Browse Topic: Gas turbines
This document is reissued for application to helicopters. It is primarily intended to apply to the engine or engines, but it shall also apply to fire protection of lines, tanks, combustion heaters, and auxiliary powerplants (APU). Post-crash fire protection is also discussed.
This document is reissued for application to helicopters.
This SAE Aerospace Recommended Practice (ARP) provides guidance for the presentation of gas turbine engine transient performance models with the capacity to be implemented as computer programs operating in real time and is intended to complement AS681. Such models will be used in those applications where a transient program must interface with physical systems. These applications are characterized by the requirement for real time transient response. These models require attention to unique characteristics that are beyond the scope of AS681. This document is intended to facilitate the development of mathematical models and the coordination of their requirements with the user. It will not unduly restrict the modeling methodology used by the supplier. The objective of this document is to define a recommended practice for the delivery of mathematical models intended for real time use. Models used in this application may also be contained in deliverable computer programs covered by AS681.
Manufacturers of fans/propellers using hydraulically-actuated pitch control claim energy efficiency gains up to 75% over fixed-pitch solutions. Unfortunately, the added cost, weight, reliability and maintenance considerations of hydraulic solutions has limited the introduction of pitch control for small-to-medium fans and propellers leaving a large market unserved by the efficiency gains associated with changing the pitch of a blade when the blade shaft’s speed changes. Pilot Systems International and Cool Mechatronics are developing an electromagnetically controlled pitch (EMCP) fan/propeller that will produce a new pareto optimal in size, weight, power, cost and cooling (SWaP-C2). The technology will substantially improve the efficiency of military ground vehicle cooling fans which is typically the third greatest power draw (~20kW)1 in the entire vehicle and provide critical performance improvements during silent watch. It will be a key enabler for the electrification of aircraft.
This document is reissued for application to helicopters.
This specification defines basic physical, chemical, and performance limits for 5 cSt grades of gas turbine engine lubricating oils used in aero and aero-derived marine and industrial applications, along with standard test methods and requirements for laboratories performing them. It also defines the quality control requirements to assure batch conformance and materials traceability and the procedures to manage and communicate changes in oil formulation and brand. This specification invokes the Performance Review Institute (PRI) product qualification process. Requests for submittal information may be made to PRI at the address in 2.1.3, referencing this specification. Products qualified to this specification are listed on a Qualified Products List (QPL) managed by PRI. Additional tests and evaluations may be required by individual OEMs before an oil is approved for use in their equipment. Approval and/or certification for use of a specific gas turbine engine oil in aero and aero
This document establishes general design criteria, tolerances, and limits of application for tooling, fixtures, and accessories for mounting and driving gas turbine engine rotors on horizontal and vertical balancing machines.
Improvement and evolution of all aircraft technologies and the commercialization of new technologies are essential to the carbon-net-zero goal of air mobility. Passenger aircraft are required to provide the ultimate in comfort, economy, and safety, and gas turbine engines will not disappear, while promoting the conversion to SAF and hydrogen fuels. The More Electric Engine (or MEE) concept, which has been proposed since the late 2000s, is one alternative. This paper focuses on the electrification of engine accessories. When the concept of electrification of engine accessories was first presented at Aerotech 10 years ago, the discussion at Aerotech seemed to be negative. Attaching a motor to conventional engine accessories would obviously increase the weight. Next, the conventional engine accessories are centrally controlled and only FADEC is in command, but electrification of engine accessories will increase the cost by adding intelligence to all the accessories. On a more academic
A tested method of data presentation and use is described herein. The method shown is a useful guide, to be used with care and to be improved with use.
This SAE Aerospace Standard (AS) provides a performance station designation system for aircraft propulsion systems and their derivatives.
This SAE Aerospace Information Report (AIR) provides an overview of temperature measurement techniques for various locations of aircraft gas turbine engines while focusing on current usage and methods, systems, selection criteria, and types of hardware.
This Aerospace Information Report (AIR) is limited in scope to the general consideration of environmental control system noise and its effect on occupant comfort. Additional information on the control of environmental control system noise may be found in 2.3 and in the documents referenced throughout the text. This document does not contain sufficient direction and detail to accomplish effective and complete acoustic designs.
As the world looks to net-zero emissions goals, hybrid electric vehicles may play an increasingly important role. For passenger electric vehicles (EVs) that predominantly make short journeys but occasionally need to make longer trips, electrofuel range extension may be more cost effective than either hydrogen or rapid charging. Micro gas turbines and catalytic combustion show significant potential to deliver low-cost, low-maintenance, lightweight engines with virtually no emissions, and hydrocarbon consuming solid oxide fuel cells show even greater potential in these areas. Aditioanlly, sodium-ion batteries for EVs, dispatachable vehicle-to-grid power and buffering, and variable intermittent renewable energy could also play key roles. The Role of Hybrid Vehicles in a Net-zero Transport System explores the costs, considerations, and challenges facing these technologies. Click here to access the full SAE EDGETM Research Report portfolio.
This document provides the specifications of horizontal hard-bearing balancing machines, which make such machines suitable for gas turbine rotor balancing.
The turbine-engine-inlet flow distortion descriptors summarized in this document apply to the effects of inlet total-pressure, planar-wave, and total-temperature distortions. Guidelines on stability margin, destabilizing influences, types and purposes of inlet data, AIP definition, and data acquisition and handling are summarized from AIR5866, AIR5867, ARP1420, and AIR1419. The degree to which these recommendations are applied to a specific program should be consistent with the complexity of the inlet/engine integration. Total-pressure distortion is often the predominant destabilizing element that is encountered and is often the only type of distortion to be considered, i.e., not all types of distortion need to be considered for all vehicles.
Liquid jet atomization is one of the key processes in many engineering applications, such as IC engines, gas turbines, and the like, to name a few. Simulating this process using a pure Eulerian or a pure Lagrangian framework has its own drawbacks. The Eulerian–Lagrangian spray atomization (ELSA) modeling seems like a viable alternative in such scenarios. ELSA simulations consist of solving an additional transport equation for the surface area density (Σ) of the issuing jet. In this study we have proposed a dynamic approach to compute the turbulent timescale constant (α1), which appears in the source of Σ-transport equation and is responsible for restoring the surface area back to its equilibrium. The dynamic approach involves an analytical computation of the turbulent timescale constant (α1), thereby eliminating the need for ad hoc adjustments to surface area values during computational fluid dynamics (CFD) simulations. Unlike previous research which suggests using constant values in
This SAE Aerospace Recommended Practice (ARP) provides recommendations for: The audit process in general A list of specific areas of attention to be audited Maintaining the test facility in such a manner that it meets audit requirements
Additive manufacturing (AM) is currently the most sought-after production process for any complex shaped geometries commonly encountered in Aerospace Industries. Although, several technologies of AM do exits, the most popular one is the Direct Metal Laser Sintering (DMLS) owing to its high versatility in terms of precision of geometries of components and guarantee of highest levels of reduction in production time. Further, metallic component of any complex shape such as Gas Turbine Blades can also be developed by this technique. In the light of the above, the present work focuses on development of iron silicon carbide (Fe-SiC) complex part for ball screw assembly using DMLS technique. The optimized process parameters, hardness and wear resistance of the developed iron-SiC composite will be reported. Further, since the material chosen is a metallic composite one, the effect of SiC on the thermal stresses generated during the DMLS processing of Fe-SiC composite will also be discussed. A
This document defines the process steps involved in collecting and processing engine test data for use in understanding engine behavior. It describes the use of an aero-thermal cycle model for reduction and analysis of those data. The analysis process may include the calculation of modifiers to match the model to measured data and prediction of engine performance based on that analysis.
The purpose of this SAE Aerospace Information Report (AIR) is to disseminate qualitative information regarding foreign object debris (FOD) damage to the gas path of rotorcraft gas turbine engines and to discuss methods of FOD prevention. Although turbine-powered fixed-wing aircraft are also subject to FOD, the unique ability of the rotorcraft to hover above, takeoff from, and land on unprepared surfaces creates a special need for a separate treatment of this subject.
This SAE Aerospace Information Report (AIR) provides an overview of temperature measurement techniques for various locations of aircraft gas turbine engines while focusing on current usage and methods, systems, selection criteria, and types of hardware.
Hybrid electric aircraft propulsion is an emerging technology that presents a variety of potential benefits along with technical integration challenges. Developing these new propulsion architectures with their complex control systems, and ultimately proving their benefit, is a multistep process. This process includes concept development and analysis, dynamic simulation, hardware-in-the-loop testing, full-scale testing, and so on. This effort is being revolutionized and indeed enabled by new digital tools that support increasing the technology readiness level throughout the maturation process. As part of this Digital Transformation, NASA has developed a suite of publicly available digital tools that facilitate the path from concept to implementation. This paper describes the NASA-developed tools and puts them in the context of control system development for hybrid electric aircraft propulsion. The three MATLAB®-based software packages are the Toolbox for the Modeling and Analysis of
This SAE Aerospace Standard (AS) provides the method for presentation of gas turbine engine steady-state and transient performance calculated using computer programs. It also provides for the presentation of parametric gas turbine data including performance, weight, and dimensions computed by computer programs. This standard is intended to facilitate calculations by the program user without unduly restricting the method of calculation used by the program supplier. This standard is applicable, but not limited to, the following program types: data reduction, steady-state, transient, preliminary design, study, specification, status, and parametric programs.
This SAE Aerospace Information Report (AIR) addresses many of the significant issues associated with effects of inlet total-pressure distortion on turbine-engine performance and stability. It provides a review of the development of techniques used to assess engine stability margins in the presence of inlet total-pressure distortion. Specific performance and stability issues that are covered by this document include total-pressure recovery and turbulence effects and steady and dynamic inlet total-pressure distortion.
This paper describes a recommended practice and procedure for the correlation of test cells that are used for the performance testing of turboprop and turboshaft engines. This Aerospace Recommended Practice (ARP) shall apply to both dynamometer and propeller based testing. Test cell correlation is performed to determine the effect of any given test cell enclosure and equipment on the performance of an engine relative to the baseline performance of that engine. Although no original equipment manufacturer (OEM) documents are actually referenced, the experience and knowledge of several OEMs contributed to the development of this document. Each engine manufacturer has their own practices relating to correlation and they will be used by those OEMS for the purpose of establishing certified test facilities.
This document describes a recommended practice and procedure for the trending of parameters to maintain the test cell correlation status. Trending is performed to monitor test cells for changes that can affect engine performance or the data acquired from engine tests.
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