Search Results

The NET EMF of a thermoelectric circuit can be thought of as originating entirely in the regions of temperature gradient. Any extraneous materials, such as switch or connector terminals, in a temperature gradient may cause an error in the temperature measurement. In addition to circuitry errors, jet engine thermocouple indications require correction for the effects of conduction, radiation, response rate, and gas velocity. The magnitudes of the corrections depend on the thermocouple design and the environmental conditions. Performance curves for several typical jet engine thermocouples are presented, with the methods of making the various corrections.

This SAE Aerospace Information Report (AIR) reviews the precautions that must be taken and the corrections which must be evaluated and applied if the experimental error in measuring the temperature of a hot gas stream with a thermocouple is to be kept to a practicable minimum. Discussions will focus on Type K thermocouples, as defined in National Institute of Standards and Technology (NIST) Monograph 175 as Type K, nickel-chromium (Kp) alloy versus nickel-aluminium (Kn) alloy (or nickel-silicon alloy) thermocouples. However, the majority of the content is relevant to any thermocouple type used in gas turbine applications.

This SAE Aerospace Information Report (AIR) reviews the precautions that must be taken and the corrections which must be evaluated and applied if the experimental error in measuring the temperature of a hot gas stream with a thermocouple is to be kept to a practicable minimum. Discussions will focus on Type K thermocouples. These are defined in NBS Monograph 125 as nickel-chromium alloy versus nickel-aluminum alloy thermocouples.

This SAE Aerospace Recommended Practice (ARP) defines the nomenclature of temperature measuring devices. General temperature measurement related terms are defined first, followed by nomenclature specifice to temperature measuring devices, particularly thermocouples.

The thermocouple design recommended herein is presented as one for which the correction to the observed emf, because of thermal conduction along the stem and wires, is within the limits presented in the accompanying figure. On referring to the figure, it is seen that no restriction is placed upon the diameter of the thermocouple or stem, and the longitudinal dimensions are expressed in terms of wire and stem diameters. The type of stem, such as packed ceramic stick, refractory insulating tubing, etc., also is left open to choice. Thus the sizes of wires and supporting stems may be varied over wide ranges to match particular requirements where conduction errors are to be limited or controlled.

To establish a specification for software input and output interfaces for condition monitoring and performance programs used to monitor equipment from multiple manufacturers. The purpose of standardizing these interfaces is to improve operational flexibility and efficiency of monitoring systems as an aid to cost effectiveness (e.g., easier implementation).

The ice bath recommended herein is similar to that described in SAE AIR 46. Some material not presented in AIR 46, including preferred dimensions, has been added.

The SAE E-32 Committee is requested to develop standards for Commercial Aircraft Engine Monitoring to support the Continued Airworthiness of aircraft in general, with particular emphasis on the ETOPS (Extended Operations) to support the regulations. 14CFR A33.3 (c) ETOPS Requirements. For an applicant seeking eligibility for an engine to be installed on an airplane approved for ETOPS, the Instructions for Continued Airworthiness must include procedures for engine condition monitoring. The engine condition monitoring procedures must be able to determine prior to flight, whether an engine is capable of providing, within approved engine operating limits, maximum continuous power or thrust, bleed air, and power extraction required for a relevant engine inoperative diversion. For an engine to be installed on a two-engine airplane approved for ETOPS, the engine condition monitoring procedures must be validated before ETOPS eligibility is granted.

This document applies to prognostics of gas turbine engines and its related auxiliary and subsystems. Its purpose is to define the meaning of prognostics with regard to gas turbine engines and related subsystems, explain its potential and limitations, and to provide guidelines for potential approaches for use in existing condition monitoring environments. It also includes some examples.

This document applies to prognostics of aerospace propulsion systems. Its purpose is to define the meaning of prognostics in this context, explain their potential and limitations, and to provide guidelines for potential approaches for use in existing condition monitoring environments. This document also includes some examples. The current revision does not provide specific guidance on validation and verification, nor does it address implementation aspects such as computational capability or certification.

This SAE Aerospace Information Report (AIR) presents metrics for assessing the performance of prognostic algorithms applied for Engine Health Management (EHM) functions. The emphasis is entirely on prognostics and as such is intended to provide an extension and complement to such documents as AIR5871, which offers information and guidance on general prognostic approaches relevant to gas turbines, and AIR4985 which offers general metrics for evaluating diagnostic systems and their impact on engine health management activities.

This SAE Aerospace Information Report (AIR) presents metrics for assessing the performance of prognostic algorithms applied for Engine Health Management (EHM) functions. The emphasis is entirely on prognostics and as such is intended to provide an extension and complement to such documents as AIR5871, which offers information and guidance on general prognostic approaches relevant to gas turbines, and AIR4985 which offers general metrics for evaluating diagnostic systems and their impact on engine health management activities.

Scope is unavailable.

This Aerospace Information Report (AIR) presents considerations specific to machine learning (ML) applied to propulsion system health management (aka EHM), illustrated via examples. These examples are used to highlight concerns and approaches that are unique to EHM, including the typical design space for propulsion systems, terminology, data collection and processing methods, requirements, and characteristics of machine learning models that have been developed and are being implemented.

SAE Aerospace Information Report AIR1871 provides valuable insight into lessons learned in the development, implementation, and operation of various health monitoring systems for propulsion engines and drive train systems. This document provides an overview of the lessons learned for ground-based systems, oil debris monitoring systems, lubrication systems, and Health and Usage Monitoring Systems (HUMS) for military and commercial programs. For each case study, this document presents a brief technical description, the design requirements, accomplishments, lessons learned, and future recommendations. The lessons learned presented in this document represent a fragment of the knowledge gained through experience when developing and implementing a propulsion health management system. Previous versions of this document contain additional lessons learned during the 1980’s and 1990’s that may be of additional value to the reader.

SAE Aerospace Information Report AIR1871 provides valuable insight into lessons learned in the development, implementation, and operation of various health monitoring systems for propulsion engines and drive train systems. This document provides an overview of the lessons learned for ground-based systems, oil debris monitoring systems, lubrication systems, and Health and Usage Monitoring Systems (HUMS) for military and commercial programs. For each case study, this document presents a brief technical description, the design requirements, accomplishments, lessons learned, and future recommendations. The lessons learned presented in this document represent a fragment of the knowledge gained through experience when developing and implementing a propulsion health management system. Previous versions of this document contain additional lessons learned during the 1980’s and 1990’s that may be of additional value to the reader.

This SAE Aerospace Information Report (AIR) discusses physical and functional integration of main engine and auxiliary power unit (APU) monitoring with other on-board systems. It includes General Considerations, Parameter Selection and Requirements, Signal Sources, Signal Conditioning, Data Processing, Data Storage, and Data Retrieval. Engine monitoring hardware and software are discussed so that they may be properly considered in an integrated design. Civil and military aviation applications are included and delineated where requirements differ.