequency spectrum of flow perturbations: a high-frequency Shack-Hartmann wavefront sensor (aerooptical method), highfrequency PCB™ pressure sensors, and a laser differential interferometer. The magnitude and frequency of flow oscillations measured by all three methods provide comprehensive and complementary results in determining spectra of gas disturbances within the flow. Of these measurement methods, the Shack-Hartmann wavefront sensor is shown to be the most suitable tool for analysis of the high-speed flow. Aerooptical measurements detect modification to the flow structure when plasma actuation is employed or when Re l is varied. In this work, flow characterization by the Shack-Hartmann sensor at individual points over the ramp has shown three flow regimes depending on the unit Reynolds number: turbulent, transitional, and laminar. At higher Re l , the freestream disturbances become strong enough to significantly affect the perturbations in the boundary-layer and the separation zone on the compression ramp. Frequency spectrum measurements during high-frequency plasma actuation (F 100 kHz) indicate amplification of the perturbations from the natural state that occur over the separation region.

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“…where P xy is the cross-power spectral density of the two signals,x and y; see Eqs. (1) and (2). P xx and P yy are the power spectral densities of x and y.…”

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Measurement of Flow Perturbation Spectra in Mach 4.5 Corner Separation Zone

et al. 2018

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“…The tiny water droplets will condense due to a sudden temperature drop when the flow is expanded through the divergent section of the nozzle [35]. As a result, nanometer-sized particles will be generated in the test section [37]. In the captured PLS images, the jet plume from PSJA is seen as darker region because of sublimation of the water particle at the lower density and higher, whereas the free stream is seeded with the particles.…”

Section: Measurement Methodsmentioning

confidence: 99%

Characterization of transverse plasma jet and its effects on ramp induced separation

Tang

Wang

et al. 2018

Experimental Thermal and Fluid Science

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Plasma synthetic jet actuator (PSJA), which produces pulsed jets, is used to control the shock wave boundary layer interaction at a compression ramp at Ma=2.0. The flow topology of the wall jets from the PSJA is first visualised through particle laser scattering (PLS) photography. The PSJA aperture effect is also examined by comparing the jets out of the apertures of 1,2 mm and 2 mm respectively. The control effect is later investigated by both PLS and particle image velocimetry (PIV). , which was erupted from different jet apertures of 1.2mm and 2mm, were compared experimentally in a wind tunnel of Mach 2. Further, the interaction between the TPJ and the ramp induced separation was explored. The phase-locked two-component particle image velocimetry (PIV) and particle laser scattering (PLS) were used for flow visualizations. The K-H vortices and hairpin vortices due to the shear stress between the jet plume and high-speed mainstream were identified.The results show that the TPJ in supersonic flow is characterized by two typical parts: the attached jet plume (AJP) and the detached jet plume (DJP). The penetration height of the jet plume, which is closely related to the jet aperture, plays a dominant role in the proportion of the two parts. The higher jet penetration height leads to the more detached jet plume. As for the interaction between the jet plume and separation zone, the attached jet plume was blocked by the separation zone, which formed a recirculation zone and contributed to an expansion of the separation. In contrast, the detached jet plume transited along the shear layer and then enhanced the velocity exchange between the shear layer and mainstream. Ultimately, the reduction of the separation zone was revealed with the overall shear layer reduced. Furthermore, a conceptual model based on two typical morphological features was suggested to reveal the interaction mechanism.

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“…This tunneling process is termed field emission and is accounted for by the modified Paschen's curve [8]. Surface discharges generated by dielectric bar rier discharge (DBD) actuators have been widely used to manipulate flow [9][10][11][12][13][14][15][16]. The electrohydrodynamic (EHD) body force generated by the plasma transfers momentum from charged particles to neutrals, which enables directed flow actuation [17].…”

Section: Introductionmentioning

confidence: 99%

Plasma-flow interactions in field-emission discharges with applications in microcombustion

Shivkumar¹,

Li²,

Alexeenko³

2019

J. Phys. D: Appl. Phys.

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Field emission based microplasma actuators generate highly nonneutral surface discharges that can be used to heat, pump, and mix the flow through microchannels and offer an innovative solution to the problems associated with microcombustion. They provide a constant source of heat to counter the large heat loss through the combustor surface, they aid in flow transport at low Reynolds numbers without the use of moving parts, and they provide a constant supply of radicals to promote chain branching reactions. In this work, we present two actuator concepts for the generation of field emission microplasma, one with offset electrodes and the other with planar electrodes. They operate at input voltages in the 275-325 V range at a frequency of 1 GHz which is found to be the most suitable value for flow enhancement. The momentum and energy imparted by the charged particles to the neutrals as modeled by 2D particleincell with Monte Carlo collisions are applied to actuate flow in microchannels using 2D computational fluid dynamics modeling. The planar electrode configuration is found to be more suitable for the purpose of heating, igniting and mixing the flow, as well as improving its residence time through a 10 mm long microcombustor. The combustion of hydrogen and air with the help of 4 such actuators, each with a power consumption of 47.5 mW cm −1 , generates power with an efficiency of 90.5%. Such microcombustors can be applied to all battery based systems requiring micropower generation with the the ultimate goal of 'generating power on a chip'.

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The manipulation of an unstarting supersonic flow by plasma actuator

Cited by 35 publications

References 34 publications

Measurement of Flow Perturbation Spectra in Mach 4.5 Corner Separation Zone

Measurement of Flow Perturbation Spectra in Mach 4.5 Corner Separation Zone

Characterization of transverse plasma jet and its effects on ramp induced separation

Plasma-flow interactions in field-emission discharges with applications in microcombustion

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