Shahrin Hisham Amirnordin

Spray Characteristic of Diesel-Water Injector for Burner System

NOx and PM are the major product results from the combustion of diesel either in internal combustion engine or external burner system. Thus, the emulsification concept from diesel and water were studied with focusing in controlling of combustion process in order to minimize the harmful emission. The main purpose of this research is to investigate the effects of diesel-water emulsification on mixture formation, burning process and flame development in burner system. The studied parameters include equivalent ratio, water content in diesel-water emulsification and spray characteristics such as spray penetration length, spray angle and spray area. The spray image of different diesel-water ratio and equivalence ratio can be investigated by direct photography method with a digital camera. The real spray images with the time changes was analyzed and compared with based diesel fuel. The results show that the higher of water contents due to higher viscosity influences the higher penetration length and lower spray angle thus predominantly the lower combustible mixture and lower the flame penetration.

Pressure Drop Analysis of Square and Hexagonal Cells and its Effects on the Performance of Catalytic Converters

Stringent emission regulations around the world necessitate the use of high-efficiency catalytic converters in vehicle exhaust systems. Therefore, determining the optimum geometry of the honeycomb monolith structure is necessary. This structure requires a high surface area for treating gases while maintaining a low pressure drop in the engine. In the present paper, an adapted sub-grid scale modeling is used to predict the pressure loss of square- and hexagonal-cell-shaped honeycomb monoliths. This sub-grid scale modeling represents the actual variations in the pressure drop between the inlet and outlet for various combinations of wall thickness and cell density. A comparison is made between the experimental and numerical results established in literature. The present approach is found to provide better and more comprehensive results than the single channel technique.

Effect of zeta potential of stanum oxide (SnO2) on electrophoretic deposition (EPD) on porous alumina

Zeta potential analysis of stanum oxide (SnO2) aqueous suspensions (pH7 to pH11) was performed prior to the electrophoretic deposition (EPD) of SnO2. Deposition of SnO2 on porous alumina was obtained by applying the EPD technique carried out by applying voltage of 18V for duration of four minutes. It was found that the depositions SnO2 suspended at pH 7 to pH 11 were successful. The relation between the SnO2 deposition with SnO2 pH and zeta potential values was established in which increased value of pH causes decreased value of zeta potential and decreased SnO2 deposition through EPD technique.

Spray Characteristic of Rapid Mixing Jatropha Oil Biodiesel in Burner System

Jatropha Oil (JPO) is an alternative fuel proposed to be used especially for renewable sources and energy efficiency. Its characteristics need further investigation particularly for the use in an external burner system. The aim of this research is to investigate experimentally the spray characteristics of Jatropha oil in premixing injector for burner system. The Jatropha oil was blended with diesel at different ratio; JPO5, JPO10, and JPO15 at water content of W0, W5, W10 and W15. Fuel, water and air are injected in premix injector, causing the spray of these mixtures to produce lower toxic emission during combustion process. The spray angle, spray penetration length and spray area of different fuel-water ratio and equivalent ratio shall be analyzed from images captured using direct photography method with a DSLR camera. The result of the spray image will be further analyzed and compared between the different batches of image captured. It is shown that the effect of equivalent ratio and water content in fuel-water mixtures will give a significant effect on spray characteristics. Addition of water content will increases the viscosity of the mixtures, hence it increases the spray penetration length, spray area and reduce the spray angle.

Pressure Drop and Heat Transfer Characteristics of Louvered Fin Heat Exchangers

This paper presents the effect of the changes in fin geometry on pressure drop and heat transfer characteristics of louvered fin heat exchanger numerically. Three dimensional simulation using ANSYS Fluent have been conducted for six different configurations at Reynolds number ranging from 200 to 1000 based on louver pitch. The performance of this system has been evaluated by calculating pressure drop and heat transfer coefficient. The result shows that, the fin pitch and the louver pitch have a very considerable effect on pressure drop as well as heat transfer rate. It is observed that increasing the fin pitch will relatively result in an increase in heat transfer rate but at the same time, the pressure drop will decrease. On the other hand, low pressure drop and low heat transfer rate will be obtained when the louver pitch is increased. Final result shows a good agreement between experimental and numerical results of the louvered fin which is about 12%. This indicates the capability of louvered fin in enhancing the performance of heat exchangers.

The effect of flow recirculation on abdominal aortic aneurysm

The presences of flow recirculation at the abdominal aortic aneurysm (AAA) region yield the unpredictable failure of aneurismal wall. The failure of the aneurismal wall is closely related to the hemodynamic factor. Hemodynamic factor such as pressure and velocity distribution play a significance role of aneurysm growth and rupture. By using the computational approach, the influence of hemodynamic factor is investigated using computational fluid dynamic (CFD) method on the virtual AAA model. The virtual 3D AAAs model was reconstructed from Spiral Computed Tomography scan (CT-scan). The blood flow is assumed as being transient, laminar and Newtonian within a rigid section of the vessel. The blood flow also driven by an imposed of pressure gradient in the form of physiological waveform. The pulsating blood flow is also considered in this simulation. The results on pressure distribution and velocity profile are analyzed to interpret the behaviour of flow recirculation. The results show the forming of vortices is seen at the aneurysm bulge. This vortices is form at the aneurysm region then destroyed rapidly by flow recirculation. Flow recirculation is point out much higher at distal end of aneurysm closed to iliac bifurcation. This phenomenon is managed to increase the possibility of aneurysm growth and rupture.

Effects of fractal grid on spray characteristics and flame development in burner combustion

Turbulence generator plays an important role in enhancing turbulence in combustion and determining the flame characteristics in burner combustion. This research demonstrated the effect of a fractal grid on the spray and flame characteristics in burner combustion. Three geometrical configurations of fractal grid were investigated with different equivalence ratios of 0.5–1.0. The images were captured using direct photographic method. The characteristics of the spray and flame were studied, including the length, angle, and area. The results from this fractal grid were compared with the swirl. The results showed that the fractal geometry and ratio of air-to-fuel mixture affected the performance of the burner. The correct combination of fractal geometry and air-to-fuel ratio resulted in complete combustion and improved the overall performance of the burner.

Thermal Imaging of Flame in Air-assisted Atomizer for Burner System

Infrared thermography was used as a part of non-intrusion technique on the flame temperature analysis. This paper demonstrates the technique to generate the thermal images of flame from the air-assisted atomizer. The multi-circular jet plate acts as a turbulence generator to improve the fuel and air mixing in the atomizer. Three types of multi-circular jet plate geometry were analysed at different equivalence ratio. Thermal infrared imaging using FLIR thermal camera were used to obtain the flame temperature. Multi-circular jet 1 shows the highest flame temperature obtained compared to other plates. It can be concluded that the geometry of the plate influences the combustion, hence affects the flame temperature profile from the air-assisted atomizer.

Spray formation of biodiesel-water in air-assisted atomizer using Schlieren photography

Biodiesels are attractive renewable energy sources, particularly for industrial boiler and burner operators. However, biodiesels produce higher nitrogen oxide (NOx) emissions compared with diesel. Although water-emulsified fuels can lower NOx emissions by reducing flame temperature, its influence on atomization needs to be investigated further. This study investigates the effects of water on spray formation in air-assisted atomizers. The Schlieren method was used to capture the spray images in terms of tip penetration, spray angle, and spray area. The experiment used palm oil biodiesel at different blending ratios (B5, B10, and B15) and water contents (0vol%-15vol%). Results show that water content in the fuel increases the spray penetration and area but reduces the spray angle because of the changes in fuel properties. Therefore, biodiesel-water application is applicable to burner systems.

Experimental Study of the Ignition Process and Combustion of Biodiesel-water-air Rapid Mixing Derived From Waste Cooking Oil, Crude Palm Oil and Jatropha Oil in Burner Combustion

The prospects of fossil oil resources and strengthen of future emission regulation have raised keen attention together with the issue of renewable alternative fuel. As one of the different solutions to these problems, emulsion fuel technology in biodiesel has received close attention because it may provide better combustion efficiency and would contribute to a reduction in emissions, such as nitrogen oxides (NOx) or particulate matter (PM).The solution of this issue is by using Biodiesel fuel as an alternative fuel from waste cooking oil (WCO), crude palm oil (CPO) and Jatropha Oil (JPO). In addition, Waste cooking oil is one of the most economical options for producing biodiesel due to the biodegradable properties and preserves energy. This study focuses on the observation of ignition and combustion characteristics of biodiesel-water-air rapid mixing of biodegradable fuel using internally rapid mixing injector in burner combustion. In this research, the relation of mixture formation, burning process and flame development of biodiesel were investigated in detail. The parameters include equivalent ratio, water content and mixture formation are studied. The flame development is analysed in term of flame longest for testing. The result shows that equivalent ratio and water content affect the combustion. Increasingly of water content will reduce the flame length and increase the probability of misfire.