Applied Mechanics and Materials Vols. 773-774

Abstract: Shortage in hydrocarbon fuel sources, energy preservation and future stringent emission regulations have been a formidable challenge to the most prominent Small and Medium Enterprise (SME ) in Malaysia especially in the burner system of boiler. Therefore, the alternative source of fuel is receiving a lot of attention especially in the application of renewable energy such as biodiesel fuel (BDF) and low quality fuel. The application of biodiesel in the burner system offer not only attractive and more economical fuel but also creates problems of higher toxic emission such as nitrogen oxide (NOx), carbon monoxide (CO) and particulate matters (PM). This review presents the current status of the several studies that had been carried out on the emission and performance characteristic of biodiesel burners burner in term of the specific fuel type that could be used, type of emissions such as NOx, CO, CO2 and others operating condition that can be used to optimize the performance of the biodiesel burner system and also comment the progress of it in some areas. Based on the review clearly indicated that this form of alternative fuel can be an attractive renewable alternative energy source for burner system.

Abstract: Atomization and fuel-air mixing is an important process in diesel combustion. It directly affects the combustion and emission of diesel engine. Optical technique has the advantage of being unobtrusive in nature when compared to other technique. nanospark unit that has spark duration of 30ns was used as a lightsource to capture high resolution spray image using still film camera. The very short duration of the spark freeze the fast movement of the spray droplet, and sharp image of fuel droplet to be successfully captured by the camera, and then analyzed for sizing and spatial distribution. In addition, by using a more elaborate optical setup, dual image of the same spray can be captured, with a very short time interval between each of them. This provides the means to study dynamic behaviors of the diesel spray and also the droplets, as the progression of the spray and trajectory and velocity of the droplet can be analyze from these images. With the proposed optical technique and optical arrangement, microscopic detail of the diesel engine spray can be captured. Critical data such as droplet sizing can be extracted from this high resolution image. Furthermore, by introducing a more sophisticated optical arrangement coined dual-nano spark photography method, the droplet dynamic behaviors such as flying angle and velocity can be study.

Abstract: The compressed natural gas (CNG) – diesel dual fuel engine is discussed through their basic operation and its characteristic. The main problem of running a diesel engine on dual fuel mode with CNG as main fuel is addressed. A brief review of knock phenomena which is widely associated with a dual fuel engine is also covered. Methods to suppress onset knock were suggested.

Abstract: Among the challenges faced by diesel engines combustion nowadays are to reduce emission especially Nitrogen Oxide (NO_x) and Particular Matter (PM) while enhancing fuel efficiency and power. The purpose of this review is to explore the mixture formation of biodiesel combustion using constant volume chamber and optical visualization. This paper will review the development of a single-shot combustion system and constant volume chamber. An overview of the relation of mixture formation and combustion process in diesel combustion is provided first. This review has shown that the application of Rapid compression Machine (RCM) is used to simulate actual condition especially the injection pressure and air motion. The review also found that the mixing between fuel and air is unavoidable and very important during ignition delay period thus predominantly influences the exhaust emission. The detailed behaviour of injection characteristic that strongly effects the mixture formation especially the spray evaporation and spray interference are discussed.Keywords: Rapid Compression Machine; Ignition Delay; Nozzle; Injection System; Air Motion; Ambient

Abstract: The energy is the most of the human existence. Consumption fossil fuels has grown substantially and consumption the energy sources that is seen as having a major environmental impacts. Diminution world oil reserves and increasing environmental concern have induced found alternative and renewable energy resources called biodiesel. Biodiesel fuel from the vegetable oil, regarded as of the best candidate for the substitute diesel fuel in diesel engines because of the characteristics closer. The application of biodiesel has shown a positive impact in resolving these issues. This paper introduces some type of alternative fuel whose oils are potential sources of biodiesel. These types are crude palm oil (CPO), straight vegetable oil (SVO), waste cooking oil (WCO) and Jatropha curcas (JPO). From the review, fuel properties are found to considerablyareon density, viscosity, acid value, water content and flash point. In conclusion, a long period of storage will reduce the quality of biodiesel does not matter what kind of conditions and environments that are exposed to. However, the rate of degradation of biodiesel can be slow if the right circumstances and environment provided.

Abstract: The use of energy and natural resources being increase due to the growth of economy and world population. One of the natural resources is being consumed heavily is diesel for transportation and burner combustion. However, the major product results from the combustions of diesel are NOx and PM emissions. This review paper focuses on the influences of the emulsified renewable biodiesel fuel such as crude palm oil and waste cooking oil with the concept fuel-air-water internally rapid mixing injector for the open burner system. Water is introduced directly into the combustion field. The concept of rapid mixing from biodiesel and water are controlling of the combustion process in order to minimize the emissions. The water content in the emulsified biodiesel fuels effectively in the reduction of NOx emissions especially the high blending biodiesel. Moreover, emulsion technology significantly reduced particulate matter (PM) emissions as compared to the standard biodiesel fuel combustion. The parameters include equivalent ratio, water content in biodiesel-water, and spray characteristics such as spray penetration, spray angle and spray area.

Abstract: An essential component of the injector nozzle geometry is to see the results spray atomization and mixture formation of the fuel-air combustion to improve performance, and reduce pollution from a burner. Studies involving the injectors in the combustion burner are still in a small proportion, particularly in the premix injector type. Thus, this study involves the efforts to determine the appropriate diameter of the premix injector where the injector spray characteristics is produced by using Computational Fluid Dynamics (CFD). Multiphase of the volume of fluid (VOF) cavitations flow in the nozzle is determined through steady simulation while Eulerian-Eulerian two-fluid approach is used for performing mixing of Jatropha oil and air. Further simulation is conducted using a spray with a discrete phase injection at the outflow hole injector nozzle. The investigation involves the modification of nozzle geometry on three different sizes of 0.8 mm, 1.0 mm and 1.5 mm with the analysis focused on nozzle flow characteristics of the injector. The results indicate that a small changes in injector gives high impact to the spray and combustion of a burner. This shows the importance of nozzle dimensions which influences the nozzle flow and affects the spray characteristics, hence influence the combustion and emission of the burner system.

Abstract: The purpose of this study is to determine the coefficient drag, C_D of the Proton PREVẾ by experimental method using Low Speed Wind Tunnel. All the relevant data are collected through the literature reviews from books and journals. First, the basic thing in aerodynamic is studied. There are two things are concern when studies aerodynamics. They were air flow and vehicle shape which we regard as aerodynamics factor that determine aerodynamic of the vehicle. Fundamental of air flow and vehicle shape is reviewed includes the relationship between air speed with pressure, boundary layer, Reynolds number, drag, lift drag and shape optimization. Wind tunnel is also studied before the experiment. Five selected speed were been tasted during the experiment to determine the C_D value.

Abstract: This paper describes simulation of combustion characteristics under high ambient and high injection of biodiesel combustion by using CFD simulation. Diesel engine performance and emissions is strongly couple with fuel atomization and spray processes, which in turn are strongly influenced by injector flow dynamics. The principal objective of this research is to seek the effect of temperature and pressure on the spray characteristics, as well as fuel-air mixing characteristics. Experiments were performed in a constant volume chamber at specified ambient gas temperature and pressure. This research was continued with injecting diesel fuel into the chamber using a Bosch common rail system. Direct photography technique with a digital camera was used to clarify the real images of spray pattern, liquid length and vapor penetration. The method of the simulation of real phenomenon of diesel combustion with optical access rapid compression machine is also reviewed and experimental results are presented. The liquid phase of the spray reaches a maximum penetration distance soon after the start of injection, while the vapor phase of the spray continues to penetrate downstream. The condition to which the fuel is affected was estimated by combining information on the block temperature, ambient temperature and photographs of the spray. The increases in ambient pressure inside the chamber resulting in gain of spray area and wider spray angle. Thus predominantly promotes for a better fuel-air mixing. All of the experiments will be conducted and run by using CFD. The simulation will show in the form of images.

Abstract: The increasing effort on the environmental impacts of fossil fuel based power generation has led to increased research with the aim of reducing emissions and improving combustion efficiency by turning to alternative fuel such as biodiesel. But the hazardous emission caused by biodiesel is still a problem that need to tackle. One of way to achieve this is by choosing the correct nozzle characteristic. In the current study, the effect of nozzle angle on mixture formation and combustion characteristic are investigate using air-assisted fuel atomizing biodiesel burner. The nozzle angle that was used are θ = 45⁰ and 50⁰. The results show with nozzle 45⁰ produce lower spray penetration, but higher spray angle and spray area compare to nozzle 50⁰. The result are similar on flame development. For the emission characteristic, the Carbon Monoxide (CO) and Hydro Carbon (HC) emission had a strong reduction by using nozzle with 45⁰ angle compare to 50⁰ angle.