Reliable Operation of Gas Turbines on Crude Oil

The paper deals with design criteria and operating experience of Authors’ Company Gas Turbine Power Plants operating on crude oils from different sources. In particular a group of power stations located in Middle East is described, where crude oils from different fields are used. While two of the above power stations use basically the same crude oil, the other ones are fed by different fuel sources. Accordingly, different fuel handling and treatment plants have been selected, different problems have been encountered and different operating experiences have been accumulated. The positive operating results obtained confirm that reliable operation on crude oil requires each individual application be “tailor made” on the basis of the knowledge of the relevant fuels properties.

Design and Application of a Natural Gas Pipeline Optimization Program

A software package which optimizes natural gas pipeline operation for minimum fuel consumption is in use on a commercial transmission pipeline. This Optimization Program has resulted in pipeline fuel savings in daily pipeline operation. In addition, the effect of a new compressor/turbine unit on the pipeline system as a whole can be accurately and easily quantified through use of the Optimization Program before the unit is even installed. The results from one turbine replacement study showed the total system fuel consumption and operating hours predicted for each unit were not directly related to a high turbine efficiency. This paper describes the simulation techniques used for the gas turbine and compressor modeling. The methodology behind the system-wide optimization is also provided, along with a detailed discussion of the program application to gas turbine and compressor replacement studies.

The Development of a Diesel Burning Combustion Chamber With a Multiple Jet Primary Zone

A new primary zone for a gas turbine combustor has been developed which achieves efficient combustion in fuel lean conditions for minimizing carbon formation. This uses a large number of jets in the head of the chamber to generate independent shear layers in a co-operative array. Good combustion performance, wide fuel/air ratio operational range and tolerance to fuel quality have been demonstrated on research rigs. The combustor itself has been developed to an engine standard for a naval gas turbine required to operate with low smoke emission on distillate diesel fuel. The rig programme used to optimise the design is described together with results from engine evaluation. Practical advantages of this type of chamber apply equally to aero applications on kerosene.

Software and Instrumentation to Monitor the Performance of Natural Gas Pipeline Turbine Systems

Software for monitoring and evaluating the performance of gas turbines is being developed under the auspices of Gas Research Institute (GRI). Reference [1] provides an overview of the GRI project. This paper describes the PEGASUS software and monitoring system. PEGASUS is an acronym for Performance Evaluation of GAS Users Systems. Field test results, on multi-shaft turbines used in the gas pipeline industry, have demonstrated the potential of the software. The software and instrumentation, can help identify maintenance and upgrade actions to improve performance.

Low Frequency Noise Emission From a Natural Gas Compressor Station

Low Frequency Noise at Gas Turbines A natural gas compressor station that was equipped with Hispano Suiza Turbines THM 1202 emitted high intensity noise between 20 Hz and 40 Hz, causing window vibrations and standing waves within the living rooms of a nearby residential area. Since additional sound attenuation by increasing the volume of the exhaust silencers was impossible, further investigations were carried out to explain the mechanism of this low frequency noise emission. By changing the flame pattern inside the combustion chambers of the turbines it was possible to achieve a remarkable reduction at 31.5 Hz amounting to 15 dB. The investigation procedure leading to the final results will be the subject of this presentation.

Influence of Ambient Air Pressure on Pressure-Swirl Atomization

The spray characteristics of six simplex atomizers are examined in a pressure vessel using a standard light diffraction technique. Attention is focused on the effects of liquid properties, nozzle flow number, spray cone angle, and ambient air pressure on mean drop size and drop-size distribution. For all nozzles and all liquids it is found that continuous increase in air pressure above the normal atmospheric value causes the SMD to first increase up to a maximum value and then decline. An explanation for this characteristic is provided in terms of the measurement technique employed and the various competing influences on the overall atomization process. The basic effect of an increase in air pressure is to improve atomization, but this trend is opposed by contraction of the spray angle which reduces the relative velocity between the drops and the surrounding air, and also increases the possibility of droplet coalescence.

An Option for High Power in Space

The stated objective of the Strategic Defense Initiative (SDI) introduces needs for space-based electric power ranging up to hundreds of megawatts (MWe). The SDI Organization is calling for the development of new and innovative concepts to meet these needs. Options for multi-megawatt and multi-hundred megawatt space power generating systems are presented in this paper. These options are based upon the gas turbine, one of the most mature and time-proven technologies available. Size- and mass-reduction studies utilizing innovative designs and new materials are conducted for the gas turbine. Two significantly different power levels with two thermal sources, nuclear and chemical combustion, are addressed.

Flexibility of the Closed Brayton Cycle for Space Power

New commercial and military applications for space power are developing over a wide range of nominal and peaking power requirements. Power levels far exceed the capabilities of photovoltaic array and battery systems. Factors such as manned and unmanned missions, long mission durations, zero-maintenance requirements, hardening from attack, and mission orbit or mission payload impact space power system specifications and dictate the type of energy source. This has led to emphasis on the closed Brayton cycle (CBC) with its inherent flexibility as a dynamic power source. Unique features of the CBC contribute to its application to the multiplicity of space power requirements. These include flexibility of design, operation, energy source selection, and future growth. The CBC with the single-phase, gas working fluid provides a simple interface for chemical, isotope, solar, and nuclear thermal energy sources. The single-phase gas is not affected by zero gravity, freezing or high temperatures, vehicle launch, or flight maneuver loads. This feature is a primary contributor to the CBC flexibility.

Experimental Study on Atomization of Plain Jet Injector Under High Pressure Co-Axial Air Flow

An experimental study has been conducted on the effect of high back pressure on the spray characteristics of a plain jet injector under coaxial high velocity air flow. The air pressures tested range from 1 to 16 atm, the range of air velocity is 60–120 m/s, the pressure drops of injector tested are 200–2000 kpa. Working fluid is water. Injector hole diameter is 0.5 mm. The key feature of the experiment is using a convergent-divergent nozzle to maintain a high air pressure inthe test chamber and at the same time to maintain a high velocity air flow in the atomization zone. Such an experimental arrangement totally eliminates air and droplets recirculation in the test chamber and problem related to slow droplet settling in a commonly used pressurized vessel for high back pressure atomization research. The results show that SMD decreases monotonicly with the increase of back pressure or air velocity, at different air velocities, the effect of air pressure is different. The drop size distribution parameter N in Rosin-Rammler distribution decreases slightly with increase of back pressure or air velocity.

Computer Predictions of Erosion Damage in Gas Turbines

In this article an iterative procedure is presented for estimating erosion in axial gas turbine blades. The procedure is applied to a two stage turbine and the erosion is estimated for a 12,000 hour engine running time. The effect of the erosion on engine performance is estimated through changes in pressure coefficient distribution around a blade section.