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

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

Comparative genetic stock structure in three species of commercially exploited Indo-Malay Carangidae (Teleosteii, Perciformes)

We examine genetic structuring in three commercially important species of the teleost family Carangidae from Malaysian waters: yellowtail scad Atule mate, bigeye scad Selar crumenophthalmus and yellowstripe scad Selaroides leptolepis, from the Indo‐Malay Archipelago. In view of their distribution across contrasting habitats, we tested the hypothesis that pelagic species display less genetic divergence compared with demersal species, due to their potential to undertake long‐distance migrations in oceanic waters. To evaluate population genetic structure, we sequenced two mitochondrial (mt)DNA [650bp of cytochrome oxidase I (coI), 450bp of control region (CR)] and one nuclear gene (910bp of rag1) in each species. One hundred and eighty samples from four geographical regions within the Indo‐Malay Archipelago including a population of yellowtail from Kuwait were examined. Findings revealed that the extent of genetic structuring among populations in the semi‐pelagic and pelagic, yellowtail and bigeye were lower than demersal yellowstripe, consistent with the hypothesis that pelagic species display less genetic divergence compared with demersal species. The yellowtail phylogeny identified three distinct clades with bootstrap values of 86–99% in mtDNA and 63–67% in rag1. However, in bigeye, three clades were also observed from mtDNA data while only one clade was identified in rag1 dataset. In yellowstripe, the mtDNA tree was split into three closely related clades and two clades in rag1 tree with bootstraps value of 73–99% and 56% respectively. However, no geographic structure appears in both mtDNA and rag1 datasets. Hierarchical molecular variance analysis (AMOVA), pair wise FST comparisons and the nearest‐neighbour statistic (Snn) showed significant genetic differences among Kuwait and Indo‐Malay yellowtail. Within the Indo‐Malay Archipelago itself, two distinct mitochondrial lineages were detected in yellowtail suggesting potential cryptic species. Findings suggests varying degrees of genetic structuring, key information relevant to management of exploited stocks, though more rapidly evolving genetic markers should be used in future to better delimit the nature and dynamics of putative stock boundaries

Characterisation of particle mass and number concentration on the east coast of the Malaysian Peninsula during the northeast monsoon

Particle mass concentrations (PM10, PM2.5 and PM1) and particle number concentration ((PNC); 0.27 μm ≤ Dp ≤ 34.00 μm) were measured in the tropical coastal environment of Bachok, Kelantan on the Malaysian Peninsula bordering the southern edge of the South China Sea. Statistical methods were applied on a three-month hourly data set (9th January to 24th March 2014) to study the influence of north-easterly winds on the patterns of particle mass and PNC size distributions. The 24-h concentrations of particle mass obtained in this study were below the standard values detailed by the Recommended Malaysian Air Quality Guideline (RMAQG), United States Environmental Protection Agency (US EPA) and European Union (EU) except for PM2.5, which recorded a 24-h average of 30 ± 18 μg m-3 and exceeded the World Health Organisation (WHO) threshold value (25 μg m-3). Principal component analysis (PCA) revealed that PNC with smaller diameter sizes (0.27-4.50 μm) showed a stronger influence, accounting for 57.6% of the variability in PNC data set. Concentrations of both particle mass and PNC increased steadily in the morning with a distinct peak observed at around 8.00 h, related to a combination of dispersion of accumulated particles overnight and local traffic. In addition to local anthropogenic, agricultural burning and forest fire activities, long-range transport also affects the study area. Hotspot and backward wind trajectory observations illustrated that the biomass burning episode (around February-March) significantly influenced PNC. Meteorological parameters influenced smaller size particles (i.e. PM1 and Dp (0.27-0.43 μm)) the most

Factors affecting commencement and cessation of smoking behaviour in Malaysian adults

<p>Abstract</p> <p>Background</p> <p>Tobacco consumption peak in developed countries has passed, however, it is on the increase in many developing countries. Apart from cigarettes, consumption of local hand-rolled cigarettes such as <it>bidi </it>and <it>rokok daun </it>are prevalent in specific communities. Although factors associated with smoking initiation and cessation has been investigated elsewhere, the only available data for Malaysia is on prevalence. This study aims to investigate factors associated with smoking initiation and cessation which is imperative in designing intervention programs.</p> <p>Methods</p> <p>Data were collected from 11,697 adults by trained recording clerks on sociodemographic characteristics, practice of other risk habit and details of smoking such as type, duration and frequency. Smoking commencement and cessation were analyzed using the Kaplan-Meier estimates and log-rank tests. Univariate and multivariate Cox proportional hazard regression models were used to calculate the hazard rate ratios.</p> <p>Results</p> <p>Males had a much higher prevalence of the habit (61.7%) as compared to females (5.8%). Cessation was found to be most common among the Chinese and those regularly consuming alcoholic beverages. Kaplan-Meier plot shows that although males are more likely to start smoking, females are found to be less likely to stop. History of betel quid chewing and alcohol consumption significantly increase the likelihood of commencement (p < 0.0001), while cessation was least likely among Indians, current quid chewers and kretek users (p < 0.01).</p> <p>Conclusions</p> <p>Gender, ethnicity, history of quid chewing and alcohol consumption have been found to be important factors in smoking commencement; while ethnicity, betel quid chewing and type of tobacco smoked influences cessation.</p

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

Strength behaviour of silica aerogel/thermoset polymer with reinforced fibre-metal laminate composites for aero-engine firewall

The study deals with the mechanical and impact properties based on tensile, compressive, flexural and impacts strength of three composites of aluminium alloy 2024-T3, kenaf fibre and three types of silica aerogel (Hamzel®, Enova® IC3100 and GEA^(TM) 0.125). The main aim of this study is to produce an eco-friendly composites and investigate the mechanical and impact properties of kenaf fibre-metal laminate with different types of silica aerogel/epoxy coating. The composites were made from metal, natural fibre, silica aerogel and epoxy resin/hardener. The mechanical test was conducted using universal testing machine that uses the ASTM standard and the impact test conducted using a helium gas gun tunnel. The result of mechanical properties test shows an improvement in the strengths where Hamzel® metal laminate shows higher values of 10-20% tensile strength and 13-30% tensile modulus than Enova® IC3100 and GEA^(TM) 0.125 metal laminate composites respectively. There are negligible differences among the composites in terms of compressive strength and modulus, while a little difference was recorded on flexural strength and modulus of the three composite with Enova® IC3100 metal laminate composites having the highest value due to the properties of silica aerogel used. For the impact strength and specific perforation energy, there is little difference in the entire composite with Enova® IC3100 metal laminate composites as the most impact strength. The study shows that application of aerogel on metal and reinforced fibre will produced a high strength composite that can be used to substitute the synthetic fibre components in aircraft, automobile and in other component for industrial purposes

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 216 N, 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

Thermal Analysis of Al2O3–water Ethylene Glycol Mixture Nanofluid for Single PEM Fuel Cell Cooling Plate: An Experimental Study

Thermal enhancement through application of nanofluid coolant in a single cooling plate of Polymer Electrolyte Membrane (PEM) fuel cell was experimentally investigated and reported in this paper. The study focuses on 0.1 and 0.5% volume concentrations of Al2O3 dispersed in 60:40 and 50:50 of water (W)–ethylene glycol (EG) mixtures as coolant in a carbon graphite PEM fuel cell cooling plate. The study was conducted in a cooling plate with 22 parallel mini channels and large fluid distributors under constant heat load of 100 W. The effect of different flow rates to heat transfer enhancement and fluid flow in Reynolds number range of 20–120 was observed. Positive heat transfer enhancement was obtained where the heat transfer was improved up to 23% and 21% for 0.5% concentration Al2O3 nanofluid in 60:40 and 50:50 (W:EG) consecutively as compared to the base fluid. However, higher pressure drop was also experienced as much as 17% and 20% for 0.5% concentration Al2O3 in 60:40 and 50:50 (W:EG) consecutively as compared to the base fluid. Combination of both heat transfer enhancements and pressure drop demerits was then analyzed using advantage ratio. The results implied that 0.1% Al2O3 in 60:40 (W:EG) is the most advantageous nanofluid candidate followed by 0.1% Al2O3 in 50:50 (W:EG). Both nanofluids have advantage ratio values of greater than 1