Turbines performance characteristics

TABLE 6.21 GE Gas Turbine Performance Characteristics Generator-Drive Gas Turbine Ratings... 

Hopkins, E. Gas Turbine Performance Characteristics, 1991 Turbine State of the Art Conference, GER-3567B, Asheville, NC, August 1991. 

Hajilouy-Benisi, A. Rad, M. and Shahhosseini, M. R. Modeling of twin-entry radial turbine performance characteristics based on experimental investigation under full and partial admission conditions. Scientialranica, Transact. B Mech. Eng. 2009,16(4), 281-290. 

Validation and Application. VaUdated CFD examples are emerging (30) as are examples of limitations and misappHcations (31). ReaUsm depends on the adequacy of the physical and chemical representations, the scale of resolution for the appHcation, numerical accuracy of the solution algorithms, and skills appHed in execution. Data are available on performance characteristics of industrial furnaces and gas turbines systems operating with turbulent diffusion flames have been studied for simple two-dimensional geometries and selected conditions (32). Turbulent diffusion flames are produced when fuel and air are injected separately into the reactor. Second-order and infinitely fast reactions coupled with mixing have been analyzed with the k—Z model to describe the macromixing process. 

A turbine flowmeter consists of a straight flow tube containing a turbine which is free to rotate on a shaft supported by one or more bearings and located on the centerline of the tube. Means are provided for magnetic detection of the rotational speed, which is proportional to the volumetric flow rate. Its use is generally restric ted to clean, noncorrosive fluids. Additional information on construction, operation, range, and accuracy can be obtained from Holzbock (Instruments for Measurement and Control, 2d ed., Reinhold, New York, 1962, pp. 155-162). For performance characteristics of these meters with liquids, see Shafer,y. Basic Eng., 84,471-485 (December 1962) or May, Chem. Eng., 78(5), 105-108 (1971) and for the effect of density and Reynolds number when used in gas flowmetering, see Lee and Evans, y. Basic Eng., 82, 1043-1057 (December 1965). 

This chapter examines the overaii performance characteristics of compressors and turbines. This materiai is presented here to famiiiarize the reader with the behavior of these machines, ciassified under the broad term tur-bomaciiinery. Pumps and compressors are used to produce pressure turbines produce power. These machines have some common characteristics. The main eiement is a rotor with biades or vanes, and the path of the fluid in the rotor may be axiai, radiai, or a combination of both. 

Rodgers, C., Efficiency and Performance Characteristics of Radial Turbines, SAE Paper 660754, October, 1966. 

Boyce, M.P., Performance Characteristics of a Steam Turbine in a Combined Cycle Power Plant, Proceedings of the 6th EPRI Steam Turbine Generator/ Workshop, August 1999. 

Utamura, M., Takaaki, K., Murata, H. and Nobuyuki, H. (1999), Effects of intensive evaporative cooling on performance characteristics of land-based gas turbine, PWR-Vol. 34, Joint Power Generation Conference, pp. 321-328. 

Figure 16-16 shows the performance characteristic of a split-shaft turbine where the only power output limitation is the maximum allowable temperature at the inlet of the turbine section. In actual practice a torque limit, increased exhaust temperature, loss of turbine efficiency, aud/or a lubrication problem on the driven equipment usually preclude operating at very low power turbine speeds. The useful characteristic of the split-shaft engine is its ability to supply a more or less constant horsepower output over a wide range of power turbine speeds. The air compressor essentially sets a power level and the output shaft attains a speed to pnivide the required torque balance. Compressors, pumps, and various mechanical tinvc systems make very good applications for split-shaft designs. 

The distinguishing performance characteristic of the torque converter, in contrast to the fluid coupling, is that It IS capable of multiplying torque. Torque multiplication is made possible by vane curvature and the presence of the reactor. When the converter is stalled—that is, the turbine and the reactor are stationary—the torque delivered to the gearbox is typically 2... 

Figure 4-192 gives the typical performance characteristics of a turbine motor. The example in this figure is a 6-J-in. outside diameter turbine motor having 212 stages and activated by a 10-lb/gal mud flowrate of 400 gal/min. 

Table 4-110 gives the performance characteristics for various circulation flowrates for the 212-stage, 6f-in. outside diameter turbine motor described briefly in Table 4-109 and shown graphically in Figure 4-192. 

The turbine motor whose performance characteristics are given in Table 4-110 is made up of two motor sections with 106 stages in each section. The turbine motor whose performance characteristics are given in Table 4-111 is made up of three motor sections. 

Steam turbines are used to convert part of the energy of the steam into power and can be configured in different ways. Steam turbines can be divided into two basic classes back-pressure turbines and condensing turbines. The efficiency of the turbine and its power output depend on the flowrate of steam to the turbine. The performance characteristics can be modeled by a simple linear relationship over a reasonable range of operation. 

The performance characteristics of power stations are commonly described by the availability and load factors, and by the forced outage factor. The availability factor is the time the station has been available for operation divided by the length of the desired time period. Thus if it has been desired to operate the station for 6000 h, but it has only been possible to run it for 5500 h (because of repair, etc.) the availability factor is 92%. Typical availability factors are 95 —100 % for water power, 75 — 85 % for conventional fossil power, and 70 % for nuclear power (usually the reactor has a higher availability, but with a lower value of 70% for the turbine). Availability factors > 80% have been achieved for LWRs. 

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