The flow inside an engine nacelle ground test simulator is studied for the purpose of understanding and optimizing the distribution of suppressant. One objective of this study is to identify conditions for which suppression will and will not be successful in order to test the models ability to discriminate between various scenarios. To do this, the distribution of suppressant during cold flow is studied to identify regions of low concentration. Available measurements are coupled with predictions using Sandia National Laboratories Vulcan fire-field model. Some measurements are required to help design the computational model, such as the inlet and outlet flows, which are boundary conditions for the simulation. Specific suppressant-concentration profiles as a function of time are helpful in evaluating the models performance. To create scenarios with insufficient distribution in regions of potential fire, the removal or capping of individual agent nozzles is used. The test matrix has been constructed by varying the loci and number of discharge nozzles, the mass of suppressant, and the air flows. Vulcans predictions of suppressant-concentration profiles to date are in qualitative agreement with test measurements and show that the suppressant is well-distributed.
Citation: Special Publication (NIST SP) - 984-4
NIST Pub Series: Special Publication (NIST SP)
Pub Type: NIST Pubs