Turbofan

About: Turbofan is a research topic. Over the lifetime, 4114 publications have been published within this topic receiving 39490 citations. The topic is also known as: fanjet & turbofan engine.

Turbofan engine and method of operating the same

Abstract: A method for operating a turbofan engine includes providing a first fan disk configured to rotate in a first rotational direction, coupling a first fan blade to the first fan disk, the first fan blade including a dovetail, an airfoil coupled to the dovetail, and a plurality of channels extending through the dovetail, and channeling airflow through the at least one fan blade such that the airflow is discharged from the airfoil trailing edge to facilitate reducing the operational noise level of the turbofan engine and improve.

Geared turbofan with independent flexible ring gears and oil collectors

Abstract: A geared turbofan engine includes a fan rotatable about an engine axis. A compressor section compresses air and delivers the compressed air to a combustor where the compressed air is mixed with fuel and ignited to drive a turbine section that in turn drives the fan and the compressor section. A gear system is driven by the turbine section for driving the fan at a speed different than the turbine section. The gear system includes a carrier attached to a fan shaft. A plurality of planet gears are supported within the carrier. Each of the plurality of planet gears includes a first row of gear teeth and a second row of gear teeth supported within the carrier. A sun gear is driven by a turbine section. The sun gear is in driving engagement with the plurality of planet gears. At least two separate ring gears circumscribe the plurality of planet gears. Each of the at least two ring gears are supported by a respective flexible ring gear mount that enables movement relative to an engine static structure. A fan drive gear system for a gas turbine engine is also disclosed.

Design and Application of a Multi-Disciplinary Pre-Design Process for Novel Engine Concepts

Abstract: Central targets for jet engine research activities comprise the evaluation of improved engine components and the assessment of novel engine concepts for enhanced overall engine performance in order to reduce the fuel consumption and emissions of future aircraft. Since CO2 emissions are directly related to engine fuel burn, a reduction in fuel consumption leads to lower CO2 emissions. Therefore improvements in engine technologies are still significant and a multi-disciplinary pre-design approach is essential in order to address all requirements and constraints associated with different engine concepts. Furthermore, an increase in effectiveness of the preliminary design process helps reduce the immense costs of the overall engine development. Within the DLR project PEGASUS (Preliminary Gas Turbine Assessment and Sizing) a multi-disciplinary pre-design and assessment competence of the DLR regarding aero engines and gas turbines was established. The application of modern preliminary design methods allows for the construction and evaluation of innovative next generation engine concepts. The purpose of this paper is to present the developed multi-disciplinary pre-design process and its application to three aero engine models. First, a state of the art twin spool mixed flow turbofan engine model is created for validation purposes. The second and third engine models investigated comprise future engine concepts: a Counter Rotating Open Rotor and an Ultra High Bypass Turbofan. The turbofan used for validation is based on publicly available reference data from manufacturing and emission certification. At first the identified interfaces and constraints of the entire pre-design process are presented. An important factor of complexity in this highly iterative procedure is the intricate data flow, as well as the extensive amount of data transferred between all involved disciplines and among the different fidelity levels applied within the smoothly connected design phases. To cope with the inherent complexity data modeling techniques have been applied to explicitly determine the required data structures of those complex systems. The resulting data model characterizing the components of a gas turbine and their relationships in the design process is presented in detail. Based on the established data model the entire engine pre-design process is presented. Starting with the definition of a flight mission scenario and the resulting top level engine requirements thermodynamic engine performance models are developed. By means of these thermodynamic models, a detailed engine component pre-design is conducted. The aerodynamic and structural design of the engine components are executed using a stepwise increase in level of detail and are continuously evaluated in the context of the overall engine system.

A Control Strategy for Turbine Electrified Energy Management

Abstract: Hybrid-electric propulsion architectures provide the infrastructure to enable additional benefits to the propulsion system that are otherwise unrealizable with the sole use of the current, state-of-the-art, gas-driven, turbine engines. The presence of electric machines (EMs) coupled to the shaft(s) of the turbine engine provide the ability to actively alter the operation of the engine to the benefit of the propulsion system and the aircraft it propels. This is the goal of the Turbine Electrified Energy Management (TEEM) concept, which at its broadest level addresses the management of energy across the electrified propulsion system. Prior work has demonstrated the use of this concept to alter steady-state operation and improve transient operability of a hybrid-electric propulsion system. The main benefits previously illustrated include the elimination of stability bleeds and expansion of the turbomachinery design space in order to enable more efficient designs. This paper focuses on the development of control strategies to implement the TEEM concept, and it explores several possible architecture variants for applying this concept. Comparison studies are conducted between a purely gas-driven turbofan (baseline engine configuration) and TEEM augmented variants of the baseline engine. The variants are distinguished by the shaft(s) that possess an EM. The configurations consider EMs on both shafts, an EM on the high pressure spool (HPS) only, and an EM on the low pressure spool (LPS) only. These configurations are referred to as the dual-spool configuration, the HPS configuration, and LPS configuration, respectively. The studies expose several options in configuring and controlling the system, including the use of a single EM coupled to a single shaft of a two-spool engine to positively impact the operability of both shafts. The studies also demonstrate the use of independently designed controllers for the electric machine(s) that allow for a decoupled control design process.