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.

Towards Lattice-Boltzmann Prediction of Turbofan Engine Noise

Abstract: The goal of the present paper is to report verification and validation studies carried out by Exa Corporation in the framework of turbofan engine noise prediction through the hybrid Lattice-Boltzmann/Ffowcs-Williams & Hawkings approach (LB)-(FW-H). The underlying noise generation and propagation mechanisms related to the jet flow field and the fan are addressed separately by considering a series of elementary numerical experiments. As far as fan and jet noise generation is concerned, validation studies are performed by comparing the LB solutions with literature experimental data, whereas, for the fan noise transmission through and radiation from the engine intake and bypass ducts, LB solutions are compared with finite element solutions of convected wave equations. In particular, for the fan noise propagation, specific verification analyses are carried out by considering tonal spinning duct modes in the presence of a liner, which is modelled as an equivalent acoustic porous medium. Finally, a capability overview is presented for a comprehensive turbofan engine noise prediction, by performing LB simulation for a generic but realistic turbofan engine configuration.

A Demonstration of a Retrofit Architecture for Intelligent Control and Diagnostics of a Turbofan Engine

Abstract: A retrofit architecture for intelligent turbofan engine control and diagnostics that changes the fan speed command to maintain thrust is proposed and its demonstration in a piloted flight simulator is described. The objective of the implementation is to increase the level of autonomy of the propulsion system, thereby reducing pilot workload in the presence of anomalies and engine degradation due to wear. The main functions of the architecture are to diagnose the cause of changes in the engine s operation, warning the pilot if necessary, and to adjust the outer loop control reference signal in response to the changes. This requires that the retrofit control architecture contain the capability to determine the changed relationship between fan speed and thrust, and the intelligence to recognize the cause of the change in order to correct it or warn the pilot. The proposed retrofit architecture is able to determine the fan speed setting through recognition of the degradation level of the engine, and it is able to identify specific faults and warn the pilot. In the flight simulator it was demonstrated that when degradation is introduced into an engine with standard fan speed control, the pilot needs to take corrective action to maintain heading. Utilizing the intelligent retrofit control architecture, the engine thrust is automatically adjusted to its expected value, eliminating yaw without pilot intervention.

Mean Flow and Noise Prediction for a Separate Flow Jet with Chevron Mixers

Abstract: Experimental and numerical results are presented here for a separate flow nozzle employing chevrons arranged in an alternating pattern on the core nozzle. Comparisons of these results demonstrate that the combination of the WIND/MGBK suite of codes can predict the noise reduction trends measured between separate flow jets with and without chevrons on the core nozzle. Mean flow predictions were validated against Particle Image Velocimetry (PIV), pressure, and temperature data, and noise predictions were validated against acoustic measurements recorded in the NASA Glenn Aeroacoustic Propulsion Lab. Comparisons are also made to results from the CRAFT code. The work presented here is part of an on-going assessment of the WIND/MGBK suite for use in designing the next generation of quiet nozzles for turbofan engines.

Effects of incidence angle in bird strike on integrity of aero-engine fan blade

Abstract: The possibilities of blade deformation and even fracture, the need for subsequent containment and reduction in thrust and power supply make bird strikes to aero-engine fan blades very serious events. Due to the different bird–plane flight paths and the different types of turbofan engines, the incidence angle between the bird and the engine fan blade can vary within a wide range. The present explicit non-linear three-dimensional finite-element analyses examine in detail the effect of the incidence angle when a canonical 4-lb bird strikes a typical engine fan blade, using the commercial code LS-DYNA. Both the bird and the blade are simulated in a Lagrangian framework. The homogenised fluidic constitutive equation of the bird follows the Brockman hydrodynamic model, while the blade is modelled as a viscoplastic material of the Perzyna type. It was found that normal incidence results in maximum impact forces and plastic strains leading to severe deformation. For the case in which the incidence angle is equal ...

Results of NASA's Energy Efficient Engine Program

Abstract: The major activity undertaken in the NASA Energy Efficient Engine Program has been completed. This paper reports on the progress made toward achieving the program goal of developing advanced technology to significantly reduce fuel consumption and operating costs of future subsonic transport-type propulsion systems. An additional goal was that the advanced concepts be compatible with future environmental regulations. Along with the results obtained, a brief overview of the design details of both the General Electric and Pratt and Whitney energy efficient engines and the overall program scope are presented. Overall, this program has been highly successful; the technology developed during its course is, and will continue to be, effectively employed in both current and future advance transport aircraft engine designs.