Influence of internal cold gas flow and of nozzle contour on spray properties of an atmospheric plasma spray torch
- DLR Inst. of Technical Thermodynamics, Stuttgart (Germany)
- Fachhochschule Muenchen, Munich (Germany)
- Univ. of the German Armed Forces, Munich (Germany)
With an automated Laser Doppler Anemometry (LDA) equipment trajectories, distributions and velocities of spray particles were measured operating a plasma spray torch under atmospheric pressure conditions. For this purpose a standard APS torch (PT F4) was used, applying different gas distribution rings and nozzle modifications to study the influence of internal plasma gas flow and of plasma jet formation. The main results are: (1) An inclined injection of the plasma cold gas results in a considerable spin of the plasma jet and a significant deviation of the particle trajectories around the plasma jet center. (2) With a plasma cold gas injection parallel to the torch axis no spin is observable, but torch voltage and the plasma jet enthalpy show considerably diminished values. (3) The flow of injected powder may be split up, if it is injected too fast. (4) In comparison with cylindrical nozzles, specially developed nozzles with a controlled expanding contour, lead to broader temperature profiles across the plasma jet and hence to better melting conditions for the particles.
- OSTI ID:
- 377740
- Report Number(s):
- CONF-9509182--; ISBN 0-87170-541-9
- Country of Publication:
- United States
- Language:
- English
Similar Records
The effect of nozzle design on plasma jet behavior, particle motion, and coating properties
Bell-contoured, parallel flow nozzles for reducing overspray in thermal spray processes