Papers by Keyword: Flame

Abstract: The oscillations presence of the substance condensed state parameters and the n-alkanes combustion process was analyzed. It is shown that the smallest substance structural unit that describes such features is a dimer, a hexamer for methane, and a trimer for ethane. The cluster "equivalent length" based on the framework number atoms in the continuous chain and without taking into account cluster side parts was used as a modulating parameter. Attention was drawn to the dependences similarity for water solubility and the autoignition temperature of n-alkanes. It is proposed to take into account clustering involving water molecules for the water solubility, and oxygen molecules in the peroxide groups form that form similar clusters for combustion processes. It is accepted that the solubility limit is determined by the condition of all water molecules aggregation by the substance, and in combustible mixtures the substance aggregates all available oxygen in the air. Corresponding peroxide proportions allow the burning limits, detonation limits, stoichiometric concentration and cold flame limit to be described. An approximation formula has been developed that describes the general dependence of the n-alkanes and 2-methylalkanes autoignition temperature based on values of the cluster length and the monomer molecular weight.

Abstract: It is well known that adding the appropriate amount of Ag to semiconductor materials can enhance photocatalytic performance. In our previous study, the addition of Ag nanoparticles to ZnO enhanced the photocatalytic activity. The best photocatalytic performance was obtained when Ag content was 5 wt%. However, the effect of a carrier gas flow rate has not been investigated. The objective of this study is to investigate the effect of carrier gas flow rate on the morphology of the ZnO-Ag nanocomposites as well as the photocatalytic activity of the produced nanocomposites. ZnO-Ag nanocomposite was fabricated by a one-step process using flame pyrolysis and the produced nanocomposites were characterized by a scanning electron microscope (SEM) and X-Ray Diffraction (XRD) analysis. The photocatalytic performance was evaluated by measuring the degradation of methylene blue under UV light irradiation. SEM images indicated that the morphology of ZnO-Ag nanocomposites has a spherical shape with a particle diameter of around 65 nm. Moreover, increasing the flow rate will increase the particle size of the produced nanocomposites. The photocatalytic test was determined based on the rate constant of MB degradation efficiency under UV light irradiation, where the photocatalytic activity decreased when the carrier gas increased. Finally, the produced nanocomposites were also tested several times (recycling test), where photocatalytic performance showed that the degradation value of methylene blue for each recycle did not vary much with the variable before being recycled.

Abstract: Present paper is an attempt to illustrate a specific character of gas combustion and thermo-electrical processes in small-sized power energy-supply devices with thermoelectric methods of heat conversion. The efficiency of the heat conversion into electricity by using of thermo-elements embedded in the solid walls is estimated for a system with heat regeneration by means of the heat conductivity of the solid elements.

Abstract: To full utilization of crushed straw in civil engineering industry is necessary to know its technical parameters. During previous projects on VŠB – TUO, Faculty of Civil Engineering have found parameters like settlement, thermal conductivity or airborne sound insulation. The research on these parameters have had favorable results, therefore the research is going on and other characteristics of crushed straw are finding out. These days the research team deals with determination of important fire characteristics of crushed straw. Fire characteristics play substantial character by building materials and their design in buildings. Nature materials are generally regarded as flammable. If some material is pressed, the same rule as in the phonebook – if you ignite one sheet of paper, it burns. But if you try to ignite the whole phonebook, it will be not so easy. This article is reported the first step of research on the reaction to fire. This is the preliminary classification of crushed straw into reaction to fire. The test was made according to methods which are described below. There are some changes in methods due to different structures of crushed straw.

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: 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 (NO_x) 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.

Abstract: The mixtures formation process based only on molecular diffusion proved to be the slowest. The mixing speed is reduced due to the collision of molecules of two or more gases which are subjected to the mixing process. The gases concentrations have an important role in mixture formation. Air is one of the combustion gases in the case of mixing in order to achieve the burning process.

Abstract: At present, most of the researches on carbide surface modification are focused on the method of chemical vapor deposition and physical vapor deposition in order to enhance its wear resistance and surface hardness. In this paper, C2H2 and O2 of flame are used to deposit carbon coatings on YG 16 cemented carbide surface. The influence of deposition time have been investigated with the method of XRD, SEM. Carbon coatings structure, quality and Cross sectional microstructures of carbon coating was analyzed.The experimental result show that after different deposition time, the typical spherical diamond\nanometer carbon tube and diamond-graphite-no crystal carbon coatings have been formed on the surface of cemented carbide.

Abstract: Today, global warming is the biggest issues due the increasing of emissions from diesel fuel in transportation and manufacturing sectors [1-. The solution for this issue is by using Biodiesel fuel as alternative fuel in both sectors. Malaysia government has introduced the Biodiesel (B5) in the diesel engine for transportations [3]. Biodiesel fuel (BDF) in alternative fuel and renewable energy but it has low quality of fuel and can reduce the performance compared to the diesel fuel (DF)[4-6].

Abstract: This paper reviews the effects of premix fluids between biodiesel, air, and water for external combustion especially open burner. During burning process, biodiesel combustion involves the fuel-air mixing characteristic such as oxidation stability, stoichiometric point, bio-fuel composition, antioxidants and viscosity that influences more NOx emissions than diesel fuel. The strategies to reduce NOx emission are acquired with water additional in biodiesel fuel mixing during early stage of burning process. The method to mix biodiesel-water with injector was acquired in burner system. A vast majority of author reported that the variation in mixing of blending biodiesel ratio and water was found to enhance the burning process and mixture formation thus predominantly reducing the NOx emissions.