The influence of high spanwise chamber extent on HLFC performance

Abstract

In the scope of the European Clean Sky 2 project HLFC-WIN, the benefits and integrational aspects of HLFC on a long-range wing are investigated. Due to leading edge space being allocated by other systems (e.g. high-lift, anti-icing) the spanwise extent of the internal HLFC plenum chamber, which in former designs covers the majority of the HLFC segment, is reduced to multiple narrow suction ribs, containing the compressors. In combination with the high spanwise extent of the HLFC segments, this leads to a large volume of air being transported via the narrow suction chambers in spanwise direction, rather than semi-directly relayed to a plenum. This spanwise chamber flow causes additional pressure losses within the HLFC system. In order to investigate the magnitude of these pressure losses and their potential impact on the HLFC performance, CFD simulations have been performed, based on a simulation setup previously developed. For validation purposes, the pressure loss along a simplified chamber test rig of 2,75 meters has been measured. The results are presented in this paper along with an estimation of the HLFC wing design impact.