Showing papers on "Combustion published in 1975"

Internal combustion engine with auxiliary combustion chamber

Abstract: An internal combustion engine with an auxiliary combustion chamber is provided with a main combustion chamber for the combustion of an air-fuel mixture, an auxiliary combustion chamber communicating with the main combustion chamber through a passage, such that the ignition of an air-fuel mixture in the auxiliary combustion chamber induces ignition and combustion of the air-fuel mixture in the main combustion chamber, and an intake valve provided in the auxiliary combustion chamber for opening and closing a passage which leads to a fuel supply means. The engine further includes an intake valve lifter having a piston member which is associated with the intake valve and a cylinder member in which such piston member moves, a fluid pressure supply device driven in synchronism with the rotation of the engine to supply a fluid pressure, and a fluid pressure supply passage for feeding the fluid pressure which is supplied by the fluid pressure supply device to the intake valve lifter. Accordingly, the control of the opening and closing operations of the intake valve of the auxiliary combustion chamber can be performed in accordance with any driving conditions by feeding the fluid pressure supplied by the fluid pressure supply device to the intake valve lifter through the fluid pressure supply passage and moving the piston member in synchronism with the rotation of the internal combustion engine.

Flame retardant polymeric materials

Abstract: 1 The Flame Retardation of Polyolefins.- 1. Introduction.- 2. Flame Retardancy Tests.- 3. Polypropylene.- 4. Polypropylene Copolymers.- 5. Low-Density Polyethylene (LDPE).- 6. High-Density Polyethylene.- 7. Cross-Linked Polyethylene.- 8. Ionomers.- 9. Polybutylene.- 10. Ethylene-Propylene-Dimer Rubber.- 11. Ethylene-Propylene-Dimer (EPDM) Rubber Wire and Cable Insulation.- 12. References.- 2 Methods for Reduction of Smoke from Burning Polymers.- 1. Introduction.- 2. Smoke.- 2.1. Phenomenon.- 2.2. Smoke Measurement.- 2.3. Factors Affecting Measured Smoke Values.- 3. Smoke Inhibition Technology.- 3.1. Background.- 3.2. Smoke Inhibition in Polymers.- 4. Summary and Conclusions.- 5. References.- 3 Experimental Evaluation of Flammability Parameters of Polymeric Materials.- Abstract.- Objectives.- 1. Introduction.- 2. Experimental Procedures.- 2.1. Sample and Sample Container.- 2.2. Total Flow Rate of Mixture of Air-O2-N2 and Mass Fraction of Oxygen.- 2.3. External Heat Flux.- 2.4. Ignition.- 2.5. Mass Loss Rate.- 2.6. Total Mass Flow Rate of Mixture of Products and Air.- 2.7. Convective Heat Release Rate.- 2.8. Mass Generation Rates of Gaseous Pyrolysis-Combustion Products.- 2.9. Mass Generation Rate of the Pyrolyzate Fraction Collected on a Filter Paper.- 2.10. Optical Transmission Through the Mixture of Pyrolysis-Combustion Products and Air.- 3. Ignition.- 3.1. Concept.- 3.2. Measurements and Calculations.- 3.3. Data for Ignition Parameters.- 3.4. Conclusion.- 4. Mass Loss Rate in the Pyrolysis and Combustion of Polymers.- 4.1. Pyrolysis.- 4.2. Combustion.- 4.3. Conclusions.- 5. Mass Generation (or Depletion) Rates of Products.- 5.1. Concept.- 5.2. Measurements and Calculations.- 5.3. Data for the Distribution of Carbon in the Combustion Products.- 5.4. Conclusions.- 6. Heat Release Rate.- 6.1. Concept.- 6.2. Measurements and Calculations.- 6.3. Data for the Heat Release Rate Fractions.- 6.4. Conclusions.- 7. Optical Transmission Through the Mixture of Pyrolysis-Combustion Products and Air.- 7.1. Concept.- 7.2. Measurements and Calculations.- 7.3. Data for Modified Mass Absorbancy Index of "Pyrolyzate".- 7.4. Conclusions.- 8. Generation of Toxic Compounds.- 8.1 Concept.- 9. Fire Extinction.- 9.1 Concept.- 10. Nomenclature.- 11. List of Components for Experimental Apparatus.- 12. References.- 4 Flammability Evaluation Methods for Textiles.- 1. Introduction.- 2. Evaluation Methods for Fabrics Which Are Expected to Self-Extinguish.- 2.1. Vertical Tests.- 2.2. Horizontal Tests.- 3. Standards for Both Self-Extinguishing and Flammable Fabrics.- 4. Test Methods for Flammable Fabrics.- 4.1. Flame Spread Rate Tests.- 5. Ignition Time Tests.- 6. Heat Evolution Measurements.- 7. Extinguishability.- 8. Effect of Laundering, Soiling, and Weathering on Flammability.- 9. OI and Other Research Methods.- 10. Evaluation Methods for Specific End-Use Items.- 10.1. Blankets.- 10.2. Carpets.- 10.3. Curtains and Draperies.- 10.4. Mattresses.- 10.5. Upholstered Furniture.- 10.6. Protective Clothing.- 11. Thermal Behavior of Textile Materials.- 12. References.- 5 The Analysis of Polymers and Polymer Degradation Products by Mass Spectrometry.- 1. Introduction.- 2. Direct Analysis of Polymers.- 3. Analysis of Polymer Degradation Products.- 3.1. Thermal Degradation.- 3.2. Dielectric Breakdown.- 3.3. Mechanical Stress-Induced Degradation.- 3.4. Photolytic Degradation.- 4. Conclusion.- 5. References.

A computer program for calculating properties of equilibrium combustion products with some applications to i.c. engines

Abstract: A computer program which rapidly calculates the equilibrium mole fractions and the partial derivatives of the mole fractions with respect to temperature, pressure and equivalence ratio for the products of combustion of any hydrocarbon fuel and air is described. A subroutine is also given which calculates the gas constant, enthalpy, internal energy and the partial derivatives of these with respect to temperature, pressure and equivalence ratio. Some examples of the uses of the programs are also given. /GMRL/

A New Class of Combustion Processes

Abstract: A short information is given on the results of work carried out at the Branch of the Institute of Chemical Physics, U.S.S.R. Academy of Sciences, since 1967 on studying the combustion processes caused by the interaction of chemical elements in the condensed phase and leading to the formation of refractory compounds. New phenomena and processes are described which are revealed when investigating the combustion of the systems of this class, viz solid-phase combustion.fast combustion in the condensed phase, filtering combustion, combustion in liquid nitrogen, spinning combustion, self-oscillating combustion and repeated combustion. A new direction in employment of combustion processes is discussed, viz. a self-propagating high-temperature synthesis of refractory nitrides, carbides, borides, silicides and other compounds.

Hydrogen rich gas generator

Abstract: A process and apparatus is described for producing a hydrogen rich gas by injecting air and hydrocarbon fuel at one end of a cylindrically shaped chamber to form a mixture, igniting the mixture to provide hot combustion gases, by partial oxidation of the hydrocarbon fuel. The combustion gases move away from the ignition region to another region where water is injected to be turned into steam by the hot combustion gases. The steam which is formed mixes with the hot gases present to yield a uniform hot gas whereby a steam reforming reaction with the hydrocarbon fuel takes place to produce a hydrogen rich gas.

Measurement of atomic oxygen and nitrogen oxides in jet-stirred combustion

Abstract: Direct spectroscopic measurement of continuum chemiluminescence at 3500 A, due presumably to the reaction CO+O→CO 2 + hv , was used to determine super-equilibrium atomic oxygen concentrations in situ for near-homogeneous, continuous-combustion of either carbon monoxide or methane with 133% theoretical air in a jet-stirred reactor operated near blowout, at atmospheric pressure. Reactor CO and NO x concentrations were measured by gas sampling. The motivation for this initial optical spectroscopic examination of the jet-stirred reactor was the elucidation of NO x formation in high-intensity, backmixed combustion. Measured gas temperatures were in the ranges T =1350 to 1500°K for carbon monoxide combustion, and T =1400° to 1800°K for methane combustion. Peak atom oxygen concentrations occurred just prior to reactor blowout. Partial equilibrium was indicated for the reactions CO+OH⇆CO 2 +H and O 2 +H⇆O+OH, at throughput rates sufficiently less than reactor blowout. Atomic oxygen measurements were used to compare NO x measurements with values predicted for plausible NO x kinetic formation mechanisms, considering only O, OH, and H as reaction radical intermediates. Agreement between the comparisons was obtained only for carbon monoxide combustion, indicating that nitrous oxide probably acts as an intermediate in NO x formation in the presence of super-equilibrium concentrations of atomic oxygen.

In situ hydrogenation of hydrocarbons in underground formations

Abstract: A process and system for insitu hydrogenation employing a gas generator in a borehole for burning a hydrogen-rich mixture of hydrogen and oxygen. The gas generator comprises a housing forming a chamber with a combustion zone at one end and a restricted outlet at the other end. A cooling annulus surrounds the chamber with passages leading from the annulus to the chamber. Hydrogen and oxygen are supplied downhole to the generator to form a hydrogen-rich combustible mixture in the combustion zone which is burned whereby hydrogen and steam are injected from the restricted outlet. Hydrogen also is supplied to the cooling annulus. The flow of hydrogen and oxygen to the generator is controlled to maintain the temperature of the exhaust gases at a level sufficient to crack the hydrocarbons in the formations into lighter segments for reaction with the excess hot hydrogen to form lighter and less viscous end products which are recovered from a production well.

In situ coal combustion heat recovery method

Abstract: A method for recovery of heat generated by the combustion of coal in situ within coal seams in the earth. Three embodiments are described: one, in which the coal seam crops out and into which can be drilled and inserted a pipe, through the coal seam, to a central point, where it is joined with a vertical pipe drilled from the surface. Water is supplied to the pipe at the point of outcrop. Fires are started within the coal seam and supplied with air from the surface by means of drilled boreholes. The heat of combustion converts the water in the pipe to steam which travels up the vertical pipe and is used to drive a turbine generator system. A second embodiment is used where there is an overlying aquafer above the coal seam. Fires are started by means of air supplied through boreholes leading from the surface into the coal seam. The heat of combustion converts the water in the aquafer to steam, which then is circulated out of the aquafer and up to the surface where it drives a turbine generator system. A third embodiment uses the hot combustion gases to heat water to steam in pipes in a vertical borehole.

Clear and stable liquid fuel compositions for internal combustion engines

Abstract: A fuel composition, preferably for use in internal combustion engines, comprising a water-in-oil emulsion of (a) a hydrocarbon fuel, such as gasoline, diesel fuel or fuel oil; (b) water; (c) preferably a water-soluble alcohol; and (d) a novel combination of surface-active agents to provide a clear composition which is stable against phase separation over a wide range of temperatures.

Extreme toxicity from combustion products of a fire-retarded polyurethane foam.

Abstract: The products from nonflaming combustion of wood and a trimethylol-propane-based rigid-urethane foam that was not fire-retarded produced elevated carboxyhemoglobin levels but no abnormal neurological effects. However, when this type of foam contained a reactive phosphate fire retardant, the combustion products caused grand mal seizures and death in rats. The toxic combustion product responsible for the seizures has been identified as 4-ethyl-1-phospha-2,6,7-trioxabicyclo(2.2.2.)octane-1-oxide.

Burner configurations for staged combustion

Abstract: Burner arrangements for staged combustion to decrease nitrogen oxides (NOx) during the combustion of hydrocarbon fuel with air. The burner arrangements have a combustion into which hydrocarbon fuel and less than 70% of the stoichiometric air are introduced, and a path for the secondary air around the combustion chamber. A flame holding means is provided in one end of the combustion chamber to stabilize the substoichiometric combustion so that a partially burned gas containing mainly H2 and CO as combustible components is obtained. The combustion chamber has an exit, and there is an exit from the secondary air path near the exit of the combustion chamber. A discharging means for the partially burned gas is provided at the exit of the combustion chamber to vary the pattern of the flow of said partially burned gas by converting the enthalpy of said partially burned gas into kinetic energy. A discharging means for the secondary air is also provided at the exit for the secondary air to vary the pattern of the flow of the secondary air.

Manufacture of combustible gases

Abstract: Substantially sulfur-free combustible fuel gas under superatmospheric pressure is produced by partial combustion or gasification under superatmospheric pressure of a sulfur-containing solid, liquid or gaseous fuel. The gasification is effected within a fluidized bed of particles containing alkaline earth metal compounds (e.g. the oxides) which are capable of reacting with, and of fixing, the fuel sulfur as sulfides under reducing conditions. Sulfide-containing particles are exposed to an oxidizing atmosphere and the sulfides are thereby converted to oxides with the liberation of SO 2 in useful concentrations, and with the liberation of heat. Particles containing regenerated oxides are re-used for fixing more sulfur during fuel gasification. Expedients are described by which it is ensured that the sulfur-fixing activity of the particles is substantially maintained and that the temperatures of the particles during sulfur-fixing and regeneration are maintained within predetermined ranges. The pressurized sulfur-free fuel gas may be directly used to power a gas turbine.

Catalytic abatement system

Abstract: An apparatus for the thermal-catalytic abatement of hydrocarbons, carbon monoxide, nitrogen oxides and particulates from effluent gas streams. The apparatus has a preheat section wherein the effluent is heated to 400°-1000° F by hot combustion gases. The effluent and combustion gases are directed by a baffle through a filter where combustible particulates are incinerated and noncombustible particulates are collected. The baffle followed by a diffuser cone, axially located on the filter, intimately mixes the effluent with the combustion gases so as to provide uniform flow and temperature distribution of the mixed gases across the filter. The filtered gases then pass through a catalytic reactor section containing a catalyst, preferably catalyst-coated ceramic honeycombs. In the presence of the catalysts the hydrocarbons and carbon monoxide in the heated gas stream are oxidized to carbon dioxide and water and the nitrogen oxides are reduced.

Effects of Equivalence Ratio and Dwell Time on Exhaust Emissions From an Experimental Premixing Prevaporizing Burner

Abstract: A flame-tube study was performed to determine the effects of equivalence ratio and residence time on exhaust emissions with premixed, prevaporized propane fuel. Nitrogen oxides emissions as low as .3 g NO2/kg fuel were measured with greater than 99% combustion efficiency at 800 K inlet temperature and an equivalence ratio of .4. For a constant combustion efficiency, lower nitrogen oxides emissions were obtained by burning very lean with relatively long residence times than by using somewhat higher equivalence ratios with shorter times.

Flame propagation in fuel droplet-vapor-air mixtures

Abstract: As a simple model of spray combustion, a mono-sized ethanol droplet-vapor-air system has been realized using an expansion apparatus based on the principle of the Wilson cloud chamber, in which the mean droplet diameter can be varied up to 7 microns at its maximum. The burning time, peak pressure, flame speed and burning velocity have been measured for mixtures containing droplets, as well as for homogeneous vapor-air mixtures. The effects of fuel droplets on the burning characteristics are more significant for fast burning mixtures than for slow burning mixtures, suggesting that ethanol droplets of several microns in diameter are not completely evaporated in the preheating zone. Microphotographic studies have also been made for mixtures containing larger droplets (about 20 microns in diameter) to observe the fine structure of the flame propagating in a droplet-vapor-air mixture. Shadow photographs of droplets suspended in the chamber and schlieren photographs of the flame have been taken by means of a high-magnification camera. Many spots probably due to the vapor from droplets are noticeable ahead of the flame boundary, which is rough and difficult to determine precisely.

Studies on the structure of a spray combustion flame

Abstract: To clarify the flame structure of a spray burner, the following experiments and analysis were carried out. (1) Droplet and temperature distributions, flow velocity, and gas composition were measured in the flame of an air-atomizing burner. It was found that the region where the droplets exist is limited to a small area above the burner nozzle. From the correlation between the above various distributions, it was concluded that most of the droplets in the flame do not burn individually, but that fuel vapor from the droplets concentrates and burns like a gas diffusion flame. (2) Various measurements were then made on a spray combustion flame and a turbulent gas diffusion flame under the same conditions. Comparing the two sets of data, it was found that the flames are similar in structure. (3) Assuming that the droplets evaporate in the flame, their behavior was analyzed by making use of the knowledge which has been obtained for a single droplet. The calculated results were in fairly close agreement with the experimental results. The above facts suggest the possibility that the spray combustion flame could be treated theoretically by applying the information for a single droplet and for a turbulent gas diffusion flame.

Reduction of gaseous pollutants in combustion flue gas

Abstract: Fuel is burned in a primary combustion chamber with less than the air required for stoichiometric combustion so that the combustion gases have a high carbon monoxide (CO) and a hydrocarbon content and the temperature of the gases is held below that at which significant nitrogen oxides (NOx) would be produced. The combustion gases are then passed through a secondary combustion zone in which more air is injected into the gas stream to oxidize the CO and hydrocarbons to carbon dioxide (CO2). The secondary burner comprises a plurality of foraminous tubes through which secondary air is emitted. Combustion in the secondary zone is maintained at a temperature below that at which nitrogen oxides (NOx) will be produced in significant quantities.

Thermodynamic prime mover with heat exchanger

Abstract: The useful life of a gas turbine combustion chamber and especially its flame pipe is increased by an improved cooling arrangement which branches off a small proportion of the air from the compressor upstream of the combustion chamber. The branched off air is directed into the combustion chamber and onto the flame pipe so that it flows in a cooling manner around at least the front end of the flame pipe without initially substantially participating in the combustion.

Physiological and toxicological aspects of smoke produced during the combustion of polymeric materials.

Abstract: Normally one expects that flame contact is the major cause of injury and death during fires. Analysis of the factors involved in numerous fires has revealed that most deaths were not due to flame contact, but were a consequence of the production of carbon monoxide, nitrogen oxides, and other combustion products, such as aldehydes, low molecular weight alcohols, hydrogen cyanide, and other noxious species. The major emphasis within the scope of this paper relates to the physiological and toxicological aspects of smoke produced during the combustion of materials. Special emphasis is directed toward laboratory procedures which have been developed to determine the qualitative and quantitative analysis of smoke, factors pertaining to smoke development, and to measure the response of laboratory animals exposed to smoke. The effects that fire retardants, incorporated into polymeric materials as a means of improving flammability characteristics, may have on smoke development, the mechanism of polymer degradation, and on the survival response of laboratory animals are also considered.

Further investigations of combustion of free droplets in a freely falling chamber including moving droplets

Abstract: For the further investigation of the combustion of free droplets under a zero-gravity condition in a freely falling chamber, the experimental apparatus and technique were improved as follows: Increased duration of zero-gravity condition; observation of moving droplets as well as stationary droplets; and schlieren system to observe the hot gas zone. In addition to n -heptane, ethyl alcohol and benzene were also used as fuels. The effects of the initial droplet diameter on the evaporation constant and the variation of the flame/droplet diameter ratio were found to be completely consistent with predictions based on the authors' previous experiment. The influence of the relative velocity of moving droplets on their combustion characteristics such as the evaporation constant, flame shape and behavior of the hot gas zone were investigated, and the combustion of fuel droplets in weak forced convection, not disturbed by natural convection, has been studied for the first time.

Burning rate control in hydrogen fuel combustor

Abstract: To a mixture of hydrogen and oxygen or air having the stoichiometric oxygen-to-hydrogen ratio, a diluent gas such as carbon dioxide or argon is added before the mixture is fed to the combustor when the burning rate of the mixture is excessively high. The diluent in the combustion gas can be reused after separation of water.