bluuebunny/crossref_metadata_2025 huggingface dataset:
Underfeed Stokers From the Standpoint of Coal Selection
Authors: Tobey J. E.
Published: February 2023

As an example of the benefits to be secured from careful selection of coal for underfeed stokers, the paper cites the experience of a Middle West industrial power plant burning 700 tons of coal per day, where the boiler capacity was increased from approximately 2100 hp in 1917 to more than 13,000 hp in 1924. Errors in design of the original boilers were repeated in each of the three subsequent additions and caused combustion troubles with resulting interruptions to power service and factory shutdowns. Mechanical changes to boiler equipment and an exhaustive coal-selection program resulted in marked improvement in operation. When the latter was adopted, coal might be supplied by any one of 60 different mines which rendered any segregation impossible and compelled burning the fuel as mixtures. In the three years that elapsed before the program was completed, coals from 130 mines were analyzed and given burning tests under service conditions and the output of 18 mines, none of which were included among the original 60, was found suitable for plant use. Differences between these coals, such as quality, price, degree of satisfaction, mine capacity, and general availability, reduced the number to 6 and these fuels were given trials for longer periods, with the result that a single coal was finally chosen and has been burnt exclusively for a number of years. The coal-selection program is described in considerable detail in the paper and combustion troubles encountered during the burning tests are mentioned and commented upon.
Relation of Wahl Correction Factor to Fatigue Tests on Helical Compression Springs
Authors: Zimmerli F. P.
Published: February 2023

This paper presents the results obtained in an effort to test Wahl’s correction factor for spring stresses. Fatigue tests were run on springs of various indexes which were coiled from the same bundle of wire and blued at the same time to insure uniform treatment. As the results were not uniform, four series of tests were made, with additional tests to demonstrate the inertia effect of the walking beam of the testing machine and the influence of speed and stroke. With high spring loads the inertia effects of the beam during the down stroke were neutralized by the spring pressure. Stress ranges for the various indexes as obtained in the tests were corrected for (a) spring rate, (b) stroke, and (c) motor speed and the corrected values plotted. From this chart, the conclusion is drawn that the Wahl factor overcorrects the stress values for low indexes.
Hot-Pressing Technique for Plywood
Authors: Perry Thomas D. , Bretl Martin F.
Published: February 2023

The authors review briefly the history of the cold pressing of plywood with various adhesives, and discuss the development and adoption of hot pressing with thermosetting synthetic-resin adhesives which are more water resistant than the adhesives developed for cold pressing. The various types of domestic and foreign hot presses and their characteristic features are described. It is shown that several factors in the behavior of wood under heat are common to all known types of resin adhesives; these are the speed of heat penetration through various thicknesses of veneer and the heat losses encountered in practicable bonding periods of time, both differentiated as to core thicknesses, moisture content, and temperature. Specific pressure and wood species are found to have little if any influence on these factors. Another factor is the effect of heat on the tensile strength of wood, which is shown to be relatively unchanged in practicable bonding periods. These phenomena are shown by tables and graphs and are fully described. Other factors individual to the adhesive used, and the characteristics of a resin film, are outlined in tables and are described. The authors predict that the rapidly growing adoption of hot pressing and resin adhesives is widening the plywood market.
The Hydraulic Jump in Sloped Channels
Authors: Bakhmeteff B. A. , Matzke A. E.
Published: February 2023

The discussion of a previous paper on the hydraulic jump in sloped channels (1) made it evident that the existing literature carried no clear exposition of the subject, and moreover that no systematic experimental evidence was available which would permit an engineer to draw practical conclusions regarding the matter. The research described in this paper is an attempt to clarify this situation.
Influence of Pressure on Film Viscosity in Heavily Loaded Bearings
Authors: Needs Sydney J.
Published: February 2023

Extensive investigations of heavily loaded journal bearings were conducted in Dr. Kingsbury’s laboratory several years ago in connection with studies of roll-neck bearings. The problem of maintaining complete fluid-film lubrication under loads of several thousand pounds per square inch of bearing area was visualized as one of bearing design and the provision of an adequate supply of the proper lubricant to suit operating conditions. Following this line of approach, it was found that the usually available lubricants are entirely satisfactory for the formation of a complete metal-separating oil film when the bearing has been constructed in such manner as to make the formation of this protecting film possible. Hence, except at the moments of starting and stopping, metallic friction and wear may be eliminated under operating conditions.

Results of the tests were found to be in good agreement with published theory when the operating conditions were reasonably close to those upon which the theory is based. For example, theory indicates that with constant speed and film viscosity the friction coefficients of fitted journal bearings and plane surfaces will continue to decrease indefinitely with increasing load. At constant speed and temperature it was observed that when the load was increased to several thousand pounds per square inch the friction-coefficient curves for fitted journal bearings reached a minimum and then started to increase with added load. In the absence of metallic contact this discrepancy between observed and theoretical frictions suggested the probability of the high pressures in the bearing oil film causing an increase in film viscosity. The present paper undertakes a mathematical explanation of this phenomenon by calculating the effect of viscosity increase under pressure on the operating characteristics of plane surfaces of infinite width. Some of the more interesting of the test results are given in the form of curves and these are compared with calculations for plane surfaces of infinite width assumed to be operating under the same conditions.
Investigation of Stress Conditions in a Full-Size Welded Branch Connection
Authors: Everett F. L. , McCutchan Arthur
Published: February 2023

This paper presents the results of an investigation of stress conditions in an 8-in.-diam, 0.500-in.-wall test manifold having a full-size welded branch connection. Stresses were determined from strain-gage measurements on the outer surface of the manifold at some 50 stations in the vicinity of the welded juncture of header and branch. High stresses were found to exist on the outer surface at the flat portion on the side of the manifold. No evidence of high stress was found on the outer surface of either the unreinforced or reinforced manifold in the vicinity of the crotch, although high stresses were deduced analytically as probably existing in the inside wall at this location in the unreinforced manifold.

The ring-type of reinforcement was found to assume its share of the load in the region which it covered but to have little significant effect on adjoining areas, even increasing the measured strains where the ring joined the header at the side of the manifold. While permanent distortion occurred at the sides of the reinforced manifold at a pressure only 70 per cent of the pressure calculated to cause yielding of the pipe proper, eventual failure occurred in the header outside of the reinforced region at a pressure approximately the same as would be expected to burst a straight length of pipe. It is concluded that the ring type of reinforcement described herein will develop the full strength of the pipe.
Combination Oil-and-Gas Burners
Authors: Campbell O. F.
Published: February 2023

The author gives combustion data pertaining to the burning of petroleum fuels in combination oil-and-gas burners for industrial use, and discusses the principles of combustion involved in burning such fuels. He also gives a brief description of nine representative types of combination oil-and-gas burners, describes their operation, and discusses their advantages and disadvantages.
The Proportioning of Materials in Process Engineering
Authors: Witt J. C.
Published: February 2023

In all process industries in which two or more raw materials are used, proportioning is an essential step. A search of the literature indicates that proportioning calculations have received less study than other types of calculations, or other details of process industries. As the number of raw materials and the number of the required constituents of a product increase, the calculations become more difficult. Generally, equations are set up and solved for each problem, individually. This requires considerable time and encourages the substitution of approximations for accurate calculations.

The author has developed formulas which are applicable to proportioning problems involving as many as four raw materials and four required constituents of the product to be manufactured. The number of raw materials and constituents could be extended. A graph has been prepared by the use of which preliminary information on the suitability of a set of raw materials for a given product may be obtained. In some cases, this eliminates many preliminary calculations. The author’s formulas were developed for use in one process industry, but are applicable to all industries in which corresponding calculations are required. They decrease the time for making calculations to a small fraction of the time that would be required otherwise, without affecting the accuracy.
An Oil-Bath-Lubricated Railway Bearing
Authors: Vigne Albert , Cox I. Eugene
Published: February 2023

The history of the development of an oil-bath-lubricated bearing is introduced by a brief summary of conditions showing its need. Problems encountered in the application of this developed journal unit to standard car axles are described with recommendations for modification of practices and tolerances. Material tests and temperature and frictional characteristics of the new journal unit and their derivations are presented, and oriented by similar characteristic determinations on A.A.R. journal units.
The Fundamentals of the Design of Cracking Furnaces
Authors: Baker A. L. , Rickerman J. H. , Lobo W. E.
Published: February 2023

The great number of variables necessarily considered in the composite design of cracking furnaces in petroleum refining requires unusual engineering attention, resulting in a marked prevalence of custom designs, as contrasted with the usual steam-boiler designs. In this paper the procedure of design of cracking furnaces is discussed from the standpoints of processing, surface requirements, arrangement of heating surface, efficiencies, and heat distribution. The importance of obtaining good heat distribution by the proper combination of heating surface, well-designed burners, and handling of furnace draft is emphasized.

Due to the relatively short life of the average refinery furnace, the question of capital cost is of prime importance. In addition, the nature of the fluids handled, under relatively severe conditions of pressure and temperature, requires the closest possible check on the materials of construction in order to insure safety of operation, combined with low capital cost. The various materials, such as tubes, headers, brickwork, which enter into the mechanical construction of the furnace itself, are considered, and typical detailed designs presented. The increased use of high temperatures and pressures and the trend toward higher heating rates make this part of the subject of increasing interest to the oil refiners.
The Distribution of Energy in the Pulverized-Coal Furnace
Authors: Wohlenberg W. J. , Wise D. E.
Published: February 2023

In this analysis the coal particle while burning is distinguished from the resulting ash particle and the concept of radiant-mean positions of burning and of ash particles is introduced. This makes it possible to differentiate between the radiant-mean temperatures of burning particles, ash particles, gases, refractory walls, and cold walls. The direct transfer of energy between each class of particles and the gases also is introduced into the equations of condition. It is found that this process is of primary importance in the energy distribution. In fact, it may be thought of as a powerful binding property which holds the energy distribution in the configuration which it assumes. It provides among other things for a small difference between the values of radiant-mean temperature of ash particles and gases. Hence for any reasonable length of gas travel in the cavity the ash-particle temperature is substantially that of the gases except for regions close to cold surface. In view of the importance of ash fusion in actual operation of furnaces this disclosure is of considerable practical significance.

With respect to the radiation absorption at walls of the cavity, it is found that burning particles are the least important of the three radiators—burning particles, ash particles, and gases. The burning particles are primarily a source for releasing energy and most of this is transferred directly to the gases by thermal conduction. Thus it is seen that the gases serve momentarily as a great sump or reservoir into which most of the released energy is dumped. A part of this large fraction of the total released energy is subsequently redistributed by radiation and thermal conduction.

The foregoing information results from a solution of the equilibrium conditions for a steady state in a given cavity. On the basis of information furnished in this way it becomes possible to approximate the distribution of energy absorption as heat over the cold walls of the cavity. The results for a given case are included in the paper. In a qualitative sense these results contain implications of rather general significance.

Finally it may be noted that on the basis of information furnished in the equilibrium solution it is possible to approximate the gradient along the flame axis of a single radiant-mean temperature as representing the temperature condition of the contents of the cavity. Such a gradient has, however, little practical significance except in its lower reaches. Nevertheless a method of arriving at it together with a more detailed discussion is included in Appendix 6.
Industrial Applications of Spiral Bevel Gears and Hypoid Gears
Authors: Candee Allan H.
Published: February 2023

The paper includes a definition of terms and a general comparison of spiral bevel gears and hypoid gears with other types. The features and advantages peculiar to each type are discussed as are also tooth-contact conditions, elements of good and bad design, the importance of accurate mounting and assembling, size range and ratios, materials, and lubrication.

Numerous illustrations of equipment used in gear manufacture are shown and also photographs of applications of both small and large sizes in various fields.
Pressure-Responsive Elements
Authors: Exline Paul G.
Published: February 2023

Pressure-responsive elements commonly used in indicating and recording instruments are manometers, free-piston gages, Bourdon tubes, diaphragms, and bellows. The mathematics of the primary elements, manometers, and free-piston gages is simple and direct. Analyses of Bourdon tubes and diaphragms show that predictions of their performance curves are not amenable to precise calculation even under the simplest conditions, which conditions do not generally obtain in instruments. Generally, the instrument maker must rely upon empirical knowledge, coupled with approximate calculations, for design data. Linkage adjustments must be provided to correct for variations in dimensions and materials normally encountered in manufacture.

Emphasis is placed on the usefulness of bellows as pressure elements, and approximate formulas for calculating their behavior are given. The results of considerable experimental work on the characteristics of bellows of various sizes and materials show that in many cases they are ideal elements for pressure-responsive instruments. An example of such use in a special-duty pressure gage is given.
Pressure-Type Thermometer Systems
Authors: Bean L. G.
Published: February 2023

This paper, which deals exclusively with the common forms of industrial temperature-measuring systems working on a pressure principle, analyzes the essential elements of a basic pressure-type system with reference to the design problems involved and describes various typical instruments in the conventional classifications in order to illustrate the development of these thermometer systems into reliable instruments for commercial measurements. Included in these classifications are liquid-filled, vapor-tension, and gas-filled thermometers, all of which are described and illustrated.
Theory of Elastic Engine Supports
Authors: Rosenzweig S.
Published: February 2023

It is obvious that the application of spring suspension to a foundation represents a great departure from the methods previously used. Instead of rigidly bolting down a machine, it is now installed so as to operate on a yielding structure. Instead of comparatively simple static laws, complicated dynamic conditions have to be considered. This paper presents the theory of the dynamic principles underlying machine operations. It is shown that not only capacity, speed, and weight of a machine must be considered, but also acceleration and free forces of reciprocating and rotating engines, irregularity of motion, inertia forces of individual parts, forced frequencies of operation, and natural frequencies of the subsoil.
The Mechanical Characteristics of Rubber
Authors: Haushalter F. L.
Published: February 2023

The author presents some of the characteristics of rubber in which engineers may be interested from a design standpoint, without going into detail on every phase of the subject which might affect design. He points out that there is a vast amount of data still to be collected, especially to establish accuracy on some points that seem to be in doubt. He suggests that to obtain data accurately, it will be necessary to conduct tests in rooms where humidity and temperature are closely controlled. The author presents data showing that moduli of elasticity and the creep of shear and torsion springs are decidedly affected by temperature. Presented graphically are curves showing load-deflection, shear, and torsion characteristics of various rubber specimens including compression pads, rubber shear sandwiches, and torsion springs.
The Use of the Piezoelectric Gage in the Measurement of Powder Pressures
Authors: Kent R. H. , Hodge A. H.
Published: February 2023

The development of a piezoelectric gage for the measurement of powder pressures in guns is reviewed. A gage is obtained having a high natural frequency, insensitivity to shock, and accuracy. Details concerning the construction of the gage, the recording apparatus, and the method of calibration are given. Records are reproduced showing pressure waves in a gun and a closed chamber. Such records have been of value in the improvement of the design of powder charges and the determination of interior ballistic data.
The High-Pressure High-Temperature Turbine-Electric Steamship “J. W. Van Dyke”
Authors: Goldsmith Lester M.
Published: February 2023

The author discusses the features of various steamship designs which were considered in the development and final adoption of the construction of the tanker S.S. J. W. Van Dyke. After data on steamship designs had been collected and analyzed an intensive study was made of hull form, propeller design, and power-plant requirements. The author describes the results of model tests conducted at model basins in Hamburg, Germany, and Washington, D. C.; the results of these tests were the deciding factor in selecting the propeller and hull designs. The paper includes a complete description of the steam-generating equipment, electrical equipment, high-pressure piping, controls, and miscellaneous electrical equipment which were finally selected for the ship. The author presents graphically the results of trial runs made with this turbine-electric steamship.
Creep in Tubular Pressure Vessels
Authors: Norton F. H.
Published: February 2023

The paper is a report of tests on the circumferential and longitudinal creep, under internal pressure and high temperature, in steel tubes such as are used in boilers and oil stills. A description of the testing apparatus is given and the results are shown in the form of tables and curves comparing the tubular creep with the creep of tensile specimens at the same stress.

The tentative conclusion is reached that the circumferential creep is about half that of tensile specimens. The longitudinal creep is negligible.
Effect of High Temperatures and Pressures on Cast-Steel Venturi Tubes
Authors: Pardoe W. S.
Published: February 2023

The author presents results of tests showing the expansion in the main and throat diameters of cast-steel venturi tubes under dry heat and pressure, respectively. From these data values are obtained for the coefficient of expansion and the modulus of elasticity, and the comparative effects of high temperatures and pressures are shown.
The Effect of Pulsations on Orifice Meters
Authors: Beitler S. R.
Published: February 2023

The paper describes three test setups made for investigating the effects of pulsation on orifice flowmeters for the measurement of gases. Arrangements are described for subjecting meters to pulsation from either the inlet or outlet side and determining the error in measurement.

The work so far is admittedly just a start toward a possible solution of the problem of metering pulsating flow, but the results show the extent and seriousness of the problem and point the way for further research which is of vital interest to the measurement industry.
Atomization of Oil by Small Pressure-Atomizing Nozzles
Authors: Glendenning E. B. , Black A. R. , Ventres L. H. , Sullivan W. A.
Published: February 2023

This paper develops the importance of atomization, carburetion, and oil characteristics for efficient combustion, and demonstrates the effect of pump pressure, oil viscosity, variation in oil temperature, and nozzle design on the rate of efflux and spray characteristics. It includes a study of hollow- and center-spray nozzles with relation to oil viscosity, aerodynamic design of the oil burner, and combustion efficiency.
Problems and Trends in Centrifugal-Machine Applications
Authors: Pecker Joseph S.
Published: February 2023

The paper deals with the factors that govern the design and choice of a centrifugal machine for some specific application so that a prospective user or purchaser may appreciate the scope of the problems involved in the construction of a machine that would meet his requirements.

The article describes the various types of machines that are available and specifically calls attention to the newer types of development not generally known. The author surveys the trends in centrifugal-machine development and endeavors to indicate to manufacturers, prospective inventors, developers, and users of these machines the direction in which the art may be extended and expanded by the judicious choice and application of new materials, drives, and methods of construction, as a means of securing maximum production with required safety.
Investigation of Errors of Pitot Tubes
Authors: Hubbard C. W.
Published: February 2023

In late years some hydraulic engineers have come to distrust the pitot tube as an accurate instrument for measuring the flow of water in pipes. It has been found that some pitot tubes do not have the same coefficient for all conditions of flow. There is, therefore, general disagreement as to the coefficient which must be applied for a particular set of conditions to obtain the velocity within 1 per cent or less of the true value. The following experiments were made in an effort to find the reasons for this variation of the coefficient.

Tests made on an 84-ft rotating boom in still water showed the coefficient of the impact tip to be unity. The pitot deflection was balanced against a centrifugal head.

A method of measuring the angularity of turbulent flow in pipes by use of the law of probability was devised. The measurements made in pipes 12, 40, and 78 in. in diameter check the Prandtl and von Kármán theories of turbulent flow closely and show the mean angularity to be about 2 deg. The effect of the pitot support rod on the reading of the pressure-head piezometers and impact tip was determined. Tests were also made to determine the effect of pulsations.

Tests made to determine the effect of the pitot support rod showed that the support rod did not cause an error in the impact-tip reading, but did affect the pressure measured by the wall piezometer. The rod was also found to affect the reading of the pressure orifice of the pitot-static tube. It follows that any form of combined type of pitot tube in which the error could be determined by calibration of the instrument alone would give accurate results.

The average magnitude of pulsations was found to be too small to cause an error in reading of the pitot tube.

The conclusions drawn from these tests were that the impact tip correctly registered the true dynamic head whether the flow was smooth or turbulent, but that the pressure piezometers were likely to be in error. Since the pressure piezometer of the pitot-static tube was a part of the instrument and calibrated with it, this instrument was considered more reliable than the simple pitot tube using wall piezometers.
To the Question of Balancing Reciprocating Weights in Steam Locomotives
Authors: Lipetz A. I.
Published: February 2023

The Association of American Railroads has been recommending since 1933 cross-counterbalancing of revolving weights for main wheels of steam locomotives. For coupled wheels the old method of static balancing is still being considered as sufficiently accurate. For reciprocating weights the static method is also retained by the new Manual of the A.A.R. The author takes exception to this scheme. He is of the opinion that for high-speed locomotives, and for these locomotives especially, greater clearness should be introduced in this subject. The dynamic augment, which plays such an important part in all high-speed calculations, should not exceed the limit allowed for the strength of the rails and the stiffness of the roadbed. An accurate evaluation of the dynamic augment for each wheel is possible only when the revolving weights are correctly balanced for each wheel, coupled as well as main. If this is not done, some of the wheels are dynamically deficient and a uniform distribution of dynamic augments is impossible. This destroys the effectiveness of proper balancing of reciprocating weights.

The author discusses the percentage of balancing the reciprocating weights in steam locomotives and how this depends on the method of calculating counterbalancing, whether static or dynamic. He shows, on the basis of existing locomotives, that a smaller total percentage of counterbalancing reciprocating weights of a locomotive is quite adequate for modern locomotives.

The author further calls attention to the existence of the steam component on the main axle and suggests that no reciprocating balance should be placed on main wheels, even if this should somewhat reduce the total percentage of balancing. He would rather increase the dynamic augment on coupled wheels in order to spare the main wheels from excessive blows. In his opinion the disregarding of the action of the steam component is responsible for the objection of some railroads to cross-counterbalancing of locomotives. This attitude should disappear when the problem is clarified.

In conclusion the author gives an example of a correct calculation of cross-counterbalancing of all weights, revolving and reciprocating, and for all axles, main and coupled, and proves that this method involves no more work, even less, than the static method, when angling of counterbalances on wheels is attempted.
The Characteristics of Atmospheric-Type Burners When Used With Natural Gas
Authors: Howe E. D. , Johnson H. G.
Published: February 2023

In this paper it is determined that the design of atmospheric-type gas burners depends upon the stability of the flame produced, which is related to the speed of flame propagation in the combustible mixture. Experiments made upon single-port gas burners have served to show that the effective velocity of flame propagation is greater than the velocity of flame propagation in still mixtures. It has been found that natural gas can be burned at a rate of approximately 30 cu ft per hr per sq in. of port area. The authors summarize the matter of hydraulic design of inspirators in the form of an equation, the validity of which is demonstrated by experiment. This equation suffices to determine the mixture ratio when the gas rate and density are known.
Burning Pulp-Mill Waste From Sulphite Mill
Authors: Keeth Grover
Published: February 2023

After first outlining the problem of stream pollution, as applied to sulphite pulp mills, this paper describes the recovery of lignin from digester waste and the elimination of stream pollution by the Howard process. This process produces a lignin fuel which can be and is burned in power-plant furnaces for the production of steam. Mechanical problems, such as the development of a filter press and various methods of burning the fuel so produced, are explained.
Bagasse Furnaces
Authors: Kerr E. W.
Published: February 2023

This paper deals with the design of furnaces for burning bagasse, a woody product resulting from the removal of sugar juice from cane. Its calorific value when dry is about 8300 Btu, which is reduced considerably because of the moisture content averaging about 50 per cent. Because of the high moisture content large combustion-chamber volume is essential and the net boiler efficiency is limited. However, in a properly designed and balanced sugar factory, the heat from the bagasse will generate the necessary steam for operating it although some additional fuel (usually oil) is required during mill stops. Practically all makes and types of boilers are used for burning bagasse, water-tube boilers predominating. The author classifies the types of bagasse furnaces as grate, hearth, and combination grate and hearth. Examples of each are described and tests covering a wide range of furnace types over a long period of time are cited. The best installations range from 55 to 60 per cent boiler and furnace efficiencies; average practice about 50 per cent. A furnace developed recently by the late G. P. Ward has given an efficiency of 66 per cent.
Burning Various Types of Oil-Refinery Fuels
Authors: Wilson A. L.
Published: February 2023

The paper describes the various types of waste by-product fuels which are produced in an oil refinery and the burning of them in boiler furnaces. Composition and characteristics of these by-products are given together with the methods of handling and utilization. Burner design and the use of steam for atomization are considered and attention is called to the fact that combination burners have been developed to burn simultaneously five different fuels in liquid, gaseous, and solid form.
Mechanical Purification of Steam Within the Boiler Drum
Authors: Baker M. D.
Published: February 2023

The paper is a report of tests run on new high-pressure high-temperature boiler installations to determine a baffle arrangement for the steam drums that would prevent objectionable carry-over during normal operation.

The arrangements of three types of baffle are illustrated and the results are given in tables and graphs as conductivity measurements on condensed steam samples taken from eight different points in the drum.

The cyclone-separator baffle finally developed will deliver steam containing solids approximating 0.5 ppm with boiler-water concentrations up to 1600 ppm, and will permit a large range of load change and water-level variation.
Boiler-Plant Performance With Natural-Gas Firing
Authors: Philo F. G.
Published: February 2023

With its diversified operations, the Long Beach Steam Station of the Southern California Edison Company, Ltd., using natural gas as fuel has been required to solve many problems. The author presents the boiler-plant performance obtained with this fuel and outlines the methods and equipment adopted to give economic operation. A feature of this paper is the detailed instruction chart developed for the guidance of the boiler-plant operators. During the last fifteen years 120,000,000,000 cu ft of natural gas from three main sources have been burned in the installation. It is the author’s opinion that a properly designed gas-piping system in the hands of competent operators probably presents fewer problems and no greater hazard than does the use of liquid or powdered fuels.
Problems Encountered in the Design and Operation of Impulse Turbines
Authors: Quick Ray S.
Published: February 2023

Because of present-day demands on high-head hydroelectric installations, calling for continuous maximum overload operation of impulse turbines, unusual problems of wear and fatigue of materials have developed. The author discusses such problems frankly and suggests solutions for them. One of the important factors influencing unit efficiency of impulse turbines is the arrangement and design of approach piping due to the effect on the jet of turbulence in the nozzle. Flow-straightening vanes have been developed to correct this turbulence. Various successful forms are illustrated and their characteristics plotted. The form of needle and nozzle tip also has a marked influence upon the appearance and form of the power jet. Another factor affecting the performance of the unit is that of the design, shape, and arrangement of buckets on the water wheel. Investigations have been made on all these elements of the impulse turbine, the results of which have been incorporated in present successful applications. Two outstanding impulse-turbine installations in California are mentioned. A comparison is drawn between field tests on one of these at the Tiger Creek Plant of the Pacific Gas and Electric Company and model tests. The paper concludes with a discussion of the governing problem.
Performance Characteristics of a Mechanically Induced Draft, Counterflow, Packed Cooling Tower
Authors: London A. L. , Mason W. E. , Boelter L. M. K.
Published: February 2023

Predicted and test results of a packed cooling tower are presented in this paper. The geometrical form of the air-water interface may be described as a sheet conforming to the streamlined shape of the tower packing, in contrast with jets and drops encountered in other types of towers. Tower performance is expressed in terms of its effectiveness as an energy exchanger, as compared to the performance of an infinitely high tower. The effectiveness was found to vary from approximately 0.3 at low water rates and high air rates to 0.8 at high water rates and low air rates. Experimentally determined unit conductances for diffusion vary with the 0.48 power of the gas rate, for Reynolds numbers of from 7000 to 24,000, which is in substantial agreement with published thermal-convection data for similar shapes. The height of the transfer unit (HTU) was found to vary from 3.3 to 6.3 ft, depending predominantly upon the fraction of wetted packing area and the air rate. A simple method, analogous to that employed for counterflow heat-exchanger calculations, is presented for predicting tower performance analytically. This method is based upon the integration of the energy and material-balance equations together with the rate equations, subjected to the simplification that the unit over-all conductance for thermal convection may be approximated by the product of the air-water-vapor-mixture unit-heat capacity and the unit over-all conductance for mass transfer.
Wear of Diesel-Engine Cylinders and Rings
Authors: Lane Paul S.
Published: February 2023

This paper considers wear mainly from the viewpoint of cylinder and ring materials, rather than from the design or operating angle. The types of iron used, though important factors, have received only limited attention in published data. Existing wear rates in medium- and heavy-duty Diesel and gas engines in various fields of service are reviewed, followed by several examples of cylinder wear as affected by the hardness and structure of the iron alloy. By means of laboratory wear tests, correlated with service experience, the nature and characteristics of the materials used in cylinders and rings are surveyed and discussed in detail, covering the effects of section size, hardness, analysis, and structure. Initial engine wear, as influenced by bore finishes and wear-resistant or chemical surface treatments, is considered, together with the action of bimetallic or composite rings, in retarding scuffing and over-all wear rates.
A Supersensitive Governor for Hydraulic Turbines
Authors: White W. M.
Published: February 2023

A supersensitive governor is defined in this paper as one that will move the gates of a hydraulic turbine in the corrective direction by reason of a change of speed of 0.02 per cent and will then move the gates back by reason of a change of the speed back to the former speed. The author outlines the elements essential to a supersensitive governor in order to accomplish this fine degree of regulation. The application of these principles to governor design is then outlined.
Constant System Speed and the Steam-Turbine Governor
Authors: Schwendner A. F.
Published: February 2023

The demand for constant system speed is a current problem of power-generating systems. Electrical stability, governor, governing-valve characteristics, and other factors play their part in the problem. In this paper only the effect the governors and governing valves have in maintaining or disturbing the system speed is discussed. New governing systems are described to show the extent to which the turbine manufacturers go in trying to meet the demand for better system speed. The author points out that, when the governor characteristics of all units in a power-generating system are known, the combination of units used for certain load blocks can be determined not only for the best generating economy but also for better system speed. This information can be used to specify required governor characteristics for new units to further improve the system speed. Attention is called to the need for uniform governor performance and testing specifications.
Automatic Control in the Presence of Process Lags
Authors: Mason C. E. , Philbrick G. A.
Published: February 2023

In this paper, the methods of “Quantitative Analysis of Process Lags” developed in a previous paper are extended to include automatic control. Carrying on the idea of representation by liquid-level systems, a specific system is postulated as a model for a typical industrial process which may or may not be thermal. Continuing the quantitative approach, the mathematical machinery is demonstrated by which the operation of control on processes may be investigated. A selected succession of controllers, characterized by the laws of control which govern them, are considered in connection with their performance on the model system. Although no attempt has been made to formulate rules governing the proper application of the various types of controllers considered or governing the adjustment of any of these individual types, the authors consider that analyses of this sort may well serve as a guide to practical theorems in a technology of automatic control.
Photoelastic Analysis of Stresses in a Steam-Turbine Blade Root
Authors: Ryan J. J. , Rettaliata J. T.
Published: February 2023

The analysis of the stresses in steam-turbine blade roots by photoelastic methods has particular reference to the determination of the loadings on the multiple steps. In this paper, from a comparison of test and calculated values, the stress-concentration factors are obtained for the neck and step sections.
Laminar-Flow Heat-Transfer Coefficients for Ducts
Authors: Norris R. H. , Streid D. D.
Published: February 2023

In this paper, theoretically derived values of the heat-transfer coefficient for flat ducts with constant surface temperature are presented and compared with the corresponding results for round ducts which have been previously published. A few test data for air in flat ducts are compared with the theoretical results. For both flat ducts and round ducts the results are presented both in customary terms and in terms of the logarithmic-mean temperature difference. The latter results provide a consistent basis for comparisons with heat-transfer data for turbulent flow. Some limiting values of the local heat-transfer coefficient for both constant surface temperature and constant heat input per unit length are tabulated, and some equations pertinent to very short ducts are included.
Fuels for Diesel Engines in Marine Transportation
Authors: Joachim W. F. , Nutt H. V.
Published: February 2023

After reviewing briefly developments in the field of Diesel fuels over the last 30 years, the authors discuss in detail the present-day requirements for marine-Diesel-engine fuels. A summary of engine troubles and casualties caused by unsuitable fuels is also given. The paper includes a series of tables and explanatory matter concerning Diesel-fuel specifications for various types of marine engines.
Properties of Hydrogen Mixtures
Authors: Brunot A. W.
Published: February 2023

With the increased use of hydrogen as a cooling medium in rotating electrical machines, it has become important to know the properties of hydrogen diluted by small amounts of another gas. Using these properties it is possible to predict the operation of the machine in a hydrogen mixture from the results of tests made in air or pure hydrogen. It is the purpose of this paper to present a summation of data on the properties of hydrogen, air, nitrogen, and carbon dioxide, as well as empirical formulas for the properties of the mixture of hydrogen with any of the other three gases, and to show how accurately the performance of a heat exchanger in hydrogen or hydrogen mixtures may be predicted from tests in air.
Heat Transfer to Falling-Water Films
Authors: McAdams W. H. , Drew T. B. , Bays G. S.
Published: February 2023

Data are presented in this paper for heating water as it flows by gravity in turbulent motion down the inner walls of vertical copper pipes, ranging in height from 0.41 to 6.1 ft. Heat balances check within 5 per cent and the temperature of the inlet water ranges from 38 to 146 F. The data are adequately correlated by the equation: h = 120Γ1/3, where Γ ranges from 600 to 15,000 lb of water per hr per ft of width of stream. Steam-side and over-all coefficients are given. The rather inadequate data for streamline flow by gravity over nearly horizontal pipes (trombones) are reviewed.
Steam-Turbine Blading
Authors: Allen R. C.
Published: February 2023

This paper reviews the blading-design practice associated with modern high-pressure high-temperature steam turbines. The design problems encountered in the development of partial-admission impulse blading for topping units are described, as well as the current engineering practice employed in the manufacture of such blading. The stress analysis used in the construction of full-admission blading is reviewed. The design procedure adopted for high-tip-speed last-row blading and the natural limits in capacity imposed on 3600-rpm turbine construction are also discussed. Materials for turbine blading are considered, as well as the metallurgical problems associated with the fabrication and welding of the high-grade alloy steels now available.
Nonlinear Beamforming Based on Amplitude Coherence Applied to Ultrasonic Imaging of Coarse-Grained Steels
Authors: Carcreff Ewen , Laroche Nans , Varray Francois , Nicolas Barbara
Published: February 2023

This paper deals with ultrasonic imaging in a nondestructive evaluation (NDE) context. In particular, we are focused on the inspection of coarse-grained steels having a heterogeneous composition that creates structural noise in the ultrasonic signals and images. The standard way to beamform the acquired ultrasonic data is by delay-and-sum (DAS). This method is fast but suffers from low signal-to-noise ratio (SNR) for coarse-grained steel inspection. In this paper, we propose to adapt a coherence-based beamformer called pDAS from the medical imaging community. pDAS beamforming is based on DAS structure but includes p-root and p-power before and after summations, respectively. It results in an enhancement of the coherent summation of signals that improves both resolution and contrast. Coherence-based beamformers are known to enhance information whose acoustic response correlates with geometrical information, that is why they decrease grating lobes and side lobes, specular echoes, reconstruction artifacts, and noise due to multiple scattering. In this paper, the pDAS beamformer is proposed for two common acquisition schemes employed in NDE that are plane wave imaging (PWI) and full matrix capture (FMC). The beamformers have been efficiently implemented for parallel computing on graphics processing unit (GPU) in a context of real-time imaging and fast part scanning in NDE. First, experimental results are presented from an austenitic-ferritic sample from the power generation industry that contains side drilled holes (SDH) with diameter 0.4 mm at several depths. pDAS (for p from two to three) shows improvements in terms of SNR and resolution compared to standard DAS, both in PWI and FMC modalities. We also show that the computation cost of pDAS is equivalent to DAS. A real application on a sample containing a fatigue crack connected to the backwall is exposed. We show that pDAS beamformer can enhance crack response compared to grains, but it also decreases unwanted information such as backwall specular echoes and reconstruction artifacts.
Identification of anomalies in microphone array measurements of trailing edge noise by eigenstructure analysis
Authors: Defreitas Aaron , Alexander W. Nathan
Published: February 2023

An eigenstructure analysis is used to identify anomalies in large acoustic array measurements of airfoil trailing edge noise. Cross-spectra of 102 microphones distributed in a spiral configuration were inspected considering a range of inflow conditions and airfoil configurations. A measurement expectation is set by repeat measurements of non-anomalous data and is used for the analysis of additional data. This method is based solely on the comparison between the eigenstructure of cross-spectral matrices and can be used to efficiently inspect data for anomalies without having to beamform, as is conventional. Thus, processing and reviewing beamform maps can be relegated to post-processing after the experiment when more time is available.