Zambri Harun

The Roles of Professional Engineers at the Institutions of Higher Learning in Nation-Building.

This paper discusses the roles of professional engineers (PEs) who are attached to the Institutions of Higher Learning (IHLs) and how their contributions are as important as their counterparts in the industry. This paper highlights the roles for PEs at IHLs based on a survey conducted at selected IHLs in Malaysia. Academician-professional engineers have crucial responsibilities to develop graduates who later promote safer and cutting-edge engineering solutions. These new technologies will make Malaysia an environmentally healthier place and further prepare Malaysia towards a developed nation at the end of the decade. From the survey, we conclude that PEs at IHLs make use of their professional qualifications to enhance their knowledge therefore provide better work quality. We also found that lecturers with these qualifications have higher confidence in their own ability to success in their careers and to face and help the public.

Analysis of boost conversion process for a thermoelectric module

Thermoelectric modules are a useful way to extract waste energy from a readily available low quality heat source. However, the voltage generated by these modules varies with the temperature difference across its surfaces which are prone to fluctuations. Furthermore, the amount of voltage generated by individual modules is low. This can be rectified using voltage converters to stabilise the output voltage at the expense of some efficiency. In the case where a minimal number of modules are being used, a boost converter can be used to increase the input voltage from the thermoelectric modules to a higher level. Our previous study showed the results of the boost conversion process for multiple temperature differences, resulting in multiple input voltages and currents and found that the conversion efficiency increases with increasing input voltage at an almost constant input current. In this paper, we compare the experimental results for conversion efficiency against the expected values provided by the manufacturer, and find that when the input voltage is closer to the desired output voltage, the conversion efficiency increases.

Ordered roughness effects on NACA 0026 airfoil

The effects of highly-ordered rough surface - riblets, applied onto the surface of a NACA 0026 airfoil, are investigated experimentally using wind tunnel. The riblets are arranged in directionally converging - diverging pattern with dimensions of height, h = 1 mm, pitch or spacing, s = 1 mm, yaw angle α = 0o and 10o The airfoil with external geometry of 500 mm span, 600 mm chord and 156 mm thickness has been built using mostly woods and aluminium. Turbulence quantities are collected using hotwire anemometry. Hotwire measurements show that flows past converging and diverging pattern inherit similar patterns in the near-wall region for both mean velocity and turbulence intensities profiles. The mean velocity profiles in logarithmic regions for both flows past converging and diverging riblet pattern are lower than that with yaw angle α = 0o. Converging riblets cause the boundary layer to thicken and the flow with yaw angle α = 0o produces the thinnest boundary layer. Both the converging and diverging riblets cause pronounced outer peaks in the turbulence intensities profiles. Most importantly, flows past converging and diverging pattern experience 30% skin friction reductions. Higher order statistics show that riblet surfaces produce similar effects due to adverse pressure gradient. It is concluded that a small strip of different ordered roughness features applied at a leading edge of an airfoil can change the turbulence characteristics dramatically.

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.

Applying Science, Technology, Engineering and Mathematics Approach in the Design and Construction of a Low-Speed Wind Tunnel

The relatively wide acceptance of Science, Technology, Engineering and Mathematics (STEM) has enabled the Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia (UKM) to produce its own-designed and constructed wind tunnel. This article describes the participations of staff of the faculty, a PhD, a Master’s and a final year student in delivering their different expertise. Prior to detailed design works, computational fluid dynamics simulations using Fluent were performed to ensure flow uniformity in the test section. Detailed designs were carried out using COMSOL to produce each section i.e. diffuser, settling chamber, contraction nozzle, test sections, supports, traverse and a rotating table. The test section is 1.2 m (wide) × 0.5 m (high) × 3 m (length) with a maximum speed of 30 m/s. It is made of transparent material i.e. 15 mm acrylic sheets with a stainless steel frame. The transparent test section, the rotating table, the access and the two-axis traverse allows testing of complex geometries such as airfoils, helmets and simpler ones such as for the use of flow device calibration. Automations for controlling velocities, traverse and acquiring data are performed with a single open sourced software – Scilab. The different skills have enabled the faculty to produce a very cost-effective low speed, open-loop wind tunnel. The experience acquired by staff and students could be used in more challenging tasks and more importantly the tunnel is currently used for various activities enhancing STEM educations.

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.

Skin Friction Coefficient and Boundary Layer Trend on UKM Aster i-Bond

This study concerns with aerodynamic drag on a passenger car. By using computational fluid dynamics (CFD) method, we found that values of skin friction coefficients for three different parts of the car: front, top and rear parts, are different. This study addresses three different basic possible flows around a car: favourable, zero and adverse pressure gradients. Generally, cars use approximately 20% of their engine power to overcome aerodynamic drag, which is generally proportional to the frontal area. The boundary layer at each position has been analyzed to ascertain the effect of wall shear stress on the car surface. It is found that the value of wall shear stress velocity is highest at the rear part, followed by front and top parts. Subsequently, it is shown that the front part has the thinnest viscous region despite not being the part with the highest local ambient velocity compared with the top and rear parts. Despite its supposed aerodynamic shape, the rear part of the car sees separation of flow and the total drag per unit area here is the largest, twice as large as front part and more than seven times larger than the top part.

Smoke Simulation in an Underground Train Station Using Computational Fluid Dynamic

The design of the ventilation and fire safety systems for the Johor Bahru Sentral, a semi-underground train station, part of the Integrated Custom, Immigration and Quarantine Complex (ICIQ) is based on normal Malaysian Standards (MS), British Standards and the local fire department’s requirements. However, the large and complex space in the underground station coupled with scheduled diesel-powered locomotives which frequent the station by stopping or passing require detailed simulations. Both ventilation and the fire safety systems employ Computational Fluid Dynamic (CFD) methods to provide realistic balance against the typical calculations based on spread sheets and certain design software. This study compares smoke simulations results performed by the mechanical and fire consultants with the simulations carried out through this project. An assumption of a locomotive catches fire near the main platform is made. The burning locomotive is the source of the smoke while the occupants on platforms and waiting areas are the subjects to escape safely. The process of the simulation includes modelling and meshing processes on the structure of the railway station imported from Inventor CAD Autodesk software drawing. The CFD simulations are performed using Star-CCM+. The smokes flow around the building with buoyancy forces and extracted via exhaust fans. Through these simulations, we found that when a locomotive catches fire, the passengers could evacuate the building safely before the fire department machinery arrives. Furthermore, we notice that the ventilation fans activation based on detection of hazardous gases may not be efficient way to remove the latter. A schedule clean-up sync with train arrivals effectively removes toxic gas.

Interpolation Techniques in Computational Particle Tracking inside a Direct-Injection Diesel Engine Cylinder

Radial Basis Function (RBF) interpolation and trilinear interpolation techniques are compared in the soot particle tracking inside the cylinder of a direct injection engine. The interpolation techniques are used separately in an efficient routine written in Matlab codes which is developed to track the movement or pathline of soot particles in the engine operation cycle ranged from inlet valve closing (IVC) to exhaust valve opening (EVO). Soot particles are treated as a massless body and in spherical shape which will move under the influence of bulk gases flow inside the cylinder. Movement of soot particles are examined through the selection factors of particles initial coordinate (r,Ɵ,z) and soot concentration level at different instant crack angle. Results obtained from both interpolation techniques are compared and good agreement is achieved with some minor relative difference. However, RBF interpolation has wider applications potential where it can be applied to variety type of mesh geometry as compared to trilinear interpolation which is best used in mesh with hexahedral shape.

Condition Based Monitoring Application in Predictive Maintenance Strategies for Total Asset and Facility Management Service

Buildings, plants and equipment are strategic resources and the maintenance of these assets are utmost important. However, the management and maintenance of such assets involve a significant amount of money and human power. The appointed management team of these assets usually hires very experienced maintenance personnel to ensure the technical aspects are taken care of. Tenants, passengers, customers or visitors comfort are compromised when there are breakdowns. To make matter worse, frontline workers are exposed to high degree hazards. Management team has to adopt a new approach to handle large facility, where typical smart Building Management System (BMS) seems not intelligent enough to predict equipment failures. With the increasing complexity and sophistication of modern facilities, the needs for specialists to manage and coordinate these strategic resources become crucial. Routine Condition-based Monitoring (CbM) programme minimizes the unexpected equipment failure and it is a proactive way to prevent equipment mortality. Advanced diagnostic tools are used to create historical data based on assets conditions; from this, assets’ analyses could be performed. Through the study, when failures are avoided, a potential saving is predicted and disturbances to end users are minimized.