Propfan propulsion systems for the 1990's

Reynolds, C.; Riffel, Ronald E.; Ludemann, S. G.

doi:10.2514/6.1987-1729

Cited by 5 publications

(3 citation statements)

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“…The lower stress levels in these gears contribute to the durability targets of a high-power CROR gearbox. These targets are defined through the Mean Time Between Unscheduled Removals (MTBUR), which is the standard measure of design life used for gear systems [34].…”

Section: Accepted Manuscript N O T C O P Y E D I T E Dmentioning

confidence: 99%

Preliminary Design Framework for the Power Gearbox in a Contra-Rotating Open Rotor

Pastor

Nalianda

Sethi

et al. 2021

Journal of Engineering for Gas Turbines and Power

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This study introduces an innovative approach to sizing a differential planetary gearbox for a counter-rotating open rotor application. An updated methodology is proposed for the design of maximum load capacity gears based on the power transmitted, durability and space-envelope requirements of the application. The reported methodology has been validated by comparing the results to published data, demonstrating a maximum difference of 0.6% in geometry. Parametric analyses have also been performed to assess the impact of the design assumptions on gearbox dimensional trends. The proposed methodology enables the assessment of the impact of the preliminary transmission system design on engine performance and general arrangement. The characteristics of the gearset lead to an unequal torque split between output shafts (i.e. the propeller shafts). Given the design assumptions made, the study indicates that valid torque ratios would lie between 1.1 and 1.33. The impact of the torque ratio on the size of the gearbox has been analysed for equal rotational speeds and for different speeds between the output shafts. The study established that the transmission system design needs to be considered prior to selection of the torque ratio at engine design level.

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Section: Accepted Manuscript N O T C O P Y E D I T E Dmentioning

confidence: 99%

Preliminary Design Framework for the Power Gearbox in a Contra-Rotating Open Rotor

Pastor

Nalianda

Sethi

et al. 2021

Journal of Engineering for Gas Turbines and Power

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show abstract

“…In addition, the reduction of exhaust velocity lowers noise level. Apart from turbofans, open rotors, propfans, and unducted fan engines can also be used in improving fuel consumption as their propulsive efficiency is better than that of turbofan engines owing to their low exhaust velocities [4]. However, flight speed is the main limitation of these concepts.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic and Aerodynamic Analysis of an Air-Driven Fan System in Low-Cost High-Bypass-Ratio Turbofan Engine

Huang

Xiang

et al. 2019

Energies

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In some cases, the improvement of the bypass ratio (BPR) of turbofans is pursued for military or civilian purposes owing to economic, environmental, and performance reasons, among others. However, high-BPR turbofans suffer from incompatibility of spool speed, complex structure for manufacture, development difficulty, and substantially increasing costs, especially for those with small batch production. To deal with the issues, a novel low-cost concept of high-BPR turbofan with air-driven fan (ADTF) is presented in this research. First, the problems faced by high-BPR turbofans are discussed, and the difficulties of geared turbofan (GTF), which is developed as a solution to the problems, are analyzed. A novel turbofan with potential advantages is proposed, and its basic theory is interpreted. Second, high-BPR ADTF is analyzed at the top level, and the design principle and important primary parameters are discussed. Some important concepts and criteria are proposed, enabling the comparison between ADTF and GTF. Finally, an air-driven fan system, the core part of ADTF, is exploratorily designed, and numerical simulation is performed to demonstrate its feasibility.

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“…The contra-rotating open rotor concept (acronym CROR, see sketch in Fig. 1) was developed in the 1980s after the first oil crisis with the objective to reduce aircraft fuel consumption (1,2,3,4) . Within the last decade (5) , the interest at CROR has revived again as the fuel consumption represents a growing part of airliner direct operating costs.…”

Section: Introductionmentioning

confidence: 99%

Performance prediction and progress towards multi-disciplinary design of contra-rotating open rotors

Guérin¹,

Schnell²,

Becker³

2014

Aeronaut. j. (1968)

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At DLR's Institute of Propulsion Technology, the prediction tools and multi-disciplinary optimisation strategies developed for turbofan engines have been extended to contra-rotating open rotors (CROR). Thereby the objective has been to appraise and improve the performance of CROR engines and thus to reduce their environmental impact. The present paper reviews the intermediate progress achieved in this scope. The prediction is based on analytical and CFD methods and covers the fields of engine performance analysis, aerodynamics and acoustics. The aerodynamic and acoustic results could be partly validated through the comparison to experimental data obtained from wind-tunnel tests. In a multi-disciplinary approach the aforementioned aspects are optimised together. First results of an aero-acoustic optimisation are presented. Furthermore this paper undertakes some comparison between high-bypass ratio turbofan engines and open-rotor concepts.

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Propfan propulsion systems for the 1990's

Cited by 5 publications

References 0 publications

Preliminary Design Framework for the Power Gearbox in a Contra-Rotating Open Rotor

Preliminary Design Framework for the Power Gearbox in a Contra-Rotating Open Rotor

Thermodynamic and Aerodynamic Analysis of an Air-Driven Fan System in Low-Cost High-Bypass-Ratio Turbofan Engine

Performance prediction and progress towards multi-disciplinary design of contra-rotating open rotors

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