Purified orbit diagram and numerical study for a failure analysis of a Sirocco fan

• Main Authors: José González, Laura Delgado, Jesús M Fernández Oro, Sandra Velarde-Suárez, Katia Mª Argüelles, David Rodríguez
• Format: Article
• Language: English
• Published: SAGE Publishing 2017-11-01
• Series: Advances in Mechanical Engineering
• Online Access: https://doi.org/10.1177/1687814017733439

Sirocco fan units are very common and widespread solution for air conditioning used in public transportation applications (buses or trains). The users’ comfort and tranquillity are main concerns in the automotive industry. Inside such turbomachines, the flow structure always becomes highly three dimensional and unsteady, compromising the referred comfort, and sets the focus on the working flow variables. A mathematically exact solution for that flow, which would provide any required information on pressure or forces, is out of scope at the current engineering design processes. Nevertheless, some flow features and mechanical data are needed to progress in the frame of a modern industrial environment, which each time more strongly, besides the different design procedures, involves maintenance protocols. The correctness of a given maintenance protocol relies on its feasibility to handle a set of machine working parameters or variables, including a number of them as wide as possible. Doing so, a set of non-dangerous ranges for them can be established. Such ranges are often defined promoting a series of failures similar to real ones, when the machine is in its usable lifetime. In what refers to the flow analysis, a reasonably good tool has been developed using a computational fluid dynamics technique and, from the experiments, a better understanding of the fan operating conditions is accomplished. For a Sirocco fan unit and to establish proper working ranges for maintenance purposes, a series of failures have been experimentally and numerically tested. Initially, real data from industry have been required and a list of main failures was made. It included impeller or rotor unbalance, impeller channel obstruction and blocked inlet. The first two failures are studied using a purified orbit diagram technique and the last one is numerically analysed. All four working conditions are studied for at least three different flow rates and, therefore, a deeper insight into the fan working parameters and options is made feasible. In the frame of the maintenance protocol, a full set of ranges for the considered failures have been obtained.