bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impeller Manufacturing: Design for Machining
Authors: Cave Michael , Ji Min 
Published: August 2017

Today, there are 3 primary methods Solar Turbines, Inc. uses for manufacturing shrouded centrifugal impellers for the Oil and Gas industry. Impellers can be made by an investment casting process, single piece integrally-machined using point milling, or fabricated using a flank milled, open faced impeller and brazing a shroud in place. Investment cast impellers give the aero designer the greatest flexibility in the design, since the designer doesn’t need to be concerned about tool access or other manufacturing constraints. It is common to use this process for any impeller. Single piece integrally-machined impellers are relatively straightforward for high flow coefficient impellers, as the wide flow-path provides plenty of room for tool access. For lower flow coefficients, brazed shrouded impellers can be made very precisely, but at a substantially higher cost than the other methods. Each of these manufacturing methods also has a cost and aerodynamic performance associated with them.
With the advent of high-speed machining and better cutting tools, integrally-machined impellers can offer an alternative manufacturing process over cast or fabricated impellers. However, determining the ability to integrally-machine an impeller historically is done late or even after the detailed design process. This can lead to costly redesigns to make sure the impeller can be machined, with flow-path and blade adjustments done after the aerodynamic design. Sometimes these adjustments are unsuccessful and the manufacturing process is abandoned.
In this paper, 2 medium flow coefficient impellers are redesigned. These impellers are used in pipeline applications for the transmission of natural gas. The original designs were cast. By incorporating highly customized commercial software written exclusively for defining tool paths of integrally-machined shrouded impellers into the aerodynamic design process, new impeller geometry was defined that was able to be integrally-machined, while meeting or exceeding existing impeller performance and improved design cycle time.
This paper will discuss how the machining software was used concurrently with CFD and FEA analysis during the design process. Test results from rig tests will be presented, showing measured results from both the original and redesigned stages.
Investigation of an Industrial Gas Turbine Combustor and Pollutant Formation Using LES
Authors: Mallouppas George , Goldin Graham , Zhang Yongzhe , Thakre Piyush , Krishnamoorthy Niveditha , Rawat Rajesh , Gosman David , Rogerson Jim , Bulat Ghenadie 
Published: August 2017

An experimental variant of a commercial swirl burner for industrial gas turbine combustors operating at 3 bar is numerically investigated using high-fidelity Computational Fluid Dynamics models using STAR-CCM+ v11.06. This work presents the computational results of the SGT-100 Dry Low Emission gas turbine provided by Siemens Industrial Turbomachinery Ltd. The related experimental study was performed at the DLR Institute of Combustion Technology, Stuttgart, Germany. The objective of this work is to compare the performance of the Flamelet Generated Manifold model, which is the widely accepted combustion model in Gas Turbines with the Complex Chemistry model. In particular this work examines the flame shape and position, pollutant formation predicted by the aforementioned models with Large Eddy Simulations.
Mean and RMS quantities of the flow field, flame temperatures and major species are presented and compared with the experiments. The results show that the predictions are insensitive on the meshing strategy and at the evaluated mesh sizes of ∼10 million and ∼44 million cells. The mean and RMS errors are ∼8% compared to the reported experiments and these differences are within the measurement errors. The results show that the calculated flame positions are in very good agreement with the reported measurements and the typical M-shape flame is reproduced independent of the combustion model. Pollutant formation in the combustor predicted by two combustion models is scrutinised. The predicted NO and CO emissions levels are in agreement with the literature.
Part Load Behavior of the LP Part of an Industrial Gas Turbine
Authors: Petrovic Milan V. , Wiedermann Alexander , Nedeljkovic Srecko M. , Banjac Milan 
Published: August 2017

The operation under off-design conditions of a two-stage LP part of a 6.5 MW industrial gas turbine was analyzed in this work. Since the turbine is able to vary the rotation speed in a wide range from 40 to 140% of the design speed, a flow with extremely large positive and negative incidence angle appears.
The flow field was calculated applying 2D through-flow code for the analysis of axial multistage turbines with cooling by air from compressor bleed. The code was developed by the authors and validated by calculation of a number of test cases with different configurations. The method is based on a stream function approach and a finite element solution procedure. In parallel, the flow in the turbine was calculated using a commercial CFD code. Based on the calculated flow field, the turbine efficiency and pressure ratio and also different stage parameters were determined for the design point and for a wide range of off-design conditions. Comparison of the predicted results and measured test data for a number of parameters showed good agreement.
The Use of Variable Inlet Guide Vane or Speed Control to Maintain Constant Compressor Pressure Ratio in Wet Gas Flow and Their Effect on Diffuser Stability
Authors: Vigdal Levi André B. , Bakken Lars E. 
Published: August 2017

Improving offshore gas production requires the process compressor to be moved closer to the wellhead. This will yield such benefits as enhanced well output, longer well life and the possibility of exploiting smaller fields. However, the harsh environment, remote location and variable two-phase characteristics of an untreated gas stream pose increased challenges for operational performance and robustness. Several methods are available to ensure that a process compressor maintains constant outlet pressure regardless of inlet stream properties and flow.
Two pressure-ratio control methods — variable inlet guide vanes (IGV) and variable speed — have been investigated. Their effect on diffuser stability has been tested and analysed in dry and wet conditions. Increased diffuser stability in wet conditions with IGV has been discussed and results are presented.
Multidisciplinary Optimization of the Working Process of Uncooled Axial Turbine According to Efficiency and Strength Criteria
Authors: Marchukov Evgeny Yu. , Egorov Igor , Popov Grigorii , Salnikov Anton , Goriachkin Evgenii , Kolmakova Daria 
Published: August 2017

The results of multicriteria multidisciplinary optimization of three-stage low-pressure turbine are described in the paper. The aim of the optimization is to improve turbine operation process by three criteria: turbine outlet flow angle, value of residual swirl at the turbine outlet, and turbine efficiency. Moreover, the requirements of static and dynamic strength must be fulfilled for rotor blades.
Full reprofiling of all blade rows is carried out while solving optimization problem. Reprofiling includes a change in both shape of flat blade sections (profiles) and threedimensional shape of the blades.
The study is carried out with 3D numerical models of turbines both gas-dynamic and strength.
The gas-dynamic improvement of turbine operation is performed as the first step. Then, strength improvement is carried out for the best variants in order to provide satisfactory margins of static and dynamic strength. Mutual strength and gas-dynamic optimization is done as the next step. The final variant of turbine that meets best the gas-dynamic and strength criteria is found as the result of this optimization.
Towards Higher Micro Gas Turbine Efficiency and Flexibility: Humidified MGTS — A Review
Authors: De Paepe Ward , Montero Carrero Marina , Bram Svend , Parente Alessandro , Contino Francesco 
Published: August 2017

Micro Gas Turbines (mGTs) offer several advantages for small-scale Combined Heat and Power (CHP) production compared to their main competitors, the Internal Combustion Engines (ICEs), such as low vibration level, cleaner exhaust and less maintenance. The major drawback is their lower electrical efficiency, which makes them economically less attractive and explains their low market penetration. Next to improving the efficiency of the components of the traditional recuperated mGT, shifting towards more innovative cycles may help enhancing the performance and the flexibility of mGTs.
One interesting solution is the introduction of water in the mGT cycle — either as auto-raised steam or hot liquid —, preheated with the waste heat from the exhaust gases. The so-called humidification of the mGT cycle has the potential of increasing the electrical performance and flexibility of the mGT, resulting in a higher profitability. However, despite the proven advantages of mGT humidification, only few of these engines have been experimentally tested and up to now, no cycle is commercially available.
With this paper, we give a comprehensive review of the literature on research and development of humidified mGTs: we examine the effect of humidification both on the improvement of the cycle efficiency and flexibility and on the performance of the specific mGT components. Additionally, we will present the different possible layouts, both focusing on the numerical and experimental work. Finally, we pinpoint the technological challenges that need to be overcome for humidified mGTs to be viable. In conclusion, humidification of mGT cycles offers great potential for enhancing the cycle’s electrical efficiency and flexibility, but further research is necessary to make the technology commercially available.
Experimental and Computational Investigation of Rayleigh-Bénard Flow in the Rotating Cavities of a Core Compressor
Authors: Puttock-Brown M. R. , Rose M. G. , Long C. A. 
Published: August 2017

This paper presents new experimental measurements, at conditions representative of an aero engine, of heat transfer from the inner peripheral surface (shroud) of a rotating cavity. The results are taken from the University of Sussex Multiple Cavity Rig, which is designed to be similar to a gas turbine high pressure compressor internal air system. The shroud Nusselt numbers are shown to be dependent on the shroud Grashof number and insensitive to throughflow axial Reynolds number. The magnitude of the shroud Nusselt numbers are consistent with accepted correlations for turbulent free convection from a horizontal plate, yet show a trend (gradient of Nusselt to Grashof numbers) that is similar to laminar free convection.
A supporting high-resolution 3D unsteady RANS simulation was conducted to investigate the cavity flow structure with particular attention paid to the near shroud region. This demonstrated flow structures that are consistent with published work but also show the existence of a type of Rayleigh-Bénard flow that manifests as a series of streaks that propagate along the periphery of the cavity. These structures can be found in the literature albeit in different circumstances. Whilst these streaks have been shown in the simulation their existence cannot be ratified without experimental confirmation.
Development of the New Ansaldo Energia Gas Turbine Technology Generation
Authors: Ruedel U. , Stefanis V. , Ramaglia A. D. , Florjancic S. 
Published: August 2017

This paper provides an overview of the ongoing development activities for the Ansaldo Energia gas turbines AE64.3A, AE94.2, AE94.2K, AE94.3A, GT26 (2006), GT26 (2011), GT36-S6 and GT36-S5. The improvements significantly reduce the energy consumption in gas turbine combined cycle (GTCC) power plants and are directed towards improved operational and fuel flexibility, increased GT power output, GT efficiency and improved component lifetime.
The collaborative development, validation and application of the constant pressure sequential combustion system (‘CPSC’) for the GT36 engine will be introduced. Based on the well-established sequential burner technology as installed since 1994 on all legacy GT26 gas turbines, the operation turndown, fuel flexibility and the overall system robustness is described. The development and engine validation of the first stage burner for Improved Durability and Turndown as well as the design of a Combustor Sequential Liner within a can combustion system is shown. The reconstruction and analysis of the acoustic transfer matrix of the flame in the sequential burner together with the applied air and fuel management facilitate emission and dynamics control at both, the extremely high and low firing temperature ranges.
The axial flow turbine of the GT36 heavy duty gas turbine, which has evolved from the existing and proven GT26 design, consists of an optimized annulus flow path, higher lift airfoil profiles, optimized aerodynamic matching between the turbine stages and a new and improved cooling systems of the turbine vanes and blades. A major design feature of the turbine has been to control and reduce the aerodynamic losses, associated with the airfoil profiles, trailing edges, blade tips, end walls and coolant ejection. The advantages of these design changes to the overall gas turbine efficiency have been verified via extensive experimental testing.
Improving Turbomachinery Health Monitoring Using Advanced Shaft Telemetry System
Authors: Hesler S. H. , Suprock C. A. 
Published: August 2017

Turbine-generator shaft systems used in power generation applications are exposed to degradation mechanisms that could result in high consequence failures if not discovered prior to damage accumulation. Grid-induced torsional vibration, growth of cracks in the shaft forging, and large blade vibration are some examples of degradation that remains unmonitored in most commercial plants today. In many cases, the sensing and subsequent trending of high-quality vibration data obtained directly from the shaft surface can be the basis for a decision to continue to operate versus inspect or repair. Detection of small changes in torsional and lateral vibration mode properties can be sensed at a single shaft location and trended using techniques such as Advanced Pattern Recognition to reveal the very early signs of rotor distress.
Contemporary barriers to widespread application of wireless shaft vibration measurements for health monitoring were studied and addressed in the development of the Turbine Dynamics Monitoring System (TDMS). The resulting design evolved around the industry need for low sensor maintenance, high reliability, ease of installation, and high data quality to enable early detection of critical component changes. These improvements capitalized on advances in strain gage and accelerometer technology, micro-telemetry, radio-frequency power systems, and advanced adhesives for installation. The new system has been successfully applied in the field on large steam turbine-generators to detect grid-induced torsional vibration.
The paper will describe background of turbine-generator torsional vibration as well as the technical features of this advanced telemetry application with examples of field data.
Experimental Investigation of Two Competitive High Pressure Turbine Blade Cooling Systems
Authors: Risnyk Sergiy , Artushenko Andriy , Kravchenko Igor , Borys Sergii 
Published: August 2017

Aeroengine high-pressure turbine (HPT) is the key engine component.
HPT blade must withstand high inlet temperatures and mechanical loads providing the necessary level of the efficiency. To achieve these objectives effective and complex blade cooling systems (internal convective and film cooling) are used in the HPT design.
The objective of this project is to design and investigate the aeroengine HPT blade cooling system that is able to withstand the blade inlet gas temperature level of approx. 1900K but with the minimal cooling airflow amount.
HPT blade of the aeroengine with unducted fan (UDF) was taken as a baseline design, namely, the monocrystal blade with a convective multipass system and the film cooling.
Advanced HPT blade inter-wall cooling system was designed, investigated and compared with the typical baseline HPT blade. In the advanced HPT blade inter-wall cooling system special types and structure of cooling channels are used.
Both types of cooling systems were investigated experimentally in the turbine rotor of the high temperature core engine. Measurements of turbine blades temperatures were performed using crystal temperature sensors (CTS). HPT blades with two competitive cooling systems incorporated with CTS (0,2–0,3 mm size) were installed in the turbine rotor of the core engine and tested on the engine Maximal rate.
After tests and the engine disassembly CTSs were extracted and the characteristics of the CTS crystal lattice were transcribed in temperature values.
Thermal state of both two competitive cooling systems was validated by experimental data.
Numerical and experimental results obtained in the research of HPT blade cooling system are presented in the article. Aeroengine high pressure turbine blade cooling systems designs are described.
Biomass Microturbine Based EFGT and IPRP Cycles: Environmental Impact Analysis and Comparison
Authors: Zampilli Mauro , Bidini Gianni , Laranci Paolo , D’Amico Michele , Bartocci Pietro , Fantozzi Francesco 
Published: August 2017

The global microturbine market will grow at an interesting Compound Annual Growth Rate during the period 2016–2020 and a key driver will be distributed generation also with unconventional fuels. This paper compares the performances of two different microturbine based technologies for biomass micro CHP. One is the Integrated Pyrolysis Regenerated Plant (IPRP), technology developed by the authors by coupling a pyrolyzer to a mGT fuelled by biomass pyrolysis gas. Two IPRP versions are considered: one in which char is burned to provide pyrolysis energy and one in which it is used as a carbon sink. The second technology is the Externally Fired Gas Turbine (EFGT) based on biomass combustion in a dedicated burner and high temperature heat exchangers used to heat up compressed air which expands in the mGT. Hot air at the turbine exhaust is used as combustion air for biomass. The layout and operational conditions considered were optimized by the authors in previous works. The environmental performance of the two technologies when fuelled with the same biomass at the same power output, is assessed through a Life Cycle Assessment (LCA) analysis, calculating impacts on acidification, carbon footprint and Cumulative Energy Demand (CED). Two sensitivity analysis are also performed on different vegetal oils used for scrubbing and different methods of allocation, referred to CHP products.
Results show that both technologies have negative carbon footprints, however the IPRP has the worst performance because of the sunflower oil, used for syngas scrubbing, which offsets the additional carbon sink benefit of biochar. If water it used as a scrubbing medium in the IPRP plant, this configuration obtains similar results in terms of environmental impact, compared to IPRP plant using vegetable oil as a scrubbing medium. However, when the effect of a different vegetal oil is considered, namely a waste frying oil, the former introduces extraordinary benefits resulting in the IPRP outperforming the EFmGT in terms of carbon negative technology.
Experimental Evaluation of Thermal and Mass Transfer Techniques to Measure Adiabatic Effectiveness With Various Coolant to Freestream Property Ratios
Authors: Wiese Connor J. , Rutledge James L. , Polanka Marc D. 
Published: August 2017

As gas turbine engine temperatures increase, experimentally evaluating the necessary cooling schemes becomes increasingly cost prohibitive at engine conditions. Thus, researchers conduct film cooling experiments near room temperature and attempt to scale the results to engine conditions. Although thermal measurements of film cooling adiabatic effectiveness are common, an increasingly popular method of evaluating adiabatic effectiveness employs pressure sensitive paint and the heat-mass transfer analogy. Mass transfer methods are attractive because an impermeable model can be used as an analog for a perfectly adiabatic wall; however, the mass transfer analogy is imperfect. The suitability of mass transfer methods as a substitute for thermal methods is of interest in the present work.
Much scaling work has been dedicated to the influence of the coolant-to-freestream density ratio, but other fluid properties that differ between experimental and engine conditions have only been considered in more recent work. Most notably in the context of an examination of the ability of mass transfer methods to serve as a proxy for thermal methods are the properties that directly influence thermal transport — thermal conductivity and specific heat. That is, even with an adiabatic wall there is still heat transfer between the freestream flow and the coolant plume and the mass transfer analogy would not be expected to account for the specific heat or thermal conductivity distributions within the flow field. Using various coolant gases (air, carbon dioxide, nitrogen and argon) and comparing with thermal experiments, the efficacy of the pressure sensitive paint method as a direct substitute for thermal measurements was evaluated on a simulated leading edge model with compound coolant injection. The results thus allow examination of how the two methods respond to different property variations. Overall, the pressure sensitive paint technique was found to over predict the adiabatic effectiveness of a particular coolant flow when compared to the results obtained from infrared thermography, but still reveals a great deal of valuable information regarding the coolant flow structure.