A Study of the Magnetic Field inside the Discharge Chamber of an Ion Thruster

One of the characteristics that ion thrusters are known for is its high efficiency.  In the process of designing an ion thruster the study of the magnetic field alongside the discharge chamber is crucial to achieve optimal efficiency. This work shows the importance of taking into consideration the materials in the vicinities of the magnets as well as the expected intensity of the magnetitic field inside the thrusters in study. The procedures used to study the magnetic field in the open software used are described in this work. The thruster in study is an oversizing done of a previous one, so the desired results are to obtain the ones obtained for the original engine. Keywords: Ion thruster, High efficiency, Magnetic fiel

Designing an Eddy Current Brake for Engine Testing

An Eddy Current Brake (ECB) has several advantages making it suitable for using in a dynamometer for testing engines. In this paper, a model is presented which considers the electromagnet’s core saturation to predict the performance of an ECB. A design is then proposed for a dual coil, single rotor ECB that meets the design requirement to dissipate a power of 30 kW at 3000 rpm. A comparison between the results obtained for a few different materials considered to be used in the rotating disc are also presented. Keywords: Antimagnetic force, Dynamometer, Eddy current brake, MATLAB Mode

Substitution of a Conventional Gas Turbine By a HT-PEMFC APU: Feasibility Study

The aviation industry is increasing leading to a harmful environmental impact. APU is liable for 20% of airport ground-based emissions, 50% of aircraft maintenance costs and more than 5% of the daily fuel consumption [1]. Aware of this growing problem and its consequences, research should be conducted targeting new, non-polluting energy sources capable of meeting or even exceeding the aircraft’s electrical needs. With this in mind, the main goal of this article was to analyze the feasibility of implementing a HT-PEMFC system as a more sustainable alternative for the gas turbine APU in  an Airbus A320. The fuel used was methane which requires a fuel processor to convert it into hydrogen before entering the fuel cell. The maximum output work of this methane-supplied system is estimated at 250 kW. Therefore, a fuel processor and a fuel cell mathematical models were required. The two models along with the thermodynamic analysis were performed in MATLAB. The aims of this project were to evaluate fuel processing of methane and its conversion into electric energy through a fuel cell; to perform the thermodynamic analysis of HT-PEMFC APU based on the first and second laws of thermodynamics; and estimate the total weight, emissions and fuel consumption of the HT- PEMFC APU. The results of this research were  very encouraging, as it shows that the breakeven weight of the HT-PEMFC, for a mass increment of 854 kg, was compensated by a fuel efficiency of ∼2.7 times the conventional APU. Keywords: APU, HT-PEMFC, Fuel cel

Prediction of Pollutants Emissions in a CFM56-3 Combustor, Using Large Eddy Simulation

In the present work a CFD simulation was performed using a CFM56-3 combustor.   It was intended to simulate the combustion and emission of pollutants (CO2, CO, UHC and NOx) from the different jet fuels ( Jet A, Jet B and TS-1), when burning these through ICAO’s LTO cycle. Being this a continuity study, the CAD model of CFM56-3 made by Oliveira [5] was used. The mesh was constructed with HELYX-OS software and the numerical study was made using the commercial software ANSYS Fluent16.2. It can be concluded, amongst all the fuels simulated that increasing the power produces higher NOx. There was also an erratic behaviour in the emissions of UHC and CO results, because an empiric model was used and not a detailed chemical model. Keywords: Jet Fuels, ANSYS Fluent, Pollutants emissions, ICAO’s LTO cycle, CFM56-

Theoretical Analysis of Ammonium-perchlorate Based Composite Propellants with RDX Containing Small Size Particles of Beryllium

Rocket engines have been developed for at least the last six decades. There is a need to improve the actual solid propellant grain for rocket engines through the addiction of metallic fuels in the mixture as well as the addiction of energetic binders to stabilize the combustion. The rocket industry expects the launchers to be reliable, to be faster, stable and to have longer times of operation for the most possible payload weight (operational envelope). New propellants should have optimized ignition and combustion time rates reducing the possibility of negative oxygen balance thus reducing detonation process. Deflagration process should be optimized for best performance of the rocket. In this evolution, small quantities of explosives have been used in the propellant in order to increase the operational burning time, hence, the specific impulse. Adding metallic fuels such as aluminum, boron or beryllium on double based composite propellants and ammonium perchlorate are expected to increase the propellant density over chemical stability and aging resistance. The study of heterogeneous propellants containing large amounts of fine beryllium and ammonium perchlorate,   it is necessary to understand the combustion products so to a proper evaluation of specific impulse, Mach number and mass flow of the mixture. In this study a mixture with nitramides (RDX – Cyclotrimethylene trinitramide) and ammonium perchlorate was analyzed with and without the addiction of small size particles of beryllium using a numerical algorithm. Therefore, this study relates the influence of beryllium  in the performance parameters of ammonium perchlorate based composite propellants. Keywords: Propellant, Rocket engine, RDX, Ammonium perclorat

A Study of the Magnetic Field Inside the Discharge Chamber of an Ion Thruster

One of the characteristics that ion thrusters are known for is its high efficiency.  In the process of designing an ion thruster the study of the magnetic field alongside the discharge chamber is crucial to achieve optimal efficiency. This work shows the importance of taking into consideration the materials in the vicinities of the magnets as well as the expected intensity of the magnetitic field inside the thrusters in study. The procedures used to study the magnetic field in the open software used are described in this work. The thruster in study is an oversizing done of a previous one, so the desired results are to obtain the ones obtained for the original engine. Keywords: Ion thruster, High efficiency, Magnetic fiel

Prediction of Pollutants Emissions in A CFM56-3 Combustor, Using Large Eddy Simulation

In the present work a CFD simulation was performed using a CFM56-3 combustor.   It was intended to simulate the combustion and emission of pollutants (CO2, CO, UHC and NOx) from the different jet fuels ( Jet A, Jet B and TS-1), when burning these through ICAO's LTO cycle. Being this a continuity study, the CAD model of CFM56-3 made by Oliveira [5] was used. The mesh was constructed with HELYX-OS software and the numerical study was made using the commercial software ANSYS Fluent16.2. It can be concluded, amongst all the fuels simulated that increasing the power produces higher NOx. There was also an erratic behaviour in the emissions of UHC and CO results, because an empiric model was used and not a detailed chemical model. Keywords: Jet Fuels, ANSYS Fluent, Pollutants emissions, ICAO's LTO cycle, CFM56-

Substitution of A Conventional Gas Turbine by A HT-PEMFC APU: Feasibility Study

The aviation industry is increasing leading to a harmful environmental impact. APU is liable for 20% of airport ground-based emissions, 50% of aircraft maintenance costs and more than 5% of the daily fuel consumption [1]. Aware of this growing problem and its consequences, research should be conducted targeting new, non-polluting energy sources capable of meeting or even exceeding the aircraft's electrical needs. With this in mind, the main goal of this article was to analyze the feasibility of implementing a HT-PEMFC system as a more sustainable alternative for the gas turbine APU in  an Airbus A320. The fuel used was methane which requires a fuel processor to convert it into hydrogen before entering the fuel cell. The maximum output work of this methane-supplied system is estimated at 250 kW. Therefore, a fuel processor and a fuel cell mathematical models were required. The two models along with the thermodynamic analysis were performed in MATLAB. The aims of this project were to evaluate fuel processing of methane and its conversion into electric energy through a fuel cell; to perform the thermodynamic analysis of HT-PEMFC APU based on the first and second laws of thermodynamics; and estimate the total weight, emissions and fuel consumption of the HT- PEMFC APU. The results of this research were  very encouraging, as it shows that the breakeven weight of the HT-PEMFC, for a mass increment of 854 kg, was compensated by a fuel efficiency of ∼2.7 times the conventional APU. Keywords: APU, HT-PEMFC, Fuel cel