Performance Assessment of a Higher Bypass Ratio Engine Installation on a Rear-mounted Regional Aircraft

Abstract

The unceasing growth of the bypass ratio of civil aircraft engines reduces the specific fuel consumption while simultaneously complicating engine installation. This paper assesses the cumulative advantages of employing engines with superior bypass ratios in rear-mounted regional aircraft. The aerodynamic analysis of the engine intake and exhaust ramifications is based on the RANS CFD methodology, validated by the NASA CRM model and AIAA DSFRN model. An engine cycle model was developed to supply the engine inlet and outlet conditions for CFD calculations. In the case of the rear-mounted regional aircraft scrutinized herein, the fan diameter expanded from 53 inches to 60 inches, with the bypass ratio escalating from 5.3 to 11. This resulted in a roughly 9.33% reduction in specific fuel consumption. Nonetheless, the adverse impact of engine dimensions counteracts the cycle advantages, culminating in a 4.23% decrease in the aircraft’s lift-to-drag ratio and an aggregate benefit of 5.62%.