KR420: How can we achieve target thrust at a mass-flow-inlet boundary? (Solution ID: 718)
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For external aero applications involving the modeling of a full aircraft with engine and pylon, client typically knows the massflow rate incoming to the engine fan inlet and also the thrust produced by the engine. The mfo UDF/Scheme (or the new mfo in Fluent 6.1) can be used at the pressure-outlet boundary representing the engine fan inlet to achieve the target massflow rate. Typically, at the engine exit boundary (incoming to the external fluid domain), the massflow inlet boundary type is used where user specify the massflow rate (known) and the total temperature. While the total temperature at the engine exit is usually known, client often prefers to specify the thrust instead. How to do this ? User can manually adjust the total temperature at the massflow-inlet boundary until the desired thrust is achieved. However, this manual procedure is tedious and time consuming. A UDF similar to the mfo procedure has been written to adjust the total temperature automatically to acquire the target thrust. As with the mfo UDF, to avoid non-convergence, this UDF should only be applied when the actual thrust is about 20% from the target value. |
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