Analysis of the enthalpy probe technique for thermal plasma diagnostics

Rahmane, Mohamed; Soucy, Gervais; Boulos, Maher I.

doi:10.1063/1.1145517

Cited by 63 publications

(29 citation statements)

References 14 publications

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“…It is worth mentioning that the powder particles were radially injected into the plasma jet. More detailed theoretical information on the two measurement systems can be found in [17][18][19][20]. Figure 2 depicts the relative position of plasma torch and enthalpy probe system, while the DPV-eVOLUTION is located at the same position as the enthalpy probe system.…”

Section: Diagnostic Equipmentmentioning

confidence: 99%

The Influence of Anode Inner Contour on Atmospheric DC Plasma Spraying Process

Wen¹,

Liu²,

Zhou³

et al. 2017

Advances in Materials Science and Engineering

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In thermal plasma spraying process, anode nozzle is one of the most important components of plasma torch. Its inner contour controls the characteristics of plasma arc/jet, determining the motion and heating behaviors of the in-flight particles and hence influencing the coating quality. In this study, the effects of anode inner contour, standard cylindrical nozzle, and cone-shaped Laval nozzle with conical shape diverging exit (CSL nozzle) on the arc voltage, net power, thermal efficiency, plasma jet characteristics, in-flight particle behaviors, and coating properties have been systematically investigated under atmospheric plasma spraying conditions. The results show that the cylindrical nozzle has a higher arc voltage, net power, and thermal efficiency, as well as the higher plasma temperature and velocity at the torch exit, while the CSL nozzle has a higher measured temperature of plasma jet. The variation trends of the plasma jet characteristics for the two nozzles are comparable under various spraying parameters. The in-flight particle with smaller velocity of CSL nozzle has a higher measured temperature and melting fraction. As a result, the coating density and adhesive strength of CSL nozzle are lower than those of cylindrical nozzle, but the deposition efficiency is greatly improved.

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Section: Diagnostic Equipmentmentioning

confidence: 99%

The Influence of Anode Inner Contour on Atmospheric DC Plasma Spraying Process

Wen¹,

Liu²,

Zhou³

et al. 2017

Advances in Materials Science and Engineering

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“…Enthalpy probes were developed in the 1960s and their applicability has been approved in many cases (Ref 5,6). Examples are the investigation of the impact of the ambient atmosphere on the characteristics of the plasma jet (Ref 7), the understanding of nonequilibrium situations in plasma jets (Ref 8), demixing effects and entrainment of surrounding cold gas with effects on plasma-particle interaction (Ref 9), nozzle design and optimization (Ref 10,11), oxidation control in different plasma gas compositions (Ref 12), and the characterization of new plasma torch concepts (Ref 13).…”

Section: Enthalpy Probementioning

confidence: 99%

Plasma and Particle Temperature Measurements in Thermal Spray: Approaches and Applications

2010

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Growing demands on the quality of thermally sprayed coatings require reliable methods to monitor and optimize the spraying processes. Thus, the importance of diagnostic methods is increasing. A critical requirement of diagnostic methods in thermal spray is the accurate measurement of temperatures. This refers to the hot working gases as well as to the in-flight temperature of the particles. This article gives a review of plasma and particle temperature measurements in thermal spray. The enthalpy probe, optical emission spectroscopy, and computer tomography are introduced for plasma measurements. To determine the in-flight particle temperatures mainly multicolor pyrometry is applied and is hence described in detail. The theoretical background, operation principles and setups are given for each technique. Special interest is attached to calibration methods, application limits, and sources of errors. Furthermore, examples of fields of application are given in the form of results of current research work.

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“…For example, non-transferred DC torches with hot cathodes normally produce a hot ionized flame with temperatures in the range of 8,000~16,000 K at the torch exit [2]. The velocities of this flame can reach to hundreds m/s or to several thousand m/s depending on the torch nozzle structures at a given gas flow rate [2,[12][13][14]. On the other hand, RF plasma torches produce relatively large flame of 5,000~10,000 K moving at mild velocities of up to several tens m/s [2,5,[15][16][17].…”

Section: Introductionmentioning

confidence: 99%