Results are presented for a series of fire-suppression tests conducted in a full-scale nacelle along with the results of pretest predictions carried out using the Vulcan fire-physics simulation code. The purpose of these tests was to assess the utility of using a CFD fire-physics computer code (Vulcan) to predict the performance of a fire-suppression system. The test plans and test matrix were made to correspond to Vulcan simulations previously run to predict the test results. Twenty-five fire tests were conducted successfully in the NAVAIR ground nacelle simulator to validate this fire-modeling code. This simulator is a full-scale iron bird mockup of an engine nacelle assembly typical of a combat aircraft with a four-nozzle suppressant-distribution system. JP-8 pool fires in a variety of locations were considered, and both the suppressant and the overall air flow rates through the nacelle were varied to simulate a wide range of operating conditions. In addition, the effects of varying the inhomogeneities were investigated by capping individual nozzles. The pretest Vulcan simulations correctly predicted the success or failure of extinction in nearly all cases. In only two cases were there disagreements between the Vulcan predictions and the test results. In both of these cases, when either of the two forward nozzles was capped, the test results found that the fires were suppressed using a bottle pressure 25% lower than the Vulcan simulations had predicted. This indicates that the Vulcan simulations were somewhat conservative in their predictions of the mixing in the forward nacelle region. Detailed data analyses of the twenty-five fire tests are presented in this paper.
Citation: Special Publication (NIST SP) - 984-4
NIST Pub Series: Special Publication (NIST SP)
Pub Type: NIST Pubs