High Horsepower Research Articles

The Regenerator Principle in the Stirling and Ericsson Hot Air Engines

During the first half of the nineteenth century the Stirling brothers and John Ericsson made significant attempts to design hot air engines which could provide an economical alternative to high-pressure steam. They believed that it would be possible to gain fuel efficiencies superior to those obtained with steam by employing a heat exchanger within the air engine cycle, erroneously supposing that such a heat exchanger could eliminate the large loss of heat incurred in the condenser of the steam engine. The Stirling brothers called their heat exchanger an economizer because it prevented the waste of heat, but Ericsson coined the term regenerator because he imagined that the power of the heat (caloric) could actually be regenerated, i.e. re-used in the engine to generate mechanical work. Ericsson's term became commonly accepted, so that Stirling's economizer is now also referred to as a generator. These attempts to attain high horsepower outputs with hot air engines were abandoned after the dramatic failure of Ericsson's notorious paddle steamer in the early 1850s. Further ventures were aimed at the more limited goal of low horsepowers and generally ignored the regenerator principle.

A SUMMARY OF CONTROLLABLE PITCH PROPELLER SYSTEMS EMPLOYED BY THE U. S. NAVY

The principle objective of this paper is to describe the hydraulically actuated controllable pitch propeller systems actively employed by the U.S. Navy. Advantages of controllable pitch propellers, including the ability to reverse ships' way without changing the direction of shaft rotation, improved ship maneuverability and increased fuel economy while cruising under reduced load conditions, are all discussed. The discussion of the systems themselves is limited to the hydraulically actuated systems primarily because it is felt that this is the only design suitable for high horsepower applications. The system descriptions are of necessity brief. Their intent is to give a general understanding of the configuration and the method of operation of each system.

Oil: the omnipotent energy source

Whether oil will be used as a weapon or club to force a reappraisal by the U.S. of its attitudes and political relationships toward other nations, time alone will tell. Since 1960, the domination of the world's oil supply has been shifting from the affluent oil-consuming industrial nations to the underdeveloped oil-producing countries. In the U.S., since oil will be the predominant energy fuel during the next 12 years (in fact, the only fuel capable of meeting our escalating energy requirements), the potentially adverse effects of Middle East manipulation of the oil flow on the balance-of-payments deficient, alone, are staggering. The immediate problem confronting the U.S. is in part a matter of logistics; it must develop new oil sources, construct refineries within its continental borders, and establish conservation policies that will mitigate the coming crunch. But, at the present time, it does not seem likely that such a large order can be filled. Furthermore, U.S. autos are getting less economical to operate, with more power options, higher horsepower, lower compression ratios (and hence decreased efficiency), while gas consumption in these outsized jalopies has increased markedly.

Rheology of Viscous Fracturing Fluids

A rheological study of a new viscous fluid system reveals that fluid mixtures containing highly viscous oils can be pumped at fracturing rates with tubular friction losses less than that obtained with water alone because of annular water ring lubrication and because of the slippage layer in the water-in-oil dispersion. Introduction Many different fluids, from water to very viscous oils, have been used to break down or fracture formations. The use of viscous or low-penetrating fluids was discussed in early patents on fracturing, but full appreciation of the advantages of very viscous Newtonian fluids is a recent development. These oils and asphalt residue are called Newtonian because they have a constant viscosity at any reasonable shear rate. By contrast, viscous water-based gels have a variable viscosity with shear rate and are called non-Newtonian fluids. Some of the advantages of viscous Newtonian fluids for fracturing are increased fracture width, good fluid-loss control, and better sand-carrying ability. The increased fracture width obtained with the viscous fluids is due to increased propagation pressure or friction loss in the fracture and by the inherently high viscosity of the fluids in the fracture. This increased fracture width can be ascertained either by allowing large sand (8–12 mesh) to be used routinely at high concentrations, or by using an impression packer to actually measure wellbore fracture widths. packer to actually measure wellbore fracture widths. The predicted width of the fractures varies approximately as the cube root of the viscosity. This is shown in Fig. 1, which indicates that a 50-cp fluid generates a fracture width of 0.2 in., whereas a 1,000-cp fluid generates a fracture width of almost 0.5 in. These results are calculated by using Kristianovich and Zheltov's solution, modified by Kiel, for a partially pressurized crack, and involving a flow rate of 5 bpm, pressurized crack, and involving a flow rate of 5 bpm, fracture length of 180 ft, and time of 30 minutes after fracture initiation. Both increased length and increased width are obtained as a result of the improved fluid-loss control secured with very viscous oils and with viscous oils containing fluid-loss additives. This makes fracturing applicable to many more formations. Reasonable fluid efficiencies can be obtained in formations with very high permeabilities. The settling rate of sand in viscous oils is low. High viscosity facilitates the transportation of 8–12 mesh sand through surface equipment, down the tubing, and into the fracture. Good conductivity contrast between the fracture proppant and the formation can be obtained in very permeable formations, including those with permeabilities greater than 1 darcy. As a result of these advantages, the use of viscous Newtonian fluids can result in productivity improvements considerably greater than can be obtained by conventional fracturing. Some drawbacks to the use of viscous Newtonian fracturing fluids have been the extremely high friction losses, and the high horsepower and high pumping rates required to initiate the fractures. Viscous fluids are difficult to pump if the formation is very deep or if fracturing is carried out through tubing. An example of the way normal fluid friction loss depends upon viscosity is shown in Fig. 2. The friction loss for a 10,000-ft well at 5 bpm can be calculated for fluid of any viscosity by multiplying by 100 the friction loss per 100 ft, shown in Fig. 2. JPT P. 711

New Inverter Supplies for High Horsepower Drives

A review of basic ac induction motor characteristics establishes the requirements of a static ac variable-speed drive. Both voltage and frequency impressed onto an ac motor must be programmed in correct proportion if required operating torque is to be maintained. The means of voltage control used characterizes the various inverter designs and likewise dictates their limitations. Pulsewidth modulation for variable voltage control eliminates many of the restrictions heretofore placed on inverters. Their operating capabilities, while not economically favorable in every case, are technically equal to or better than those of a dc system.

U.S. NAVY GAS TURBINE POWERED OCEAN ESCORT

ABSTRACT“This article is from a paper presented in Washington, D. C. at the Association of Senior Engineers Naval Ship System Command 6th Annual Technical Symposium. The paper describes the special features of a gas turbine propulsion system concept of integrating high horsepower and C. P. propellers into a complete propulsion system. This advanced propulsion system design is unique in that it was developed to fit into an existing D. E. ship design and proposed for the fiscal year 1968 building program. The ship has been cancelled, however, the design should be of interest to people both within the Navy and in that sector of private industry concerned with the future of our Navy shipbuilding programs. The focus is now on the gas turbine as a prime mover for warships, and it seems likely that there will be an increased emphasis on the use of gas turbines in the U.S. Navy's future shipbuilding programs.”

Paper 3: Development of the Napier Deltic Charge Cooled Engine

This third generation of Deltic engine, of higher horsepower, is basically similar in design to the earlier units but a redesigned turbo-blower of increased efficiency has been introduced and charge-air coolers are interposed between the blower and cylinder blocks, thus enabling a greater mass of air to be trapped at a lower temperature with the charge pressure remaining unchanged. By this arrangement the power of the engine, for fast patrol boat application, has been increased to 3700 b.h.p. from 3100 b.h.p. at 2100 crankshaft rev/min. The engine is generally of light alloy construction and for marine use includes an integral ahead and astern gearbox. The paper gives a survey of the design changes made to the engine and the development problems encountered before a 1000-hour endurance test was satisfactorily completed.

Self-Cleaning Oil Bath Engine Intake Filter for Locomotive Applications

The self-cleaning oil bath air filter has been used for over 30 years for filtering intake air for large, stationary diesel engines. It has proven successful under all types of operating conditions, from the hot, sandy climate of the Southwest to the subfreezing temperatures in the North. Only recently has it been adapted successfully to locomotive applications. Previous performance standards required of locomotive engine air filters did not require the high filtering performance of this type of filter. Only since the introduction of the high horsepower diesel locomotives, where air filter standards have been considerably increased beyond the abilities of conventional locomotive filters, has the self-cleaning principle of good oil bath filtration become feasible. The purpose of this paper is to show how, through design, testing, and applications, this type of oil bath principle can be adapted to meet the critical air-cleaning needs of today’s modern locomotive engines.

New Nema Rerating of AC Motors

The motor and generator section of the National Electrical Manufacturers Association (NEMA) has adopted new suggested standards for future design which assign higher horsepower rating to a given motor frame size. The rerating will make available standard 1-to 50-hp ac motors smaller by two frames than those motors produced in the past; this will, later, affect ratings to 200 hp. Per rating reductions of 50 percent of volume and 75 percent of weight are shown to be typical. Development of improved and new materials plus advancements in the art of polyphase induction motor design, are given as factors that make the revision possible.

COMBINED DIESEL‐GAS TURBINE POWER PLANTS IN COAST GUARD VESSELS

SUMMARYAs was pointed out in the beginning of this paper, the gas turbine as a means of marine propulsion, is making inroads into a field once dominated by steam turbines and diesel engines. More important, it is being realized to a greater extent, that the gas turbine when used in conjunction with other prime movers illustrates definite advantages to be realized. Most important of these is the high horsepower to weight ratio, even realizing at the same time the turbine's additional specific fuel consumption and added weight due to larger inlet and exhaust ducts.The two applications discussed previously are both of the CODAG variety with minor variations. CODAG was selected in both instances due to the fuel requirement for Coast Guard vessels of long range with good top speed characteristics. In both cases, the vessel can operate for most of its normal duties on the diesel engines, realizing the low specific fuel consumption of the diesel and hence the relatively long range produced. For top speed, the turbines are employed; in the 210 footer as a boost power plant, and in the 350 footer as the sole means of propulsion. In this manner it is felt that the most optimum plant was selected in each case to meet the various and many faceted duties of the Coast Guard.A conclusion to this paper cannot really be written. Only after successful vessel trials and successful operating experience can a purely objective conclusion be reached. It is the author's opinion, however, that more combined plants will be used for marine propulsion in the future, whether they be CODAG, COSAG, or COGAG. As the frequency of successful applications grow, the natural reluctance many feel toward these types of propulsion schemes will most certainly diminish, until someday gas turbines combined with other modes of propulsion will be as common as the presently out‐moded Scotch marine boiler and triple expansion engine.

Lubricants for Engines for Supersonic Aircraft

MOST of the aircraft engines of the 1900 era were little more than adaptations of the existing reciprocating internal combustion engines used in motor cars, but progressive design improvements eventually led to the very efficient power plants of high horsepower which had by the 1940's enabled piston‐engined bomber aircraft to reach cruising speeds of 300 m.p.h. and piston‐engined fighter aircraft to attain level‐flight speeds in excess of 400 m.p.h. At this stage, piston engines had almost reached their peak performance and aircraft speeds could be significantly increased only by the adoption of some radically different type of engine. The development of the gas turbine resulted in this new power plant and aero gas turbines are now in the final stages of replacing piston engines as propulsive units for medium and large aircraft.

Latest Dredging Practice

Description of improvements incorporated in modern hydraulic dredge; trend is to higher and higher horsepower on main pump and cutter; all lined dredge pumps, pump and shutter shafts of high alloy steel, larger diameter dredge spuds of structural or cast-alloy steel, and dredge cutters with removable wear edges; universal use of anchor handling booms; direct suction pipe-cutter drive; pontoon line ball joints that eliminate usual bolted connections.

19 街路騒音とその伝播性状に関する研究

In recent years, the air velocity in an ari-conditioning duct system is going to become higher, so the fan noise is increasing because of the higher pressure and the higher horse power. The greater parts of the eneryg of the fan noise are contained in low frequencies. Therefore, it seems to be unsuitable to attenuate the fan noise with acoustic lining ducts, for ordinary sound absorptive materials, as linings, have small sound absorption coefficient at low frequencies, and have high pressure losses of friction in a high speed duct system. The box type sound attenuator has good attenuation characteristics at low frequencies by calculating the length and the enlarging ratio of the cross sectional area of the box to that of the straight duct. To apply the box type sound attenuator to the practical use of the high speed duct system, an experimental research of the pressure losses due to area changes of the box type sound attenuator has been done. This report shows, as the result of the experimental research of the practical scale of the box and air velocity, that: 1. The normal box type attenuator has a smaller total pressure loss coefficient "ξ_t" than the sum of the pressure loss coefficient of abrupt expansion and abrupt contraction. 2. "ξ_t" becomes 3. "ξ_t" becomes 4. By adding the normal type. 5. By adding the the normal type. 6. But it has not hausting side of smaller as the enlarging ratio "m" becomes larger, larger as the length of the box "l_0" becomes larger. cone type hopper to the entering side of the box, "ξ_t" becomes larger than "ξ_t" of the cone type hopper to the exhausting side of the box, "ξ_t" becomes smaller than "ξ_t" of so large effect on "ξ_t" to add cone type hopper either to the entering side or to the ex-the box.

THERMAL INSTABILITY IN HIGH SPEED GEARING

ABSTRACTThermal expansion effects in gearing have usually been considered from a steady state point‐of‐view. A theory of thermal instability is developed which takes into account the tendency of the thermal effects to be regenerative. This theory provides an adequate and complete explanation for several heretofore unexplained cases of tooth failure in high speed high horsepower reduction gears. Experimental verification of the theory is presented and some of the conditions for avoiding thermal instability are described.

High Horsepower and High Torque Performance of EP Gear Lubricants

In recent months a series of premature gear failures in field operated vehicles produced indications of insufficient load carrying qualities in extreme pressure lubricants of the GL-4 specification conforming to the new Military L-2105A. This condition prompted dynamometer testing in an investigation of horsepower absorption and high torque absorption of these lubricants as compared with extreme pressure lubricants conforming to Military L-2105 specifications. The results of the dynamometer testing showed that lubricants conforming to the new Military L-2105A were capable of withstanding continuous high horsepower applications where relatively low torque was required, but were not able to compare favorably with the extreme pressure lubricants of the Military L-2105A specification in regard to continuous high torque applications. The gear-tooth surfaces on such tests with lubricants conforming to the new Military L-2105A were severely scored, whereas the Military L-2105A lubricants produced a satisfactory tooth condition under identical testing conditions.

Automatic feathering to reduce the hazard of aircraft engine failure at take-off

FAILURE OF AN aircraft engine in flight changes the propeller of that engine from a source of thrust to a parasitic source of drag. Present-day propellers, selected for the efficiency with which they convert tremendous horsepower into thrust with comparatively small blade area, absorb proportionately high horsepower when wind-milling the engine. The propeller used on the Martin model 202 airplane converts a maximum of 2,400 horsepower into thrust at take-off. The same engine and propeller combination exerts a drag equivalent to approximately 220 horsepower when being windmilled at take-off air speed. In contrast, the drag of the feathered propeller is equivalent to 12 horsepower. Thus, it is evident that in the event of an engine failure, in addition to the immediate loss of half the thrust, a windmilling propeller steals approximately 10 per cent of the horsepower available from the remaining engine, reducing the net thrust to approximately 45 per cent of normal. With one propeller producing drag and the other producing thrust, a turning moment exists, tending to turn the airplane in the direction of the faulty engine.

Automatic Feathering-To Reduce the Hazard of Aircraft Engine Failure at Take-off

FAILURE OF AN aircraft engine in flight changes the propeller of that engine from a source of thrust to a parasitic source of drag. Present-day propellers, selected for the efficiency with which they convert tremendous horsepower into thrust with comparatively small blade area, absorb proportionately high horsepower when wind-milling the engine. The propeller used on the Martin model 202 airplane converts a maximum of 2,400 horsepower into thrust at take-off. The same engine and propeller combination exerts a drag equivalent to approximately 220 horsepower when being windmilled at take-off air speed. In contrast, the drag of the feathered propeller is equivalent to 12 horsepower. Thus, it is evident that in the event of an engine failure, in addition to the immediate loss of half the thrust, a windmilling propeller steals approximately 10 per cent of the horsepower available from the remaining engine, reducing the net thrust to approximately 45 per cent of normal. With one propeller producing drag and the other producing thrust, a turning moment exists, tending to turn the airplane in the direction of the faulty engine.

Electric locomotive application

ELECTRIC locomotives were first used for the movement of main-line traffic over 45 years ago. This early application was for tunnel work but it may be taken as the beginning of a new era in main-line transportation. In this era the steam locomotive has been transformed in appearance and characteristics. More recently the Diesel engine has been applied to passenger and freight trains. During all this period of development the characteristics of the electric locomotive have continued to be superior to those of either the steam or the diesel-electric locomotive. Many of the early ideas with regard to the application of electric locomotives are still valid today, but progress in transportation engineering has become so accelerated that a periodic review of each type of motive power must be made by those who are responsible for their application. A discussion of the engineering fundamentals which enter into the selection of an electric motive power unit for main-line work will be presented. An understanding of these fundamentals is essential to the specification of a balanced design. A locomotive which is specified on this basis will give all of the advantages of momentum operation augmented by high electrical horsepower at high speed. This is one of the unique advantages of the electric locomotive.

Electric Locomotive Application

ELECTRIC locomotives were first used for the movement of main-line traffic over 45 years ago. This early application was for tunnel work but it may be taken as the beginning of a new era in main-line transportation. In this era the steam locomotive has been transformed in appearance and characteristics. More recently the Diesel engine has been applied to passenger and freight trains. During all this period of development the characteristics of the electric locomotive have continued to be superior to those of either the steam or the diesel-electric locomotive. Many of the early ideas with regard to the application of electric locomotives are still valid today, but progress in transportation engineering has become so accelerated that a periodic review of each type of motive power must be made by those who are responsible for their application. A discussion of the engineering fundamentals which enter into the selection of an electric motive power unit for main-line work will be presented. An understanding of these fundamentals is essential to the specification of a balanced design. A locomotive which is specified on this basis will give all of the advantages of momentum operation augmented by high electrical horsepower at high speed. This is one of the unique advantages of the electric locomotive.

Large Oil Engines, With Special Reference to the Double-Acting Two-Cycle Type

Abstract Efforts to build large oil engines have been growing in number and in variety of means selected to meet marine requirements, stimulated by the success of motorships and the desire to increase their size or utility in prevailing sizes. Possible stationary applications of larger oil engines have also contributed additional motives and other solutions. Much of this work has not been published and is therefore not as well known to the engineering profession as it deserves by reason of its high quality and the foundation it lays for the future. This paper is concerned with a review of some of this work, with special reference to double-acting engines. One of the problems considered is that of the possibility of raising the mean pressure in the cylinder to get high horsepower per cubic foot of displacement and without rise of maximum pressure to thereby reduce the weight per horsepower. High injection-air pressures, extra injection air, and supercharging of cylinders are included here in addition to studies of shape of combustion chamber, position of sprayer, and design of spray valve. A second one is that of determining the maximum diameter of cylinder that can be operated at very high or at moderate mean pressures without injury to the metal of cylinder, piston, or cylinder head, with particular reference to the effect of special designs of these parts for resisting heat damage at a given heat-generation rate or the corresponding relation of diameter and mean indicated pressure. A third problem is that of securing results in two-cycle cylinders as nearly as possible equal to those of the earlier developed and more widely standard four-cycle, to determine how close the former can be brought to half the weight per horsepower of the latter on the one hand, and on the other, for the same size of cylinder and similar engine structures, how close to twice the maximum horsepower of a four-cycle engine it may be possible to build the two-cycle. Still another, from the standpoint of double action of the piston, assuming a given diameter and mean pressure or heat-generation rate established in four- or two-cycle single-acting cylinders, and a construction of cylinder, piston and cylinder head not injured for these values, is that of determining the practicability of making both ends develop the same power in both four-cycle and two-cycle engines. This includes the determination of how close to half the weight per horsepower of the single-acting it may be possible to build the double-acting engine or how close to twice the maximum horsepower of the single-acting it may be possible to make the maximum horsepower of the double-acting engine. Some of the double-acting designs published are reviewed, including the rodless piston and the double opposed pistons.