Jet engine performance: Difference between revisions

Revision as of 02:38, 28 December 2024

Revision as of 19:34, 12 February 2025

Line 1:

{{Short description|Measurement indicator of fuel conversion}}

A '''jet engine performs''' by convertingconverts fuel into thrust. HowOne wellkey itmetric performsof performance is anthe indication[[thermal ofefficiency]]; whathow proportionmuch of itsthe chemical energy (fuel) goesis toturned waste.into Ituseful transferswork heat(thrust frompropelling burningthe fuelaircraft toat airhigh passingspeeds). throughLike thea engine.lot Inof doing[[heat soengine]]s, itjet producesengines thrusttend workto whennot propellingbe aparticularly vehicleefficient but(<50%); a lot of the fuel is "wasted".{{citation andneeded}} onlyIn appearsthe as1970s, heat.rconomic Propulsionpressure engineers aimdue to minimize the degradationrising cost of fuel energyresulted intoin unusable thermal energy. Increasedincreased emphasis on performanceefficiency improvements for commercial airliners came in the 1970s from the rising cost of fuel.

The meaning of jetJet engine performance has been phrased as 'the end product that a jet engine company sells'<ref>Gas Turbine Performance, Second Edition, Walsh and Fletcher 2004, {{ISBN|0 632 06434-X}}, Preface</ref> and, as such, criteria include thrust, and(specific) fuel consumption, life,[[time weight,between emissionsoverhauls]], diameter[[power-to-weight and costratio]]. PerformanceSome criteriamajor reflectfactors theaffecting levelefficiency of technology used ininclude the designengines of[[overall anpressure engine and the technology has been advancing continuously since the jet engine entered service in the 1940s. Categories of performance include performance improvementratio]], performanceit's deterioration,[[bypass performance retention, bare engine performance (uninstalled)ratio]] and performancethe whenturbine partinlet of an aircraft powerplant (installed)temperture.

Performance criteria reflect the level of technology used in the design of an engine, and the technology has been advancing continuously since the jet engine entered service in the 1940s. It is important to not just look at how the engine performs when it's brand new, but also how much the performance degrades after thousands of hours of operation. One example playing a major role is the creep in/of the rotor blades, resulting in the aeronautics industry utilizing [[directional solidification]] to manufacture turbine blades, and even making them out of a [[single crystal]], ensuring creep stays below permissible values longer. A recent development are [[ceramic matrix composite]] turbine blades, resulting in lightweight parts that can withstand high temperatures, while being less susceptible to creep.{{citation needed}}

JetThe enginefollowing performanceparameters (thrustthat andindicate fuelhow consumption)the foregine ais pilotperforming isare displayed in the cockpit: as [[engine pressure ratio]] (EPR), and [[exhaust gas temperature]] (EGT) orand fan speed (N1) and EGT. EPR and N1 are indicators for thrust., wheras EGT is an indicatorvital for fuelgauging flowthe buthealth moreof importantlythe is a health monitorengine<ref>"EGT margin indicates engine health"' pp. 5–11, Safety first The Airbus Safety magazine, February 2022</ref>, as it rises progressively with engine use over thousands of hours, as parts wear, until it reachesthe aengines has the limitingbe valueoverhauled.

The performance of an engine is calculated using a thermodynamic analysis of the engine cycle. It works out what happens inside the engine. The conditions inside the engine, together with the fuel used and thrust produced, may be shown in a convenient tabular form summarising the analysis.<ref name="doc">{{Cite web |title=A Variable Cycle Engine for Subsonic Transport Applications - PDF Free Download |url=https://docplayer.net/140309337-A-variable-cycle-engine-for-subsonic-transport-applications.html |access-date=2023-11-16 |website=docplayer.net}}</ref>

<!-- should I just delete the paragraph below? -->

The performance of an engine iscan calculated using a thermodynamic analysis of the engine cycle. It works outcalculates what happens insidewould thetake engine. The conditionsplace inside the engine. This, together with the fuel used and thrust produced, maycan be shown in a convenient tabular form summarising the analysis.<ref name="doc">{{Cite web |title=A Variable Cycle Engine for Subsonic Transport Applications - PDF Free Download |url=https://docplayer.net/140309337-A-variable-cycle-engine-for-subsonic-transport-applications.html |access-date=2023-11-16 |website=docplayer.net}}</ref>

==Introduction==