A.R. Abu Talib

Performance Evaluation of a Small-Scale Turbojet Engine Running on Palm Oil Biodiesel Blends

The experimental and simulated performance of an Armfield CM4 turbojet engine was investigated for palm oil methyl ester biodiesel (PME) and its blends with conventional Jet A-1 fuel. The volumetric blends of PME with Jet A-1 are 20, 50, 70, and 100% (B20, B50, B70, and B100). Fuel heating values (FHV) of each fuel mixture were obtained by calorimetric analysis. The experimental tests included performance tests for Jet A-1 and B20, while the performances of B50 to B100 were simulated using GasTurb 11 analytical software. In terms of maximum measured thrust, Jet A-1 yielded the highest value of 216u2009N, decreasing by 0.77%, 4%, 8%, and 12% with B20, B50, B70, and B100. It was found that B20 produced comparable results compared to the benchmark Jet A-1 tests, particularly with thrust and thermal efficiency. Slight performance penalties occurred due to the lower energy content of the biodiesel blends. The efficiency of the combustor improved with the addition of biodiesel while the other component efficiencies remained collectively consistent. This research shows that, at least for larger gas turbines, PME is suitable for use as an additive to Jet A-1 within 50% blends.

Ballistic impact velocity response of carbon fibre reinforced aluminium alloy laminates for aero-engine

Aerospace and other industries use fibre metal laminate composites extensively due to their high specific strength, stiffness and fire resistance, in addition to their capability to be tailored into different forms for specific purposes. The behaviours of such composites under impact loading is another factor to be considered due to the impacts that occur in take-off, landing, during maintenance and operations. The aim of the study is to determine the specific perforation energy and impact strength of the fibre metal laminates of different layering pattern of carbon fibre reinforced aluminium alloy and hybrid laminate composites of carbon fibre and natural fibres (kenaf and flax). The composites are fabricated using the hand lay-up method in a mould with high bonding polymer matrix and compressed by a compression machine, cured at room temperature for one day and post cure in an oven for three hours. The impact tests are conducted using a gun tunnel system with a flat cylindrical bullet fired using a helium gas at a distance of 14 inches to the target. Impact and residual velocity of the projectile are recorded by high speed video camera. Specific perforation energy of carbon fibre reinforced aluminium alloy (CF+AA) for both before and after fire test are higher than the specific perforation energy of the other composites considered before and after fire test respectively. CF +AA before fire test is 55.18% greater than after. The same thing applies to impact strength of the composites where CF +AA before the fire test has the highest percentage of 11.7%, 50.0% and 32.98% as respectively compared to carbon fibre reinforced aluminium alloy (CARALL), carbon fibre reinforced flax aluminium alloy (CAFRALL) and carbon fibre reinforced kenaf aluminium alloy (CAKRALL), and likewise for the composites after fire test. The considered composites in this test can be used in the designated fire zone of an aircraft engine to protect external debris from penetrating the engine shield due to higher values of impact strength and specific perforation energy as highlighted by the test results.

Temperature and heat flux measurement techniques for aeroengine fire test: a review

This review is made of studies whereby some types of fire test measuring instrument were compared based on their mode of operation, sensing ability, temperature resistance and their calibration mode used for aero-engine applications. The study discusses issues affecting temperature and heat flux measurement, methods of measurement, calibration and uncertainties that occur in the fire test. It is found that the temperature and heat flux measurements of the flame from the standard burner need to be corrected and taken into account for radiation heat loss. Methods for temperature and heat flux measurements, as well as uncertainties analysis, were also discussed.

Towards an aerogel-based coating for aerospace applications: reconstituting aerogel particles via spray drying

Silica aerogel is an ultralight and highly porous nano-structured ceramic with its thermal conductivity being the lowest than any solids. Although aerogels possess fascinating physical properties, innovative solutions to tackle todays problems were limited due to their relative high manufacturing cost in comparison to conventional materials. Recently, some producers have brought forward quality aerogels at competitive costs, and thereby opening a panoply of applied research in this field. In this paper, the feasibility of spray-drying silica aerogel to tailor its granulometric property is studied for thermal spraying, a novel application of aerogels that is never tried before in the academic arena. Aerogel-based slurries with yttria stabilised zirconia as a secondary ceramic were prepared and spray-dried according to modified T aguchi experimental design in order to appreciate the effect of both the slurry formulation and drying conditions such as the solid content, the ratio of yttria stabilised zirconia:aerogel added, the amount of dispersant and binder, inlet temperature, atomisation pressure and feeding rate on the median particle size of the resulting spray-dried powder. The latter was found to be affected by all the aforementioned independent variables at different degree of significance and inclination. Based on the derived relationships, an optimised condition to achieve maximum median particle size was then predicted.

Three dimensional numerical investigations on the heat transfer enhancement in a triangular facing step channels using nanofluid

In this paper, laminar flow for the distilled and SiO2-water nanofluid flow and heat transfer were numerically investigated in three-dimensional triangular facing-step channel. The nanoparticle volume fraction and Reynolds number considered are in the range of 0-1% and 100-1500, respectively. Numerical solutions are obtained by using finite difference method to solve the governing equations. The effects of the volume fraction of nanoparticle, triangular facing-step channel amplitude height, wavelength and Reynolds number on local skin-friction coefficient, average Nusselt number and enhancement of heat transfer are presented and discussed. The results show that the Nusselt number and friction coefficient increases as the amplitude height of triangle channel increases. As the nanoparticle volume fraction increases, the Nusselt number is also found to be significantly increased, accompanied by only a slight increase in the friction coefficient. In addition, it is found that the heat transfer enhancement mainly depends on the amplitude height of the triangle wall, nanoparticle volume fraction and Reynolds number rather than the wavelength.

An analytical study on the performance of the organic Rankine cycle for turbofan engine exhaust heat recovery

Due to energy shortage and global warming, issues of energy saving have become more important. To increase the energy efficiency and reduce the fuel consumption, waste heat recovery is a significant method for energy saving. The organic Rankine cycle (ORC) has great potential to recover the waste heat from the core jet exhaust of a turbofan engine and use it to produce power. Preliminary study of the design concept and thermodynamic performance of this ORC system would assist researchers to predict the benefits of using the ORC system to extract the exhaust heat engine. In addition, a mathematical model of the heat transfer of this ORC system is studied and developed. The results show that with the increment of exhaust heat temperature, the mass flow rate of the working fluid, net power output and the system thermal efficiency will also increase. Consequently, total consumption of jet fuel could be significantly saved as well.

The Influence of impact on Composite Armour System Kevlar-29/polyester-Al2O3

An experimental investigation of high velocity impact responses of composite laminated plates using a helium gas gun has been presented in this paper. The aim of this study was to develop the novel composite structure that meets the specific requirements of ballistic resistance which used for body protections, vehicles and other applications. Thus the high velocity impact tests were performed on composite Kevlar-29 fiber/polyester resin with alumina powder (Al2O3). The impact test was conducted by using a cylindrical steel projectile of 7.62mm diameter at a velocity range of 160-400 m/s. The results (shown in this work) are in terms of varying plate thickness and the amount of energy absorbed by the laminated plates meanwhile we obtained that the 12mm thickness of composite plate suitable for impact loading up to 200m/s impact velocity. Therefore this composite structure (it is used to reduce the amount of Kevlar) considered most economical armoure products. We used the ANSYS AUTODYN 3D- v.12 software for our simulations. The results have been obtained a4.1% maximum errors with experimental work of energy absorption.

Significance of Solar Radiation on Aircraft Engine Under Cowl Temperature

Literature on solar radiation effect on aircraft engine under cowl temperature is very limited. This paper describes an experimental work to quantify the effect of solar radiation levels on a range of aircraft engine nacelle surface finish and orientation in a representative way. The investigation was carried out on four aircraft engine nacelle representations during static ground running conditions. The nacelle models were fabricated using aluminium and surface coated with four different aircraft paint finish. Thermocouples were mounted at locations around the nacelle model. Effects of different solar radiation levels on the temperature distributions on the nacelles were presented. The contributions of radiative and convective heat transfer on the overall distribution of temperature inside the under cowl were quantified.Copyright