Additive thermochemical effects in turbulent erosive boundary layers
Previously obtained interior ballistics and wall boundary layer modeling results indicate that significant reduction in erosive heating can be expected when finely divided particles are dispersed through the propellant combustion flow field. Attention was first placed on the particle size influences, together with particle dispersal dynamics in both turbulent combustion core flow and the erosive wall boundary layer region. Submicron thermochemically inert particles were predicted to disperse readily to the near wall region where they were then entrained in the boundary layer. This was estimated to substantially reduce the predicted erosive heat and mass transfer and experimentally confirmed. Examination of the time-averaged turbulent boundary layer macrostructure changes indicated that inertial influences were primarily responsible for this reduction in erosive heating to gun barrel walls. The boundary layers were thickened by the additives and erosive diffusion gradients were correspondingly reduced. The isolated inertial mechanisms are now understood but are difficult to apply in general dimensional analysis scaling or in analytical heat transfer correlation predictions. Three major factors which contribute to these difficulties are: time dependence of both developing mean flow and particle field; turbulence-particle interactions; and thermochemical heat release and exchange between reactive gas components and particles, particles and wall surface, and reactive gas and wall surface. To help illustrate the influence of thes mechanisms and provide a basis for prediction, the influence of submicron additives in unsteady turbulent boundary layer growth and interaction regions adjacent to a model of a chemically active metallic (steel) surface are examined. Equilibrium chemistry is assumed for all phases.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6458838
- Report Number(s):
- UCRL-87251; CONF-830206-1; ON: DE83006278
- Resource Relation:
- Conference: Joint Army-Navy-NASA-Air Force propulsion meeting, Monterey, CA, USA, 14 Feb 1983
- Country of Publication:
- United States
- Language:
- English
Similar Records
Modeled heating and surface erosion comparing motile (gas borne) and stationary (surface coating) inert particle additives
Modeling additive and hostile particulate influences in gun combustion turbulent erosion
Related Subjects
42 ENGINEERING
COMBUSTION PRODUCTS
TURBULENT FLOW
TWO-PHASE FLOW
PROPELLANTS
HEAT TRANSFER
BOUNDARY LAYERS
COMBUSTION
EROSION
FLUIDS
HEATING
MATHEMATICAL MODELS
PARTICLES
ROCKETS
SURFACES
CHEMICAL REACTIONS
ENERGY TRANSFER
FLUID FLOW
LAYERS
OXIDATION
THERMOCHEMICAL PROCESSES
450100* - Military Technology
Weaponry
& National Defense- Chemical Explosions & Explosives
420400 - Engineering- Heat Transfer & Fluid Flow