The Burning of a Thermoplastic Material Under a Forced-Flow Boundary Layer Flame

Abstract

This report presents experimental results of the characterization of forced flow boundary layer burning of poly(methyl methacrylate) (PMMA) without water mist. Small samples (7.5 x 9.5 x 2.5 cm) of black PMMA were burnt at the exit of a wind tunnel at free stream velocities between 60 and 168 cm/s, in tests lasting between 2.5 min and 20 minutes. The results of the gas phase temperature mapping indicate that a stable flame is formed over the sample within a short time after ignition. The local surface regression rate is transient, decreasing with time near the leading edge and increasing with time downstream. For 60 < U,, < 168 cm/s, the time averaged regression rate in the leading section decreased by about a factor of two between 5 and 20-minute tests. The transient burning rate in the leading section is due to the presence of a valley formed in this section as a result of non-uniform surface regression. On the other hand, the transient regression rate in the trailing section seems to be due mainly to in-depth solid heat conduction.

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Document Details

Document Type
Technical Report
Publication Date
Jul 31, 2002
Accession Number
ADA405194

Entities

People

  • Chuka C. Ndubizu
  • Patricia A. Tatem
  • Ramagopal Ananth

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Boundaries
  • Boundary Layer
  • Burning Rate
  • Chemical Reactions
  • Combustion
  • Flow
  • Free Stream
  • Heat Loss
  • Heat Transfer
  • Ignition
  • Layers
  • Leading Edges
  • Materials
  • Measurement
  • Military Research
  • Temperature Gradients
  • Wind Tunnels

Readers

  • Fluid Dynamics.
  • Rocket Propulsion.
  • Thermal Physics or Thermal Science.