Estimation of Design Parameters and Performance for a State-of-the-Art Turbofan

2021 ◽  
Author(s):  
Oliver Sjögren ◽  
Carlos Xisto ◽  
Tomas Grönstedt
Keyword(s):  
Performance Metrics ◽  
State Of The Art ◽  
Low Pressure ◽  
Performance Model ◽  
Cycle Performance ◽  
Civil Aviation ◽  
Design Parameters ◽  
Pressure System ◽  
Public Data ◽  
Low Pressure System

Abstract The aim of this study is to explore the possibility of matching a cycle performance model to public data on a state-of-the-art commercial aircraft engine (GEnx-1B). The study is focused on obtaining valuable information on figure of merits for the technology level of the low-pressure system and associated uncertainties. It is therefore directed more specifically towards the fan and low-pressure turbine efficiencies, the Mach number at the fan-face, the distribution of power between the core and the bypass stream as well as the fan pressure ratio. Available cycle performance data have been extracted from the engine emission databank provided by the International Civil Aviation Organization (ICAO), type certificate datasheets from the European Union Aviation Safety Agency (EASA) and the Federal Aviation Administration (FAA), as well as publicly available data from engine manufacturer. Uncertainties in the available source data are estimated and randomly sampled to generate inputs for a model matching procedure. The results show that fuel performance can be estimated with some degree of confidence. However, the study also indicates that a high degree of uncertainty is expected in the prediction of key low-pressure system performance metrics, when relying solely on publicly available data. This outcome highlights the importance of statistic-based methods as a support tool for the inverse design procedures. It also provides a better understanding on the limitations of conventional thermodynamic matching procedures, and the need to complement with methods that take into account conceptual design, cost and fuel burn.

Preliminary Design Assessments of Pusher Geared Counter-Rotating Open Rotors: Part II — Impact of Low Pressure System Design on Mission Fuel Burn, Certification Noise and Emissions

2015 ◽  
Author(s):  
Pablo Bellocq ◽  
Inaki Garmendia ◽  
Vishal Sethi
Keyword(s):  
System Design ◽  
Rotational Speed ◽  
Low Pressure ◽  
Design Parameters ◽  
Preliminary Design ◽  
Pressure System ◽  
Regulatory Constraints ◽  
Fuel Burn ◽  
Low Pressure System ◽  
The Impact

In this 2-part publication, the impact of the main low pressure system parameters of a counter rotating Geared Open Rotor (GOR) on mission fuel burn, certification noise and emissions is presented for a 160 PAX medium haul class aircraft. Due to their high propulsive efficiency, GORs have the potential to significantly reduce fuel consumption and emissions relative to conventional high bypass ratio turbofans. However, this novel engine architecture presents many design and operational challenges both at engine and aircraft level. The assessment of the impact of the main low pressure preliminary design parameters of GORs on mission fuel burn, certification noise and emissions is necessary at preliminary design stages in order to identify optimum design regions. These assessments may also aid the development process when compromises need to be performed as a consequence of design, operational or regulatory constraints. Part I of this two-part publication describes the main low pressure (LP) system design choices for a GOR as well as the preliminary design philosophy and simulation framework developed for the assessments. Part II presents the assessment studies. A fixed reference aircraft and mission were used to evaluate the different GOR engine designs. The results are presented in the form of 1-D or 2-D plots in which one or two design parameters are varied at the same time. The changes in mission fuel burn, certification noise and emissions are expressed as differences relative to a baseline design, due to the fact that preliminary design tools were used for the assessments. The main conclusions of the study are: • Increasing spacing between the propellers (from 0.65 to 1.3m) reduces noise significantly (∼6 EPNdB for each certification point) with a relatively small fuel burn penalty (∼0.3–0.5%) • Relative to unclipped designs, 20% clipped CRPs reduce flyover noise by at least 2.5 EPNdB and approach noise by at least 4.5 EPNdB. The corresponding fuel burn penalty is ∼2%. • Sideline and flyover noise can be reduced by increasing the diameter of the CRP and appropriately controlling CRP rotational speeds. Approach noise can be reduced by either reducing the diameters or the rotational speeds of the propellers. • Regardless of clipping, reducing the rotational speed of the rear propeller relative to the forward propeller reduces noise and, to a certain limit, also mission fuel burn. Further reductions in rotational speed would have an adverse effect on fuel burn. • For given rotational speeds of the propellers, the torque ratio of the gearbox is fixed within ±3%.

Preliminary Design Assessments of Pusher Geared Counter-Rotating Open Rotors: Part I — Low Pressure System Design Choices, Engine Preliminary Design Philosophy and Modelling Methodology

2015 ◽  
Author(s):  
Pablo Bellocq ◽  
Iñaki Garmendia ◽  
Vishal Sethi
Keyword(s):  
System Design ◽  
Low Pressure ◽  
Design Parameters ◽  
Preliminary Design ◽  
Simulation Framework ◽  
Pressure System ◽  
Design Philosophy ◽  
Fuel Burn ◽  
Low Pressure System ◽  
The Impact

In this 2-part publication, the impact of the main low pressure system parameters of a pusher counter rotating Geared Open Rotor (GOR) on mission fuel burn, certification noise and emissions is presented for a 160 PAX medium haul class aircraft. Due to their high propulsive efficiency, GORs have the potential to significantly reduce fuel consumption and emissions relative to conventional high bypass ratio turbofans. However, this novel engine architecture presents many design and operational challenges both at engine and aircraft level. The assessment of the impact of the main low pressure preliminary design parameters of GORs on mission fuel burn, certification noise and emissions is necessary at preliminary design stages in order to identify optimum design regions. These assessments may also aid the development process when compromises need to be performed as a consequence of design, operational or regulatory constraints. Part I of this two-part publication describes the main low pressure (LP) system design choices for a GOR as well as the preliminary design philosophy and simulation framework developed for the assessments. Part II presents the assessment studies. The simulation framework described in this paper comprises the following models: engine and aircraft performance, engine mechanical design and weight, engine certification noise and emissions. A novel aspect of the presented simulation framework is that the design point efficiency and the design feasibility of the low pressure components are calculated for each engine design.

The effect of vasoactive drugs on the low-pressure system

1978 ◽  
Vol 73 (2) ◽  
pp. 220-229 ◽  
Author(s):  
K. Kirsch ◽  
A. Ameln ◽  
H. J. Wicke
Keyword(s):  
Low Pressure ◽  
Vasoactive Drugs ◽  
Pressure System ◽  
Low Pressure System

scholarly journals Synoptic perspectives on pollutant transport patterns observed by satellites over East Asia: Case studies with a conceptual model

2016 ◽  
Author(s):  
Hyun Cheol Kim ◽  
Soontae Kim ◽  
Seok-Woo Son ◽  
Pius Lee ◽  
Chun-Sil Jin ◽  
...  
Keyword(s):  
High Pressure ◽  
East Asia ◽  
Southern China ◽  
Low Pressure ◽  
Pressure System ◽  
Weather Patterns ◽  
High Pressure System ◽  
Synoptic Weather ◽  
Low Pressure System ◽  
Transport Patterns

Abstract. We demonstrate that daily pollutant transport patterns in East Asia are visible from satellite images when inspected with corresponding synoptic weather analyses. Transport pathways of air pollutants in East Asia are investigated using satellite observations, surface weather charts, and chemical-transport model simulations. It is found that during cool season (fall to spring), pollutant transports in East Asia are largely determined by synoptic weather patterns associated with high pressure system over southern China, which is extended from the Siberia High, and low pressure system over Manchuria, which is initiated by Altai-Sayan cyclogenesis. Based on the relative location and strength of these weather systems, three types of synoptic weather patterns that may contribute to pollutants transport in East Asia, especially in China and Korea, are identified: i.e., (1) a strengthening of the Siberian High and its southeastward propagation; (2) a high-pressure system over southern China followed by a frontal passage associated with a northern low-pressure system; and (3) a stagnant high-pressure system over southern China. For all three patterns, the high-pressure system in southern China is essential for the development of regional air pollution, while frontal activities associated with low-pressure system provide a forcing mechanism to transport those pollutants eastward or southeastward. Observed and simulated surface PM distributions show good agreement in both aerosol optical depth and NO2 column density further implying that anthropogenic emissions also contribute to regional events of high surface PM concentrations. It is argued that the quasi-periodic migration of synoptic weather systems in East Asia works as an efficient pump of pollutants; i.e., regional air pollutions developed under high-pressure systems are transported downstream by low-pressure systems.

Synoptic and Mesoscale Background of the Disastrous Heavy Rainfall in Sri Lanka Caused by a Low Pressure System

2021 ◽  
pp. 407-416
Author(s):  
A. R. P. Warnasooriya ◽  
K. H. M. S. Premalal ◽  
A. W. S. J. Kumara ◽  
Chathuska G. Premachandra
Keyword(s):  
Sri Lanka ◽  
Heavy Rainfall ◽  
Low Pressure ◽  
Pressure System ◽  
Low Pressure System
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