Ram air turbine enhancement for auxiliary power unit replacement

M. Saad, Magedi Moh (2017) Ram air turbine enhancement for auxiliary power unit replacement. Doctoral thesis, Universiti Tun Hussein Onn Malaysia.


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Fossil fuels are currently the primary energy source of aircraft and cause harm to the environment. This study highlights the use of clean energy instead of fossil fuels in aircraft. This work aimed to study the possibility of dispensing auxiliary power unit (APU) in aircraft powered by fossil fuels to reduce air pollution and the total fuel cost used in aircraft. Multiple drawbacks were recorded from APU usage, such as relatively high operating cost, undesired emissions, and noise. In this project, ram air turbine (RAT), which are already equipped in aircraft, was enhanced to generate the amount of energy produced by APU. Two approaches were adopted in order to achieve the goal. The number of RAT units in the aircraft body were increased, and the classical RAT design was improved by adding a counter-rotating system (counter-rotating RAT - CRRAT). The design of RAT blades was based on blade element momentum (BEM) theory. The performance of RAT and CRRAT was analyzed using FLUENT software. The adopted numerical scheme was the Navier–Stokes equation with k–ω (SST) turbulence modeling. In order to numerically simulate the actual turbine operation, the dynamic mesh and user define function (UDF) were used to revolve the rotor turbine via wind. This study was performed in two stages. The first stage was conducted to evaluate the power produced from a single-rotor RAT. Three RATs were required to fulfill the APU power output, and the best location for RAT placement was under the wings and the belly of the aircraft. The second stage aimed to evaluate the amount of power generated from CRRAT and select the optimum axial distance of CRRAT. Results indicated that the optimum axial distance was 0.087 of rotor diameter, and the efficiency increased to 81.63% compared to that of the single-rotor RAT (conventional RAT). The power output of CRRAT placed at the optimum axial distance was assessed. The power produced by CRRAT was in positive agreement with simulation results. Thus, CRRAT could be used for all aircraft equipped with traditional RAT.

Item Type: Thesis (Doctoral)
Subjects: T Technology > TJ Mechanical engineering and machinery
T Technology > TA Engineering (General). Civil engineering (General) > TA174 Engineering design
T Technology > TJ Mechanical engineering and machinery > TJ266-267.5 Turbines. Turbomachines (General)
Divisions: Faculty of Mechanical and Manufacturing Engineering > Department of Mechanical Engineering
Depositing User: Mrs. Sabarina Che Mat
Date Deposited: 22 Jul 2021 07:18
Last Modified: 22 Jul 2021 07:18
URI: http://eprints.uthm.edu.my/id/eprint/338

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