Showing papers in "Journal of Engineering for Power in 1965"

Heat-Transfer and Flow-Friction Characteristics of Skewed-Passage and Glass-Ceramic Heat-Transfer Surfaces

Abstract: Experimental results for convective heat-transfer and flow-friction characteristics of three skewed-passage and four glass-ceramic compact heat-exchanger surfaces are presented which should be of practical use, particularly in the design of gas-turbine regenerators. The heat-transfer data were obtained by the transient technique.

A Review of Recent Air Force Research on Selective Solar Absorbers

Abstract: This paper presents a review of recent Air Force research efforts to develop new and improved solar absorber coatings for solar power generation. The work of several laboratories is described as it relates to a particular experimental approach or technique for producing selectively absorbing surfaces. Such unique techniques as microporous surfaces and metallo-organic solution decomposition are discussed as well as the more conventional optical interference methods. A discussion of the applications of these coatings to fulfill Air Force coatings needs in this area is also given.

Radiation From a Directional Source: Beam Divergence in Solar Simulators

Abstract: Solar beam divergence effects on thermal characteristics of spacecraft tested in solar simulator

SO3 Formation in H2S Flames

Abstract: The microstructure of H2 S-O2 flames has been developed in terms of composition and temperature profiles. With the aid of these profiles, rates of formation of SO2 and SO3 are reported and discussed. With the aid of kinetics and thermodynamic data developed for the principal reaction steps, it is shown that a major part of the SO3 -problem may be related to the O-atom oxidation of SO2 in the flame. These fundamental studies of thermochemical reactions provide the basic information needed as the next step in understanding how reactions in flames and on surfaces affect external corrosion and deposits in boiler furnaces.

Solar Thermionic Generators for Space Power

Abstract: All solar space power systems are subject to the condition that the amount of solar energy available in space depends on the collector-sun distance, which generally differs among missions and which may change markedly during the course of any one mission. Thus the design problem exists of how to tailor the system so as to best use the available solar flux. Furthermore, particularly in the case of thermionic systems, it is difficult to change arbitrarily the size of the system. It is therefore of interest to find the system size which can best fit a variety of missions without need for alterations which increase cost and decrease reliability. An approach to handle this design problem is presented, and numerical examples are given based on the data obtained from tests on the hardware prototype of a solar thermionic generator.

Hydrogen Evolution and Steam Dissociation in Steam Generators

Abstract: The paper discusses the metal-steam reaction and the evolution of hydrogen in steam generating plants both from this reaction and from thermal dissociation. An analysis is made of the quantity of hydrogen expected at outlet from a particular monotube steam generator, expressions being derived from which the degree of dissociation can be calculated when the fluid no longer has a stoichiometric composition because of oxygen used up in the metal-steam reaction. The effect of oxygen in the feedwater is considered and the oxygen and hydrogen contents of the steam at outlet calculated for various cases.

Flow With Losses

Abstract: Even when one is willing to estimate the various loss coefficients in a given system, it is not always an easy matter to determine the flow rate and/or the total pressure drop across the system. Heretofore, a tedious trial-and-error approach (at the least) has been indicated, and this has often been based on a Darcy approximation which is questionable under certain conditions. In this paper we present, for compressible and constant-density flows with losses, the developments of exact, albeit simplified, numerical and graphical solutions which are free from all iterative procedures. Comparisons are drawn between these exact analytical solutions and several Darcy approximations. Sample problems are given to illustrate the graphical and tabular solutions as presented here.

A Progress Report—Fundamentals of Thermochemical Corrosion Reactions

Abstract: This paper describes original work on the reactions of sulfur with oxygen in flame systems of H2 S-O2 -Ar, where the stabilized thin flame was microprobed and the quenched products of reaction were examined with a mass spectrometer. Problems in identifying reaction products are described. Although the mass spectrometer was shown capable of checking wet analyses for mixtures of gases, the composition of combustion products was not determinable accurately by this method. Preliminary kinetic data are presented for both, homogeneously and heterogeneously (catalytically) produced SO2 and SO3 .

Piston-Boss and Wrist-Pin Design

Abstract: A brief survey is given of previous investigations into piston-boss and wrist-pin design, and it is concluded that although a theoretical stress analysis of the pin is possible, the use of such analysis is limited by assumptions which have to be made regarding the effect of case-hardening the pin surfaces. A description is then given of fatigue tests carried out by the author’s company on wrist pins to determine the effects of various materials and alternative heat-treatments. The result of the investigation enables lower-grade materials and cheaper methods of production to be used, while at the same time enhancing the overall life of the wrist pin. Investigations employing photoelastic and brittle-lacquer stress analysis of piston-boss and boss-support webs are described, leading to recommendations for the detail design of the boss, boss-support, and wrist-pin assembly. In view of the necessity for engine outputs to be increased in the near future, it is considered that there is a need for the wrist-pin assembly to be reconsidered in order to increase the load-carrying capacity. It is concluded that each piston design must be subjected to both rig and engine tests and that continued investigation will eventually lead to improved designs capable of withstanding higher gas loads without a proportionate increase in weight.