Creep Rupture Behavior of Selected Turbine Materials in Air, Ultra-High Purity Helium, and Simulated Closed Cycle Brayton Helium Working Fluids

1981 ◽  
Vol 103 (2) ◽  
pp. 331-337 ◽  
Author(s):  
R. L. Ammon ◽  
L. R. Eisenstatt ◽  
G. O. Yatsko

Five turbine materials, IN100, 713LC, MAR-M-509, MA-754 and TZM were selected as candidate materials for use in a Compact Closed Cycle Brayton System (CCCBS) study in which helium served as the working fluid. The suitability of the alloys to serve in the CCCBS environment at 927 C (1700 F) was evaluated on the basis of creep-rupture tests conducted in air, ultra-high purity helium (>99.9999 percent), and a controlled impurity helium environment. Baseline reference creep rupture properties for times up to 10,000 hr were established in a static ultra-high purity helium environment.

1980 ◽  
Author(s):  
R. L. Ammon ◽  
L. R. Eisenstatt ◽  
G. O. Yatsko

Five turbine materials, IN100, 713LC, MAR-M-509, MA-754 and TZM were selected as candidate materials for use in a Compact Closed Cycle Brayton System (CCCBS) study in which helium served as the working fluid. The suitability of the alloys to serve in the CCCBS environment at 927 C (1700 F) was evaluated on the basis of creep-rupture tests conducted in air, ultra-high purity helium (> 99.9999 percent), and a controlled impurity helium environment. Baseline reference creep rupture properties for times up to 10,000 hr were established in a static ultra-high purity helium enviroment.


Author(s):  
Emmanuel O. Osigwe ◽  
Arnold Gad-Briggs ◽  
Theoklis Nikolaidis ◽  
Pericles Pilidis ◽  
Suresh Sampath

One major challenge to the accurate development of performance simulation tool for component-based nuclear power plant engine models is the difficulty in accessing component performance maps; hence, researchers or engineers often rely on estimation approach using various scaling techniques. This paper describes a multi-fluid scaling approach used to determine the component characteristics of a closed-cycle gas turbine plant from an existing component map with their design data, which can be applied for different working fluids as may be required in closed-cycle gas turbine operations to adapt data from one component map into a new component map. Each component operation is defined by an appropriate change of state equations which describes its thermodynamic behavior, thus, a consideration of the working fluid properties is of high relevance to the scaling approach. The multi-fluid scaling technique described in this paper was used to develop a computer simulation tool called GT-ACYSS, which can be valuable for analyzing the performance of closed-cycle gas turbine operations with different working fluids. This approach makes it easy to theoretically scale existing map using similar or different working fluids without carrying out a full experimental test or repeating the whole design and development process. The results of selected case studies show a reasonable agreement with available data.


Author(s):  
M.M. Barjesteh ◽  
S.M. Abbasi ◽  
K.Z. Madar ◽  
K. Shirvani

Creep deformation is one of the life time limiting reasons for gas turbine parts that are subjected to stresses at elevated temperatures. In this study, creep rupture behavior of uncoated and platinum-aluminide coated Rene?80 has been determined at 760?C/657 MPa, 871?C/343 MPa and 982?C/190 Mpa in air. For this purpose, an initial layer of platinum with a thickness of 6?m was applied on the creep specimens. Subsequently, the aluminizing were formed in the conventional pack cementation method via the Low Temperature-High Activity (LTHA) and High Temperature-Low Activity (HTLA) processes. Results of creep-rupture tests showed a decrease in resistance to creep rupture of coated specimen, compared to the uncoated ones. The reductions in rupture lives in LTHA and HTLA methods at 760?C/657 MPa, 871?C/343 MPa and 982?C/190 MPa were almost (26% and 41.8%), (27.6% and 38.5%) and (22.4% and 40.3%), respectively as compared to the uncoated ones. However, the HTLA aluminizing method showed an intense reduction in creep life. Results of fractographic studies on coated and uncoated specimens indicated a combination of ductile and brittle failure mechanisms for all samples. Although, the base failure mode in substrate was grain boundary voids, cracks initiated from coating at 760?C/657MPa and 871?C/343. No cracking in the coating was observed at 982?C/190MPa.


1963 ◽  
Vol 85 (1) ◽  
pp. 71-86 ◽  
Author(s):  
G. H. Rowe ◽  
J. R. Stewart ◽  
K. N. Burgess

The creep-rupture behavior of 34 capped end, thin-wall tubular specimens was correlated with results for 54 uniaxial tensile specimens in tests at 1350 F, 1500 F, and 1650 F. Basic tests established isotropy in creep-rupture properties as well as metallurgical stability for the material used in the study. Significant correlations of creep rate, rupture life, and rupture ductility were established for the cases of stress ratios 1/0 and 2/1 in the biaxial tension quadrant. Data from tests at 1500 F were evaluated for a statistical argument. This same material was subsequently utilized in a high temperature structures research program to be reported separately.


Author(s):  
Emmanuel O. Osigwe ◽  
Arnold Gad-Briggs ◽  
Nasiru Tukur ◽  
Pericles Pilidis

Abstract A unique benefit of using the closed-cycle gas turbine and gas turbomachines employed in the Gen-IV nuclear power plant is the flexibility it offers in terms of working fluid usage. This is so because of the self-containing nature of the closed-cycle gas turbine. To this end, the selection of the working fluid for the cycle operation is driven by several factors such as the cycle performance, system design, and component material compatibility with fluid properties, availability, and many more. This paper provides an understanding of the design and operational challenges of switching working fluids for a nuclear powered closed-cycle gas turbine. Using the plant output power of a simple closed-cycle configuration as a baseline condition, two case studies have been presented in this paper to explore the design and operational challenges of switching working fluids. In the first case study, the fluid was switched from nitrogen to air and in the second case study, helium and argon were utilised. In both cases, using thermodynamic flow relationship, the closed-cycle gas turbine turbomachinery components maps were analysed to understand the operational requirements for switching the working fluids. The paper also provided an insight into the turbomachinery component design considerations for this to be achieved. The overarching results from a thermodynamic perspective showed fluids with similar thermodynamic behaviour could be switched during idle synchronous speed.


1967 ◽  
Vol 89 (2) ◽  
pp. 229-236 ◽  
Author(s):  
G. Angelino

The possibility of performing a liquid phase compression in closed cycle gas turbine through the use of particular working fluids is discussed. From the results of calculations carried out for different fluids there is evidence that efficiency of the resulting cycle is considerably higher than that of regenerative Brayton cycles and comparable with that of regenerative Rankine cycles. The working fluid selection is recognized as the major problem in view of practical applications. Available data strongly support the conclusion that fluids meeting the needed requirements, at least for moderate temperature operation, can be found. Nuclear power stations appear to be one of the most promising fields of application of the liquid phase compression cycle.


Author(s):  
James H. Anderson

Ocean thermal energy plants are thermal power plants that use warm ocean surface water as a source of heat and cold seawater from the deep ocean as a heat sink. A historical perspective along with the development of the technology will be presented. A short description describing the subtle differences between OTEC and fossil and nuclear plants will be presented. Open cycle OTEC and closed cycle OTEC will be described with a focus on the influence of choice of working fluid on the design of a plant. Various working fluids could be selected for use in closed cycle OTEC plants. A review and comparison of potential working fluids will address the advantages and disadvantages of the individual fluids. Their characteristics along with a comparison to water as a working fluid in open cycle OTEC will be explained.


Author(s):  
C. Casci ◽  
G. Angelino

The adoption of the closed cycle and of working fluids other than steam or air gives the possibility of utilizing for power cycles regions of the temperature-entropy diagram which are inaccessible when the working media are water or combustion products and which enjoy some useful peculiarities. A number of fluids are presented which are suitable for industrial applications and which allow the organization of power cycles covering the liquid, gaseous, and hypercritical regions of the state diagram of a typical substance. Efficiency, specific work, heat transfer surfaces, dimensions of turbomachines, distribution of losses among the various components relating to different fluids and cycles are analyzed and reported. The results strongly support the conclusion that the nature of the working fluid is a powerful tool to adapt the characteristics of power cycles to the widely differing requirements encountered in technical applications.


Author(s):  
J. C. Lee ◽  
J. Campbell ◽  
D. E. Wright

Characteristic requirements of a closed-cycle gas turbine (CCGT) working fluid were identified and the effects of their thermodynamic and transport properties on the CCGT cycle performance, required heat exchanger surface area and metal operating temperature, cycle operating pressure levels, and the turbomachinery design were investigated. Material compatibility, thermal and chemical stability, safety, cost, and availability of the working fluid were also considered in the study. This paper also discusses CCGT working fluids utilizing mixtures of two or more pure gases. Some mixtures of gases exhibit pronounced synergetic effects on their characteristic properties including viscosity, thermal conductivity and Prandtl number, resulting in desirable heat transfer properties and high molecular weights. Typical examples of such synergetic gas mixture are helium-xenon and helium-carbon dioxide.


2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Jianying Gong ◽  
Tieyu Gao ◽  
Guojun Li

Closed cycle ocean thermal energy conversion (CC-OTEC) is a way to generate electricity by the sea water temperature difference from the upper surface to the different depth. This paper presents the performance of a 15 kW micropower CC-OTEC system under different working fluids. The results show that both butane and isobutane are not proper working fluids for the CC-OTEC system because the inlet stable operating turbine pressure is in a very narrow range. R125, R143a, and R32, especially R125, are suggested to be the transitional working fluids for CC-OTEC system for their better comprehensive system performance. Moreover, it is recommended that propane should be a candidate for the working fluid because of its excellent comprehensive properties and environmental friendliness. However, propane has inflammable and explosive characteristics. As for the natural working fluid ammonia, almost all performance properties are not satisfactory except the higher net output per unit sea water mass flow rate. But ammonia has relative broader range of the stable operating turbine inlet pressure, which has benefits for the practical plant operation.


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