Abas Ab Wahab

An Evaluation of Economic Model for Assessing Aviation Environmental Impacts towards Airline Operations

Environmental concerns due to aviation emissions and noise have resulted in introduction of emission and noise charges imposed by airports to airline operators. In order to assess the impact of emission and noise towards the airlines operating costs, this paper presents the initial work in developing an economic model and explains the validation and application of the direct operating cost (DOC) estimation used by the model. A comparison with another two DOC estimation methods has also been performed. The results indicate that the estimated cost is in a good agreement with the data from the public domain despite the differences with data from other estimation methods due to the variation of approach adopted by each model. Finally, an inclusion of environmental charges in DOC is also presented, which shows the amount is relatively small. Nonetheless, in order to ensure a sustainable airline operations, further actions in reducing aviation emission and noise are essential.

Turbulence kinetic energy performance on wind turbine blade using CFD

Wind represents the kinetic energy of the atmosphere. Wind energy is currently supplying as much as 1% of the world electricity used, and could supply as much as 20% of global electricity in power and can be created through the use of wind turbines. Wind turbine blade is the most promising technology for the production of energy by using wind energy. Good design of wind turbine blade depends on performance of increasing to generate electricity which related with drag coefficient , lift coefficient and turbulence kinetic energy. However, the efficiency of wind turbine blade could be predicted by simulation due to flow streamline on wind turbine blade. This paper discuss the result obtain from simulation in CFD using CFX on NACA 4412 and NACA 4415.

Simulation Study on the Performance of Vertical Axis Wind Turbine

The present study considered the design improvement of Savonius rotor, in order to increase the efficiency of output power. An investigation was conducted to study the effect of geometrical configuration on the performance of the rotor in terms of coefficient of torque, coefficient of power and power output. Modification of conventional geometry has been designed by combining the effect of number of blades and shielding method. CFD simulation was conducted to analyze the flow characteristic and calculate the torque coefficient of all the rotor configurations. The continuity and Reynolds Averaged Navier-Stokes (RANS) equations and realizable k-ε epsilon turbulence model are numerically solved by commercial software Ansys-Fluent 14.0. The results obtained by transient and steady method for the conventional two bladed Savonius rotor are in agreement with those obtained experimentally by other authors and this indicates that the methods can be successfully applied for such analysis. The modified 3 and 4 bladed rotors with hybrid shielding method gave the highest maximum power coefficient which 0.37 at TSR 0.5 and output power exceed 4 watts with rotor dimensions of 0.2m width and 0.2m height. This blade configuration also is the best configuration by several percentages compared to the other model from the previous study

Impact of Operating and Health Conditions on a Helicopter Turbo-Shaft Hot Section Component Using Creep Factor

The paper investigates the effects of various gas turbine operating and health conditions on its hot section component’s creep life via a simple relative creep life parameter known as Creep Factor. Using the Creep Factor, the correlation between individual gas turbine operating and health parameter and component’s creep life was established and the weight of the impact was measured. Analytical-parametric-based creep life estimation model combined with the Creep Factor approach was developed and integrated with an existing engine performance model to allow the estimation of various hot section component creep lives and the computation of the Creep Factors. The impact analysis was carried out on the high pressure turbine blade of a model turbo-shaft helicopter engine. The results indicate that for a clean engine, the change in engine rotational speed was seen to provide the highest impact on changing the blade’s creep life consumption while for a degraded engine, the presence of compressor fouling has the highest threat in changing the blade’s creep life. The analysis also shows that the Creep Factor is a good indicator of creep life consumption and provides a good technique to rank the influencing factor according to the threat they imposed.

Assessment of wind energy potential in the capital city of Chad, N’Djamena

In this study, statistical analysis of a long term meteorological data of 10 years have been presented to reveal the potential of wind power as a source of energy generation in the capital of Chad, N’Djamena. The recent ten-year period wind data were collected from the Hassan Djamous International Airport at N’Djamena. The wind characteristics and wind energy potential were analyzed using Weibull distribution function. The results show that the values of the shape parameter k, and scale parameter c, varied over a wide range. The annual highest values of the Weibull shape parameter k, and scale parameter c, were 1.59 and 4.12 m/s respectively. It was also found that higher wind speeds occurred during dry season, i.e. November to July and the lower wind speeds occurred during the wet season, i.e. August to October. The annual average of the most probable wind speed and wind speed carrying maximum energy were respectively 1.86 m/s and 6.48 m/s. Likewise, the wind power density was ranging between 55.96 W/m2 ...

Aircraft LTO emissions regulations and implementations at European airports

Aviation affects the environment via the emission of pollutants from aircraft, impacting human health and ecosystem. Impacts of aircraft operations at lower ground towards local air quality have been recognized. Consequently, various standards and regulations have been introduced to address the related emissions. This paper discussed both environmental regulations by focusing more on the implementations of LTO emissions charges, an incentive-based regulation introduced in Europe as an effort to fill the gap in addressing the environmental issues related to aviation.

The Aerodynamics Investigation of Vortex Trap on Helicopter Blade

During helicopter forward flight, the retreating blade revolves at high angle of attack compared to advancing blade in order to balance the lift and also to stabilise the helicopter. However, due to the aerodynamics limitations of the retreating blade at forward flight, stall may occur at high angle of attack compared with the advancing blade. This phenomenon is dangerous for pilot when controlling and balancing the helicopter while flying against strong wind. This paper investigates the capabilities of introducing multiple vortex traps on the upper surface of the helicopter airfoil in order to delay the stall angle of retreating helicopter blade. Blade Element Theory (BET) was applied to scrutinize the lift force along the helicopter blade. Computational Fluid Dynamic (CFD) analyses using the Shear-Stress Transport (SST) turbulence model was carried out to investigate the effect of groove on delaying the stall and to predict the separation of flow over the airfoil. Based on the CFD analyses, the optimization of the groove was done by analyzing the numbers and locations of the grooves. Finally, the results from both BET and the CFD analyses were utilised to obtain the lift force achieved by the vortex trap. The study showed that the presence of multiple vortex traps has successfully increased the lift coefficient and most importantly, delaying the stall angle.

Towards the conceptual design and construction of an unmanned small-scale air-land-water vehicle

This paper describes towards the conceptual design and construction of an unmanned small-scale air-land-water vehicle. Conceptual design refers to the initial design of parts followed by the assemblies to form components of the vehicle. The vehicle features a unique device system consists of four main components; a coaxial rotor set, propeller, suspension, and pontoon set. It independence for another when fly on-air, move on-land, and capable of traversing across aquatic. The design procedure includes design requirements followed by solid modeling and design parametrization concept using Solid Works. The proposed design specifications and integration of vehicle systems as well as experimental evaluations were used to construct a fully functional unmanned vehicle, namely Unmanned Small-scale Air-Land-Water Vehicle (USALWaV). Various component to support maneuver on three mode operation (i.e. ground, air and water) feature has been constructed to verify the feasibility and reliability of USALWaV. The conceptual design and construction of an unmanned small-scale air-land-water vehicle were illustrated and verified with an integration of the vehicle system.