The Gas Turbine Family GT13E and GT13E2 Provides Reliable Power for Asia

Many Asian countries are experiencing economic growth which averages 5–10% per year. This environment has led to a privatization process in the power generation industry from typically state-run utilities to a system in which a federal agency oversees a market divided by private utilities and independent power producers (IPP) with the need for high efficiency, reliable power generation running on natural gas and diesel oil. In the 50 Hz market, modem, high efficient gas turbines of the type GT13E and GT13E2 have been chosen as prime movers in many combined cycle power plants in Asian countries. This paper includes a product description, and a general overview of GT13E and GT13E2 operating experience, well as an economic evaluation of a typical 500 MW combined cycle power plant.

Experimental and Numerical 3-D Investigations of the Flow Field Behind the Trailing Edge of a Cooled Turbine Guide Vane

Experimental investigations have been carried out to analyze the hot gas flow and cooling gas flow in the direct vicinity of the trailing edge of a modern gas turbine vane, with cooling gas ejection through the trailing edge. The investigations were performed in one of the institute’s test turbines. The experimental set-up is designed to establish variable blowing ratios between cooling gas mass flow and hot gas mass flow. An alternative density ratio between hot gas and cooling gas was established by the use of CO2 instead of air as the cooling gas for cold test runs. The experimental investigations have been carried out for different radial positions. The measurement plane was located 0.2mm to 0.5mm downstream of the trailing edge (trailing edge width 1.6mm). Local regions of high anisotropic turbulence were detected in the mixing zone. For low blowing ratios, the trailing edge pressure side in the tip vicinity was found to be subjected to direct hot gas contact. The trailing edge ejection has an influence of at least one chordlength in axial direction. The experimental investigations were accompanied by 3-D Navier-Stokes computational simulations. The calculated velocity distributions were found to be quite consistent with the experimental results. The calculated flow angles differed locally from the measurements. This may be due to the turbulence model employed.

Reduction of Secondary Flow Effects in a Linear Cascade by Use of an Air Suction From the Endwall

The objective of this study is to reduce secondary flow effects in a linear cascade by sucking the working fluid from the endwall. It is widely known that the secondary flow developed in a cascade has a significant impact on the cascade loss or blade erosion in steam turbines. Therefore, a number of studies have been made on the physics of the secondary flow and several devices to control the secondary flow, such as a fence, have been examined. In this study, considering the application to nozzles in gas turbines or steam turbines, the air suction approach is investigated for reducing the secondary flow effects. A suction slit is provided on the lower endwall of the cascade and a flow rate of the sucked air is controlled by adjusting the exit pressure of the slit. The effects of the suction upon the flow nearby the endwall and the secondary flow are observed through several flow visualizing techniques, for example an oil flow method or a tuft method. Furthermore, velocity and stagnation pressure measurement are conducted by a five-hole pressure tube. This clearly demonstrates the vorticity and loss profiles downstream of the cascade with and without the endwall suction.

Part Load Conditions of Complex Cycle Power Plants With Intercooled Gas Turbine

The present paper evaluates the behavior, in design and part load working conditions, of a complex gas turbine cycle with multiple intercooled compression, and the optional preheating of the air at the high pressure compressor outlet by means of the gas turbine outlet hot gas. The results are then compared with those obtained by a Brayton cycle gas turbine, with or without preheating of the air at the high pressure compressor outlet. Subsequently, the performance of complex combined cycles, with intercooled gas turbine as topper and one, two or three pressure level steam cycle as bottomer, in design and part load working conditions is also evaluated. The performance of these complex combined plants is then compared with that obtained by a Brayton cycle gas turbine as topper and one, two or three pressure level steam cycle as bottomer. Part load working conditions are realized by varying either the inlet guide vane angle of the first compressor nozzles or the maximum temperature at the combustor outlet. The study shows that in part load working conditions obtained by varying IGV, the complex cycles, in the examined gas turbine or in the combined cycle power plants, give conversion efficiencies decidedly greater than those obtainable by varying combustor exit temperature. Furthermore it is found that these complex power plant efficiencies, in part load working conditions, are far greater than those obtained by the Brayton cycle gas turbine, or by combined cycle with Brayton cycle gas turbine as topper, if IGV adjustment is adopted. If power variation is obtained with combustor outlet temperature adjustment, the efficiencies of the combined power plants with complex or Brayton cycle gas turbines, are substantially the same, for the same relative power variation.

Heat Transfer Computations for Turbine Blade Airfoils

The design and optimization of turbine blades subjected to high temperature flows require the prediction of aerodynamic and thermal flow characteristics. A computation of aerothermal viscous flow model has been developed suitable for the turbine blade design process. The computational time must be reduced to allow intensive use in an industrial framework. The physical model is based on a compressible boundary layer approach, and the turbulence is a one-equation model. Special attention has been paid to the influence of wall curvature on the turbulence modelling. Tests were performed on convex wall flows to validate the turbulence model. Turbine blade configurations were then computed. These tests include most difficulties that can be encountered in practice : laminar-turbulent transition, separation bubble, strong accelerations, shock wave. Satisfactory predictions of the wall heat transfer are observed.

Heat Transfer Predictions for U-Shaped Coolant Channels With Skewed Ribs and With Smooth Walls

A computational study was performed for the flow and heat transfer in coolant passages with two legs connected with a U-bend and with dimensionless flow conditions typical of those in the internal cooling passages of turbine blades. The first model had smooth surfaces on all walls. The second model had opposing ribs staggered and angled at 45° to the main flow direction on two walls of the legs, corresponding to the coolant passage surfaces adjacent to the pressure and suction surfaces of a turbine airfoil. For the ribbed model, the ratio of rib height to duct hydraulic diameter equaled 0.1, and the ratio of rib spacing to rib height equaled 10. Comparisons of calculations with previous measurements are made for a Reynolds number of 25,000. With these conditions, the predicted heat transfer is known to be strongly influenced by the turbulence and wall models. The k-e model, the low Reynolds number RNG k-e and the differential Reynolds-stress model (RSM) were used for the smooth wall model calculation. Based on the results with the smooth walls, the calculations for the ribbed walls were performed using the RSM and k-e turbulence models. The high secondary flow induced by the ribs leads to an increased heat transfer in both legs. However, the heat transfer was nearly unchanged between the smooth wall model and the ribbed model within the bend region. The agreement between the predicted segment-averaged and previously-measured Nusselt numbers was good for both cases.

Performance Analysis of a Turbine Stage Having Cooled Nozzle Blades With Trailing Edge Ejection

This work presents an aerothermodynamic modeling of a cooled turbine blade and the performance analysis of a turbine stage having cooled nozzle blades with trailing edge coolant ejection. A mean line analysis, based on the well-known Ainley-Mathieson scheme, is adopted for the basic loss prediction of the blade rows without cooling. A unique model regarding the interaction between coolant and main gas is proposed. The interactions considered are the heat transfer from main gas to coolant and the temperature and pressure losses by the mixing of two streams due to the trailing edge coolant ejection. For a model turbine stage with nozzle cooling, parametric analyses are carried out to investigate the effect of main design variables (amount of coolant flow, coolant temperature and coolant ejection area) on the stage performance. The influences of coolant mass flow ratio and temperature on the mixing loss and specific work are investigated. The results are also rearranged to investigate the effect of blade temperature on the specific work. Analysis is also carried out by varying the ejection area, which may give useful criteria in determining the coolant condition and ejection hole size of real gas turbine engines.

Heavy-Duty Gas Turbine Plant Aerothermodynamic Simulation Using Simulink

This paper presents a physical simulator for predicting the off-design and dynamic behaviour of a single shaft heavy-duty gas turbine plant, suitable for gas-steam combined cycles. The mathematical model, which is non linear and based on the lumped parameter approach, is described by a set of first-order differential and algebraic equations. The plant components are described adding to their steady state characteristics the dynamic equations of mass, momentum and energy balances. The state variables are mass flow rates, static pressures, static temperatures of the fluid, wall temperatures and shaft rotational speed. The analysis has been applied to a 65 MW heavy-duty gas turbine plant with two off-board silo-type combustion chambers. To model the compressor, equipped with variable inlet guide vanes, a subdivision into five partial compressors is adopted, in serial arrangement, separated by dynamic blocks. The turbine is described using a one dimensional row by row mathematical model, that takes into account both the air bleed cooling effect and the mass storage among the stages. The simulation model considers also the air bleed transformations from the compressor down to the turbine. Both combustion chambers have been modelled utilising a sequence of several sub-volumes, to simulate primary and secondary zones in presence of three hybrid burners. A code has been created in Simulink environment. Some dynamic responses of the simulated plant, equipped with a proportional-integral speed regulator, are presented.

Experimental Refinement of Technologies for Environmental Update of Gas Turbine Units Applied to Electrogenerator Driving

The results of experimental elaboration of engineering approaches relating to environmental update of combustors for the GTK-10 10 MW, GTG-1500 1.5 MW and GT-100 100 MW gas turbine engines are presented. The combustor update was carried out by a technique of directed dosed air blow into the maximum temperature zone with in the fire space. The advantages of the technique are as follows: • feasibility of reduction of Nox concentration in waste gases to 50 ppm; • simplicity and adaptability to manufacture of the structure; • no need in changing the design of the engine components and systems; • short-time outage of the unit at update.

A Full-Scale Testing of an Annular Turbo-Fan Combustor Including Emission Characteristics

Korea Aerospace Research Institute has performed a joint research with the Central Institute of Aviation Motors of Russia on the design, manufacturing, and testing of an annular combustor for a turbo-fan engine with the thrust of 8,000 lbf. In order to reduce smoke generation, a rather large amount of air is introduced to the primary zone. Presented in this paper is a description of the full-scale annular combustor, the test facility, the test procedure, and the test results. The measured parameters include the pressure loss and its dependence on flow velocity, the combustion efficiency by gas analysis, the exit temperature pattern factor for a wide range of air excess ratio, the lean blow-off limit, and the emission characteristics. The main test conditions are the ‘ground idle’ condition and the ‘altitude cruise’ condition. It was confirmed that the exit temperature profile is closely related to the location of dilution holes on the flame tube. Lean blow-off limit is rather narrow since the combustor was designed to provide a large amount of air to the primary zone with an aim of smoke reduction.