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Heat Transfer

1987;():V004T09A005. doi:10.1115/87-GT-102.
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The temperature of gas turbine blades is a critical parameter in determining the expected life of the blades.

Commentary by Dr. Valentin Fuster
1987;():V004T09A013. doi:10.1115/87-GT-135.
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Numerous experimental investigations have been performed with a model V84.2 100 MW / 60 Hz gas turbine up to peak load conditions. The paper presents an overview of the most interesting experiments.

In detail, pyrometric measurements of the first stage turbine blade are described and discussed. Surface temperature distributions are presented in the form of contour plots, and a comparison with theoretical predictions is shown exemplarily. Moreover, the effect of turbulence promoters on the cooling channel side walls is demonstrated.

Commentary by Dr. Valentin Fuster
1987;():V004T09A014. doi:10.1115/87-GT-136.
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Gas turbine blades have previously been shown to corrode due to condensation of sulfide vapor on a cooled blade surface. In the present investigation, water vapor was condensed on a film cooled surface, simulating the condensation of sulfide vapor on a turbine blade. The injection section consisted of one row of holes (inner diameter of 1.0 cm) inclined 30 degrees with the surface and inline with the main turbulent boundary layer flow. Experiments were carried out in a subsonic, zero pressure gradient, turbulent boundary layer with free stream velocities of 10.5, 15.75, and 21.0 m/sec. A cooling fluid (water at near 0°C) was circulated through the plate, cooling the test surface and causing free stream water vapor to condense. Measurements were made at three Reynolds numbers (based on hole diameter and free stream velocity): 7,000, 10,500, and 14,000; and at three blowing ratios: 0.4, 0.8, 1.2. The results show the existence of a “dryout” region downstream of each cooling hole. This region was dry while regions between the jets had water on the surface. This dryout region was triangularly shaped, with the apex as much as 30 jet diameters from the downstream edge of the jet. For each Reynolds number the lowest blowing ratio (M = 0.4) had the largest dryout region. These results indicate that injection can be used to prevent condensation of corrosive vapors on a film-cooled gas turbine blade.

Topics: Condensation
Commentary by Dr. Valentin Fuster
1987;():V004T09A015. doi:10.1115/87-GT-137.
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The demand for higher efficiency, higher temperature industrial gas turbines used for the combined cycle plants has increased. The key technology of such high-temperature gas turbines with a turbine inlet temperature of 1300°C is the development of reliable air-cooled turbine vanes and blades. The life prediction of such air-cooled turbine vanes is strongly dependent on an accurate prediction of the metal temperature. The problem of temperature prediction is essentially one of obtaining the convective heat transfer boundary conditions on the external and internal surfaces of the vane. In this paper, typical heat transfer data which are indispensable for the analysis, are presented. Improvement of the temperature prediction accuracy within 25°C, the final goal, is sought by feeding the discrepancy between the cascade test and the analysis back into the fundamental heat transfer tests.

Commentary by Dr. Valentin Fuster
1987;():V004T09A023. doi:10.1115/87-GT-212.
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The failure of a turbine airfoil is a local phenomena. However, to date, the design of these airfoils has been based on steady state heat transfer tests that are capable of yielding only locally averaged data. To overcome this limitation, a transient technique using active surface coatings has been developed and is capable of yielding local data. This technique has been used to determine the Nusselt number distributions within augmented passages typical of gas turbine airfoils. However, certain assumptions have been made in these analyses without verification. This paper will address this aspect of the problem, as well as an improved data reduction procedure, and an alternative error analysis.

The data reduction procedure has been improved by incorporating a higher order approximation to the convective boundary condition, and by introducing a means of calculating the fluid bulk temperature-time-space profile. An image analysis system which yields an unbiased means of determining the time required for the surface to reach a specified temperature is introduced. Furthermore, it was observed that for augmented surfaces, the one dimensional conduction assumption made in the heat transfer solution is not valid for all times. Finally, treating the experimentally obtained quantities as values that are randomly distributed about some true value is not correct for all experimentally measured quantities.

Commentary by Dr. Valentin Fuster
1987;():V004T09A024. doi:10.1115/87-GT-213.
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Two methods were used to calculate the heat flux to full-coverage film cooled airfoils and, subsequently, the airfoil wall temperatures. The calculated wall temperatures were compared to measured temperatures obtained in the Hot Section Facility operating at real engine conditions. Gas temperatures and pressures up to 1900 K and 18 atm with a Reynolds number up to 1.9 million were investigated. Heat flux was calculated by the convective heat transfer coefficient adiabatic wall method and by the superposition method which incorporates the film injection effects in the heat transfer coefficient. The results of the comparison indicate the first method can predict the experimental data reasonably well. However, superposition overpredicted the heat flux to the airfoil without a significant modification of the turbulent Prandtl number. The results of this research suggests that additional research is required to model the physics of full-coverage film cooling where there is significant temperature/density differences between the gas and coolant.

Commentary by Dr. Valentin Fuster

Electric Power

1987;():V004T10A001. doi:10.1115/87-GT-2.
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A study was undertaken to determine the engineering and economic feasibility of repowering several conventional pulverized coal and oil fired units with combustion turbines.

Both feedwater repowering and hot windbox repowering were examined. Performance was evaluated using PEPSE.

The results of the most promising units are presented in detail.

The duration of the study was six months and the project cost approximately $75,000.

Commentary by Dr. Valentin Fuster
1987;():V004T10A002. doi:10.1115/87-GT-3.
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The general analysis of the part load performance of gas turbines indicates that the intercooled cycle with two shafts and power output at constant speed on the high-pressure shaft can have a good part load efficiency. Calculations with fixed geometry of the turbomachines show an intolerable increase of the turbine inlet temperature above the permissible level. By introducing variable geometry in the turbomachines, this disadvantage can be overcome. With variable inlet guide vanes at the high-pressure compressor an excellent part load performance is achieved. Further improvements are possible by adding an internal heat exchanger.

Commentary by Dr. Valentin Fuster
1987;():V004T10A003. doi:10.1115/87-GT-4.
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This paper describes the conversion of existing conventional steam power plants into combined cycle plants.

A number of Dutch utility companies are currently performing or planning this conversion on their gas-fired power stations, mainly in order to conserve fuel.

Modifications of boiler and steam cycle, necessary for the new concept, are presented in general terms, together with a detailed description of one of the projects.

Commentary by Dr. Valentin Fuster
1987;():V004T10A004. doi:10.1115/87-GT-5.
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This paper deals with problems of noise control involving gas turbine plants, particularly where they are installed near residential areas already subject to noise nuisance.

Noise control measures for existing industrial or power-generating plant are often designed to achieve an overall immitted noise level only marginally below the legal maximum.

Considerably enhanced measures are thus required for additional plant. However, the noise from a gas turbine plant has numerous individual sources and it is shown that a differentiated approach is required. Generally, progressive reductions in noise levels involve disproportionately greater increases in expenditure on appropriate measures.

Stringent environmental protection requirements necessitate cost-intensive solutions.

Commentary by Dr. Valentin Fuster
1987;():V004T10A008. doi:10.1115/87-GT-23.
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The thermodynamic performance of some representative CAES (Compressed Air Energy Storage) plant configurations is computed both at steady-state nominal point and during time-variable conditions, by making use of a simulation technique capable of accounting for thermal inertia of recuperators and TES (Thermal Energy Storage), for part-load characteristics of turbomachinery and for power regulation modes. The results of the analysis are presented in terms of the energy losses caused by the irreversibilities occurring in the various plant components, with reference to the second law of thermodynamics.

Commentary by Dr. Valentin Fuster
1987;():V004T10A009. doi:10.1115/87-GT-27.
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This paper describes a computer program designed to calculate and analyze cogeneration plant heat balances and equipment and to plot heat balance diagrams. For normal design point conditions, the program calculates gas turbine performance, designs a heat recovery boiler to suit the process requirements, calculates a steam turbine performance and deaerator balance to complete the cycle. In addition, the program will calculate off-design performance for a supplementary firing option or for changes in ambient conditions, gas turbine part load or process conditions.

Commentary by Dr. Valentin Fuster
1987;():V004T10A010. doi:10.1115/87-GT-33.
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Solar heating of gas turbine plants is moving back to the focus of current research. The mainly unsteady operation of solar turbine power plants can only be predicted with sufficient accuracy if the transient behavior of the solar radiation receiver is known. Therefore the transient behavior of cavity receivers of different designs is investigated. The mathematical model used to simulate heat transfer and energy storage is illustrated. Computed results for two receivers with different inner lining are compared and evaluated concerning their use in practice.

Commentary by Dr. Valentin Fuster
1987;():V004T10A011. doi:10.1115/87-GT-34.
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A previous study of an indirect fired air turbine cogeneration system has been extended to include the concept of regeneration. The effect of regenerator effectiveness and full regeneration as well as partial regeneration on system performance parameters (such as fuel utilization efficiency, power-to-heat ratio and second-law efficiency) are examined. An important conclusion of this study is that a regenerative gas turbine cogeneration system is capable of producing large power-to-heat ratios for various process conditions requiring the use of only moderate compressor compression ratio and moderately effective regenerators. It appears that this is an attractive system which could compete in a market that is currently dominated by internal combustion engines when a viable fludized bed air heater is available.

Commentary by Dr. Valentin Fuster
1987;():V004T10A012. doi:10.1115/87-GT-35.
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A new power generation technology often referred to as the Kalina cycle, is being developed as a direct replacement for the Rankine steam cycle. It may be applied to any thermal heat source, low or high temperature. Among several Kalina cycle variations there is one that is particularly well suited as a bottoming cycle for utility combined cycle applications. It is the subject of this paper.

Using an ammonia/water mixture as the working fluid and a condensing system based on absorption refrigeration principles the Kalina bottoming cycle outperforms a triple pressure steam cycle by 16 percent. Additionally, this version of the Kalina cycle is characterized by an intercooling feature between turbine stages, diametrically opposite to normal reheating practice in steam plants.

Energy and mass balances are presented for a 200 MWe Kalina bottoming cycle. Kalina cycle performance is compared to a triple pressure steam plant. At a peak cycle temperature of 950° F the Kalina plant produces 223.5 MW vs. 192.6 MW for the triple pressure steam plant, an improvement of 16.0 percent. Reducing the economizer pinch point to 15° F results in a performance improvement in excess of 30 percent.

Commentary by Dr. Valentin Fuster
1987;():V004T10A013. doi:10.1115/87-GT-36.
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In the traditional pressurized fluid bed (PFB) power system, the PFB is located in the highest pressure portion of the power cycle, Figure 1. This results in the smallest volume flow through the PFB, but also requires the combustion products to flow through the entire expansion train. This is not expected to be a major problem when the PFB temperature is limited to 1600°F for effective sulfur capture and to avoid alkali vapors in the products of combustion. However, when topping combustion is added ahead of the turbine so as to reach state-of-the-art turbine inlet temperatures, a major risk for turbine corrosion and fouling develops.

Commentary by Dr. Valentin Fuster
1987;():V004T10A014. doi:10.1115/87-GT-37.
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A new 13 MW class heavy duty gas turbine “MF-111” with the combustor outlet temperature of 1250°C (1523 K) was developed and tested.

The thermal efficiency of MF-111 is designed to be 32% for simple-cycle and 45% in combined-cycle operation.

MF-111 has single-shaft configuration, 15-stage axial flow compressor, 8 cannular type combustors and 3-stage axial flow turbine.

Advanced cooling technology was incorporated for the turbine and the combustor design to be capable of higher combustor outlet temperature.

The prototype was shoptested at full load in April, 1986. The performance and the metal temperatures of hot parts were confirmed to well satisfy the design goal. The first machine of MF-111 started the commercial operation from August, 1986 and has logged satisfactory operations.

Topics: Gas turbines , Testing
Commentary by Dr. Valentin Fuster
1987;():V004T10A015. doi:10.1115/87-GT-38.
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Retrofitting existing steam turbine power plants with a gas turbine topping cycle can greatly enhance their efficiency to levels comparable with those of plants originally constructed as fully fired combined cycles. The economic benefits of this approach make it so attractive that utilities in the Netherlands are at present converting well over 3000 MW of conventional steam power. This paper describes various technical and economic aspects of topping the natural gas-fired 600 MW Eemscentrale 2 unit. In particular, the improvements made to the thermodynamic cycle, the adaptation of its components and the partial load behavior of the plant are discussed. The economic analysis reveals that significant fuel savings justify the capital investment.

Commentary by Dr. Valentin Fuster
1987;():V004T10A016. doi:10.1115/87-GT-42.
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A CAES plant consists of three (3) major systems; the turbomachinery train, the underground air storage chamber and the balance of plant. The turbomachinery train and the underground air storage chamber interrelationship needs to be optimized with respect to performance and cost while the balance of plant supports this relationship and is dependent upon the site conditions. The qualitative relationship between the air storage chamber and the operation of the turbomachinery train have been reported in the literature. This paper takes a salt dome geology and examines the factors affecting optimization of a 100 MWe CAES plant design.

Commentary by Dr. Valentin Fuster
1987;():V004T10A017. doi:10.1115/87-GT-154.
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The paper deals with the development of TG 50 gas turbine and its evolution in the years from the original to the present configuration with mention of substantial improvements in both compressor and turbine sections that initiated the growth of power output from the original 75 MW to the 110 MW present rating.

Successful solution of some basic operating problems encountered mainly in the compressor section, required quite an extensive research and development work.

In addition, comprehensive test programs have been carried out for the development of the present configuration and for the confirmation of the validity of the selected solutions.

Topics: Gas turbines
Commentary by Dr. Valentin Fuster
1987;():V004T10A019. doi:10.1115/87-GT-263.
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The final target of development of the advanced gas turbine sponsored by MITI of Japan is a thermal efficiency of over 55% at an HPT inlet temperature of 1400°C as a combined plant. In order to attain this target, a feasibility study of the design and various R & D tasks have been conducted.

This paper will first present the basic plan and then some important R & D items.

Commentary by Dr. Valentin Fuster
1987;():V004T10A020. doi:10.1115/87-GT-264.
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In 1978, the Japanese government started a national project for energy conservation called the Moonlight Project. The Engineering Research Association for Advanced Gas Turbines was selected to research and develop an advanced gas turbine for this project.

The development stages were planned as follows: First, the development of a reheat gas turbine for a pilot plant (AGTJ-100A), and second, a prototype plant (AGTJ-100B). The AGTJ-100A has been undergoing performance tests since 1984 at the Sodegaura Power Station of the Tokyo Electric Power Co., Inc. (TEPCO).

The inlet gas temperature of the high pressure turbine (HPT) of the AGTJ-100A is 1573K, while that of the AGTJ-100B is 100K higher. Therefore, various advanced technologies have to be applied to the AGTJ-100B HPT. Ceramic coating on the HPT blades is the most desirable of these technologies.

In this paper, the present situation of development, as well as future R & D plans for ceramic coating, is taken into consideration. Steam blade cooling is applied for the IGSC.

Topics: Gas turbines , Cycles , Steam
Commentary by Dr. Valentin Fuster

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