Performance prediction of inlet barrier filter systems for rotorcraft engines

An insight into the design parameters that dictate engine inlet barrier filter performance is presented. The work represents the first part of a two-part study into the factors affecting the performance of engine inlet barrier filter to ultimately enable the prediction of turboshaft engine performance during use of this air-particle separating device. The problem is initially described and is followed by a parametric study to ascertain the effect of pleat shape, turbulence, and inflow velocity on overall pressure drop across a pleated filter for an engine inlet barrier filter. It is shown that turbulence has little effect on engine inlet barrier filter performance, whereas increases in pleat count and inflow velocity both result in a larger pressure drop across the filter. The results are explained by analysis of the flow. Adiscussion of the possible consequences of pleat shape on the three engine inlet barrier filter performance indicators (pressure drop, holding capacity, and collection efficiency) is also given. Finally, a formula is provided to ascertain the pressure drop across a given pleated filter in a given flow. Copyright © 2011 by N. Bojdo and A. Filippone.