Compressor Applications Research Articles

Structure/Property Relationships and Applications of Rapidly Solidified Aluminum Alloys

ABSTRACTDuring the last five years Pratt & Whitney Aircraft has developed rapid solidification powder metallurgy and consolidation techniques to produce advanced aluminum alloys. A centrifugal rotary atomization device with forced high velocity helium convective cooling has been developed to pilot-plant stage, to produce aluminum alloys of novel compositions for advanced gas turbine engine applications. Rapidly solidified aluminum alloys solidify as spherical droplets up to 100 μm diameter with cooling rates of 105 — 106 K/sec, and demonstrate new microstructural features which have been exploited to develop elevated temperature mechanical properties. Alloys have been developed for 400 — 500°F fan and compressor applications that have traditionally used titanium alloys, and this paper reviews the microstructural evolution of rapidly solidified structures during thermomechanical processing.

Application of axial flow compressors for long distance pipeline transmission of hydrogen

In Natural gas pipeline recompressor stations, centrifugal compressors have been preferred to reciprocating compressors; yet they have upper limits on the volumetric flow rate (200,000 m 3/h) and the required power (about 30,000 kW). In a hydrogen energy transmission system, the flow rates are expected to be considerably higher, where the choice for efficiency operation switches to axial flow compressors. The fluid dynamics aspects of hydrogen recompression is discussed and it is noted that axial flow compressors are indeed efficient for the purpose. A power requirement of less than 20,000 kW is obtained for an energy transimission of 4000 MW th for an axial flow compressor with 12 stages and mean speed of 350 m/s.

Recent Developments on Gas Turbine Control Systems

The paper briefly outlines some of the activities undertaken on gas turbine logic and control systems. The frequent requirement for gas turbines to operate in polluted hostile environments has encouraged the development of ancillary equipment which will reliably withstand onerous site conditions. The design requirements, philosophy, component selection and progress made on fuel control and solid state logic systems, specifically introduced to meet arduous service requirements are reviewed. A computer control system designed for more temperate environments is also examined, enabling a comparison of the theoretical reliabilities of the respective systems to be assessed when installed on gas compressor applications.

The Thermodynamic Performance of Oil-Flooded Helium Screw Compressors

In recent years the cryogenic community has become interested in the application of hermetic screw compressors for helium refrigeration/liquefaction systems. In the past the screw compressor had not been an attractive compressor for cryogenic systems because of the problems associated with both dry and oil-flooded screw compressors. However, oil separation technology has evolved to a point where oil can successfully be separated from helium gas. The screw compressor has exhibited excellent reliability and performance characteristics for various refrigeration gases, and preliminary test results reveal that the same is true for helium gas. The present paper presents the thermodynamic performace characteristics of 30-kW (40-HP) and 113-kW (150-HP) oil-flooded hermetic screw compressors with various built-in volume ratios operating with helium gas at pressure ratios between 2.0 and 18.0, and for suction pressures of 0.5 atm, 1.0 atm, and 2.0 atm. The thermodynamic parameters of interest are the volumetric efficiency and the isentropic efficiency. It is found that the volumetric efficiency decreases with pressure ratio; however, depending on the built-in volume ratio of the compressor, the maximum value of the isentropic efficiency occurs in a narrow range of values for the pressure ratio at which the optimum isentropic efficiency occurs. The results of the tests indicate that oil-flooded screw compressors may successfully be used for helium service.

Application of CAD/CAM in Forging Turbine and Compressor Blades

The design and manufacturing of dies for forging of turbine and compressor blades represent excellent applications for CAD/CAM. Computer programs have been developed to predict the load, the optimum die design, the best preform position before forging, and the minimum stock volume necessary to fill the die cavity. The predicted forging loads and forging positions agreed well with practical values. For numerical-control machining of forging dies, or of electrodes for Electro Discharge Machining (EDM) of the dies, special-purpose programs have been developed. Thus, the necessary fundamentals are available for an integrated CAD/CAM approach in forging of blades for turbine and compressor applications.

A Comparison of the Matrix and Streamline Curvature Methods of Axial Flow Turbomachinery Analysis, From a User’s Point of View

In recent years two general methods for flow analysis in turbomachinery have been developed, one generally called the Streamline Curvature Method, the other the Matrix Through-Flow Method. Both methods solve the same flow equations but the differences in technique introduce different operational constraints and difficulties. A comparative assessment of the relative merits of the two methods has been difficult because the various authors did not use similar cascade models to represent cascade loss and deviation, a necessary adjunct to each technique. This paper outlines the two methods, and a common cascade model for both, and compares two programs written to implement the two techniques for ease of use, computer time and storage requirements, flexibility and inherent limitations. The programs are used to compute the flow field in three axial flow compressor applications: an interconnecting duct, a transonic fan, and three stage axial compressor. The predicted performance for the above machines was fairly good, although no attempt was made to “tune” the cascade model for the specific type of machine, as the relative merits of each method were of interest. It is concluded that there is a small operational advantage to the matrix method.

Adjustable Speed AC Drive Systems for Pump and Compressor Applications

The paper covers the application and performance of a cycloconverter type frequency converter and a doubly fed wound rotor ac motor as applicable to adjustable speed drive systems for pump and compressor loads. The paper covers the subject by discussion of the following: 1) basic theory and operation of a cycloconverter and a doubly fed wound rotor motor; 2) motor and converter ratings to meet the performance requirements of typical pump and compressor applications; 3) control schemes for starting, running, and process control; 4) efficiency and power factor; and 5) summation, including advantages of adjustable speed ac drive systems and static frequency conversion equipments.

Long Time Stability Of Inconel 718

Inconel 718, a compressor and turbine wheel material suited for 900–1200°F applications in advanced gas turbine engines, was evaluated for long time properties and structural stability. This work included creep rupture testing and residual tensile property determination after extended times under stress exposure. Tests were conducted at 1000°F to 21,000 hr, at 1100°F to 33,000 hr, at 1200°F to 10,000 hr, and at 1300°F for 6,000 hr. In addition, optical and electron microscopy, X-ray diffraction, and X-ray fluorescence methods of phase analyses before and after exposure were carried out. Except for the expected overaging at 1300°F, there were no detrimental instabilities observed. This alloy has been selected for critical compressor and turbine wheel applications that will see service to 36,000 hr.

Paper 20: Compressors: What the User Wants and Why

Some problems experienced in the operation of large centrifugal and reciprocating compressors, and the steps taken to overcome them, are described. The fields covered include noise, vibration, lubrication, and general operation and an underlying theme arising from them is the importance of the environment in specific compressor applications. To avoid recurrence of many of these problems it is important that the user should feed back his own practical operating experience to the manufacturer and also ensure that economic competition does not result in unsatisfactory technical standards. A carefully prepared enquiry specification has been found to be of assistance in achieving these objectives.

Choked flow - A generalization of the concept and some experimental data.

The equation of choking for two or more unmixed streams flowing in the same channel is derived in a general form applicable to both self-entrainment and heterogeneous entrainment. The derivation is based on an extension of a method that is shown to give the correct answer when applied to a single stream. Experimental data are presented that show generalized choking to be a reasonable flow-limiting mechanism in situations where other mechanisms are somewhat implausible. Generalized choking is believed to be more likely when the ejector principle is used to modify the degree of expansion that takes place in the exhaust of a jet engine than when the principle is used in the more usual pump and compressor applications.

Compressor applications for caprone

Compressor applications for caprone

Discussion: “Development of a Special High-Efficiency Turbocharger Compressor for Application on Straight Turbocharged Two-Cycle Engines” (Niemczewski, T., 1965, ASME J. Eng. Power, 87, pp. 99–104)

Discussion: “Development of a Special High-Efficiency Turbocharger Compressor for Application on Straight Turbocharged Two-Cycle Engines” (Niemczewski, T., 1965, ASME J. Eng. Power, 87, pp. 99–104)

Discussion: “Development of a Special High-Efficiency Turbocharger Compressor for Application on Straight Turbocharged Two-Cycle Engines” (Niemczewski, T., 1965, ASME J. Eng. Power, 87, pp. 99–104)

Discussion: “Development of a Special High-Efficiency Turbocharger Compressor for Application on Straight Turbocharged Two-Cycle Engines” (Niemczewski, T., 1965, ASME J. Eng. Power, 87, pp. 99–104)

Closure to “Discussions of ‘Development of a Special High-Efficiency Turbocharger Compressor for Application on Straight Turbocharged Two-Cycle Engines’” (1965, ASME J. Eng. Power, 87, p. 104)

Closure to “Discussions of ‘Development of a Special High-Efficiency Turbocharger Compressor for Application on Straight Turbocharged Two-Cycle Engines’” (1965, ASME J. Eng. Power, 87, p. 104)

Development of a Special High-Efficiency Turbocharger Compressor for Application on Straight Turbocharged Two-Cycle Engines

Conversion of the two-cycle engine from the “in-series” system of turbocharging (turbo-charger followed by the engine-driven centrifugal blower) to a straight turbocharged one, requires a radical increase in the aerodynamic performance of the turbocharger compressor. This paper describes how a wide-range, high-efficiency blower was developed within a relatively short time by using, as a chief design guide, conclusions of the aerodynamic analysis which preceded each development stage. A method is presented, advocating the use of a well-controlled velocity-diffusion system, as compared with a plenum-chamber configuration.

Predicting Process Gas Performance of Centrifugal Compressors From Air Test Data

The application of centrifugal compressors to the handling of gases in the process industries is of increasing importance. The problems associated with performing tests at the manufacturer’s plant under process conditions and the lack of a universally accepted method of performance correlation are matters of concern. This paper presents a recommended correlation procedure evolved from the review of technical papers embracing aspects of the subject. A program for the free interchange of air and process test data between manufacturer and user is submitted. This recommended procedure and proposed program (1) provides designers with essential information previously unavailable to them, and (2) ultimately benefits the user by the production of higher-performance machines.

Some NACA Research on Centrifugal Compressors

Abstract This paper presents a summary of some of the results obtained in the NACA program of aerodynamic research on centrifugal compressors, including both theoretical and experimental aspects. The material presented is not intended to give specific design rules, but rather is intended to give some insight into the flow processes in centrifugal turbomachinery, to establish general trends of good design practice, and to indicate portions of the field that remain to be explored. The paper is arranged in three sections; (a) impeller research, (b) diffuser research, and (c) general aspects of application of centrifugal compressor to aircraft gas-turbine engines.

Axial-Flow Compressors for Gas Turbines

Abstract The development of the gas turbine during the last decade has opened a new field for compressor application. The compressor is an essential component of every gas-turbine power plant. It delivers air at some elevated pressure to the burner in sufficient quantity to maintain an efficient combustion of fuel and to cool the products of combustion to some acceptable temperature at the turbine inlet. The axial-flow compressor is particularly adaptable to gas-turbine applications for aviation, marine, or land service. This paper deals with the operating principles, characteristics, types, and other data pertaining to the axial-flow compressor.