The Metal-Halide Lamp Under Varying Gravity Conditions Measured by Emission and Laser Absorption Spectroscopy

Flikweert, AJ Arjan; Nimalasuriya, T Tanya; Kroesen, Gmw Gerrit; Haverlag, M Marco; Stoffels, WW Winfred

doi:10.1007/s12217-009-9106-z

Cited by 6 publications

(11 citation statements)

References 25 publications

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“…We use the axial inhomogeneity Figure 1. The Fischer curve shows the axial segregation as a function of the ratio between the convection and diffusion speeds [16][17][18]22]. In our case the amount of convection is changed by changing the gravitational acceleration.…”

Section: Introductionmentioning

confidence: 79%

“…The amount of convection in the lamps depends on gravity [1,5,[20][21][22][23][24][25]. A centrifuge was built to investigate the lamp under varying gravitational accelerations.…”

Section: Centrifugementioning

confidence: 99%

“…Beside lab experiments [2,12,18,19], the lamp was sent to the International Space Station (micro-gravity 0g; in this paper the amount of acceleration is given in terms of g = 9.81 m s −2 ) [20]. Furthermore parabolic flights were carried out (0-2g, for periods of about 20 s) [21,22]. More recently a centrifuge was built, in which we can achieve gravity conditions from 1-10g [1,5,23].…”

Section: Introductionmentioning

confidence: 99%

“…More recently a centrifuge was built, in which we can achieve gravity conditions from 1-10g [1,5,23]. The additive distribution in the lamp has been measured by means of ALI measurements [2,12,20,23] and ILAS [1,5,22,24,25]. By using ALI absolute number densities of Dy and Hg, and temperature profiles were obtained.…”

Section: Introductionmentioning

confidence: 99%

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Emission spectroscopy for characterizing metal-halide lamps

Flikweert

Nimalasuriya

Kroesen

et al. 2008

J. Phys. D: Appl. Phys.

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The metal-halide (MH) lamp shows an unwanted axial non-uniform distribution of the metal additives when burning in vertical position, which is caused by the interplay between convection and diffusion. Various MH lamps are investigated by means of emission spectroscopy under varying gravity conditions (1–10g) in a centrifuge. The method yields spectra, axial inhomogeneity parameters and axially integrated intensities. The method is easier than methods used before on the same type of lamp. Measurements on lamps with DyI3 as salt filling are used as a calibration of the setup. After comparison with the earlier measurements, we conclude that the new emission spectroscopy is valid for characterization of MH lamps. Next, we apply the method on commercial lamps (Philips MASTER CosmoWhite). For these lamps, in addition NaI densities at the wall and axial temperature profiles are obtained by using self-reversed lines of Na and Hg, respectively.

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Section: Introductionmentioning

confidence: 79%

“…The amount of convection in the lamps depends on gravity [1,5,[20][21][22][23][24][25]. A centrifuge was built to investigate the lamp under varying gravitational accelerations.…”

Section: Centrifugementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Emission spectroscopy for characterizing metal-halide lamps

Flikweert

Nimalasuriya

Kroesen

et al. 2008

J. Phys. D: Appl. Phys.

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“…Single-walled carbon nanotubes were produced by arc discharge method in hypergravity [11] and also microgravity [12,13]. The flow phenomena in metal-halide arc discharge lamps were intensively investigated under varying gravity conditions [14][15][16]. Low pressure radio frequency plasmas with dust particles are currently researched in various gravity conditions, too [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Hypergravity effects on glide arc plasma

et al. 2013

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Abstract. The behaviour of a special type of electric discharge -the gliding arc plasma -has been investigated in hypergravity (1g-18g) using the Large Diameter Centrifuge (LDC) at ESA/ESTEC. The discharge voltage and current together with the videosignal from a fast camera have been recorded during the experiment. The gliding of the arc is governed by hot gas buoyancy and by consequence, gravity. Increasing the centrifugal acceleration makes the glide arc movement substantially faster. Whereas at 1g the discharge was stationary, at 6g it glided with 7 Hz frequency and at 18g the gliding frequency was 11 Hz. We describe a simple model for the glide arc movement assuming low gas flow velocities, which is compared to our experimental results.

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Semi-empirical model for axial segregation in metal-halide lamps

Flikweert¹,

Beks²,

Nimalasuriya³

et al. 2008

J. Phys. D: Appl. Phys.

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Diffusive and convective processes in the metal-halide lamp cause an unwanted non-uniform distribution of the radiating metal additive (Dy in our case), which results in colour separation. The axial segregation has been described by Fischer (1976 J. Appl. Phys. 47 2954) for infinitely long lamps with a constant axis temperature. However, for our lamps this is not valid. We propose a semi-empirical extended model. The density inhomogeneity gives a measure for the non-uniformity of the Dy density distribution in the lamp. As an example, this parameter is calculated for some measurements obtained by imaging laser absorption spectroscopy.

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The Metal-Halide Lamp Under Varying Gravity Conditions Measured by Emission and Laser Absorption Spectroscopy

Cited by 6 publications

References 25 publications

Emission spectroscopy for characterizing metal-halide lamps

Emission spectroscopy for characterizing metal-halide lamps

Hypergravity effects on glide arc plasma

Semi-empirical model for axial segregation in metal-halide lamps

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