Volume 8: Oil and Gas Applications; Steam Turbine最新文献

{"title":"Two Phase Flow CFD Modeling of a Steam Turbine Low Pressure Section: Comparison With Data and Correlations","authors":"N. Maceli, Lorenzo Arcangeli, A. Arnone","doi":"10.1115/gt2021-59645","DOIUrl":"https://doi.org/10.1115/gt2021-59645","url":null,"abstract":"\u0000 Testing a sub-component or testing a scaled model are the approaches currently used to reduce the development cost of the new low-pressure (LP) section of a steam turbine. In any case, testing campaigns are run at a limited number of operating conditions. Therefore, some correlations are used to build a performance model of the LP module and expand the usage of a limited set of experimental data to cover the application range encountered in the steam turbine market. Another approach, which has become feasible during the last decade, is the usage of CFD calculations.\u0000 These two approaches include a certain amount of uncertainty in the performance of the LP section, mainly related to the losses caused by the moisture content in the flow.\u0000 In the present paper, the results of the analysis of a cutting-edge low-pressure section for small steam turbines are presented. The results are obtained by using a CFD commercial code with a set of user defined subroutines to model the effects of droplets nucleation and growth. Different operating conditions are considered, with different wetness at the exit and different pressure ratios, in order to clearly show the loss trend for different levels of exit moisture. The numerical results are compared with the experimental data, showing a significant improvement in the performance predictability for the considered case and demonstrating the benefit of using a CFD approach instead of using existing correlations.","PeriodicalId":252904,"journal":{"name":"Volume 8: Oil and Gas Applications; Steam Turbine","volume":"334 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134124126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detached Eddy Simulation of Rotating Instabilities in a Low-Pressure Model Steam Turbine Operating Under Low Volume Flow Conditions","authors":"Ilgit Ercan, D. Vogt","doi":"10.1115/gt2021-58704","DOIUrl":"https://doi.org/10.1115/gt2021-58704","url":null,"abstract":"\u0000 Rotating instability (RI) in steam turbines is a phenomenon occurring during operation at very low volume flow conditions. Whereas RI is well-known in compressors, it is rather uncommon in turbines, where it is limited to the last stages of low-pressure steam turbines. The phenomenon has been studied numerically by means of viscous 3D CFD simulations employing mainly URANS equations. Given the possible difficulties to accurately predict heavily separated flows using such methods, this paper deals with the question whether the more sophisticated Improved Delayed Detached Eddy Simulation (iDDES) model is applicable in an industrial environment and whether it is capable of capturing the complex unsteady flow physics in a more realistic manner. For this purpose, the commercial CFD solver STAR-CCM+ is employed.\u0000 A three-stage low-pressure model steam turbine featuring a non-axisymmetric inlet and an axial-radial diffuser is used as a test object. In order to capture the asymmetry, the model spans the full annulus and comprises the inlet section, all three stages, the diffuser as well as the exhaust hood. URANS and iDDES simulations have been performed at various low-volume flow part-load operating points and compared to test data. Unsteady pressure fluctuations at the casing as well as time-resolved probe traverse data have been used to validate the simulations. It is found that both models capture the overall flow physics well and that the iDDES model is superior at the most extreme part-load operating condition.\u0000 In addition to the model accuracy and applicability of the CFD tool used, the paper discusses the challenges encountered during simulation setup as well as during initialization.","PeriodicalId":252904,"journal":{"name":"Volume 8: Oil and Gas Applications; Steam Turbine","volume":"42 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131939598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unit Health Assessment- Oil & Gas Equipment Probabilistic Case Study","authors":"Noor Azman Mohamat Nor, A. Findlay","doi":"10.1115/gt2021-59318","DOIUrl":"https://doi.org/10.1115/gt2021-59318","url":null,"abstract":"\u0000 The focus of this case study is the analysis of offshore Oil & Gas facilities recorded downtime data which are classified into gas turbine downtime categories and causes. Each event is then correlated with the maintenance repair records to determine the respective root cause. The key objective of this study is to establish the Critical Success Factors (CSF) for unit health after a gas turbine has been in operation for more than 10 years. The outcome is used to enhance the unit performance, efficiency, maintainability, and operability. As a first step, Content Analysis technique was employed to systematically decipher and organize the downtime causes from collected data. Over 500 data samples collected over a period of 3 years were sorted into relevant categories and causes: comprising a total downtime of 11,410 hours. The downtime data, which is interval scale in nature that is in ‘hours’, is meticulously tabulated against respective downtime categories and causes location by location for the 11 gas turbines sites and correlating this to the repair work. Within scope is downtime related to: Forced Outage Automatic Trip; Failure to Start; Forced Outage Manual Shutdown; and Maintenance Unscheduled while those out of scope are Non-Curtailing and Reserve Shutdown as these are external to gas turbine operational influence. In the second step, descriptive statistics analysis was carried out to understand the key downtime drivers by categories. Pattern recognition is used to identify whether the cause is a “One Time Event”, “Random Event” or “Recurring Event” to confirm data integrity and establish the problem statement. This approach assists in the discovery of erroneous data that could mislead the outcome of statistical analysis. Pattern recognition through data stratification and clustering classifies issue impact as reliability or availability. Simplistic analyses can miss major customer impact issues such as: frequent small shutdowns that do not accumulate a lot of hours per event but cause operational disruption; or infrequent time consuming events resulting from a lack of trained personnel, spares shortages, and difficulty in troubleshooting. In the third step, statistical correlation analysis was applied to establish the relationship between gas turbine downtime and repair works in determining the root causes. Benchmarking these analyses outcome with the actual equipment landscape provides for high probability root cause, thus facilitating solutions for improved site reliability and availability. The study identified CSF in the following areas: personnel training and competency; correct maintenance philosophy and its execution in practice; and life cycle management including obsolescence and spares management. Near term recommendations on changes to site operations or equipment based on OEM guidelines and current available best practices are summarized for each site analyzed.","PeriodicalId":252904,"journal":{"name":"Volume 8: Oil and Gas Applications; Steam Turbine","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128505505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fouling Effects on Wet Gas Compressor Performance: An Experimental Investigation","authors":"Dagfinn Mæland, L. Bakken","doi":"10.1115/gt2021-59543","DOIUrl":"https://doi.org/10.1115/gt2021-59543","url":null,"abstract":"\u0000 Achieving profitability in mature areas such as the Norwegian continental shelf forces the oil and gas industry to apply innovative solutions to increase oil recovery and to reduce both operational and investment costs. Wet gas compressors are promising machines for increasing oil recovery from existing fields and to allow for production from small satellite fields in the proximity of existing infrastructure. A prerequisite for successful implementation of subsea wet gas compressors high reliability. Knowledge of possible failure modes is important.\u0000 The effect of performance degradation due to fouling has been observed during wet gas compressor testing at K-Lab and has initiated further work to better understand and quantify the effects of fouling in wet conditions compared to dry conditions. A test campaign was conducted at the Norwegian University of Science and Technology (NTNU) to investigate the effect of fouled centrifugal compressor performance in both wet and dry conditions. The results documenting these effects are presented together with a proposed model for correcting the effects of fouling between dry and wet conditions.","PeriodicalId":252904,"journal":{"name":"Volume 8: Oil and Gas Applications; Steam Turbine","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116056575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Quantitative Approach for the Estimation of the Fouling Rate on the Stationary Parts of a Multistage Test Compressor","authors":"Alessandro Vulpio, A. Suman, N. Casari, M. Pinelli","doi":"10.1115/gt2021-59449","DOIUrl":"https://doi.org/10.1115/gt2021-59449","url":null,"abstract":"\u0000 Gas turbine particle ingestion may lead to the deposition of contaminants in the compressor section, inducing the performance losses of the whole engine. The economic losses derived from this issue push great interest in the investigation of such a phenomenon from a numerical and experimental standpoint. This paper describes a quantitative approach to predict particle deposition on the vanes of an axial compressor starting from the flow field obtained employing CFD simulations. The results are then compared to the experiments performed on the Allison 250 C18 compressor unit subject to particle ingestion under controlled conditions. The results derived from the experimental and numerical investigations are presented, providing insight into the mass deposited on the vanes and the corresponding zones most affected by the particle deposition issue. The numerical model showed good agreement in the estimation of the predicted values of the deposited mass and the corresponding patterns through the compressor stages. The low-complexity approach proposed here, helps the designer to predict the contamination of the stationary rows starting from a simple set of single-phase numerical results. Furthermore, with the implementation of this approach into the design path, the designer could reduce the impact of fouling, looking at the effects of their solutions under the fouling-reduction light.","PeriodicalId":252904,"journal":{"name":"Volume 8: Oil and Gas Applications; Steam Turbine","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121948137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mathematical Modeling of the Polytropic Process Using the Sequential Cubic Polynomial Approximation","authors":"Matt Taher","doi":"10.1115/gt2021-59715","DOIUrl":"https://doi.org/10.1115/gt2021-59715","url":null,"abstract":"\u0000 The polytropic process is used to signify the effect of “energy degradation” associated with the equipment losses, which is as an inherent irreversibility in a compression process. The polytropic process is path dependent, which entails the irreversibility associated with the system. The change of gas composition and operating conditions affect the energy degradation. In this paper the polytropic process of real gas is explained and thermodynamics and mathematical model used in Taher-Evans Cubic Polynomial Method [1], [2] is presented. The elegance of Taher-Evans Cubic Polynomial Method is its rapid solution technique and high precision for calculating polytropic efficiency as required for compressor performance testing by the ASME PTC-10 [3].","PeriodicalId":252904,"journal":{"name":"Volume 8: Oil and Gas Applications; Steam Turbine","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122042588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Measurements and Numerical Investigations on the Aerodynamic Performance and Internal Flow Fields of Tangential Admission Volutes for Steam Turbines","authors":"Wensong Xue, Yang‐Jen Chen, Zhigang Li, Jun Li","doi":"10.1115/gt2021-59140","DOIUrl":"https://doi.org/10.1115/gt2021-59140","url":null,"abstract":"\u0000 Steam turbines are applied in production plants characterized by very large injections of steam. For this reason, the design and optimization of the admission are fundamentals to obtain an adequate level of turbine efficiency and ensure uniform flow at the inlet of the low pressure stages downstream the injection. In conjunction with a flexible operation and partial load conditions, it is important to estimate the losses appearing at those admissions sufficiently.\u0000 The aerodynamic performance and flow field of the individual tangential admission volute and tangential admission volute coupled with the downstream vanes were experimentally measured and numerically simulated in this paper. The total pressure loss, outlet flow angle and mass flow rate of the individual tangential admission volute at three different outlet Mach numbers and tangential admission volute coupled with the downstream vanes at four different inlet total pressures were measured. The flow field of the experimental tangential admission volute for the steam turbine was numerically investigated using threedimensional Reynolds-Averaged Navier-Stokes (RANS) and SST turbulence model. The numerical aerodynamic parameters of the tangential admission volute were in good agreement with the experimental data. The accuracy of the presented numerical method was validated. The flow field and aerodynamic parameters of tangential admission volute coupled with the downstream vanes were discussed under different inlet total pressure flow conditions. Then, three volute cases with different transverse distance were designed to investigate the influence of different outlet airflow angles on the aerodynamic performance of the downstream vanes.\u0000 Results show that the outlet airflow angle of the individual tangential admission volute and tangential admission volute coupled with the downstream vanes usually keep constants when the inlet total pressure is increases. The averaged outlet airflow angle of the individual tangential admission volute and tangential admission volute coupled with the downstream vanes equal 152.0° and 166.6°, respectively. Comparing with the individual tangential admission volute, the outlet airflow angle of the tangential admission volute coupled with the downstream vanes is more uniform. The total pressure loss and mass flow rate of the individual tangential admission volute and tangential admission volute coupled with the downstream vanes increase with the inlet total pressure. With the increase of the inlet total pressure, the total pressure loss coefficient of the individual tangential admission volute increases from 0.73% to 1.64%. In the same case, the total pressure loss of the tangential admission volute coupled with the downstream stator vane increases from 0.82% to 2.66%. The average airflow angle of the volute increases with the increase of the transverse distance. With the increase of the transverse distance, the total pressure loss coefficient of the volute incre","PeriodicalId":252904,"journal":{"name":"Volume 8: Oil and Gas Applications; Steam Turbine","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132868144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On Small Scale LNG Concepts","authors":"R. Kurz, Min Ji, Griffin C. Beck, T. Allison","doi":"10.1115/gt2021-58989","DOIUrl":"https://doi.org/10.1115/gt2021-58989","url":null,"abstract":"\u0000 The different economics of small scale LNG plants put more emphasis on capital expenses over process efficiency, and thus favors simpler refrigeration cycles. We typically find reverse Brayton cycles, or SMR (Single mixed refrigerant) cycles. These cycles have specific requirements to the compression equipment, and typically have smaller drivers, either electric drives or gas turbines. The relationship between output, driver size, and process preferences is explained. The type of compressors, and expanders needed are discussed, together with thoughts and the driver preferences. This includes the different control methods that can be used, both for the cycle adaptation, as well as the related control of the compressors, expanders, valves and drivers. Equipment performance maps are created to highlight the required different operating conditions. This result allows for subsequent optimization discussions.","PeriodicalId":252904,"journal":{"name":"Volume 8: Oil and Gas Applications; Steam Turbine","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121352880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Centrifugal Compressor Polytropic Performance Evaluation Using Cubic Polynomial Approximation for the Temperature-Entropy Polytropic Path","authors":"Matt Taher, B. F. Evans","doi":"10.1115/gt2021-59678","DOIUrl":"https://doi.org/10.1115/gt2021-59678","url":null,"abstract":"\u0000 A highly accurate centrifugal compressor polytropic performance approximation method has been developed that is easy to employ. The method is based upon a constant efficiency, temperature-entropy path for real gases. The elegance of this method is its exceedingly simple way of calculating polytropic efficiency with sufficiently high precision as required for compressor performance testing. A constant efficiency polytropic path can be modeled as either a single or several sequential cubic polynomial segments affording solutions that allow for determining thermodynamic state variables along a continuous path. New analytic terms have been developed for slope and curvature of temperature versus entropy along the constant efficiency polytropic path. A broad range of example case results verify the accuracy and ease of use of the method.","PeriodicalId":252904,"journal":{"name":"Volume 8: Oil and Gas Applications; Steam Turbine","volume":"57 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123006362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improvement of Surface Cracking Risks by Controlling Dilution of Cobalt-Based Hardfacings","authors":"T. Yokoyama, T. Kurimura, N. Sakakibara, Fumiyuki Suzuki","doi":"10.1115/gt2021-58497","DOIUrl":"https://doi.org/10.1115/gt2021-58497","url":null,"abstract":"\u0000 Cobalt-based hardfacings have been widely applied to the main valve seats of steam turbines for the purpose of improving durability. With the aim of decreasing the surface cracking risks of the hardfacings, the dilution of the hardfacing on their surface was controlled and the properties of the dilution-controlled materials were investigated in this study. Mixtures of cobalt-based hardfacings and base materials were cast in order to simulate the dilution of base material to hardfacing, which occurs in the process such as PTA welding. It was confirmed that the grain size matched that produced by PTA welding by controlling the cooling rate. To investigate the effect of aging on the microstructures and mechanical properties of the cast samples, the samples were aged in electric furnaces where the temperature was controlled to the steam temperature of steam turbines and above. The test results show that the phase transitioned from face-centered cubic to hexagonal closed-packed in low-dilution samples, while carbides precipitated along the grain boundaries in high-dilution samples after aging. Both samples showed an increase in hardness and reduction in ductility and fracture toughness. In addition, the variation in microstructures and strength properties was suppressed for a 20 % dilution sample. To validate the influence of dilution as investigated with the cast samples, test specimens were machined from the surface and bottom layers of multi-layered hardfacing that had different dilutions by PTA welding. It was confirmed that the influence of dilution on the strength properties of hardfacing layers had a similar tendency to the cast samples. The results above lead to the possibility of reducing the surface cracking risks by controlling the dilution of hardfacings and suppressing embrittlement after aging. We have applied dilution-controlled hardfacings to steam valves and successfully reduced surface cracking.","PeriodicalId":252904,"journal":{"name":"Volume 8: Oil and Gas Applications; Steam Turbine","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127600714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}