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.

Evaluation of wind tunnel performance testings of an advanced 45 deg swept 8-bladed propeller at Mach numbers from 0.45 to 0.85

Abstract: The increased emphasis of fuel conservation in the world and the rapid increase in the cost of jet fuel has stimulated a series of studies of both conventional and unconventional propulsion systems for commercial aircraft. The results of these studies indicate that a fuel saving of 15 to 30 percent may be realized by the use of an advanced high-speed turboprop (Prop-Fan) compared to aircraft equipped with high bypass turbofan engines of equivalent technology. The Prop-Fan propulsion system is being investigated as part of the NASA Aircraft Energy Efficient Program. This effort includes the wind tunnel testing of a series of 8 and 10-blade Prop-Fan models incorporate swept blades. Test results indicate efficiency levels near the goal of 80 percent at Mach 0.8 cruise and an altitude of 10.67 km (35,000 ft). Each successive swept model has shown improved efficiency relative to the straight blade model. The fourth model, with 45 deg swept blades reported herein, shows a net efficiency of 78.2 at the design point with a power loading of 301 kW/sq meter and a tip speed of 243.8 m/sec (800 ft/sec.).

Control Design for an Advanced Geared Turbofan Engine

Abstract: This paper describes the design process for the control system of an advanced geared turbofan engine. This process is applied to a simulation that is representative of a 30,000 lbf thrust class concept engine with two main spools, ultra-high bypass ratio, and a variable area fan nozzle. Control system requirements constrain the non-linear engine model as it operates throughout its flight envelope of sea level to 40,000 ft and from 0 to 0.8 Mach. The control architecture selected for this project was developed from literature and reflects a configuration that utilizes a proportional integral controller integrated with sets of limiters that enable the engine to operate safely throughout its flight envelope. Simulation results show the overall system meets performance requirements without exceeding system operational limits.

Partial span inlet guide vane for cross-connected engines

Abstract: A pair of turbofan engines are cross connected such that during normal-mode operation horsepower can be shared by the respective cores, and when one engine core becomes inoperative the fan of that engine can be driven by the turbine of the operative engine to thereby maintain a substantial thrust output. In order to balance the respective thrust outputs, variable inlet guide vanes are controlled to decrease the fan mass flow in the operative engine and increase the fan mass flow in the inoperative engine. The variable inlet guide vanes are so constructed as to only partially span the fan duct so as to not appreciably affect the airflow to the core when the inlet guide vane angle setting is altered to allow the core to thereby retain a high level of supercharging during this operational period of maximum power demand.

Exergoeconomic analysis of an aircraft turbofan engine

Abstract: This study deals with an exergoeconomic analysis of an aircraft turbofan engine utilising the kerosene as fuel. A new parameter is developed to define the thrust cost rate. The cost of exergy destruction, the relative cost difference and the exergoeconomic factor are investigated. The variation of the relative cost difference and exergoeconomic factor according to the operating and maintenance costs and the annual operating hour are also studied. For a high by-pass and high thrust rated engine, the cost rate of thrust is obtained to be 304.35 $(hkN) −1 for the hot thrust and 138.96 $ (hkN)−1 for the cold thrust, respectively.