Plasma expulsion from the plasma jet igniter

Smy, P. R.; Clements, R. M.; Simeoni, D.; Topham, D. R.

doi:10.1088/0022-3727/15/11/015

Cited by 14 publications

(9 citation statements)

References 9 publications

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“…The striations running almost normal to the shock bands arise from variations in the jet luminosity and probably have their origin in arc instabilities. Their slopes are indicative of the local flow speed (typically 5 x lo3 m/s, compared with the frontal velocity of 5 x lo2 m/s) as demonstrated by Smy et al (1982), and the velocity changes across the shock bands can be discerned on the original photograph. Figure 1 ( b ) is a sequence of submicrosecond exposure photographs taken with an image-converter camera.…”

Section: The Initial Discharge Periodmentioning

confidence: 97%

Turbulent mixing in a pulsed plasma-jet exhaust

1984

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High-speed schlieren cinéphotography of the firing of a high-energy plasma-jet igniter reveal turbulent structures similar in appearance to laboratory models of thermals or turbulent puffs. Measurements of the growth rates of these features together with those of their impulse and thermal energy confirm this similarity. A simple model based on the entrainment assumption gives a good description of the motion of the element and also of the decay of the internal temperature.

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Section: The Initial Discharge Periodmentioning

confidence: 97%

Turbulent mixing in a pulsed plasma-jet exhaust

1984

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“…This analysis was successfully employed in [21] to obtain the exit velocity from a plasma igniter. Considering the rapidity of the heating by electric discharge in the present application, we expect that the shock-tube analysis should yield a reasonable estimate of the jet exit velocity for the pulsedplasma jet also.…”

Section: Nonequilibrium Effects In the Dischargementioning

confidence: 99%

“…Another advantage of pulsed-plasma jets is that the jet momentum can be directed by changing the angle at which the jet issues into the flow. We note that a similar design, albeit at a much higher electrical power, was also used in "plasma igniters" developed for use in ignition of internal combustion engines [21]. The exit velocity of the gas from these plasma igniters is experimentally found to be about 500-1000 m=s for an energy input of about 1 J [22].…”

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confidence: 95%

Characterization of a High-Frequency Pulsed-Plasma Jet Actuator for Supersonic Flow Control

2010

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An experimental study is conducted to characterize the performance of a pulsed-plasma jet (called a "spark jet" by other researchers) for potential use in supersonic flow control applications. A pulsed-plasma jet is a high-speed synthetic jet that is generated by striking an electrical discharge in a small cavity. The gas in the cavity pressurizes owing to the heating and is allowed to escape through a small orifice. To obtain an estimate of the relative strength of the pulsed-plasma jet, the jet is injected normally into a Mach 3 crossflow and the penetration distance is measured by using schlieren imaging. These measurements show that the jet penetrates 1.5 boundary-layer thicknesses into the crossflow and the jet-to-crossflow momentum flux ratio is estimated to be 0.6. A series of experiments was conducted to determine the characteristics of the pulsed-plasma jet issuing into stagnant air at a pressure of 35 torr. These results show that typical jet velocities of about 250 m=s can be induced with discharge energies of about 30 mJ per jet. Furthermore, the maximum pulsing frequency was found to be about 5 kHz, because above this frequency the jet begins to misfire. The misfiring appears to be due to the finite time it takes for the cavity to be recharged with ambient air between discharge pulses. The velocity at the exit of the jet is found to be primarily dependent on the discharge current and independent of other discharge parameters such as cavity volume and orifice diameter. Temperature measurements are made using optical emission spectroscopy and reveal the presence of considerable nonequilibrium between rotational and vibrational modes. The gas heating efficiency was found to be 10% and this parameter is shown to have a direct effect on the plasma jet velocity. These results indicate that the pulsed-plasma jet creates a sufficiently strong flow perturbation that holds great promise as a supersonic flow actuator.Nomenclature j = density of the pulsed-plasma jet 1 = freestream density u j = exit velocity of the pulsed-plasma jet u 1 = freestream velocity

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“…Even when extrapolating the velocity change back to just within the igniter to allow for the thickness of the front face of the igniter the plasma does not appear to exceed 1 × 10 3 m s −1 . Other workers examining automotive applications of the igniter have previously quoted [10,11] plasma speeds of (2-5)×10 3 m s −1 , using a shock tube model [12] to predict the behaviour of the plasma igniter. This approach is a good starting basis but should not be relied upon to give accurate quantitative predictions of plasma jet properties.…”

Section: Plasma Igniter Generationmentioning

confidence: 99%

Ultrasonic generation using a plasma igniter

Dixon

Edwards

Palmer

et al. 2001

J. Phys. D: Appl. Phys.

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This paper describes some preliminary results of the ultrasonic generation characteristics of a new ultrasonic transducer, the plasma igniter. Epicentral out-of-plane responses have been measured using a wide bandwidth stabilized Michelson interferometer. An electromagnetic acoustic transducer (EMAT) has been used to measure the longitudinal wave directivity pattern generated by the plasma source and it compares well to those previously published for laser generated ultrasound. The fields of application of the plasma igniter ultrasonic generation source are limited for reasons that will be explained, but its relatively low cost means that it does merit consideration in some cases.

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Plasma expulsion from the plasma jet igniter

Cited by 14 publications

References 9 publications

Turbulent mixing in a pulsed plasma-jet exhaust

Turbulent mixing in a pulsed plasma-jet exhaust

Characterization of a High-Frequency Pulsed-Plasma Jet Actuator for Supersonic Flow Control

Ultrasonic generation using a plasma igniter

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