Aerodynamic optimization of the exhaust system of an aft-mounted boundary layer ingestion propulsor

Abstract

Purpose Novel aircraft propulsion configurations require a greater integration of the propulsive system with the airframe. As a consequence of the closer integration of the propulsive system, higher levels of flow distortion at the fan face are expected. This distortion will propagate through the fan and penalize the system performance. This will also modify the exhaust design requirements. This paper aims to propose a methodology for the aerodynamic optimization of the exhaust for novel embedded propulsive systems. To model the distortion transfer, a low order throughflow fan model is included. Design/methodology/approach As the case study a 2D axisymmetric aft-mounted annular boundary layer ingestion (BLI) propulsor is used. An automated computational fluid dynamics approach is applied with a parametric definition of the design space. A throughflow body force model for the fan is implemented and validated for 2D axisymmetric and 3D flows. A multi-objective optimization based on evolutionary algorithms is used for the exhaust design. Findings By the application of the optimization methodology, a maximum benefit of approximately 0.32% of the total aircraft required thrust was observed by the application of compact exhaust designs. Furthermore, for the embedded system, it is observed that the design of the compact exhaust and the nacelle afterbody have a considerable impact on the aerodynamic performance. Originality/value This paper presents a novel approach for the exhaust design of embedded propulsive systems in novel aircraft configurations. To the best of the authors’ knowledge, this is the first detailed optimization of the exhaust system on an annular aft-mounted BLI propulsor.

Deep-Learning for Flow-Field Prediction of 3D Non-Axisymmetric Aero-Engine Nacelles

“…A thorough description of this computational method was provided in the past [14,24,25], and as such, a brief overview is presented below. The nacelle shape is defined with a parametric definition using intuitive Class-Shape Transformation (iCST) [26,27]. Each nacelle aero-line is controlled with 7 intuitive parameters: r hi , L nac , r te , r i f , f max , r max and β nac (Figure 1a).…”

A data-driven flow loss prediction model for the blade hub region of a boundary layer ingestion fan rotor

“…Consequently, it is not suitable for use in the preliminary fan design stage which often requires large amounts of fan performance predictions and evaluations. To address this challenge, low-fidelity computational methods such as the throughflow method (Valencia et al , 2017) and body force model (Hall et al , 2017; Matesanz-García et al , 2023) are developed to rapidly estimate the aerodynamic performance of fan/compressors. However, the occurrence of separation flows in the hub corner has increased the difficulty of accurate performance evaluations.…”