A two-component CFD studies of the effects of H2, CNG, and diesel blend on combustion characteristics and emissions of a diesel engine

Numerical simulations were conducted on a Ricardo Hydra diesel engine which is single cylinder engine and uses direct injection method. This study was performed by using a two-dimensional CFD code to examine the combustion characteristics and emissions of a diesel engine in diesel-CNG and diesel-H2 dual-fuel operations, as well as in the diesel-CNG-H2 tri-fuel operation at various air-fuel ratios. The results indicate that the peak in-cylinder pressure and peak temperature were increased with the addition of gaseous fuels at low and medium values of exceeds air. Compared with Diesel-H70-N30 for tri-mode and Diesel-H2 for dual mode, it is observed that there were no effects on the peak temperature at high exceed air. At 2.4 exceed air, the peak pressure increases by means of adding the limit value of hydrogen, such as H30-N70 and H50-N50, to CNG and it begins to decrease with H70-N30 and H2-Diesel operations. Diesel-H2-CNG operations decrease CO/CO2 emissions compared with Diesel-CNG operation and decrease NO emission compared with Diesel-H2 operation at every exceed air. The reduction in CO/CO2 emissions was suggested at high hydrogen fraction in CNG (H70-N30) with all exceeds air whereas low hydrogen fraction in CNG (H30-N70) can repress uncontrolled hydrogen combustion and further limit the increment of NO emission

High velocity impact response of Kevlar-29/epoxy and 6061-T6 aluminum laminated panels

The high velocity impact response of composite laminated plates has been experimentally investigated using a nitrogen gas gun. Tests were undertaken on sandwich structures based on Kevlar-29 fiber/epoxy resin with different stacking sequence of 6061-T6 Al plates. Impact testing was conducted using cylindrical shape of 7.62 mm diameter steel projectile at a range of velocities (180–400 m/s) were investigated to achieve complete perforation of the target. The numerical parametric study of ballistic impact caused by same conditions in experimental work is undertaken to predict the ballistic limit velocity, energy absorbed by the target and comparison between simulation by using ANSYS Autodyn 3D v.12 software and experimental work and study the effects of shape of the projectile with different (4, 8 and 12 mm) thicknesses on ballistic limit velocity. The sequence of Al plate position (front, middle and back) inside laminate plates of composite specimen was also studied. The Al back stacking sequence plate for overall results obtained was the optimum structure to resist the impact loading. The results obtained hereby are in good agreement with the experimental (maximum error of 3.64%) data where it has been shown that these novel sandwich structures exhibit excellent energy absorbing characteristics under high velocity impact loading conditions. Hence it is considered suitable for applications of armor system

Influence of cut-out hole on multi-layer Kevlar-29/epoxy composite laminated plates

This paper presented the effect of cutout hole on multi layer of Kevlar-29/epoxy composite laminated plates this effect occurred and fiber orientation angle. An experimental procedure was developed to study the performance of these effects under quasi-static compressive and tensile load using a servo-hydraulic testing machine. The work involved investigation on the variety of orientation angles of Kevlar-29 fiber. The ultimate load of failure for each Kevlar-29/epoxy laminated plates had been determined and specified the optimum angle orientation and the load reduction due to the effect of fiber orientation angle (+45°/−45°) was low in the case for compared (0°/90°) orientation angle of fiber. To simulate this problem the researcher used Explicit Mesh for AUTODYN under ANSYS-12.1 software, where the researcher found that the results obtained via this simulation agreed reasonably well with the experimental results and the maximum difference between the experimental conditions and the simulation was 5.8%

Lecture-Centred or Student-Centered: A Case Study in a Public University

This study is aimed to investigate the current practice of teaching methods among lecturers in Universiti Teknologi Malaysia. A total of 357 lecturers participated in this study. The result showed that the general practice was influenced by lecturer’s field and years of teaching experience, not gender, qualification and designation. Comparing the specific teaching methods applied in three fields, it found that lecturers in science and technology used lecture and discussion much more frequently than those from engineering and social science. Among the six specific teaching methods, discussion and lecture were the most frequently used teaching method, which is scored significantly higher than the other four teaching methods. However, an interesting finding was reported  when  lecturers were asked to rate their preference in the six specific teaching methods.  Lecture was rated at the lowest level of preference but it was reported as one of the most frequently used teaching method. It may imply the changes on lecturers’ perspectives. Discussion method obtained the highest preference score, which is also applied frequently in current teaching practice. Keywords: general teaching practice, teaching method, lecture

Developing a hybrid, carbon/glass fiber-reinforced, epoxy composite automotive drive shaft

In this study, a finite element analysis was used to design composite drive shafts incorporating carbon and glass fibers within an epoxy matrix. A configuration of one layer of carbon–epoxy and three layers of glass–epoxy with 0°, 45° and 90° was used. The developed layers of structure consists of four layers stacked as [+45glass°/-45glass°/0carbon°/90glass°]. The results show that, in changing carbon fibers winding angle from 0° to 90°, the loss in the natural frequency of the shaft is 44.5%, while, shifting from the best to the worst stacking sequence, the drive shaft causes a loss of 46.07% in its buckling strength, which represents the major concern over shear strength in drive shaft design

Sustainable hydrogen energy in aviation-A narrative review

In the modern world, zero-carbon society has become a new buzzword of the era. Many projects have been initiated to develop alternatives not only to the environmental crisis but also to the shortage of fossil fuels. With successful projects in automobile technology, hydrogen fuel is now being tested and utilized as a sustainable green fuel in the aviation sector which will lead to zero carbon emission in the future. From the mid-20th century to the early 21st numerous countries and companies have funded multimillion projects to develop hydrogen-fueled aircraft. Empirical data show positive results for various projects. Consequently, large companies are investing in various innovations undertaken by researchers under their supervision. Over time, the efficiency of hydrogen-fueled aircraft has improved but the lack of refueling stations, large production cost, and consolidated carbon market share have impeded the path of hydrogen fuel being commercialized. In addition, the Unmanned Aerial Vehicle (UAV) is another important element of the Aviation industry, Hydrogen started to be commonly used as an alternative fuel for heavy-duty drones using fuel cell technology. The purpose of this paper is to provide an overview of the chronological development of hydrogen-powered aircraft technology and potential aviation applications for hydrogen and fuel cell technology. Furthermore, the major barriers to widespread adoption of hydrogen technology in aviation are identified, as are future research opportunities

Automobile compression composite elliptic spring

An automotive suspension system is designed to provide both safety and comfort for the occupants. When a vehicle encounters a road surface irregularity, the tire deforms and the suspension displaces. Some of the energy caused by the disturbance is dissipated in the tire, while in the old design, some energy is dissipated in the shock absorber and the remainder of the energy is stored in the coil spring. In this paper, Finite element models were developed to optimize the material and geometry of the composite elliptical spring based on the spring rate, log life and shear stress. The influence of ellipticity ratio on performance of woven roving wrapped composite elliptical springs has been investigated both experimentally and numerically, this study demonstrated that composites elliptical spring can be used for light and heavy trucks and meet the requirements, together with substantial weight saving. The results showed that the ellipticity ratio significantly influenced the design parameters. Composite elliptic spring with ellipticity ratios of a/b 2 displayed the optimum spring model

Thermal performance of four-lobe swirl generator and its transition parts under a different type of nanofluids

Due to the importance of promoting the thermal performance of heat exchangers, innovating a new technique is the main goal of many researchers. In swirl flow techniques, keeping the pressure drop at the practical level still requires more and more attention. In the current paper, a numerical study is conducted to explore the impact of a novel lobe swirl generator and its transition parts on forced convective heat transfer and friction factor in a circular pipe subjected to constant heat flux.The swirl mechanism is investigated at the pitch to a diameter of P/D = 8 as the optimum design. The transition part under several parameters of variable beta (β), transition multiplier (n= 0.5) and variable helix (t = 1) have been adopted. The effect of SiO2, Al2O3, and CuO volume concentrations (1 to 5%) in water under various Reynolds numbers (Re) from 15,000 to 35,000 have been carried out. The turbulent swirling flow was modelled using the applicable shear-stress transport (SST) k-ω. The outcome demonstrated an enhancement in heat transfer value ranging from 1.35 to 1.87 with an increased pressure drop value from 1.23 to 1.67. It was also found that using SiO2/water at 5% volume concentration and Re 15000 created the highest thermal performance, with a significant factor of 1.67

K-Chart: a tool for research planning and monitoring

The importance of planning and monitoring in any activities, more particularly researches can never be over-emphasized. Inadequate research planning and monitoring leads to delayed delivery of results, inefficient use of resources and increased cost. There are various research tools available and being used to assist in research planning and monitoring. An efficient tool should address the issues under study, the methodologies used, the expected results in sufficient details, the timelines, and monitoring features. However, there is arguably no existing tool that can support all the features individually. In this paper, a new research planning and monitoring tool, K-chart is proposed. K-chart provides all the features mentioned above and presents them in a simple way. This paper elaborates on the construction of K-chart and its advantage

Lecture-centered or student-centered: a case study in a public university

This study is aimed to investigate the current practice of teaching methods among lecturers in Universiti Teknologi Malaysia. A total of 357 lecturers participated in this study. The result showed that the general practice was influenced by lecturer’s field and years of teaching experience, not gender, qualification and designation. Comparing the specific teaching methods applied in three fields, it found that lecturers in science and technology used lecture and discussion much more frequently than those from engineering and social science. Among the six specific teaching methods, discussion and lecture were the most frequently used teaching method, which is scored significantly higher than the other four teaching methods. However, an interesting finding was reported when lecturers were asked to rate their preference in the six specific teaching methods. Lecture was rated at the lowest level of preference but it was reported as one of the most frequently used teaching method. It may imply the changes on lecturers’ perspectives. Discussion method obtained the highest preference score, which is also applied frequently in current teaching practice