Combustion

& Carbon Dioxide Essay, Research Paper

COMBUSTIOn & carbon Dioxide

Research

By Rabon Hutcherson II.

Combustion and carbon dioxide, what are they. When people think of combustion they probably think of simple just bursting into flames; and for carbon dioxide you probably think of what we breath out and what plants take from the air and turn to oxygen. Even though these thoughts are true there is much more to combustion and carbon dioxide. Things you might not think of about combustion are, mathematical equations, models, solutions and chemical reactions, and for carbon dioxide dry ice, combustion and it being a solid. All of these factors you may not have known are now here for you to see.

One of the things that has lead the way for the study of combustion is the Combustion Theory. Combustion Theory is the use of theoretical methods (mathematics, modeling, numerics, etc. in the study of combustion phenomena. Although Faraday and others in the middle of the 19th century and around beginning of the 20th century laid some early foundations, it was not until the middle of the 20th Century that von Karman and a Russian School, involving Frank-Kamenetskii and Zeldovich, prepared a sound basis for the theory. Von Kerman referred to this as “aerothermochemistry”, in which every imaginable physical transport, chemical and thermodynamic process is thrown into the melting pot – a vast field of developing knowledge in Physics, Chemistry, Engineering and Mathematics. The development of systematic asymptotic techniques in Caltech during the 1960s opened the way towards revealing an underlying simplicity in many combustion processes, involving fairly simple mathematical models and solutions. Computers have also made it possible to treat many problems in their fuller, more complicated form. It can also be stated that Combustion Theory has provided a rich range of equations with fascinating mathematical properties. These include the Sivashinsky equation which approximates the destabilizing effect of density change in flames; the Kuramoto-Sivashinsky equation which approximates an anti-diffusive destabilizing effect that some flames possess; and Clarke’s equation which describes chemical and pressure-wave interactions in a detonable chemical mixture. These equations, and some milestone solutions and dimensionless numbers that have helped to punctuate the growth of this field of research can be spotted in the following artistic impression of “Combustion Theory.. The three fundamentals for combustion are fire, fuel and heat. Fire is a chemical reaction involving rapid oxidation or burning of a fuel. It needs three elements to occur, fuel can be any combustible material – solid, liquid or gas. Most solids and liquids become a vapor or gas before they will burn. The air we breathe is about 21 percent oxygen. Fire only needs an atmosphere with at least 16 percent oxygen. Heat is the energy necessary to increase the temperature of the fuel to a point where sufficient vapors are given off for ignition to occur. Heat of combustion, heat released during combustion. In particular, it is the amount of heat released when a given amount (usually 1 mole) of a combustible pure substance is burned to form incombustible products (e.g., water and carbon dioxide); this amount of heat is a characteristic of the substance. Heats of combustion are used as a basis for comparing the heating value of fuels, since the fuel that produces the greater amount of heat for a given cost is the more economic. Heats of combustion are also used in comparing the stabilities of chemical compounds. For example, if equal quantities of two isomeric hydrocarbons burn to produce equal amounts of carbon dioxide and water, the one releasing more energy is less stable, since it was the more energetic in its compounded form. Certain combustible metals, such as magnesium, titanium, potassium and sodium burn at high temperatures and give off sufficient oxygen to support combustion. They may react violently with water or other chemicals, and must be handled with care. Combustion, rapid chemical reaction of two or more substances with a characteristic liberation of heat and light; it is commonly called burning. The burning of a fuel (e.g., wood, coal, oil, or natural gas) in air is a familiar example of combustion. Combustion need not involve oxygen; e.g., hydrogen burns in chlorine to form hydrogen chloride with the liberation of heat and light characteristic of combustion. Combustion reactions involve oxidation and reduction. Before a substance will burn it must be heated to its ignition point, or kindling temperature. Pure substances have characteristic ignition points. Although the ignition point of a substance is essentially constant, the time needed for burning to begin depends on such factors as the form of the substance and the amount of oxygen in the air. A finely divided substance is more readily ignited than a massive one; e.g., sawdust ignites more rapidly than does a log. The vapors of a volatile fuel such as gasoline are more readily ignited than is the fuel itself. The rate of combustion is also affected by these factors, particularly by the amount of oxygen in the air. The nature of combustion was not always clearly understood. The ancient Greeks believed fire to be a basic element of the universe. It was not until 1774 that the French chemist A. L. Lavoisier performed experiments that led