Vaporizing and Endothermic Fuels for Advanced Engine Application: Part Iv. Preliminary Study of the Supersonic Combustion of Endothermic Hydrocarbon Fuels PDF Download

Author: W. Chinitz
Publisher:
ISBN:
Category :
Languages : en
Pages : 101

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Book Description
A theoretical and experimental investigation has been undertaken to define the supersonic combustion characteristics of endothermic hydrocarbon fuels which are of interest as a result of research carried out at Shell Development Company. In the program discussed herein, principal attention was focussed upon the propane and methylcyclohexane dehydrogenation fuel systems. The ultimate objective is to define the parameters that affect the combustion process and to establish the feasibility of burning these fuels in supersonic flows. (Author).

Author: W. Chinitz
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 101

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Book Description
A theoretical and experimental investigation has been undertaken to define the supersonic combustion characteristics of endothermic hydrocarbon fuels which are of interest as a result of research carried out at Shell Development Company. In the program discussed herein, principal attention was focussed upon the propane and methylcyclohexane dehydrogenation fuel systems. The ultimate objective is to define the parameters that affect the combustion process and to establish the feasibility of burning these fuels in supersonic flows.

Author: A. C. Nixon
Publisher:
ISBN:
Category :
Languages : en
Pages : 185

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Book Description
Studies leading toward the development of specifications for heat sink fuels for hypersonic aircraft are reported. Consideration of the effect of design parameters on the conditions under which endothermic reactions can be carried out has led to the conclusion that space velocities of 50 or higher would be necessary due to volume limitations in high-speed aircraft. Rate considerations favor catalytic reactions. Preliminary studies of the dehydrogenation of propane to propene and methylcyclohexane to toluene were made, and dehydrocyclization of various paraffins attempted. Thermal stability studies include the modification of two types of cokers to minimize contamination possibilities and improve reproducibility. Fuels may be tested at temperatures up to at least 1000F. The thermal stabilities of samples of n-dodecane, toluene and methylcyclohexane decreased in the order named. A 25 gal/hr fuel system simulation test rig which will be used for determining heat transfer coefficients, heat sinks and product compositions has been designed. (Author).

Author: A. C. Nixon
Publisher:
ISBN:
Category : Catalysts
Languages : en
Pages : 558

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Book Description
Studies leading toward the development of specifications for heat-sink fuels for hypersonic aircraft are reported. Heat sinks of about 2000 Btu/lb of fuel can be achieved at 1350 F by taking advantage of latent, sensible, and endothermic heat sinks. Rate considerations favor catalytic reactions. The dehydrogenation of methylcyclohexane (MCH) to toluene and hydrogen approaches the above heat sink over a platinum on alumina catalyst. Propane dehydrogenation will yield about 1500 Btu/lb, but the reaction is neither as clean nor as rapid. The thermal stabilities of molecular types generally increase in the order monocyclic aromatic, monocyclic naphthene, bicyclic naphthene, n-paraffin. Exclusion of oxygen increases the critical thermal stability temperature by about 200 F. The introduction of alkyl groups into either the cyclohexane or benzene rings increases thermal stability. A 20-gal/hr adiabatic heat exchanger-reactor system has been constructed and shakedown tests with water have been completed following the execution of a number of changes suggested by preliminary test work. Excellent heat balances have been achieved and satisfactory correlation of heat-transfer data with the literature has been found. Ignition delay data have been obtained utilizing a single-diaphragm shock tube under conditions useful for consideration in the design of supersonic combustion ramjets. Methylcyclohexane and its reaction products and propane and its reaction products have been studied in the range 1300-2700 F. Ignition delays ranged from 100-4000 microseconds under lean conditions, decreasing with temperature. (Author).

Author: A. C. Nixon
Publisher:
ISBN:
Category : Catalysts
Languages : en
Pages : 254

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Book Description
The investigation of the feasibility of utilizing the endothermic and enthalpic capacity of hydrocarbons to fuel and cool high speed aircraft is continued. Calculation of the cooling requirement for a Mach 8 supersonic combustion ramjet engine under standard conditions indicate that this would be about 1900 Btu per pound of fuel. The possibility of utilizing the dehydrogenation of bridged-ring naphthenes for providing additional heat sink has been studied but no suitable catalysts have been found for this reaction. Studies on methods accelerating the thermal cracking of paraffins by means of additives has shown some promise. In the dehydrogenation of naphthenes over supported platinum catalysts the stability of the catalyst was found to be inversely proportional to the pore size of the support, and is also affected by the composition of the support. Efforts to induce the dehydrogenation of methylcyclohexane using dispersed catalysts has met with some success. Also quite marked variations in the rate and type of reaction have been observed depending on the type and source of the metal used for the reactor tube. A large number of additional granular catalysts have been tested for their activity in dehydrogenation of MCH.

Author: Defense Documentation Center (U.S.)
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 784

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Author: A. C. Nixon
Publisher:
ISBN:
Category : Chemical reactions
Languages : en
Pages : 381

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Book Description
Investigation of the feasibility of using endothermic reactions to augment the latent and sensible heat of fuels for cooling engines operating under a high mach number regime is continuing. Studies in the literature continue to maintain the desirability and feasibility of producing vehicles with hypersonic flight speeds and suggest some areas of advantage of hydrocarbons. Laboratory studies on the dehydrogenation over Pt/Al2O3 of a number of mixtures of naphthenes have been made including methyl-Decalin and dicyclohexyl as well as the pure components, with additional studies on Decalin. About 220 dehydrogenation catalysts have been prepared using a variety of metals and supports. Propane and an advanced jet fuel were tested as possible heat sink fuels in our fuel system simulation test reactor under thermal cracking conditions. Our packed bed reactor program included herein, has been rewritten and simplified resulting in a considerable saving in both human and computer time. The thermal stability of MCH, Decalin and a naphthenic jet fuel were all critically, but uniquely, dependent on O2 concentration in the region below about 10 ppm. The ignition delay behavior of both ethane and ethylene was found to be considerably different from other hydrocarbons in the shock tube, the ignition delay reaching a minimum in the region of E/R = 0.5 with two different temperature coefficients which are dependent upon total reactives concentration.

Author: A. C. Nixon
Publisher:
ISBN:
Category :
Languages : en
Pages : 327

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Book Description
Investigation of the feasibility of utilizing hydrocarbons as heat-sink fuels for hypersonic aircraft has continued. Both thermal and catalytic endothermic reactions have been considered, at temperatures up to 1400 F, pressures to 1000 psi, liquid hourly space velocities up to 260 and 150, respectively. Mono- and dicyclic naphthenes appear to be the most promising feeds to date. Utilizing dehydrogenation to the corresponding aromatics over a platinum on alumina catalyst, reaction heat sinks of about 1000 Btu/lb of feed should be achievable with the lower members of the series, such as cyclohexane, methylcyclohexane, dicyclohexyl, and decalin. Laboratory studies have been made on the dehydrogenation of a wide variety of naphthenes over Pt/Al2O3 catalysts to determine approximate reaction kinetics and selectivities. Rates of reaction generally increase with alkyl substitution. Activation energies show variable behavior. Selectivities for the corresponding aromatics are high. Some problems with catalyst life and consecutive reactions have been encountered; some solutions have been found.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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The document is comprised of figures, tables and other data in support of the basic report, AD-867 045. A bibliography of 1502 items is included.

Author:
Publisher:
ISBN:
Category : Fuel
Languages : en
Pages : 362

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Book Description
A review of the literature has been made as part of an extensive study of vaporizing and endothermic fuels for advanced engine application. Abstracts are presented for 1086 references covering cooling requirements of supersonic aircraft, properties of vaporizing and endothermic fuels, thermal and catalytic reactions of hydrocarbon fuels, high temperature fuel stability, fuel contaminants and additives, fuel combustion characteristics, physical-chemical properties, heat transfer and flow behavior, and advanced engine design. The references are arranged by author. Subject and source indexes are provided. (Author).