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Encyclopedia > Combustion
Flame resulting from the combustion (burning) of a fuel

Combustion or burning is a complex sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat or both heat and light in the form of either a glow or flames. Combustion 4 is a computer program for motion graphics, compositing and visual effects (Discreet, n. ... Image File history File links Metadata Size of this preview: 450 Ã— 600 pixelsFull resolution (1200 Ã— 1600 pixel, file size: 193 KB, MIME type: image/jpeg) File historyClick on a date/time to view the file as it appeared at that time. ... Image File history File links Metadata Size of this preview: 450 Ã— 600 pixelsFull resolution (1200 Ã— 1600 pixel, file size: 193 KB, MIME type: image/jpeg) File historyClick on a date/time to view the file as it appeared at that time. ... Flame generated by the burning of a candle. ... For other uses, see Fuel (disambiguation). ... In thermodynamics, the word exothermic describes a process or reaction that releases energy in the form of heat. ... For other uses, see Fuel (disambiguation). ... An oxidizing agent is a substance that oxidizes another substance in electrochemistry or redox chemical reactions in general. ... For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ... For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ... This article does not cite any references or sources. ... Flame generated by the burning of a candle. ...

In a complete combustion reaction, a compound reacts with an oxidizing element, such as oxygen or fluorine, and the products are compounds of each element in the fuel with the oxidizing element. For example: General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... Distinguished from fluorene and fluorone. ...

CH4 + 2O2 → CO2 + 2H2O + heat
CH2S + 6F2 → CF4 + 2HF + SF6 + heat

A simpler example can be seen in the combustion of hydrogen and oxygen, which is a commonly used reaction in rocket engines: General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ...

2H2 + O2 → 2H2O + heat

The result is simply water vapor.

In the large majority of the real world uses of combustion, the oxygen (O2) oxidant is obtained from the ambient air and the resultant flue gas from the combustion will contain nitrogen: Flue gas is gas that exits to the atmosphere via a flue, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler or steam generator. ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ...

CH4 + 2O2 + 7.52N2 → CO2 + 2H2O + 7.52N2 + heat

As can be seen, when air is the source of the oxygen, nitrogen is by far the largest part of the resultant flue gas.

In reality, combustion processes are never perfect or complete. In flue gases from combustion of carbon (as in coal combustion) or carbon compounds (as in combustion of hydrocarbons, wood etc.) both unburned carbon (as soot) and carbon compounds (CO and others) will be present. Also, when air is the oxidant, some nitrogen will be oxidized to various, mostly harmful, nitrogen oxides (NOx). For other uses, see Carbon (disambiguation). ... Coal Coal (IPA: ) is a fossil fuel formed in swamp ecosystems where plant remains were saved by water and mud from oxidization and biodegradation. ... Look up Compound in Wiktionary, the free dictionary. ... In chemistry, a hydrocarbon is a cleaning solution consisting only of carbon (C) and hydrogen (H). ... For other uses, see Wood (disambiguation). ... Soot, also called lampblack, Pigment Black 7, carbon black or black carbon, is a dark powdery deposit of unburned fuel residues, usually composed mainly of amorphous carbon, that accumulates in chimneys, automobile mufflers and other surfaces exposed to smokeâ€”especially from the combustion of carbon-rich organic fuels in the... Carbon monoxide, with the chemical formula CO, is a colorless, odorless, and tasteless gas. ... Nitrogen has six different oxides: Nitric oxide (NO) Nitrous oxide (N2O) Nitrogen dioxide (NO2) Dinitrogen trioxide (N2O3) Dinitrogen tetroxide (N2O4) Dinitrogen pentoxide (N2O5) The term nitrogen oxide is imprecise and can be used to refer to any of these or to a mixture of them. ...

### Rapid

Rapid combustion is a form of combustion in which large amounts of heat and light energy are released, which often results in a fire. This is used in a form of machinery such as internal combustion engines and in thermobaric weapons. This article does not cite any references or sources. ... For other uses, see Fire (disambiguation). ... The internal combustion engine is an engine in which the combustion of fuel and an oxidizer (typically air) occurs in a confined space called a combustion chamber. ... Thermobaric weapons distinguish themselves from conventional explosive weapons by using atmospheric oxygen, instead of carrying an oxidizer in their explosives. ...

Combustion is double replacement reaction. On the other hand a chemical reaction is single replacement reaction. In chemistry, a double-replacement reaction (or double-displacement reaction) is a reaction in which the ions of two compounds exchange places in an aqueous solution to form two new compounds. ... It has been suggested that this article or section be merged with Single replacement scheme. ...

### Slow

Slow combustion is a form of combustion which takes place at low temperatures. Respiration is an example of slow combustion. Cellular respiration was discovered by mad scientist Mr. ...

### Complete

In complete combustion, the reactant will burn in oxygen, producing a limited number of products. When a hydrocarbon burns in oxygen, the reaction will only yield carbon dioxide and water. When a hydrocarbon or any fuel burns in air, the combustion products will also include nitrogen. When elements such as carbon, nitrogen, sulfur, and iron are burned, they will yield the most common oxides. Carbon will yield carbon dioxide. Nitrogen will yield nitrogen dioxide. Sulfur will yield sulfur dioxide. Iron will yield iron(III) oxide. It should be noted that complete combustion is almost impossible to achieve. In reality, as actual combustion reactions come to equilibrium, a wide variety of major and minor species will be present. For example, the combustion of methane in air will yield, in addition to the major products of carbon dioxide and water, the minor products which include carbon monoxide, hydroxyl, nitrogen oxides, monatomic hydrogen, and monatomic oxygen. Oil refineries are key to obtaining hydrocarbons; crude oil is processed through several stages to form desirable hydrocarbons, used in fuel and other commercial products. ... [1] R-phrases , S-phrases , , , , , Supplementary data page Structure and properties n, Îµr, etc. ... Sulfur dioxide (or Sulphur dioxide) has the chemical formula SO2. ... Iron(III) oxide â€” also known as ferric oxide, Hematite, red iron oxide, synthetic maghemite, colcothar, or simply rust â€” is one of the several oxide compounds of iron, and has paramagnetic properties. ... Apparatus for carrying out acid-base titration. ...

### Turbulent

Turbulent combustion is a combustion characterized by turbulent flows. It is the most used for industrial application (e.g. gas turbines, diesel engines, etc.) because the turbulence helps the mixing process between the fuel and oxidizer.

### Incomplete

Incomplete combustion occurs when there isn't enough oxygen to allow the fuel (usually a hydrocarbon) to react completely with the oxygen to produce carbon dioxide and water, also when the combustion is quenched by a heat sink such as a solid surface or flame trap. When a hydrocarbon burns in air, the reaction will yield carbon dioxide, water, carbon monoxide, pure carbon (soot or ash) and various other compounds such as nitrogen oxides. Incomplete combustion is much more common and will produce large amounts of byproducts, and in the case of burning fuel in automobiles, these byproducts can be quite unhealthy and damaging to the environment. Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Carbon monoxide, with the chemical formula CO, is a colorless, odorless, and tasteless gas. ... Nitrogen has six different oxides: Nitric oxide (NO) Nitrous oxide (N2O) Nitrogen dioxide (NO2) Dinitrogen trioxide (N2O3) Dinitrogen tetroxide (N2O4) Dinitrogen pentoxide (N2O5) The term nitrogen oxide is imprecise and can be used to refer to any of these or to a mixture of them. ...

Quality of combustion can be improved by design of combustion devices, such as burners and internal combustion engines. Further improvements are achievable by catalytic after-burning devices (such as catalytic converters). Such devices are required by environmental legislation for cars in most countries, and may be necessary in large combustion devices, such as thermal power plants, to reach legal emission standards. A burner describes several things; A mechanical device that burns a gas or liquid fuel into a flame in a controlled manner, like in a furnace or a gas stove. ... An internal combustion engine is an engine that is powered by the expansion of hot combustion products of fuel directly acting within an engine. ... In chemistry and biology, catalysis (in Greek meaning to annul) is the acceleration of the rate of a chemical reaction by means of a substance, called a catalyst, that is itself unchanged chemically by the overall reaction. ... Catalytic converter on a Dodge Ram Van. ... Oil power plant in Iraq A power station or power plant is a facility for the generation of electric power. ... Emission standards limit the amount of pollution that can be released into the atmosphere. ...

### Smoldering

Smouldering combustion is a flameless form of combustion, deriving its heat from heterogeneous reactions occurring on the surface of a solid fuel when heated in an oxidizing environment. The fundamental difference between smouldering and flaming combustion is that in smouldering, the oxidation of the reactant species occurs on the surface of the solid rather than in the gas phase. The characteristic temperature and heat released during smoldering are low compared to those in the flaming combustion of a solid. Typical values in smouldering are around 600 °C for the peak temperature and 5 kJ/g-O2 for the heat released; typical values during flaming are around 1500 °C and 13 kJ/g-O2 respectively. These characteristics cause smoulder to propagate at low velocities, typically around 0.1 mm/s, which is about two orders of magnitude lower than the velocity of flame spread over a solid. In spite of its weak combustion characteristics, smouldering is a significant fire hazard. Smouldering (or smoldering in American spelling) combustion is a flameless form of combustion, deriving its heat from reactions occurring on the surface of a solid fuel when heated in an oxidizing environment. ...

## Combustion with other oxidants

Oxygen can be assumed as the oxidant when talking about combustion, but other oxidants exist. Nitrous oxide is used in rockets and in motorsport; it produces oxygen at over 1300 C. Fluorine, another oxidizing element, can produce a combustion reaction, to produce fluorinated products (rather than oxides). For example, mixtures of gaseous fluorine and methane are explosive, just like mixtures of oxygen and methane. Chlorine trifluoride is a strong fluorinating agent that ignites fuels more readily than oxygen. General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... For other uses, see Nitrous oxide (disambiguation). ... Distinguished from fluorene and fluorone. ... Methane is a chemical compound with the molecular formula CH4. ... Chlorine trifluoride is a colourless, very poisonous gas that condenses to a pale-yellow liquid. ...

## Chemical equation

Generally, the chemical equation for stoichiometric burning of hydrocarbon in oxygen is as follows: A chemical equation is a symbolic representation of a chemical reaction. ... It has been suggested that Stoichiometric coefficient and Gas stoichiometry be merged into this article or section. ... Oil refineries are key to obtaining hydrocarbons; crude oil is processed through several stages to form desirable hydrocarbons, used in fuel and other commercial products. ...

$C_xH_y + left( x + frac{y}{4} right) O_2 rightarrow ; xCO_2 + left( frac{y}{2} right) H_2O$

For example, the burning of propane is: Propane is a three-carbon alkane, normally a gas, but compressible to a liquid that is transportable. ...

$C_3H_8 + 5O_2 rightarrow ; 3CO_2 + 4H_2O$

The simple word equation for the combustion of a hydrocarbon in oxygen is:

$textrm{Fuel} + textrm{Oxygen} rightarrow ; textrm{Heat} + textrm{Water} + textrm{Carbon dioxide}$

If the combustion takes place using air as the oxygen source, the corresponding equations are:

$C_xH_y + left( x+ frac{y}{4} right) O_2 + 3.76 left( x+ frac{y}{4} right) N_2 rightarrow ; xCO_2 + left( frac{y}{2} right) H_2O + 3.76 left( x + frac{y}{4} right) N_2$

For example, the burning of propane is: Propane is a three-carbon alkane, normally a gas, but compressible to a liquid that is transportable. ...

$C_3H_8 + 5O_2 + 18.8N_2 rightarrow ; 3CO_2 + 4H_2O + 18.8N_2$

The simple word equation for the combustion of a hydrocarbon in air is:

$textrm{Fuel} + textrm{Air} rightarrow ; textrm{Heat} + textrm{Water} + textrm{Carbon dioxide} + textrm{Nitrogen}$

## Fuels

### Liquid fuels

Combustion of a liquid fuel in an oxidizing atmosphere actually happens in the gas phase. It is the vapour that burns, not the liquid. Therefore, a liquid will normally catch fire only above a certain temperature, its flash point. The flash point of a liquid fuel is the lowest temperature at which it can form an ignitable mix with air. It is also the minimum temperature at which there is enough evaporated fuel in the air to start combustion. For other uses, see Flash point (disambiguation). ...

### Solid fuels

The act of combustion consists of three relatively distinct but overlapping phases:

• Preheating phase, when the unburned fuel is heated up to its flash point and then fire point. Flammable gases start being evolved in a process similar to dry distillation.
• Distillation phase or gaseous phase, when the mix of evolved flammable gases with oxygen is ignited. Energy is produced in the form of heat and light. Flames are often visible. Heat transfer from the combustion to the solid maintains the evolution of flammable vapours.
• Charcoal phase or solid phase, when the output of flammable gases from the material is too low for persistent presence of flame and the charred fuel does not burn rapidly anymore but just glows and later only smoulders.

For other uses, see Fuel (disambiguation). ... The fire point of a substance is the temperature at which it will combust and continue to burn of its own accord, that means the evaporation rate is high enough so new vapor-air mixture is produced at least at the same rate as it is burned. ... Dry distillation is the heating of solid materials to produce liquid or gaseous products (which may condense into solids). ... Flame can refer to: Fire A flame is a self-sustaining oxidizing chemical reaction producing energy and ionized gas (plasma). ... Charring is a process of incomplete combustion that often occurs when biological tissue (living or dead) is subjected to heat. ... Smouldering (or smoldering in American spelling) combustion is a flameless form of combustion, deriving its heat from reactions occurring on the surface of a solid fuel when heated in an oxidizing environment. ...

## Temperature

Assuming perfect combustion conditions, such as complete combustion under adiabatic conditions (i.e., no heat loss or gain), the adiabatic combustion temperature can be determined. The formula that yields this temperature is based on the first law of thermodynamics and takes note of the fact that the heat of combustion is used entirely for heating the fuel, the combustion air or oxygen, and the combustion product gases (commonly referred to as the flue gas). This article covers adiabatic processes in thermodynamics. ... The first law of thermodynamics, a generalized expression of the law of the conservation of energy, states: // Description Essentially, the First Law of Thermodynamics declares that energy is conserved for a closed system, with heat and work being the forms of energy transfer. ... It has been suggested that this article or section be merged with Heating value. ... Flue gas is gas that exits to the atmosphere via a flue, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler or steam generator. ...

In the case of fossil fuels burnt in air, the combustion temperature depends on

• the heating value
• the stoichiometric air to fuel ratio λ
• the heat capacity of fuel and air
• the air and fuel inlet temperatures

The adiabatic combustion temperature (also known as the adiabatic flame temperature) increases for higher heating values and inlet air and fuel temperatures and for stoichiometric air ratios approaching one. Air-fuel ratio (AFR) is the mass ratio of air to fuel present during combustion. ... In the study of combustion, there are two types of adiabatic flame temperature depending on how the process is completed: constant volume and constant pressure. ...

Most commonly, the adiabatic combustion temperatures for coals are around 2200 °C (for inlet air and fuel at ambient temperatures and for λ = 1.0), around 2150 °C for oil and 2000 °C for natural gas.

In industrial fired heaters, power plant steam generators, and large gas-fired turbines, the more common way of expressing the usage of more than the stoichiometric combustion air is percent excess combustion air. For example, excess combustion air of 15 percent means that 15 percent more than the required stoichiometric air is being used. A furnace is a device for heating air or any other fluid. ... A power station (also power plant) is a facility for the generation of electric power. ... This machine has a single-stage centrifugal compressor and turbine, a recuperator, and foil bearings. ... Air-fuel ratio (AFR) is the mass ratio of air to fuel present during combustion. ...

## Analysis

This section provides a combustion analysis for a few typical fuel cases (carbon, hydrogen, sulfur, coal, oil and gas) when the fuel reacts with air at stoichiometric conditions.

In the presented combustion analysis, both fuel and air are at inlet combustion conditions of 298 K and 1 atm of absolute pressure. Furthermore, combustion is complete and with no heat loss.

Figure 1: Reactants and combustion products enthalpy vs temperature

During the combustion, a large amount of reactants' chemical energy gets released in the form of thermal energy. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ...

Enthalpy of combustion (HHV or higher heating value) is the difference between the reactants enthalpy value minus the combustion products enthalpy value at the reference temperature, which is 298 K.

When the reactants enthalpy value is equal to the combustion products enthalpy value, one can calculate the combustion products adiabatic flame temperature.

The plot in Figure 1 depicts the reactants and combustion products enthalpy value change with an increase in the temperature.

Physical properties for both reactants and combustion products are very important and need to be known in order to carry out successful combustion calculations.

The plot in Figure 2 depicts how the reactants and combustion products species enthalpy values change with the temperature. The physical properties provided in this plot come from the JANAF Thermochemical Data - Tables, 1970.

Figure 2: Reactants and combustion products species enthalpy vs temperature

It is interesting to note that the enthalpy value for basic combustion elements such as carbon (C), hydrogen (H), sulfur (S), oxygen (O) and nitrogen (N) is equal to zero at the combustion conditions of 298 K and 1 atm. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ...

Also, it should be mentioned that for ideal gas species, the enthalpy value is only dependent on the temperature.

In addition to knowing the reactants and combustion products physical properties, for any kind of combustion analysis and calculations, it is important to know both fuel and oxidant compositions.

For solid and liquid type fuels, the fuel compositions is given on the weight basis for a unit mass amount. In this analysis, CH4 is the only gas fuel considered. In order to keep the combustion analysis simple and straightforward, the CH4 composition is provided on the weight basis. Oxidant composition is usually given on the mole/volume basis.

Table 1 provides some fuel compositions:

Table 1: Fuel Composition (proportion by mass)
Fuel C H S N O H2O CH4
Carbon 1.000 0.000 0.000 0.000 0.000 0.000 -
Hydrogen 0.000 1.000 0.000 0.000 0.000 0.000 -
Sulfur 0.000 0.000 1.000 0.000 0.000 0.000 -
Coal 0.780 0.050 0.030 0.040 0.080 0.020 -
Oil 0.860 0.140 0.000 0.000 0.000 0.000 -
Fuel Gas - - - - - - 1.000

Table 2 provides the composition of air:

Table 2: Oxidant/Air Composition
Oxidant N
kg/kg
O
kg/kg
N2
mol/mol
O2
mol/mol
Air 0.767 0.233 0.790 0.210

Again, in this combustion analysis, only the stoichiometric combustion is analyzed. Results of such analysis are provided, including the combustion gas products composition on weight and mole/volume basis, the adiabatic flame temperature, the stoichiometric ratio and the fuel's higher heating value (HHV).

Table 3 provides the combustion gas products composition on a weight basis:

Table 3: Combustion Products on a Weight Basis (proportion by mass)
Fuel CO2 H2O SO2 N2 O2
Carbon 0.295 0.000 0.000 0.705 0.000
Hydrogen 0.000 0.255 0.000 0.745 0.000
Sulfur 0.000 0.000 0.378 0.622 0.000
Coal 0.249 0.041 0.005 0.705 0.000
Oil 0.203 0.079 0.000 0.718 0.000
Fuel Gas 0.151 0.124 0.000 0.725 0.000

Table 4 provides the combustion gas products composition on a volume or mole basis:

Table 4: Combustion Products on Mole Basis (proportion by moles)
Fuel CO2 H2O SO2 N2 O2
Carbon 0.210 0.000 0.000 0.790 0.000
Hydrogen 0.000 0.347 0.000 0.653 0.000
Sulfur 0.000 0.000 0.210 0.789 0.000
Coal 0.170 0.068 0.002 0.759 0.000
Oil 0.133 0.127 0.000 0.740 0.000
Fuel Gas 0.095 0.190 0.000 0.715 0.000

When considering coal, oil and gas as the fuel, coal has the largest amount of CO2 in the combustion gas products on both weight and mole basis.

Table 5 provides the combustion adiabatic flame temperature, stoichiometric ratio and the fuel's higher heating value:

Table 5: Other Fuel Characteristics
Flame Temperature (K)
Stoichiometric Ratio
(see note below)
HHV (kJ/kg)
Carbon 2,460 11.444 32,779.8
Hydrogen 2,525 34.333 141,866.8
Sulfur (solid) 1,972 4.292 9,261.3
Coal 2,484 10.487 32,937.9
Oil 2,484 14.580 47,630.0
Fuel Gas 2,327 17.167 50,151.2
Note: Stoichiometric ratio is the mass of air required for complete combustion of a unit mass of fuel. Thus, 1 kg of carbon fuel requires 11.444 kg of air for complete, ideal combustion.

Today, global warming is becoming more evident and it is being said that it is primarily caused by CO2 emissions. A detailed combustion analysis, as it is provided here, can be very useful in determining different fuel and technology scenarios that would result in the reduction of current CO2 emissions.

## Instabilities

Combustion instabilities are typically violent pressure oscillations in a combustion chamber. These pressure oscillations can be as high as 180dB, and long term exposure to these cyclic pressure and thermal loads reduces the life of engine components. In rockets, such as the F1 used in the Saturn V program, instabilities led to massive damage of the combustion chamber and surrounding components. This problem was solved by re-designing the fuel injector. In liquid jet engines the droplet size and distribution can be used to attenuate the instabilities. Combustion instabilities are a major concern in ground-based gas turbine engines because of NOx emissions. The tendency is to run lean, an equivalence ratio less than 1, to reduce the combustion temperature and thus reduce the NOx emissions; however, running the combustor lean makes it very susceptible to combustion instabilities.

The Rayleigh Criterion is the basis for analysis of thermoacoustic combustion instabilities and is evaluated using the Rayleigh Index over one cycle of instability.

$G(x)=frac{1}{T}int_{T}q'(x,t)p'(x,t)dt$

When the heat release oscillations are in phase with the pressure oscillations the Rayleigh Index is positive and the magnitude of the thermoacoustic instability increases. Consecutively if the Rayleigh Index is negative then thermoacoustic damping occurs. The Rayleigh Criterion implies that a thermoacoustic instability can be optimally controlled by having heat release oscillations 180 degrees out of phase with pressure oscillations at the same frequency. This minimizes the Rayleigh Index.

#### Social applications and issues

Air-fuel ratio (AFR) is the mass ratio of air to fuel present during combustion. ... A log in a fire place. ... A weapons cache is detonated at the East River Range on Bagram Airfield, Afghanistan Detonation is a process of supersonic combustion in which a shock wave is propagated forward due to energy release in a reaction zone behind it. ... For other uses, see Fire (disambiguation). ... The combustion product gas resulting from the burning of fossil fuels (or any other combustible fuel) is called flue gas. ... Flue gas stack at GRES-2 Power Plant in Ekibastus, Kazachstan is 420 meters tall Flue gas stacks are large vertical pipes, channels or similar structures through which combustion product gases (called flue gases) produced when coal, oil, natural gas, wood or any other fuel is combusted in an industrial... Stoichiometry is the quantitative relationship between reactants and products in a chemical reaction. ... It has been suggested that this article or section be merged with Heating value. ... Phlogiston theory was a 17th century attempt to explain oxidation processes, such as fire and rust. ... Simple sketch of pyrolysis chemistry Pyrolysis usually means the chemical decomposition of organic materials by heating in the absence of oxygen or any other reagents, except possibly steam. ... A pyrophoric substance is a substance that ignites spontaneously, that is, its autoignition temperature is below room temperature. ... Smoldering (or smouldering in British spelling) is slow combustion without generating flame, barely spreading. ... Spontaneous combustion is a type of combustion which occurs without an external ignition source. ... It has been suggested that Stoichiometric coefficient and Gas stoichiometry be merged into this article or section. ... A boiler is a closed vessel in which water or other fluid is heated under pressure. ... A trio of propane hot water heaters. ... A cyclone furnace is a type of coal combustor commonly used in large industrial boilers. ... An external combustion engine is an engine which burns its fuel to heat a separate working fluid which then in turn performs work. ... A furnace is a device for heating air or any other fluid. ... This machine has a single-stage centrifugal compressor and turbine, a recuperator, and foil bearings. ... The internal combustion engine is an engine in which the combustion of fuel and an oxidizer (typically air) occurs in a confined space called a combustion chamber. ... A Pratt and Whitney turbofan engine for the F-15 Eagle is tested at Robins Air Force Base, Georgia, USA. The tunnel behind the engine muffles noise and allows exhaust to escape. ... A cold (un-ignited) rocket engine test at NASA A rocket engine is a reaction engine that can be used for spacecraft propulsion as well as terrestrial uses, such as missiles. ... Many types of rotary combustion engine, like the Quasiturbine or the Wankel engine, have been devised [1], all having the same basic concept; to avoid the reciprocating motion of the piston with its inherent vibration and rotational-speed-related mechanical stress. ... Staged combustion rocket cycle. ... A calorimeter is a device used for calorimetry, the science of measuring the heat of chemical reactions or physical changes as well as heat capacity. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... Laser Doppler velocimetry (LDV, also known as laser Doppler anemometry, or LDA) is a technique for measuring the direction and speed of fluids like air and water. ... Laser-induced fluorescence (LIF) is a spectroscopic method. ... Particle Image velocimetry (PIV) is an optical method used to measure velocities and related properties in fluids. ... Cooking is the act of preparing food. ... Global warming refers to the increase in the average temperature of the Earths near-surface air and oceans in recent decades and its projected continuation. ... Immolation means a sacrificial killing by burning, such as: Animal sacrifice Human sacrifice Sati is a Hindu funeral custom involving immolation. ...

Results from FactBites:

 Combustion | Wastes | US EPA (136 words) Combustion reduces the volume of waste that must be disposed in landfills, and can reduce the toxicity of waste. Combustion can also result in significant energy and material recovery — waste combustion can be used to generate energy, and in some cases, the ash that is generated can be recovered and beneficially-used (e.g., as landfill cover, or as aggregate in asphalt concrete). In addition, combustion ash must be managed as potentially hazardous waste under the purview of the Resource Conservation and Recovery Act (RCRA), and must meet all applicable federal and state regulations for disposal.
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