Mohd Azahari Razali

Effects of Biodiesel Derived by Waste Cooking Oil on Fuel Consumption and Performance of Diesel Engine

Biodiesel is the alternate fuel which is derived from renewable sources either is vegetable oils or animal fats. For that reason, the vehicle run by Bio-diesel Fuel (BDF) has been a potential option and the alternative sources of fuel are receiving a lot attention in the automotive industry. The use waste cooking oil (WCO) biodiesel as an alternative fuel in engines has advantages from both economic and the emissions of carbon monoxide (CO) and hydrocarbons (HC) in the exhaust gas. Purpose of this study is to investigate the effects of waste cooking oil blended fuel, engine speed and test load conditions on the fuel properties, combustion characteristics and engine performance. The engine speed was varied from 1500 to 3000 rpm, load test condition varied by dynapack chassis dynamometer in 0, 50 and 100% and blends of 5(WCO5), 10(WCO10) and 15vol%(WCO15) waste cooking oil with the diesel fuel. The results showed that the use of WCO as biodiesel results in a higher fuel consumption rate, especially at low engine speed and full load condition.

Investigation of the Piston Bowl Shape Effect on the Diesel Spray Development

The combustion in a diesel engine is a very complex process. Even more when compared to a gasoline engine where the combustion is triggered using spark plugs, since the diesel engine depends on the auto ignition of the fuel-air mixture. This auto ignition phenomenon depends on many variables, especially on the fuel-air mixing condition and this makes the piston bowl geometry an important role on the combustion characteristics of diesel engines. Each piston bowl design was tailored to work well under certain specific conditions. The usage of biomass diesel mixtures in diesel engines increases the fuel viscosity and requires that the piston bowl geometry is carefully studied. The objective of this study is to compare the effect of certain piston bowl shapes, namely the Flat Bottom to the diesel spray development. Simulations were done using the ANSYS FLUENT 16.1 computational fluid dynamics (CFD) software. The simulation was performed on different injection pressures of 40 and 100 MPa, with the ambient temperature in the combustion chamber that is holding the piston at 500 and 900 K. Results showed that if the pressure and ambient temperature increase, the spray cone angle increases. In addition, the geometry shape of the piston bowl makes the spray to head downward after the wall impingement to the bottom section and prevents spillage of fuel over the piston bowl.

Flame Spread Behavior over Kenaf Fabric, Polyester Fabric, and Kenaf/Polyester Combined Fabric

Flame spread behavior is one of the important topics related to fire safety engineering. It is essential to examine factors, which influence the flame spread behavior over fabrics. It is known that natural fibers exhibit a different flame spread behavior than the one of synthetic fibers. This difference may influence the flame spread behavior over combined fabrics. The purpose of this research is to study the effect of materials on the flame spread behavior over kenaf/polyester fabrics. Before analyzing this effect, it is important also to know the flame spread behavior over 100% kenaf fabric and 100% polyester fabric. Thus, several experiments have been conducted for different materials of fabric made up of 100% kenaf, 100% polyester, and combined fabric of kenaf/polyester. For the combined fabric, experiments have been done for different weft thread angle of θ = 0° and θ = 90°. A burner is used for igniting the fabric at a point on its top edge. The data collected is recorded via videos and captured images for measuring the flame spread rate and detail observation of characteristics during the burning process. From the results obtained, it is seen that the material and thread angle influence on the flame spread behavior over fabrics. The flame spread rate on kenaf is lower than the flame spread rate on combined fabrics of kenaf/polyester while the flame spread rate on polyester is undetermined. The flame spread velocity also changes when the weft thread angle change from θ = 0° to θ = 90°.

Comparision on dynamic behavior of diesel spray and rapeseed oil spray in diesel engine

Fuel-air mixing is important process in diesel combustion. It significantly affects the combustion and emission of diesel engine. Biomass fuel has high viscosity and high distillation temperature and may negatively affect the fuel-air mixing process. Thus, study on the spray development and atomization of this type of fuel is important. This study investigates the atomization characteristics and droplet dynamic behaviors of diesel engine spray fuelled by rapeseed oil (RO) and comparison to diesel fuel (GO). Optical observation of RO spray was carried out using shadowgraph photography technique. Single nano-spark photography technique was used to study the characteristics of the spray while dual nano-spark shadowgraph technique was used to study the spray droplet behavior. Using in-house image processing algorithm, the images were processed and the boundary condition of each spray was also studied. The results show that RO has very poor atomization due to the high viscosity nature of the fuel when compared to GO. This is in agreement with the results from spray droplet dynamic behavior studies that shows due to the high viscosity, the RO spray droplets are large in size and travel downward, with very little influence of entrainment effect due to its large kinematic energy.

Numerical study of flow past a solid sphere at high Reynolds number

The present study gives a detail description of separation flow and its effect under high Reynolds number. The unsteady three dimensional flow simulation around sphere using numerical simulation computational fluid dynamics for high Reynolds number between 300 000 < Re < 600 000 is discussed. The separation angle and drag coefficient are also presented. The results show that the increasing Reynolds number affecting the formation of vortex shedding, separation point and drag coefficient. The agreement was good, confirming the reliability of the predicted data from computational fluid dynamic in flow analysis around sphere at high Reynolds number.

Study on airflow characteristics of rear wing of F1 car

The paper aims to investigate CFD simulation is carried out to investigate the airflow along the rear wing of F1 car with Reynold number of 3 × 106 and velocity, u = 43.82204 m/s. The analysis was done using 2-D model consists of main plane and flap wing, combined together to form rear wing module. Both of the aerofoil is placed inside a box of 350mm long and 220mm height according to regulation set up by FIA. The parameters for this study is the thickness and the chord length of the flap wing aerofoil. The simulations were performed by using FLUENT solver and k-kl-omega model. The wind speed is set up to 43 m/s that is the average speed of F1 car when cornering. This study uses NACA 2408, 2412, and 2415 for the flap wing and BE50 for the main plane. Each cases being simulated with a gap between the aerofoil of 10mm and 50mm when the DRS is activated. Grid independence test and validation was conduct to make sure the result obtained is acceptable. The goal of this study is to investigate aerodynamic behavior of airflow around the rear wing as well as to see how the thickness and the chord length of flap wing influence the airflow at the rear wing. The results show that increasing in thickness of the flap wing aerofoil will decreases the downforce. The results also show that although the short flap wing generate lower downforce than the big flap wing, but the drag force can be significantly reduced as the short flap wing has more change in angle of attack when it is activated. Therefore, the type of aerofoil for the rear wing should be decided according to the circuit track so that it can be fully optimized.

Comparison on Piston Bowl Shape Effect to Diesel Spray Development

Piston bowl geometry plays an important role on the combustion characteristics of diesel engine. There are various design of piston bowl in which each utilize the shape geometry to obtaining the specific required combustion characteristics. This objective of this study is to compare the effect of certain piston bowl shapes, namely Toroidal and Flat Bottom to diesel spray development. Simulation were done using ANSYS FLUENT 16.1 software Computing Fluid Dynamics (CFD). The simulation was performed on different injection pressure of 40 MPa and 100 MPa, with the ambient temperature in the combustion chamber that holding the piston is at 500K and 900K. Results showed that if the pressure and ambient temperature increases, the spray body expand outward from the spray center axis with wider spray cone angle. In addition, the geometry shape of the piston bowl influences the spray velocity distribution and the spray propagation path, indirectly effect the spray area and mass fraction distribution.

CFD simulation of flow through an orifice plate

In this present paper, the commercial Computational Fluid Dynamics (CFD) is used to predict the flow features in the orifice flow meter. Outcomes of the CFD simulations in terms of profiles of velocity and pressure are discussed in detail. It is observed that the flow is jet-like flow in the core region and the presence of recirculation, reattachment and shear layer regions flow features downstream the orifice. The location of vena-contracta was also estimated from CFD simulations. These results are consistent with other published data.

Flame spread behavior over combustible thick solid of paper, bagasse and mixed paper/bagasse

Flame spread behavior on combustible solid is one of important research related to Fire Safety Engineering. Now, there are a lot of combustible solid composed from mixed materials. In this study, experiments have been conducted to investigate flame spread behavior over combustible solid composed by paper, bagasse and mixed paper/bagasse. Experimental data is captured by using video recording and examined flame spread shape and rate. From the results obtained, shows that the different materials produce different flame spread shape and rate. Different flame shape is seen between all types of samples. Flame spread rate of 100% paper is faster than the one of 100% bagasse. Based on the result, it is also inferred that the material composition can be influenced on the flame spread shape and flame spread rate of mixed paper/bagasse.

Numerical study of canister filters with alternatives filter cap configurations

Air filtration system and filter play an important role in getting a good quality air into turbo machinery such as gas turbine. The filtration system and filter has improved the quality of air and protect the gas turbine part from contaminants which could bring damage. During separation of contaminants from the air, pressure drop cannot be avoided but it can be minimized thus helps to reduce the intake losses of the engine [1]. This study is focused on the configuration of the filter in order to obtain the minimal pressure drop along the filter. The configuration used is the basic filter geometry provided by Salutary Avenue Manufacturing Sdn Bhd. and two modified canister filter cap which is designed based on the basic filter model. The geometries of the filter are generated by using SOLIDWORKS software and Computational Fluid Dynamics (CFD) software is used to analyse and simulates the flow through the filter. In this study, the parameters of the inlet velocity are 0.032 m/s, 0.063 m/s, 0.094 m/s and 0.126 m/s. The total pressure drop produce by basic, modified filter 1 and 2 is 292.3 Pa, 251.11 Pa and 274.7 Pa. The pressure drop reduction for the modified filter 1 is 41.19 Pa and 14.1% lower compared to basic filter and the pressure drop reduction for modified filter 2 is 17.6 Pa and 6.02% lower compared to the basic filter. The pressure drops for the basic filter are slightly different with the Salutary Avenue filter due to limited data and experiment details. CFD software are very reliable in running a simulation rather than produces the prototypes and conduct the experiment thus reducing overall time and cost in this study.