Volume 7: Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Microturbines, Turbochargers, and Small Turbomachines; Oil & Gas Applications最新文献

{"title":"Design and CFD Study of an ORC Radial Turbine for Multiple Working Fluids","authors":"Tchable-Nan Djaname, M. Deligant, F. Bakir, Marzia Marinelli, T. Capurso, M. Torresi","doi":"10.1115/gt2022-81741","DOIUrl":"https://doi.org/10.1115/gt2022-81741","url":null,"abstract":"\u0000 Organic Rankine cycle is an available solution for the conversion of low-grade thermal energy into electricity. In this way, it contributes to enhance the global plant efficiency hence to the reduction of the power plant carbon footprint (CO2 production). However, contrary to water Rankine cycle or Brayton cycle, in ORC the working fluid may change depending on the characteristics of hot and cold sources. Expander cost is estimated to be around half of the total cost of an organic Rankine cycle installation. Hence, developing a given turbine for multiple applications will help reducing the cost of ORC systems. In this work a radial turbine will be numerically investigated. The design and performance analysis of such a turbine will be analyzed for three working fluids taking into account real gas effect under expansion. An iterative process using preliminary design combined with meanline analysis allows the selection of the final geometry. Finally, 3D CFD simulations are computed on the obtained geometry with the selected working fluids for different operating conditions. Small deviations can be observed between the 3D CFD results and the prediction code. The different fluids have been selected based on safety (ASHRAE A1 and A2), environmental (GWP less than 150, ODP near to 0) and thermodynamic properties criteria (dry or isentropic fluid). The operating conditions have been selected to start the expansion in the low compressibility zone and featuring high rotational speed (up to 60000 rpm), low power (up to 9kW) and high maximum efficiency.","PeriodicalId":301910,"journal":{"name":"Volume 7: Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Microturbines, Turbochargers, and Small Turbomachines; Oil & Gas Applications","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121508377","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 Machine Learning Approach for Stress-Rupture Prediction of High Temperature Austenitic Stainless Steels","authors":"Md. Abir Hossain, Adan J. Mireles, C. Stewart","doi":"10.1115/gt2022-84352","DOIUrl":"https://doi.org/10.1115/gt2022-84352","url":null,"abstract":"\u0000 This study outlines a machine learning approach for long-term stress-rupture (SR) prediction of high temperature austenitic stainless steel. Traditional methods of lifetime estimation and alloy design for turbomachinery application rely mostly on repeated testing, prior experience, and trial-and-error approach, which are laborious, time intensive, and costly. Recent advances in machine learning offer an accelerated technique for the development of constitutive creep laws, superior alloy designs, and reliable long-term performance prediction. To that end, a machine learning approach is explored in this study for long-term stress-rupture prediction. The toolbox GPTIPS, a biologically inspired genetic programming (GP) algorithm for building accurate and intrinsically explainable non-linear regression model is employed in this study. In GPTIPS, randomly sampled tree structures, mutate and cross over the best performing trees to create a new sample. The process iterates until the best solution is found based on criteria set by the user. Herein, the stress-rupture data of 18Cr-8Ni (304 SS) stainless steel, divided into 60% training and 40% testing data irrespective of heat grades are feed into GPTIPS. The GPTIPS is iterated based on the number of genes, tournament size, tree depth, and nodes. The generated SR constitutive models are ranked according to goodness-of-fit and model complexity. The best-ranked models are compared with the experimental data and found to be free of inflection points at low-stress. Post audit validation is performed by fitting the model blindly against an extended data base of 18Cr-12Ni-Mo (316 SS) stainless steel. Based on the goodness-of-fit, the best-ranked models are investigated for future application, comprehensive understanding of their limitations, and the resultant capability of effective prediction. In future work, the ability of GPTIPS will be leveraged to develop minimum-creep-strain-rate models, alloy design based on chemical composition, potential sources of uncertainty, and their implications on the outcomes.","PeriodicalId":301910,"journal":{"name":"Volume 7: Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Microturbines, Turbochargers, and Small Turbomachines; Oil & Gas Applications","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130731187","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":"Optimal Strategy of the Energy Management Within the Microgrid Using the Hydrogen Fueled Gas Turbine","authors":"M. A. Ancona, M. Bianchi, L. Branchini, F. Catena, A. De Pascale, F. Melino, S. Ottaviano, A. Peretto","doi":"10.1115/gt2022-80385","DOIUrl":"https://doi.org/10.1115/gt2022-80385","url":null,"abstract":"\u0000 The hydrogen production by means of renewable energy exploitation has the potential to address issues that arise when an increasing share of power is generated from sources that have a highly variable output. Although these systems have been widely studied, one of the key aspects to be considered is the choice of the energy management strategy.\u0000 The aim of this paper is to define and present an optimal strategy for the energy flow management of a pilot plant consisting of a turbine gas facility making use of power produced during turbine tests — along with solar — for hydrogen production integrated with batteries storage.\u0000 Key results from the analyses are: i) increasing the hydrogen production target, the hydrogen production ratio increases up to a maximum value equal to about 100%; ii) optimizing the management strategy, the system is always able to meet the demand of hydrogen; iii) with a larger hydrogen storage capacity, the microgrid is able to exploit a higher amount of renewable production, achieving the total renewable energy exploitation.","PeriodicalId":301910,"journal":{"name":"Volume 7: Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Microturbines, Turbochargers, and Small Turbomachines; Oil & Gas Applications","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114799680","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":"Optimizing Internal Energy Streams in Micro Gas Turbines in Cogeneration Towards Flexible Heat-to-Power Ratio — Global Thermodynamic Performance Assessment and Specific Case Studies","authors":"W. De Paepe, Tom Clymans","doi":"10.1115/gt2022-83427","DOIUrl":"https://doi.org/10.1115/gt2022-83427","url":null,"abstract":"\u0000 Although the simultaneous production of heat and power, so-called Combined Heat and Power (CHP), is from a thermo-dynamic point of view still the most efficient energy conversion method, cogeneration units have nowadays problems to position themselves in the current and future energy market. The increasing renewable energy penetration requires CHP units to become more flexible, especially on their currently fixed heat-to-power ratio. Within this framework, micro Gas Turbines (mGTs), as small-scale decentralized cogeneration units, offer opportunities. Since they use the recuperated Brayton cycle, they offer the theoretic option to adjust the internal heat streams to provide a flexible heat-to-power ratio as well as the unique feature of a tunable outlet temperature, making the unit feasible/interesting for a larger range of applications having a combined heat and power demand. Hence, in this paper, we assessed the impact of the use of a recuperator bypass for enhanced operational flexibility of mGTs. In a first step, the optimal pathway for the recuperator bypass, i.e., cold or hot side bypass, is selected for a typical mGT, the Turbec T100 (currently commercially available as the AE-T100), considering both thermodynamics as well as technological feasibility. Moreover, the potential performance impact on the electrical and total efficiency is calculated as well as on the total available thermal power. In a second step, the specific performance of the option of using a recuperator bypass is assessed for 2 specific cases: flexible heat-to-power ratio at low temperature and high temperature, i.e. steam generation, cogeneration. Thermodynamic simulations show that the impact on the electric efficiency remains rather limited (maximal 6% absolute efficiency reduction for a 40% bypass ratio), while the available thermal energy and exergy increase significantly: up to 60% increase for thermal power and even 115% increase in the exergy content of the flue gases. Moreover, there is no distinct difference between cold or hot bypass, leaving the selection of the optimal bypass route a pure technical choice. Finally, considering the specific cases studied, simulation results show that heat-to-power ratio could be increased by more than 50% for all power outputs for the low temperature CHP applications, even resulting in a global efficiency increase, while for the high temperature case, recuperator bypass allows for a significant increase in steam production, at total efficiencies comparable to the separate production (i.e. boiler and grid), clearly highlighting the benefits and potential of a recuperator bypass.","PeriodicalId":301910,"journal":{"name":"Volume 7: Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Microturbines, Turbochargers, and Small Turbomachines; Oil & Gas Applications","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128783125","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":"The Evaluation of Ammonia/Hydrogen Combustion on the H Permeation and Embrittlement of Nickel-Base Superalloys","authors":"M. Kovaleva, D. Dziedzic, S. Mashruk, S. Evans, A. Valera-Medina, E. Galindo-Nava","doi":"10.1115/gt2022-82239","DOIUrl":"https://doi.org/10.1115/gt2022-82239","url":null,"abstract":"\u0000 Recent studies exploring ammonia as a green hydrogen energy carrier have established its suitability for a variety of combustion technologies including gas turbines, furnaces, and internal combustion engines. Of significant interest are ammonia/hydrogen blends, which possess combustion benefits over pure ammonia, including an extended stability range and higher laminar burning velocity. Despite extensive research characterising the flame properties of these blends, very few studies explore the suitability of existing materials for the manufacture of ammonia/hydrogen combustors. The present study evaluates the impact of ammonia/hydrogen flame chemistry on the H permeation and possible loss of ductility of nickel-superalloys through exposing the samples to pure methane and ammonia/hydrogen flames at atmospheric pressure for a 5-hour period. The effect of the two flame compositions on the materials are compared through thermal desorption analysis (TDA) and room temperature tensile testing. The results showed that exposure to an ammonia/hydrogen combustion environment led to hydrogen being absorbed by the nickel superalloys but a possible variation in ductility is influenced by the combustion conditions. Furthermore, the formation of an oxide layer was shown to likely impact the hydrogen absorption rate of the materials. This work shows that ammonia/hydrogen flame chemistry on combustor materials should not be ignored and warrants further studies on material’s mechanical and environmental stability controlled by nitrogen and hydrogen species permeating at industrially relevant conditions.","PeriodicalId":301910,"journal":{"name":"Volume 7: Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Microturbines, Turbochargers, and Small Turbomachines; Oil & Gas Applications","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127642745","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":"CFD Flow Field Assessment and Performance Map Generation of A Turbocharger Radial Turbine Attempted to Be Matched With a Downsized Diesel Engine","authors":"Mohamed Amine El Hameur, Mahfoudh Cerdoun, L. Tarabet, G. Ferrara","doi":"10.1115/gt2022-82212","DOIUrl":"https://doi.org/10.1115/gt2022-82212","url":null,"abstract":"\u0000 The present paper aims to propose an efficient methodology to match aerodynamically a 1.5 l, three cylinders downsized Diesel engine, with a selected turbocharger to boost its performance based on 1D codes and CFD simulation. In this aspect, a radial turbine’s stage was sized and designed applying 1D preliminary design in-house codes. Then, a CFD simulation was established to investigate the flow field through its components and to predict its performance. Based on the simulation data, a turbine’s map was generated via gas-dynamic simulation software. On the other hand, a turbocharger compressor was selected from a database. Therefore, the performance maps of the designed turbine and the selected compressor were matched with the engine simulation model. From the findings, the new turbocharged engine developed an operating area far from the compressor limits at the entire engine speed range, with a surge margin of 23.37% at the engine rated power. The engine thermal efficiency, brake specific fuel consumption, compressor and turbine isentropic efficiencies measured on the new turbocharged engine expressed an enhancement at the engine rated speed of about 6.79%, 6.36%, 19.91% and 3.86%, respectively, compared with the original engine. Furthermore, maximum deviations of 7.43% and 0.47% were measured between the new and the original turbocharged engines in terms of in-cylinder pressure and temperature, respectively, which guarantee the engine’s thermodynamic strength. Finally, the developed methodology reported satisfactory results in terms of the engine’s secure functioning and predicted performances, which can be considered as an important basis before initiating any detailed conception.","PeriodicalId":301910,"journal":{"name":"Volume 7: Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Microturbines, Turbochargers, and Small Turbomachines; Oil & Gas Applications","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127038455","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":"An Euler-Based Throughflow Approach for Centrifugal Compressors – Part A: Extension and Modifications of Models","authors":"Rebecca Jenzen, Christian Woiczinski, S. Schuster, D. Brillert","doi":"10.1115/gt2022-82170","DOIUrl":"https://doi.org/10.1115/gt2022-82170","url":null,"abstract":"\u0000 This paper presents the extension and validation of an Euler-based throughflow solver for the analysis of centrifugal compressors. The conservation equations are augmented with aerodynamic models suitable for describing a centrifugal compressor. The paper analyzes the impact of the varying meridional pitch angle on the blade force model and proposes two different approaches to consider this variation in the calculation. Further, the paper includes the development and implementation of additional loss models based on enthalpy loss coefficients, which take into account the different loss mechanisms in centrifugal compressors. In this contribution, the modifications are introduced and discussed. To validate the modifications, they are implemented in an existing Euler-based throughflow solver called tFlow. First, the extended solver is compared with the results of computational fluid dynamics (CFD) and calibrated with respect to the total efficiency at the design point. The resulting performance values predicted by the extended solver at off-design conditions are in good agreement with the CFD results. Subsequently, in Part B of the paper, experimental data is used to validate the predicted performance values of the extended solver. The experiments are carried out on a centrifugal compressor test rig described and explained in detail in Part B of this paper. The performance values predicted by the extended solver are in good agreement with the experimental data with respect to the pressure ratio.","PeriodicalId":301910,"journal":{"name":"Volume 7: Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Microturbines, Turbochargers, and Small Turbomachines; Oil & Gas Applications","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114939886","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":"Additive Manufacturing of Centrifugal Impellers for Solid Oxide Fuel Cell Anode Offgas Recycle Blowers","authors":"J. L. Córdova","doi":"10.1115/gt2022-83489","DOIUrl":"https://doi.org/10.1115/gt2022-83489","url":null,"abstract":"\u0000 A form of laser powder bed fusion (LPBF) 3D printing has been used to manufacture the impellers of anode offgas recycle blowers (AORBs) for solid oxide fuel cell (SOFC) applications. The material selected is Inconel 718, since it can endure the conditions and temperature ranges in which these systems typically operate. This paper presents details of the multiple process trials and the issues resolved to achieve a successful build, demonstrating the feasibility of the method for impeller manufacturing. Also discussed are the potential cost and design flexibility benefits that may be derived from 3D printing methods, particularly during integration of prototype and low count turbomachinery production runs. The paper discusses long-term goals of the project to support the reduction of cost of SOFC power plants by reducing the cost of balance of plant (BOP) subsystems, from design to integration.","PeriodicalId":301910,"journal":{"name":"Volume 7: Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Microturbines, Turbochargers, and Small Turbomachines; Oil & Gas Applications","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121490111","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":"Sensitivity Analysis of Impeller Blade Parameters to Compressor Performance and Aerodynamic Noise","authors":"Cao Yipeng, Ma Zequn, L. Chen","doi":"10.1115/gt2022-81705","DOIUrl":"https://doi.org/10.1115/gt2022-81705","url":null,"abstract":"\u0000 The effects of a series of impeller blade parameters on compressor performance and aerodynamic noise are numerical analyzed in this paper. The inversed impeller blade model of a turbocharger compressor was first constructed by the reverse engineering method. Then, the performance and aerodynamic noise of the inversed impeller blade model was validated using a numerical approach, which combines computational fluid dynamics (CFD) and computational aerodynamic acoustics (CAA). A parameterization of blade starts from the inversed impeller and then morphs it with a number of design parameters, which including tip clearance, the curvature of cut-off trailing edge, exit lean angle, inlet blade angle on shroud and inlet blade angle on hub. The influence of different structural parameters on compressor performance and noise was studied, and the sensitivity analysis of different structural parameters was carried out based on the Morris’s method. The results indicate that the tip clearance, the outlet lean angle of blade and the inlet blade angle at shroud have a significant effect on compressor aerodynamic performance, while the curvature of cut-off trailing edge and the inlet blade angle on hub have less impact. The overall sound pressure level (OASPL) of the aerodynamic noise radiated at compressor inlet shows that the inlet blade angle on shroud and the inlet blade angle on hub have a significant effect on compressor aerodynamic noise. The results of sensitivity analysis further indicate that the tip clearance and the inlet blade angle on shroud are the main parameters that affect compressor aerodynamic performance and noise.","PeriodicalId":301910,"journal":{"name":"Volume 7: Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Microturbines, Turbochargers, and Small Turbomachines; Oil & Gas Applications","volume":"154 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116412746","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":"The Design and Optimisation of a 100% Hydrogen Micro Gas Turbine Micromix Combustor: Preliminary Hydrogen Injection Depth Characterisation Using Cold Flow Steady RANS","authors":"C. Devriese, Simon Snijders, W. De Paepe, R. Bastiaans","doi":"10.1115/gt2022-80805","DOIUrl":"https://doi.org/10.1115/gt2022-80805","url":null,"abstract":"\u0000 In a modern electricity grid, with fluctuating renewable energy input and problems linked to construction of large power plants in densely populated areas, local, flexible, and zero-emission electricity and heat production becomes evermore important. Consequently, we research the design and optimisation of a hydrogen fuelled micro Gas Turbine (mGT). This paper focusses on our continued development and optimisation of the low-NOx hydrogen combustion chamber, based on the Micromix principle. Based on previous work, we observed that the hydrogen injection depth was critical in minimising thermal NOx formation. To characterise the hydrogen Jet in Cross Flow (JICF) mechanism more deeply, we first designed a simplified single nozzle variant of the micromix geometry. Using this test geometry, we analysed the relation between the hydrogen injection pressure and the hydrogen injection depth, perpendicularly into the air flow, using both an analytical model and cold flow steady RANS simulations. From these simulation results we obtained a preliminary optimal range for the injection pressure, so that the hydrogen does not protrude too far into the air stream (thereby increasing the residence time and increasing the possibility of higher thermal NOx formation), nor too little (thereby reducing the mixing of both fuel and air and increasing the chance of combustion too near to the wall). Based on these results, we can, using hot flow steady RANS simulations, validate the optimal hydrogen injection pressure range from the single-nozzle, cold flow results, for minimal thermal NOx formation, in a follow-up research.","PeriodicalId":301910,"journal":{"name":"Volume 7: Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Microturbines, Turbochargers, and Small Turbomachines; Oil & Gas Applications","volume":"604 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122939681","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}