Wan Mohd Faizal Wan Mahmood

Comparing the Effects of Hydrogen Addition on Performance and Exhaust Emission in a Spark Ignition Fueled with Gasoline and CNG

With the concern of the foreseen reduction in fossil fuel resources and stringent environmental constraints, the demand of improving internal combustion (IC) engine efficiency and emissions has become more and more pressing. Hydrogen has been proved to be a promising renewable energy that can be used on IC engines. In this paper an evaluation and assessment of numerical and experimental investigations on performance and exhaust emission with hydrogen added to a spark ignited gasoline engine fuelled with gasoline and natural gas are performed. The experimental results showed that thermal efficiency, combustion performance, NOx emissions improved with the increase of hydrogen addition level. The HC and CO emissions first decrease with the increasing hydrogen enrichment level, but when hydrogen energy fraction exceeds 12.44%, it begins to increase again at idle and stoichiometric conditions. Numerical results showed that there is an increase in engine efficiency only if Maximum Brake Torque (MBT) spark advance is used for each fuel. Moreover, an economic analysis has been carried out to determine the optimum percentage of hydrogen in such blends, showing percent increments by using these fuels about between 10 and 34%.

Reliability study of solder paste alloy for the improvement of solder joint at surface mount fine-pitch components

The significant increase in metal costs has forced the electronics industry to provide new materials and methods to reduce costs, while maintaining customers’ high-quality expectations. This paper considers the problem of most electronic industries in reducing costly materials, by introducing a solder paste with alloy composition tin 98.3%, silver 0.3%, and copper 0.7%, used for the construction of the surface mount fine-pitch component on a Printing Wiring Board (PWB). The reliability of the solder joint between electronic components and PWB is evaluated through the dynamic characteristic test, thermal shock test, and Taguchi method after the printing process. After experimenting with the dynamic characteristic test and thermal shock test with 20 boards, the solder paste was still able to provide a high-quality solder joint. In particular, the Taguchi method is used to determine the optimal control parameters and noise factors of the Solder Printer (SP) machine, that affects solder volume and solder height. The control parameters include table separation distance, squeegee speed, squeegee pressure, and table speed of the SP machine. The result shows that the most significant parameter for the solder volume is squeegee pressure (2.0 mm), and the solder height is the table speed of the SP machine (2.5 mm/s).

Performance of oil palm kernel shell gasification using a medium-scale downdraft gasifier

ABSTRACT This article focused on the performance of oil palm kernel shell (PKS) gasification using a medium-scale downdraft gasifier with a feedstock capacity of 500 kg at a temperature range of 399–700°C and at a feed rate of 177 kg/h. This article is important for evaluating the reliability of PKS gasification for commercial power generation activities from biomass. The process performance was evaluated based on the syngas calorific value (CV), syngas flow rate, and its cold gas efficiency (CGE). The syngas flow rates and CVs were measured using a gas flow meter and a gas analyzer in real time. The data obtained were then analyzed to evaluate the performance of the process. The results showed that the CGE of the process was moderately high (51%) at 681°C, with a high syngas CV (4.45–4.89 MJ/Nm3) which was ideal for gas engine applications. The PKS gasification performance increased when the reactor temperature increased. Projections were made for the CGE and the syngas CV for the PKS gasification with increased reactor temperatures and it was found that these values could be increased up to 80% and 5.2 MJ/Nm3, respectively at a reactor temperature of 900°C. In addition, the estimated power that could be generated was about 600 kWe at a maximum operation of 500 kg/h of feed rate. Based on the analysis, a medium-scale PKS gasification is observed to be a promising process for power generation from biomass due to the favorable performance of the process.

Effect of Injector Nozzle Design on Spray Characteristics for Hydrogen Direct Injection Engine Conditions

Hydrogen has a unique flammability property compared to other fuels. Previous researches proved that direct injection is the most suitable method for this particular fuel. This research aims to study the effect of injector nozzle geometry on mixture and internal combustion efficiency in four stroke automotive engine which operates using hydrogen fuel. The research will concentrate on two aspects, namely the inflow and outflow profile of the injector nozzle. For each flow profile, the effect of geometrical design of the nozzle on the parameter such as flow velocity, fuel penetration distance, average mass fuel consumption and diffusion will be studied in detail. In this study, numerical simulation analysis was done by using the computing fluid dynamics (CFD) software, Star-CCM+. Models comprise of multiple orifice nozzle geometry with single angle orifice and double angle orifice was developed with CAD software. A suitable design for a better mixing nozzle would then be determined. Nozzle which possesses a high number of orifice and a smaller diameter will result in a higher flow velocity in the cavity nozzle channel. Geometry of nozzle with different angle of orifice was found to be the most suitable due to the low flow penetration distance and fuel consumption as well as combustion enhancement by the diffusion rate.

Compressed Natural Gas Direct Injection: Comparison Between Homogeneous and Stratified Combustion

Due to abundance of natural gas, the use of natural gas for automotive use, particularly for internal combustion engine (ICE), is more practical and cheaper than their future successors. Even though natural gas is a cleaner fuel than other fossil fuels and has a higher octane number and can lead to higher thermal efficiency, its low carbon number makes it less attractive as compared to gasoline and diesel. Based on its potential, an engine referred to as compressed natural gas direct injection engine (CNGDI) was designed, developed and tested to operate on compressed natural gas (CNG) as monofuel directly and centrally injected into the engine. Computational and experimental works have been performed to investigate the viability of the design. Computational fluid dynamics (CFD) simulations and experimental works with homogenous combustion showed that the results were in good agreement. From experimental works, it is found that combustion characteristics could be improved by using a stratified charge piston configuration with some drawback on performance. In terms of exhaust emissions, stratified configuration causes slight increase in the emission of CO, CO 2 and NO x , which highlight a need for further study on this issue.

Application of Taguchi method in optimization of design parameter for turbocharger vaned diffuser

Purpose The purpose of this study is to determine the best vaned diffuser design that can generate higher pressure output at a predetermined speed. Design/methodology/approach Several vaned diffusers of thin, flat-type design with different number of blades and blade angle were fabricated. The vaned diffusers were fitted inside the turbocharger compressor and test on a cold-flow turbocharger test rig. A Taguchi L27 orthogonal array is selected for analysis of the data. Influence of number of blades, blade angle and rotational speed on output pressure is studied using the analysis of variance (ANOVA) technique. Finally, confirmation tests are conducted to validate the experimental results. Findings The optimum design parameters of the vaned diffuser using signal-to-noise ratio analysis were six blades type, blade angle of 18° and rotational speed of 70,000 rpm. Results from ANOVA showed that the speed has the highest influence on output pressure. The number of blades and blade angle produced the least effect on the pressure output. Originality/value The study used the turbocharger with the impeller size 60 mm and adapted vaned diffuser to increase the output pressure.

A computational study on effect of pitch difference in pure plunging tandem wings

Flapping wing in tandem configuration may offer enhanced aerodynamic performance at low Reynolds number, in which micro air vehicles operate. The present study aims to investigate the effect of fore-hind wing pitch difference on the aerodynamic performance of tandem wings. To that end, two-dimensional, laminar flow around two thin flat airfoils that are sinusoidally plunging in phase with each other, were computationally simulated at a Reynolds number of 10000, using a flow solver in an Arbitrary Lagrangian-Eulerian framework. The fore wing pitch angle was fixed to 10°, while the hind wing pitch angle was varied between -10°, 0°, 10° and 20°. Numerical results shows that aerodynamic performance of the fore wing may be affected by the hind wing pitch angle and that tandem wings may offer improved lift to drag efficiency at some optimal fore-hind wing pitch difference compared to twice the results of a similar single wing case. In addition, the complex fore-hind wing vortex interaction is also affected by the hind wing pitch angle.

Investigation of Physical and Mechanical Properties of 3-D Turbulent Flow in Orifice Pipe

The turbulent flow in orifice plate was investigated and solved numerically using 3-D Navier-Stockes (N-S) equations by employing commercial CFD code ANSYS. The N-S equations were solved for unsteady flow of an orifice plate at different values of Reynolds number, Re=ρVDμ, and different aspect ratios, β=dorificedpipe. Physical parameters such as velocity, differential pressure, and vorticity and mechanical properties such as stress, strain, and total deformation were examined for Reynolds numbers of 10000, 20000, and 30000 and at aspect ratios β of 0.2, 0.4, and 0.6. It was found that as Reynolds number increases, the velocity increases while the differential pressure shows very steep jump across the orifice. As aspect ratio increases, the maximum pressure declines. The vorticity patterns show that images of very condensed lines. At certain aspect ratio, the differential pressure increases as Reynolds number increases.

Numerical Investigation of 3-D Turbulent Flow in Orifice Plate within a Pipe

A numerical study of the turbulent flow in an orifice plate within a pipe is carried out by utilizing the Navier-Stokes (N-S) equations. The governing equations are solved using primitive variables with a finite volume method (FVM) and simulated using the finite volume based commercial CFD code ANSYS. The study investigates the influences of Reynolds numbers (Re = 5000, 10000, and 15000) and aspect ratio (β = 0.2, 0.3, and 0.5), on the flow characteristics, i.e. the velocity profile, the differential pressure, and the vorticity, and on the mechanical properties, i.e. the strain, the stress, and the total deformation of the flow around and beyond the orifice. It is found that as the Reynolds number increases, the flow velocity and the pressure increase. The vorticity images show a slightly different behavior. As the Reynolds number has its own effect on the results, it is also found that the aspect ratio affects the results more significantly. The flow patterns are presented for unsteady flow throughout the orifice plate at different values of the Reynolds number.

Skin friction impacts on fuel consumption

National fuel use in Malaysia is on the rise, so are its subsidies, which take a large chunk of national annual budgets. This study concerns drag reduction efforts, which are related to vehicle efficiencies by way of aerodynamics effects. The study supports the national agenda of reducing fuel use. By using the computational fluid dynamic (CFD) method, we found that the total fuel consumption contributed by the wind resistance with regard to engine thermal efficiency is 14.22% and the skin friction has minimal impact on the fuel consumption. We also found a certain boundary layer that develops over the complex surface of the car. This study benefits the local automotive industry by way of sharing the information of aerodynamic effects of a sport car.