Real Gas Effects in Carbon Dioxide Cycles

The potential performance of carbon dioxide as working fluid is recognized to be similar to that of steam, which justifies thorough thermodynamic analysis of possible cycles. The substantially better results achievable with CO2 with respect to other gases are due to the real gas behaviour in the vicinity of the Andrews curve. Simple cycles benefit from the reduced compression work, but their efficiency is compromised by significant losses caused by irreversible heat transfer. Their economy, however, is appreciably better than that of perfect gas cycles. More complex cycle arrangements, six of which are proposed and analyzed in detail, reduce heat transfer losses while maintaining the advantage of low compression work and raise cycle efficiency to values attained only by the best steam practice. Some of the cycles presented were conceived to give a good efficiency at moderate pressure which is of particular value in direct-cycle nuclear applications. The favourable influence on heat transfer coefficients of the combined variation with pressure of mechanical, thermal and transport properties, due to real gas effects, is illustrated. Technical aspects as turbo-machines dimensions and heat transfer surfaces needed for regeneration are also considered. Cooling water requirements are found to be not much more stringent than in steam stations.

Noncontacting Torquemeters Utilizing Magneto-Elastic Properties of Steel Shafts

The magneto-elastic property of steel shafts makes noncontacting torquementers possible. Early magneto-elastic torquemeters suffered from excessive sensitivity to variations in airgap and shaft temperature. These drawbacks have been eliminated in the Torductor® torquemeter, which has been very successful in low-speed industrial applications. In gas turbine applications, some special problems are encountered. These problems, and ways to minimize them, are discussed.

Some Non-Simple–Equilibrium Aspects in Axisymmetric Turbomachine Flow Theory

In turbomachines of non-free-vortex design the axisymmetric flow is mostly in a state of “disturbed equilibrium.” Methods of calculating flow fields of this kind were developed nearly 20 years ago. The examples chosen for their demonstration were rather intricate. Here, on the other hand, two very simple examples are produced which provide some insight into the — anything but self-evident — behavior of disturbed equilibrium flow. The examples serve to give some indication as to the use of definite difference methods, including the choice of boundary conditions, and a first attempt at taking incidence at the leading edges of the blades into account.

The Development of Supersonic Axial Compressor Boost Stages for Small Gas Turbines

The axial supersonic compressors of the “shock-in-rotor” type are under development for application to small gas turbines. A passage flow approach and passage criteria were used to design and develop the airfoils for the highly loaded rotor and stator blading of these 4 lb/sec machines. The overall stage performance values demonstrated to date are 2.06:1 pressure ratio at 78 percent adiabatic efficiency and 2.56:1 at 74.4 percent efficiency. The loss data and static pressure rise measured for the rotors and exit stators provide ample evidence that the higher design performance goals can be met.

Condition Monitoring

This paper discusses condition monitoring of jet aircraft engines intended for airline use. Some brief background information is presented to connect past programs with present developments, and the goal, objectives, and terminology for a condition monitoring system are defined. The various concepts and techniques being studied and developed by General Electric to accomplish condition monitoring are described and available results presented and discussed.

Process Plant Application of an Aircraft-Type Gas Turbine

The installation to be discussed in this paper was one of the first gas generator, power turbine, centrifugal compressor design combinations to be put in ground (as opposed to airplane) power applications. As a consequence the control systems, waste heat boiler installation and other parts of the facility proved to be other than adequate for continuous duty industrial plant use and as such, has gone through a subsequent development period to overcome the many problems that were encountered. This should be kept in mind as one reads the article. The present-day industrial gas generator units incorporate simplified and reliable control systems and other successful features as a result of this earlier experimental and prototype installation. Revisions to the Phillips Petroleum Company Dumas Helium Plant Pratt Whitney GG3C gas generator and related equipment have greatly increased onstream capabilities. Replacement of unreliable controls and electrical relays has decreased unwarranted shutdowns from 80 hr in 1963 to 8 hr in 1967. Improvements in lubricating oil have increased the time between oil changes from 300 to 3000 hr. Design changes in bearings, exhaust hood, and the lubricating oil system have increased the gas generator’s reliability. The Cooper-Bessemer RT-48 free power turbine has operated maintenance-free since startup. Cooper-Bessemer’s latest design has solved the reaction turbine hood stress cracking problem. Use of this type facility in helium plant service offers advantages, but lack of flexibility has caused a considerable amount of product loss at Dumas Helium Plant.

The Potential Danger of Fire in Gas Turbine Heat Exchangers

Increased emphasis is being placed on the regenerative gas turbine cycle, and the utilization of waste heat recovery systems, for improved thermal efficiency. For such systems there are modes of engine operation, where it is possible for a metal fire to occur in the exhaust heat exchanger. This paper is intended as an introduction to the subject, more from an engineering, than metallurgical standpoint, and includes a description of a series of simple tests to acquire an understanding of the problem for a particular application. Some engine operational procedures, and design features, aimed at minimizing the costly and dangerous occurrence of gas turbine heat exchanger fires, are briefly mentioned.

Gas Turbines: A Modern Approach to Industrial Power Plant Expansions

A major industrial complex with in-plant power generation required a large incremental expansion of steam and power production. Alternative approaches to achieve this expansion are reviewed and the gas turbine-heat recovery boiler cycle selected is described. The primary objective of this paper is to demonstrate the excellent results that can be achieved through integration of gas turbines with conventional industrial power equipment.

Vibration and Noise Characteristics of an Aircraft-Type Gas Turbine Used in a Marine Propulsion System

Sound and vibration data measured on a combination diesel gas turbine propulsion system in a 2000-ton antisubmarine warfare ship are presented. The data can be considered representative of the noise levels, both structureborne and airborne, that can be expected in an installation of this or a similar type. Examples of the attenuation of structureborne noise through selected structural joints illustrate the vibration isolation attainable through the use of lightweight aircraft-type structures.

Design Requirements and Objectives for Commercial Aircraft Propulsion Systems

With the past ten years commercial airlines have begun to move away from their direct dependence on equipment developed by the military. This departure from almost traditional methods of doing business has led to a need for the airlines to define in greater detail the requirements that each new type of equipment must meet for satisfactory airline use. Military equipment in the past served as a technical base line. Today there is no base line equipment and the airlines must shoulder the responsibility for defining the base line requirements. This paper is directed at a few of the important base line requirements for commercial aircraft propulsion systems. In summary, engines must be designed to be installed in aircraft not on a test stand. The design must be directed toward long life, ease of repair, and good long term installed performance. All power plant subsystems must be integrated into the installation, tested early and thoroughly as part of the power plant, and be more reliable and maintainable than current equipment in service.