An innovative approach towards fouling modeling: Microscale deposition pattern and its effect on the flow field

Solid particle ingestion is one of the main compressor degradation mechanisms for both heavy-duty and aero-propulsion gas turbines. Particles impacting the inner surfaces of the machine can stick there forming deposits. The presence of such deposits reflects on the reduction in performance of the machinery. Over last years, several methods have been developed in order to study the problem from the numerical standpoint. Examples of these techniques are the mesh morphing approach and the added-roughness-and-thickness method. In this work, an innovative procedure is proposed in order to evaluate the losses and the variation in the fluid flow due to the deposits. Particularly, an algorithm capable of determining the microscale deposition pattern has been developed. By using this methodology, a comprehensive analysis of the variation of the performance of the compressor over time can be carried out. The deposition severity and the subsequent roughness variation can be kept into account in a very detailed and precise fashion. Furthermore, this approach overcomes the difficulties that may arise by using a mesh morphing technique. The computational grid is not modified and thus its quality is retained, without re-meshing requirements, even for large deposits. The local roughness variation is accounted for without extra-effort. The procedure developed, shown here in deposition problems, can be easily extended to erosion or even icing problems. The only parameter to be changed is the model that takes care of the particle-wall interaction, using an erosion rather than an icing law.