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Mechanical Engineering Commons

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Articles 1 - 4 of 4

Full-Text Articles in Mechanical Engineering

Continuously Variable Rotorcraft Propulsion System: Modelling And Simulation, Naveen Kumar Vallabhaneni Aug 2011

Continuously Variable Rotorcraft Propulsion System: Modelling And Simulation, Naveen Kumar Vallabhaneni

Masters Theses

This study explores the variable speed operation and shift response of a prototype of a two speed single path CVT rotorcraft driveline system. Here a Comprehensive Variable Speed Rotorcraft Propulsion system Modeling (CVSRPM) tool is developed and utilized to simulate the drive system dynamics in steady forward speed condition. This investigation attempts to build upon previous variable speed rotorcraft propulsion studies by:

1) Including fully nonlinear first principles based transient gas-turbine engine model

2) Including shaft flexibility

3) Incorporating a basic flight dynamics model to account for interactions with the flight control system.

Through exploring the interactions between the various ...


Effects Of Supercooled Water Ingestion On Engine Performance, Rick Hutchings Aug 2011

Effects Of Supercooled Water Ingestion On Engine Performance, Rick Hutchings

Masters Theses

An aircraft will encounter freezing rain, snow, and ice during ground operation and flight. In cold conditions, ice may form on th einlet and internal stators and rotors of the gas turbine engine. When ice accumulates on blades (and/or stators), the aerodynamic characteristics of the blades change due to the altered size, shape, and roughness. This change causes the blade to no longer operate at its design point and decreases compressor performance. Therefore, characterization of the aerodynamic performance is required to define the associated losses due to the effects of supercooled liquid water ingestion. This characterization can be accomplished ...


Modeling And Analysis Of Turbojet Compressor Inlet Temperature Measurement System Performance, Brian A Binkley May 2011

Modeling And Analysis Of Turbojet Compressor Inlet Temperature Measurement System Performance, Brian A Binkley

Masters Theses

Accurate measurement of turbine engine compressor inlet total temperature is paramount for controlling engine speed and pressure ratio. Various methods exist for measuring compressor inlet total temperature on turbojet engines with hydromechanical control. One method involves the use of an ejector-diffuser system (eductor) to pull air from the engine inlet in order to measure the incoming total temperature. Analysis of historical test data has revealed that the inlet temperature measurement can be biased at certain flight conditions causing engine mis-scheduling and off-nominal engine operation. This bias is characterized primarily by adverse heat transfer effects and secondly by poor flow quality ...


Cross-Flow, Staggered-Tube Heat Exchanger Analysis For High Enthalpy Flows, Gary L. Hammock May 2011

Cross-Flow, Staggered-Tube Heat Exchanger Analysis For High Enthalpy Flows, Gary L. Hammock

Masters Theses

Cross flow heat exchangers are a fairly common apparatus employed throughout many industrial processes. For these types of systems, correlations have been extensively developed. However, there have been no correlations done for very high enthalpy flows as produced by Arnold Engineering Development Center’s (AEDC) H2 facility. The H2 facility uses a direct current electric arc to heat air which is then expanded through a converging-diverging nozzle to impart a supersonic velocity to the air. This high enthalpy, high temperature air must be cooled downstream by the use of a cross flow heat exchanger.

It is of interest to evaluate ...