The bypass ratio (BPR) of a turbofan engine is the ratio between the mass flow rate of the bypass stream to the mass flow rate entering the core. [1] A 10:1 bypass ratio, for example, means that 10 kg of air passes through the bypass duct for every 1 kg of air passing through the core.

2022年2月4日 · One of the viable technological pathways, is the use of even higher BPR, with the so called Ultra High Bypass Ratio (UHBPR) engine approach, which uses BPR higher that 13:1 and can be seen as the turbofan engine efficiency frontier, to be used as a promising technology for near future airplane propulsion.

Ultrahigh-bypass engines (as shown in Figure 4) may have a gearbox between the drive turbine and the fan to simplify the design of the small-diameter turbine (with the attendant high rotative speed) without compromising the performance of the very large-diameter fan (with the attendant low rotative speed). Variable-pitch fan blades are ...

The Promise and Challenges of Ultra High Bypass Ratio Engine Technology and Integration Summary In this presentation, an overview of the research being conducted by the ERA Project in Ultra High Bypass aircraft propulsion and in partnership with Pratt & Whitney with their Geared TurboFan (GTF) is given.

the Ultra High Bypass (UHB) engine cycle to determine its potential for reducing noise, increasing aerodynamic performance and decreasing emissions. The NASA definition of the UHB cycle refers to a propulsive-to-power component mass flow ratio, or bypass ratio, greater than 13 to 1. Under previous NASA technology programs, UHB propulsion research

These large span fan blades, made of composite materials, have variable pitch to provide the proper blade angle of attack to meet varying aircraft speed and power requirements. Powerplants such as the UDF® engine are capable of reducing specific fuel consumption another 20-30 percent below current subsonic turbofans.

The origins of the Ultra-High Bypass Ratio (UHBR) Turbofan Engine, also known as the ‘Geared Turbofan Engine (GTF)’, can be traced back to the 1970s [171]. Its underlying concept is to change the engine cycle parameters by increasing the operational speeds of the low-pressure turbine and of the compressor while decreasing the fan speed.

Engine configurations being considered for future large civil transport aircraft include so-called Ultra-High Bypass (UHB) engine cycles, with bypass ratios exceeding 10 to 15:1. The advantage of a UHB cycle is the significant improvement in propulsive efficiency and …

Collaborative Research on the Ultra High Bypass Ratio Engine Cycle to Reduce Noise, Emissions, and Fuel Consumption Presentation Abstract A pictorial history of NASA development of advanced engine technologies for reducing environmental emissions and increasing performance from the 1970s to present is presented. The goals of the

FIG 2 visualises the impact of engine design bypass ratio on wetted nacelle area, which is essential for the calculation of engine drag. The accordant deduced engine drag characteristics were incorporated into the computation and investigation of a high number of aircraft configurations featuring different engine design bypass