| Abstract | The National Research Council Structures and Materials Performance Laboratory has two high velocity burner rigs which experimentally simulate the mixing, flow, and combustion chemistry in gas turbine engine combustors. These capabilities make these burner rigs a valuable tool in conducting durability tests on components or coupons situated at the combustor exit in the engine.
During testing it is essential to determine the combustion gas velocity around the test specimens, since the energy exerted on the test specimens is dependent on velocity. Currently, estimates of the velocity of this flow are obtained by reading the value from a chart. This chart is a plot of the velocity as a function of the temperature inside the combustion chamber, and the pressure in two air-flow lines which deliver air into the burner rig. However, determining the velocity based solely on these temperature and pressure values is insufficient for obtaining consistent results because the velocity is dependent on additional variables. For example, during tests that run over an extended period of time, specimens show more damage in the winter than in summer. This observation is consistent with the fact that the velocity of the air is dependent on the ambient conditions, presumably temperature, and hence density, variation in the air introduced to the combustion chamber through the air-flow lines that feed into the rig. Consequently, a more comprehensive method for determining the velocity of the flow out of the burner rigs is desired. This report proposes a new method for estimating the velocity at the exit orifice of the burner rig and the velocity profile in the jet with increasing distance from the exit orifice. The method accounts for the actual conditions of the flows into the rig as well as the conditions in the test area. |
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