Inflight Engine Performance Evaluations

The measurement/determination of installed inflight engine performance on an aircraft is a complex task. To be successful requires that wind tunnel model and full-scale inflight test programs be fully planned early in the development phase of the aircraft design. In particular, methodology and instrumentation requirements must be coordinated in these programs. This paper discusses the requirements and methodology for inflight engine performance evaluations as applied to a subsonic ASW type aircraft. Data are presented which show that two independent methods of calculating steady-state engine net thrust levels agree to within ± 1.5 percent of each other over the full operating regime of the aircraft. Finally, comparisons of calculated performance with that predicted from the engine manufacturer’s cycle deck are presented.

Advanced Composite Fan Blade Flight Evaluation Program

The preparation for and conduct of the first flight by the U. S. Air Force of a turbine engine fan stage fabricated of advanced composite materials is discussed. Composite material properties and basic design philosophy is presented along with preliminary flight evaluation results. This is the first application of filamentary-reinforced metal matrix composites to a turbine engine structural component.

Fuel Economy Study of Future Metallic and Ceramic Automotive Gas Turbines

An analog simulation technique is described which can calculate the behavior of a gas turbine engine and a gas turbine automobile in steady and unsteady operating conditions. The simulation results agreed well with values measured for a research gas turbine. Possible improvements to the components of a future metallic and a ceramic power plant are discussed. The metallic engine could be developed with today’s technology, but the high temperatures proposed for the ceramic gas turbine could be utilized only after the successful development of the appropriate ceramic components. For a 1550-kg automobile, the simulation technique predicts a fuel economy of 14.7 mpg in the FDC and 24.8 mpg in the EPA highway cycle for the metallic engine. For the ceramic gas turbine, the values are 19.1 mpg in the FDC and 28.2 mpg in the EPA highway cycle. Thus, the metallic gas turbine gives a fuel economy approximately comparable to a present Otto engine automobile, and the ceramic gas turbine could give almost 20 percent better values.

Fluid Film Bearing Housing Design for a Hot Ambient Environment

Industrial gas turbine rotors sometimes require a journal bearing in a region of the machine surrounded by compressor discharge air. Ambient temperatures in this region may exceed 600 F (588 K), which poses a challenge to bearing designers. The present paper describes housing design approaches to meeting this challenge, an experimental program to evaluate them, and the application of results to operating field units. The experimental program was carried out in a special test facility on full-size housings for a 14-in. journal bearing in a hot, pressurized environment.

Fault Analysis of a Gas Turbine HTGR

The Gas Turbine High Temperature Gas-Cooled Reactor combines a helium-cooled reactor core of established design with a closed-cycle helium turbine power-conversion system. This paper discusses the design considerations which mitigate the consequences of failure of the rotating machinery located within the reactor vessel. The methods of analysis and summary of results are presented for the failure modes of most concern. The spectrum of potential incidents which have been evaluated include turbine blade, rim, and disk failures. The requirements and design methods for rotor containment are discussed. The turbomachine maintains a pressure ratio of about two between the high and low pressure portions of the loop; postulated failures can, therefore, lead to rapid rates of pressure change. The preliminary evaluation of this internal pressure equilibration is presented.

Advancements and Application of Programmable Analog Control Technology

The advantage of rapid control system adjustment is assuming increasing importance in the development of automotive gas turbine engine development. Digitally programmed analog controllers are particularly suited to these purposes, and the basis of operation of controllers of this type is explained. The detailed operation of an early development controller, type PAC 120, is described briefly and the operational short-comings of the unit are discussed. The incorporation of features 10 provide an improved unit, type PAC 250, having significant increase in capability is examined and the resultant controller is described. The application of the PAC 120 to some selected control problems of an automotive turbine engine are described. Finally, the application of the PAC 250 controller to the complete control of the power plant, including start-up and shutdown of the engine, is examined. It is concluded that the programmable analog control concept is a uniquely powerful development tool for this type of application.

A Review of Specifications for Methods of Measuring Emissions of Air Pollutants and Effluent of Water Pollutants

The measurement of air pollutants emitted to the atmosphere in exhaust gases from stationary gas turbines must be made in accordance with applicable government specifications in those cases where the measurements are being made to determine compliance with regulations. This paper reviews the methods for measuring opacity, sulfur dioxide, oxides of nitrogen, carbon monoxide, carbon dioxide, oxygen, hydrocarbons, and particulates. In addition, the paper references the Federal Register (volume, number, and page) in which the official specification appears. Other methods, including ASME, SAE, and ASTM, are listed where applicable.

Study of Light Weight Turbine Transmission Systems

Several transmission systems that are applicable to advanced marine vessels were investigated to determine if drives other than right-angle gearboxes would be practical in transmitting 50,000 (37.3 NW) hp from dual gas turbines downward through a vertical distance of 20 (6.10 m) ft to a propeller drive shaft. These systems included: hydraulic power, chain drive, steel tape drive, and a slider crank drive. Results of this survey indicated the right-angle bevel gear drive was the optimum system considering our present state-of-the-art. Further investigation was performed to optimize turbine and gearbox arrangement using weight, reliability, efficiency, serviceability, technical risks, and relative cost as the determining factors.

A Method for Calculating Cascade/Channel Endwall Boundary Layer Crossflow

A method is proposed for calculating cascade / channel endwall boundary-layer crossflow. It is based upon a numerical solution of the simple radial equilibrium equation for curved channel flow in the boundary layer with a foreknowledge of the mainstream boundary-layer conditions. The results consist of crossflow pathline patterns through the channel at various depths of the mainstream boundary layer complete with crossflow velocity and direction at any point in the channel. Secondary losses based on the crossflow energy plus the exit dump loss effect of the fluid collected in the corner vortex are shown to be calculable. The method is tested on two sets of published measurements for circular arc channels of turnings over 60 deg. Very good correlation of crossflow velocity in Johnston triangle form is indicated. An additional calculation method for tangentially moving endwalls, such as stator hub or rotor shroud, is presented for cascade geometries. Calculated results are presented for a highly loaded stator of 45-deg turning and the rotor of a 7.5:1 PR centrifugal compressor stage. The method is shown to successfully calculate the measured exit flow angle distribution for the stator.

PACE 260 at Comanche, the First Two Years

This paper describes the operating experience with the Westinghouse PACE 260 Combined Cycle Power Plant at Public Service Company of Oklahoma’s COMANCHE Station. This plant was the first PACE 260 unit to go into operation and had many new design features in the major components. The paper deals mainly with the problems that occurred and their solutions.