Calculation of the limiting parameters for oxide ceramic particles during HVOF spraying

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:160455

Kadyrov, V; Evdokimenko, Y; Kisel, V ^[1]; Kadyrov, E ^[2]

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1. Inst. for Materials Science, Kiev (Ukraine)
2. Univ. of Wisconsin, Madison, WI (United States)

The authors analyze numerically gas-dynamical schemes peculiar for HVOF spraying equipment and present methods to calculate velocity and thermal state of sprayed particles which allow one to find the limiting values of these parameters and to define the applicability limitations of modern HVOF spraying apparatus. The method includes gas dynamical calculations of gas flow in accelerating channel (AC) and calculations of sprayed particle motion and its thermal state (temperature and melted mass fraction). The calculations were performed for particles of aluminum oxide and zirconium oxide with the size distributions of 10--80 {micro}m. Three different jet schemes were considered: with supersonic AC, with subsonic AC, and with combined gas dynamical path having functionally separated regions of heating and acceleration. Analysis of the results obtained at limiting parameters of jet operation suggests that energetic potentialities of HVOF method are not utilized completely. Although accelerated to a high speed the ceramic oxide particles have a thermal state which is far from optimal. It is possible to significantly increase the powder temperature and fraction of melted material by using new configuration solutions without essential constructive complications. The authors propose one of the possible solutions to optimize gas dynamical path. The results obtained for heating and acceleration in such a path suggest that the utilized approach is correct and allows one to predict the creation of a new family of more efficient HVOF torches and an expanded applicability of HVOF method.

• OSTI ID: 160455
• Report Number(s): CONF-940684--; ISBN 0-87170-509-5
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
FLAME SPRAYING
FLOW RATE
GASES
MATHEMATICAL MODELS
MELTING
NOZZLES
PARTICLE SIZE
PARTICULATES
PREDICTION EQUATIONS
TEMPERATURE DEPENDENCE
VELOCITY
ZIRCONIUM OXIDES