ISSN:
0308-0501
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Architecture, Civil Engineering, Surveying
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Quasi-steady-state heat fluxes absorbed on the calorimeter surface in ten vertical 0.1 m high×1 m wide zones were measured by means of water calorimetry. The calorimeter surface also included an array of intrinsic thermocouples to measure surface temperatures, and an array of Schmidt - Boelter radiometers for a second, more responsive, method of heat flux measurement. The pool fire environment characterization was done with measurements from velocity probes, directional flame thermometers (DFTs), and thermocouples. The initial measurements with a 1 m×1 m water cooled vertical flat plate calorimeter located 0.8 m above and inside a 6 m×6 m JP-4 pool fire are described. Water calorimetry measured absorbed surface heat fluxes of about 65-70 kW m-2 with a gradual decrease with increasing height above the pool. Intrinsic thermocouple measurements recorded typical calorimeter surface temperatures of about 500°C, with spatial variations of ±150°C. Gas velocities across the calorimeter face averaged 3.4 m s-1 with a predominant upward component, but with an off-vertical skew. Analysis of data collected in the fire environment in the vicinity of the calorimeter was performed to characterize the fire environment and to determine the input parameters required to calibrate analytical models. For this test, the emissive power distribution near the plate was essentially linear. Flux measurement in the fire environment ranged from 75 kW m-2 to 175 kW m-2. With temperature and heat flux data, effective absorption coefficients were determined by using a two-flux method to solve the inverse problem. The results show that the optical thickness increases with increasing distance from the calorimeter surface. The effective absorption coefficient is approximately 0.8 m-1 in the vicinity (0 - 1.85 m) of the calorimeter and is approximately 2 m-1 in the vicinity (1.85 - 2.8 m) of the plume centerline. The observed decrease in heat flux on the calorimeter surface with increasing vertical height is consistent with analytical fire models derived for constant temperature surfaces. Results from several diagnostics also indicated trends and provided additional insight into events that occurred during the fire. Some events are correlated, and possible explanations are discussed.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
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