A PC-based numerical model of a hydrogen diffusion flame and flare stack in a crosswind

During the component testing for launch-class rocket engines, large amounts of unburned hydrogen must be safely transferred away from the testing area into the environment surrounding the test complex. This calls for the use of a flare stack. A large diffusion flame is created at the stack exit and a majority of the hydrogen is consumed in the reaction. Hydrogen diffusion flames release an enormous amount of heat into the air surrounding the flare stack. Because of this, environmentalists at NASA Stennis space center are greatly concerned about the vertical extent and trajectory of these flames m stagnant air and crosswinds of various velocities. The present work was a feasibility study for the use of a commercial computational fluid dynamics software package for the modeling of the large free turbulent hydrogen diffusion flame. The capabilities and limitations of the software were researched as well as the accuracy and time considerations associated with using the software for this particular purpose. The flare stack was modeled for two test cases: 1) the flow and combustion of the turbulent hydrogen diffusion flame (THDF) issuing into a stagnant, uniform ambient, 2) the THDF issuing into a crosswind of 20 mph. Three different three-dimensional models were used to model the second test case. Both test cases yielded results that were comparable to results obtained in previous flame modeling research by other authors, albeit at a much smaller scale, and thus supporting the continued use of the commercial CFD software for the purposes of obtaining a detailed PC-based numerical model of the hydrogen flare stack and the hydrogen diffusion flame in a crosswind.