M.E. Schneider, L.A> Kent

There is an interest in determining the response and survivability of a variety of items subject to engulfment in a large fire which may occur in a transportation accident. In order to estimate this response, knowledge of the thermal and flow conditions prevailing in these pool fires is required. Few experiments have been performed with large (>3 meter diameter) fires. In particular, velocity measurements in the continuous flame region of low Froude number fires are very scarce. Scaling up the results of small pool fires is problematic due to the large number of relevant dimensionless variable to be matched.

A total of 48,500 liters of JP-4 fuel was burned in a 9x18 meter pool, producing peak temperatures in excess of 1230 C (2250 F), over much of the instrumented region of the flame. Temperatures were measured at 28 locations throughout the continuous flame region with 1,587 mm OD Inconel sheathed ungrounded, type K thermocouples. Four 0.127 mm diameter bare wire thermocouples were used to make high frequency response temperature measurements. Velocities were measured at four vertical stations near the centerline of the pool, with glass coated, velocity probes. Heat fluxes were estimated from measurements on and near vertically suspended mild steel plates.

As I often the case in fires of this size, the effects of mild ambient winds on the measurements were pronounced. Attempts have been made to mitigate these effects by the application of conditional sampling. Temperatures are compared with measurements made in other large aviation fuel fires. The measured velocities are slightly less than would be predicted from an empirical model that was developed from experimental results for methane diffusion flames that are orders of magnitude smaller

A.M. Birk

A model has been developed which estimates the radiant heat transfer to a long horizontal cylinder engulfed in flames, The model estimates the various surface-to-surface and surface-to-volume exchange factors as a function of position around the circumference of the cylinder. The present model considers the two-dimensional case of an infinitely long cylinder, however, only slight modifications are unnecessary to model the full three-dimensional case. The numerical procedures used to carry out the integrations necessary in determining the exchange factors are presented.

This model was developed as part of a study concerned with thermal protection systems for railway tank cars carrying hazardous materials. In some accident situations, a tank car may be engulfed in flames, and it can be shown that the total heat flux to the tank is primarily due to thermal radiation. Radiant heat transfer calculations using this model were performed for two flame sizes with dimensions approximately those of full and fifth scale fire tests conducted on real tanks. The results of these calculations re presented with the flame temperature and absorptive as parameters.

Interior of test bus was instrumented to monitor three full-scale fire tests.

Constantine P. sarkos

The Aviation Industry has had considerable experience over the past 20 years in the development and use of Halon 1301 protection systems for the extinguishment of fires occurring within the engine nacelle. During the years of the fire-prone, piston-engine aircraft, extensive testing and development was done at the Technical Development and Evaluation Center, of TDC, in Indianapolis. The Predecessor of NAFEC. After the establishment of NAFEC in 1958, this work was continued on Turbojet and Turofan engines although the occurrence of fire was considerably less frequent than from the piston engine. Thus, the aviation industry’s first experience with the use of Halon 1301 was for the extinguishment of flammable fluid or Class B fires.

Richard G. Hill

A project was conducted at the National Aviation Facilities Experimental Center (NAFEC) to determine the capability of nitrogen inerting in preventing fuel tank explosions during post-crash ground fires. The project was conducted in two distinct phases; Phase I being small scale tests using 50 gallon capacity test tank and Phase II full scale tests using outer wing panels from a C-133 aircraft (with a capacity of approximately 1, 340 gallons.)