A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry

Film cooling represents one of the few game-changing technologies that has allowed the achievement of today's high firing temperature, high-efficiency gas turbine engines. Over the last 30 years, only one major advancement has been realized in this technology, that being the incorporation of exit shaping to the film holes to result in lower momentum coolant injection jets with greater surface coverage. This review examines the origins of shaped film cooling and summarizes the extant literature knowledge concerning the performance of such film holes. A catalog of the current literature data is presented, showing the basic shaping geometries, parameter ranges, and types of data obtained. Specific discussions are provided for the flow field and aerodynamic losses of shaped film hole coolant injection. The major fundamental effects due to coolant-to-gas blowing ratio, compound angle injection, cooling hole entry flow character, and mainstream turbulence intensity are each reviewed with respect to the resulting adiabatic film effectiveness and heat transfer coefficients for shaped holes. A specific example of shaped film effectiveness is provided for a production turbine inlet vane with comparison to other data. Several recent unconventional forms of film hole shaping are also presented as a look to future potential improvements

A review of shaped hole turbine film-cooling technology

http://www.graz-cycle.tugraz.at/pdfs/kvamsdal_et_al_ghg_2006.pdf

A quantitative comparison of gas turbine cycles with CO2 capture

Oxyfuel combustion for CO2 capture in power plants

Needs, resources and climate change: Clean and efficient conversion technologies

The introduction of closed cycle gas turbines with their capability of retaining combustion generated CO 2 can offer a valuable contribution to the Kyoto goal and to future power generation. Therefore research and development work at the Graz University of Technology since the 1990s has led to the Graz Cycle, a zero emission power cycle of highest efficiency. It burns fossil fuels with pure oxygen which enables the cost-effective separation of the combustion CO 2 by condensation. The efforts for the oxygen supply in an air separation plant are partly compensated by cycle efficiencies far higher than for modern combined cycle plants. Upon the basis of the previous work, the authors present the design concept for a large power plant of 400 MW net power output making use of the latest developments in gas turbine technology. The Graz Cycle configuration is changed, insofar as condensation and separation of combustion generated CO 2 takes place at the 1 bar range in order to avoid the problems of condensation of water out of a mixture of steam and incondensable gases at very low pressure. A final economic analysis shows promising CO 2 mitigation costs in the range of $20―30/ton CO 2 avoided. The authors believe that they present here a partial solution regarding thermal power production for the most urgent problem of saving our climate.

/pdf/design-concept-for-large-output-graz-cycle-gas-turbines-4t4nyfo9jy.pdf

Design Concept for Large Output Graz Cycle Gas Turbines

Since the Kyoto conference there is a broad consensus that the human emission of greenhouse gases, mainly CO2 , has to be reduced. In the power generation sector there are three main alternatives which are currently studied world wide. Among them oxy-fuel cycles with internal combustion with pure oxygen are a very promising technology. Within the European project ENCAP — ENhanced CO2 CAPture — the benchmarking of a number of novel power cycles with CO2 capture was carried out [1]. Within the category oxy-fuel cycles the Graz Cycle and the Semi-Closed Oxy-Fuel Combustion Combined Cycle (SCOC-CC) both achieved a net efficiency of nearly 50%. In a second step a qualitative comparison of the critical components was performed according to their technical maturity. In contrast to the Graz Cycle the study authors claimed that no major technical barriers would exist for the SCOC-CC. In this work the ENCAP study is repeated for the SCOC-CC and for a modified Graz Cycle variant as presented at the ASME IGTI conference 2006 [2]. Both oxy-fuel cycles are thermodynamically investigated based on common assumptions agreed with industry in previous work. The calculations showed that the high-temperature turbine of the SCOC-CC plant needs a much higher cooling flow supply due to the less favorable properties of the working fluid. A layout of the main components of both cycles is further presented which shows that both cycles rely on the new designs of the high-temperature turbine and the compressors. The SCOC-CC compressor needs more stages due to a lower rotational speed but has a more favorable operating temperature. In general, all turbomachines of both cycles show similar technical challenges and are regarded as feasible.Copyright © 2007 by ASME

/pdf/qualitative-and-quantitative-comparison-of-two-promising-oxy-6dmj6bfve4.pdf

Qualitative and Quantitative Comparison of Two Promising Oxy-Fuel Power Cycles for CO2 Capture

Introduction of closed-cycle gas turbines with their capability of retaining combustion generated CO 2 can offer a valuable contribution to the Kyoto goal and to future power generation. Therefore, research and development at Graz University of Technology since the 1990s has lead to the Graz Cycle, a zero emission power cycle of highest efficiency. It burns fossil fuels with pure oxygen, which enables the cost-effective separation of the combustion CO 2 by condensation. The efforts for the oxygen supply in an air separation plant are partly compensated by cycle efficiencies far higher than 60%. In this work a further development, the S-Graz Cycle, which works with a cycle fluid of high steam content, is presented. Thermodynamic investigations show efficiencies up to 70% and a net efficiency of 60%, including the oxygen supply. For a 100 MW prototype plant the layout of the main turbomachinery is performed to show the feasibility of all components. Finally, an economic analysis of a S-Graz Cycle power plant is performed showing very low CO 2 mitigation costs in the range of $10/ton CO 2 captured, making this zero emission power plant a promising technology in the case of a future CO 2 tax.

Thermodynamic and Economic Investigation of an Improved Graz Cycle Power Plant for CO2 Capture

Introduction of closed-cycle gas turbines with their capability of retaining combustion generated CO 2 can offer a valuable contribution to the Kyoto goal and to future power generation. The use of well-established gas turbine technology enhanced by recent research results enables designers even today to present proposals for prototype plants. Research and development work of TTM Institute of Graz University of Technology since the 1990s has lead to the Graz cycle, a zero-emission power cycle of highest efficiency and with most positive features. In this work the design for a prototype plant based on current technology as well as cutting-edge turbomachinery is presented. The object of such a plant shall be the demonstration of operational capabilities and shall lead to the planning and design of much larger units of highest reliability and thermal efficiency.

Design Optimization of the Graz Cycle Prototype Plant

Introduction of closed cycle gas turbines with their capability of retaining combustion generated CO2 can offer a valuable contribution to the Kyoto goal and to future power generation. Therefore research and development work at Graz University of Technology since the nineties has led to the Graz Cycle, a zero emission power cycle of highest efficiency. It burns fossil fuels with pure oxygen which enables the costeffective separation of the combustion CO2 by condensation. The efforts for the oxygen supply in an air separation plant are partly compensated by cycle efficiencies far higher than for modern combined cycle plants. At the ASME IGTI conference 2004 in Vienna a high steam content S-Graz Cycle power plant was presented showing efficiencies for syngas firing up to 70 % and a net efficiency of 57 % considering oxygen supply and CO2 compression. A first economic analysis gave CO2 mitigation costs of about 10 $/ton CO2 avoided. These favourable data induced the Norwegian oil and gas company Statoil ASA to order a techno-economic evaluation study of the Graz Cycle. In order to allow a benchmarking of the Graz Cycle and a comparison with other CO2 capture concepts, the assumptions of component efficiency and losses are modified to values agreed with Statoil. In this work the new assumptions made and the resulting power cycle for natural gas firing, which is the most likely fuel of a first demonstration plant, are presented. Further modifications of the cycle scheme are discussed and their potential is analyzed. Finally, an economic analysis of the Graz Cycle power plant is performed showing low CO2 mitigation costs in the range of 20 $/ton CO2 avoided, but also the strong dependence of the economics on the investment costs.

/pdf/a-further-step-towards-a-graz-cycle-power-plant-for-co2-y4e4bjfdpo.pdf

Herbert Jericha

Papers

Design Concept for Large Output Graz Cycle Gas Turbines

Qualitative and Quantitative Comparison of Two Promising Oxy-Fuel Power Cycles for CO2 Capture

Thermodynamic and Economic Investigation of an Improved Graz Cycle Power Plant for CO2 Capture

Design Optimization of the Graz Cycle Prototype Plant

A further step towards a graz cycle power plant for co2 capture