Three Dimensional Simulation of Flow in an Axial Low Pressure Compressor at Engine Icing Operating Points

Three-dimensional simulations of the Honeywell ALF502 low pressure compressor (sometimes called a booster) using the NASA Glenn code GlennHT have been carried out. A total of eight operating points were investigated. These operating points are at, or near, points where engine icing has been determined to be likely. The results of this study were used, in a companion paper, for further analysis such as predicting collection efficiency of ice particles and ice growth rates at various locations in the compressor. In an effort to minimize computational effort, inviscid solutions with slip walls are produced. A mixing plane boundary condition is used between each blade row, resulting in convergence to steady state within each blade row. Comparisons of the results are made to other simplified analysis. An additional modification to the simulation process is also presented. At each mixing plane (located between blade rows) it is possible to introduce ad hoc adjustments to the flow properties. The justification for making adjustments will be discussed. At each mixing plane it is possible to bring the average conditions of the simulation into agreement with the simplified analysis by introducing a jump in total pressure and total temperature across the mixing plane. The incentive for this approach would be to produce a higher fidelity solution, while minimizing required computing time. Obviously, if compute time and storage were of no consequence, the highest fidelity solution would be desirable. However, if many operating points need to be investigated, reasonable compromises may be acceptable.