No description available.

No description available.

No description available.

No description available.

No description available.

The oil circuit of a jet engine is required to lubricate and cool mechanical parts. The oil is pumped from the oil tank and flows through heat exchangers. Then it is injected on the bearings for lubrication and cooling, before being scavenged at the bottom of the sumps and finally flows back to the oil tank. During flight, the volume of oil inside the tank fluctuates depending on many parameters like the engine rotation speed and the oil temperature to name but a few. The flow inside the sumps is diphasic with oil and air mixing up. The physical phenomena taking place in the oil circuit are complex and understanding them is essential to size an oil circuit for a new engine design. Mass is a critical factor in aviation and being able to design accordingly an oil circuit is a valuable asset.This work focuses on improving a 1D model predicting the evolution of the oil level in the tank. The model relies on the geometry of the engine, the architecture of the oil circuit and real flight data provided by the airline companies. This data contains flight parameters such as engine rotation speed, oil temperature and pressure. The prediction is then compared with the real volume of oil in the tank measured during the flight. The model is compared to experimental data to access its accuracy. Finally, the model is adapted to three different engines produces by Safran to test its robustness to geometry changes. / Oljekrets behövs i en jetmotor i syfte att smörja och kyla dess inre mekaniska komponenter. Oljan som pumpas från reservoaren passerar igenom värmeväxlare. Oljan injiceras sedan på kullagren som kräver kontinuerlig smörjning och kylning innan den når sitt slutförlopp i botten av tråget där den filtreras och dirigeras tillbaka till reservoaren. Oljevolymen i reservoaren varierar under färd, och är beroende av parametrar som motorns rotationshastighet, oljetemperatur och med mera. Flödet i tråget är tvåfasisk där olja och luft blandas samman. De fysiska fenomenen som inträffar i oljekretsen är komplexa och förståelse för dessa är essentiell för att kunna dimensionera kretsen för en ny motordesign. Då massa är en viktig aspekt inom flygindustrin så är det ideellt att kunna dimensionera och designa en oljekrets utefter ett givet masskriterium.Detta arbete fokuserar på att förbättra en endimensionell modell som predicerar den periodiska variansen i oljenivån i reservoaren. Modellen beror av motorgeometrin, oljekretsens struktur och realtidsflygdata givna från fåtals flygbolag. Dessa data innehåller flygparametrar såsom motorns rotationshastighet, oljetemperatur och oljetryck. De predicerade beteenden jämfördes sedan med den faktiska oljevolymen i reservoaren uppmätt under färd. Som verifikation och överensstämmelse jämfördes modellen med experimentella data. Slutligen är denna modell anpassad efter tre motormodeller från Safran i syfte att testa dess robusthet med avseende på geometriska variationer.

Thesis. 1975. M.S.--Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. / Includes bibliographical references. / by David L. Akin. / M.S.

No description available.

Gas turbines are widely used as power sources in many industrial and transportation applications. This kind of engine is the most preferred prime movers in aircrafts, power plants and some marine vehicles. They have different configurations according to their mechanical constructions such as turbo-prop, turbo-shaft, turbojet, etc. These engines have different efficiencies and specifications and some advantages and disadvantages compared to Otto-Cycle engines. In this thesis, a small turbojet engine is investigated in order to find different control algorithms. AMT Olympus HP small turbojet engine has been used to determine the mathematical model of a gas turbine engine. Some important experimental data were taken from AMT Olympus engine by making many experiments. All components of the engine have been modeled by using laws of thermodynamics and some arithmetic calculations such as numerical solution of nonlinear differential equations, digitizing compressor and turbine map etc. This mathematical model is employed to create control algorithm of the engine. At first, standard control strategies had been considered such as P (proportional), PI (proportional integral), and PID (proportional-integral-differential) controllers. Because of the nonlinearities in gas turbines, standard control algorithms are not commonly used in literature. At the second stage fuzzy logic controllers have been designed to control the engine efficiently. This control algorithm was combined with mathematical of the engine in MATLAB environment and input-output relations were investigated. Finally, fuzzy logic control algorithm was embedded into an electronic controller.

No description available.