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Records 271 to 275 of 1067

Author:
Joseph L. Scheffey, Joseph A. Wright
Abstract:
Foam agent quantities and application rates for FAA certified airports are based on large-scale fire test data of Aqueous Film-Forming Foam (AFFF) and " protein-based foams. The philosophy is to control aircraft fuel fires in sixty seconds. Foam agents which are used for aviation applications should demonstrate this level of performance, including a safety factor which assures adequate performance under less than optimum conditions.

A review of standard test methods and performance criteria indicates a wide range of requirements. The U. S. Military Specification (MIL SPEC) for AFFF, on which the original agent criteria was developed, is the most stringent in terms of extinguishment application density. However, no direct correlation has been demonstrated between many of the required physical/chemical properties tests and fire extinguishment/burnback performance.

It was demonstrated, using comparative data from numerous small- and large-scale fire tests, that the small-scale MIL SPEC fire tests correlate with large-scale test results. MIL SPEC agents, which provide a safety factor over minimum FAA requirements, also are formulated to have proportioning, storage, stability, and shelf-life attributes appropriate for crash rescue firefighting applications. Adoption of the MIL SPEC for AFFF agents is recommended. Future work related to foam testing should focus on the use of first principles to establish fundamental foam extinguishment mechanisms.
Report:
Pages:
89
Size:
18.2 MB
Author:
P. Laing, S.N.B. Murthy
Abstract:
In a continuing effort to establish perfonnance changes due to water ingestion into an aircraft gas turbine engine and possible design improvements, an experimental investigation was perfonned with a model gas turbine prediffuser-combustor sector utilizing a number of mixture and flow conditions in a tunnel operating with a two-phase, air-liquid film-droplet mixture. For given entry conditions into the prediffuser (which can be related to the exit conditions of the core compressor in a bypass engine, and, therefore, also to ingestion conditions at the engine face) the two main issues are (1) the amount of water entering the primary zone of the combustOr, and (2) the local reduction in temperature, flame-water interactions, and the vitiation caused by the vaporizing of water. Flow,visualization and estimates of water flow and droplet size in the primary zone have been undertaken under cold flow conditions. The amount of water entering the primary zone has been found to be a complex function of (1) the air-water mixture conditions at entry to the prediffuser, and (2) the effects of gravity on the flowfield for given geometry of the prediffuser-combustor, and the flow split between the primary and the coolant streams in the combustor. Combustion tests have been carried out to establish the effects on perfonnance. occurrence of flameout, and recoverability of combustor exit temperature by enhancement of one or both of the fuel equivalence ratio and the oxygen content of air. It was tentatively concluded that the observed effects of the presence of water are a result of the interactive effe.cts of heat transfer to water, vitiation by water vapor on combustion, and the total heat release in the primary zone. The latter being the dominant factor in stabilizing the flame with a large increase in combustor exit temperature, as found in the tests with the addition of both fuel and oxygen to a given burning mixture.
Report:
Pages:
122
Size:
26.5 MB
Author:
D.C. Dodd, C.T. Hall, J. Pollard
Abstract:
A rapid burnthrough of a structurally intact fuselage occurred in the B737 accident at Manchester in 1985. This initiated a study into improvements of breakthrough resistance or fire hardening of aircraft fuselages to delay the ingress of the fire and associated toxic gases so increasing the survivability time within the cabin. On behalf of the Civil Aviation Authority, Faverdale technology Centre (FTC) is currently developing a fire test facility and procedure to enable an investigation into methods of fire hardening the fuselage in existing ad future aircraft designs to take place. Experience from both accidents and full scale tests have shown that a typical aircraft, there may be potential for the fuselage to be fire hardened to delay the penetration of an external fire into the passenger compartment.
Report:
Pages:
51
Size:
1.614 MB
Author:
D.C. Dodd
Abstract:
An investigation into the burnthrough resistance of fuselages and the effects of soot deposition in the early stages of a pool fire on burnthrough time.
Report:
Pages:
50
Size:
1.87 MB
Author:
Harry Webster
Abstract:
The burnthrough resistance of aircraft fuselages to external fuel fires was investigated in this test series. Threee tests were conducted in a wheels-up mode and three in the wheels-down configuration. A comprehensive data base was developed documenting fire entry paths, burnthrough time, and cabin environmental conditions. The overall entry paths, burnthrough time, and cabin environmental conditions. The overall resistance of the two test intact aircraft fuselages to fire penetration was documents.
Report:
Pages:
114
Size:
21.5 MB
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