Turbine Wheel Shape Optimization: Design Criteria, Multidiscipline Design Tools and Simulation Processes

2015 ◽  
Author(s):  
Paolo Di Sisto ◽  
Massimiliano Grosso
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Optimization Design ◽  
Thermal Environment ◽  
Turbine Rotor ◽  
Design Stage ◽  
Design Tools ◽  
Project Schedule ◽  
Turbine Wheel ◽  
Rotor Design

Gas turbine rotors must be reliable, stable and durable because they operate in a demanding centrifugal and thermal environment without being maintained and replaced for many years. The design of a rotor is one of the most challenging tasks that gas turbine design team should face because its basic architecture has to be decided in the early design stage together with the gas turbine flow path and combustion architecture. A wrong initial decision may require a substantial modification of the gas turbine cross section and consequently have a dramatic impact on the project schedule. This paper introduces readers to the main aspects of the gas turbine rotor design, including the multidiscipline design tools that allow a quick rotor components shaping nowadays. Thanks to the use of some of the most popular gas turbines in the O&G application, this paper will explain how the rotor design has developed over the last decades. An example of how today a new rotor is designed will be provided, by describing some of the main topics analyzed during the conceptual design phase of a General Electric (GE) engine that will be on the market since the 2016. The paper also describes some of the biggest challenges that rotor design teams will have to face in the next future.

Dynamic Modeling of Gas Turbine Rotor Shaft Faults

2009 ◽  
Vol 46 (03) ◽  
pp. 155-164
Author(s):  
E. A. Ogbonnaya
Keyword(s):  
Gas Turbine ◽  
Dynamic Modeling ◽  
Gas Turbines ◽  
Turbine Rotor ◽  
Basic Program ◽  
Design Stage ◽  
Economic Losses ◽  
Vibration Velocity ◽  
Desktop Computer ◽  
Rotor Shaft

Most imminent faults in gas turbines often emanate from the rotor shaft of the engine. Some of these faults that could lead to catastrophe include misalignment, imbalance, crack, and eccentricity. These defects are equally likely to lead to unscheduled downtime resulting in large economic losses to equipment owners. It is against this backdrop that the rotor shaft of a gas turbine system was isolated and used for this dynamic model to reduce downtime. A method of dynamic modeling was used to consider how the aforementioned faults could be addressed at the design stage of the gas turbine engine. Modeling and simulation of the faults were carried out, and the obtained results compared favorably with what theory suggests. It was observed that cracking, as the most prominent rotor shaft fault, could manifest even at a turbine speed of 7,264 rpm (0.18 m for 0.8776 mm/s vibration velocity amplitude). Artificial neural networks (ANN) were then used to validate and link the results together, which also confirmed the authenticity of the work. Also, a Visual Basic program was used in the course of the various simulations adopted for the modeling, with faults being randomized every 3000 ms, and outputs were easily displayed on desktop computer screen. The work therefore showed how an ANN could be integrated into the monitoring of gas turbine rotor shaft defects. In its totality, the monitoring technique metamorphosed into the development of a software codenamed "The MICE" for monitoring essential performance parameters in gas turbine operations.

Experience With Large Heavy-Duty Gas Turbine Rotors

1981 ◽  
Author(s):  
O. R. Schmoch ◽  
B. Deblon
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Turbine Rotor ◽  
Strength Properties ◽  
Operating Conditions ◽  
Material Strength ◽  
Heavy Duty ◽  
Turbine Rotors ◽  
Heavy Duty Gas Turbine ◽  
Response To Temperature

The peripheral speeds of the rotors of large heavy-duty gas turbines have reached levels which place extremely high demands on material strength properties. The particular requirements of gas turbine rotors, as a result of the cycle, operating conditions and the ensuing overall concepts, have led different gas turbine manufacturers to produce special structural designs to resolve these problems. In this connection, a report is given here on a gas turbine rotor consisting of separate discs which are held together by a center bolt and mutually centered by radial serrations in a manner permitting expansion and contraction in response to temperature changges. In particular, the experience gained in the manufacture, operation and servicing are discussed.

Bearing Housing Design for Vibration Control, Using Tilting Pad Bearings Instead of Lemon-Bore Type on a Gas Turbine

2020 ◽  
Author(s):  
Chippa Anil ◽  
Aparna Satheesh ◽  
Babu Santhanagopalakrishnan ◽  
Marcin Bielecki
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Structural Integrity ◽  
Plane Surface ◽  
Rotor Dynamics ◽  
Turbine Rotor ◽  
Outer Diameter ◽  
Housing Design ◽  
Tilting Pad ◽  
And Performance

Abstract Heavy duty gas turbines are usually equipped with hydrodynamic bearings which are either lemon-bore or tilting pad type. Baker Hughes legacy gas turbines use these two types of bearings, and its selection is based on 1) considering pros & cons from Rotor dynamics, 2) bearing performance, 3) bearing housing stiffness, 4) vibration detection & control. Non-contact probes are used to monitor the vibrations of rotor. Majority of legacy gas turbines are not equipped with these probes. Due to this fact, over the years it resulted in non-detection of dynamics & vibration issue, which caused frequent bearing replacement. As the increase in industry demand to apply and measure vibrations using non-contact probes on bearings, an effort was made by Baker Hughes to implement these on existing fleet units. Also, in order to increase rotor dynamics stability of low-pressure rotor, to improve bearing life and performance, effort was made to replace lemon-bore bearings with tilting pad. This paper demonstrates efforts made to design the titling pad which would fit within envelop of already available bearing housing. Bearing/shaft clearance, bearing performance, modification of bearing retainer clearances are the mandatory tasks which would be dealt in this study. The swap of bearing type, and its effect on whole gas turbine rotor dynamic stability, checking the frequency crossovers with Campbell diagram would also be dealt in this paper. This paper also focuses on assessment on oil passage routing, temperature & proximity probe instrumentation routing design. Re-design is performed by analyzing various configuration, assessing different sensitivity studies & validation of modified bearing housing from structural integrity, ultimate load capability, & split plane oil leakage retention and its comparison with baseline are most important aspects of finalization of this change, which will be showcased in this paper. Instrumentation routing was a critical task when the considering bearing replacement from lemon-bore to tilting pad. As lemon-bore type bearings just have an elliptical inner surface, it’s quite easy to install the thermocouples into a simple hole. But as replacement has tilting pads, the challenge is to instrument the pads without effecting their movement and functionality. Such best practices are also dealt in this paper. Comparison of tilting-pad with lemon-bore, considering the fixed shaft diameter, the retainer outer diameter of tilting pad is higher than lemon-bore. This effect has a change in bearing seat on bearing housing, thereby reducing the effective stiffness of the housing, and the reduced split plane surface. To tackle this situation, several sensitivities were executed, by re-modifying the bolts and bolt holes on the existing housing, without modifying the housing envelop.

Principles of Imitation for the Loading of the Test Bench for Gas Turbines of Gas Pumping Units, Adequate to Real Conditions

2021 ◽  
Vol 13 (24) ◽  
pp. 13678
Author(s):  
Anton Petrochenkov ◽  
Aleksandr Romodin ◽  
Vladimir Kazantsev ◽  
Aleksey Sal’nikov ◽  
Sergey Bochkarev ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Simulation Models ◽  
Turbine Rotor ◽  
Operating Conditions ◽  
Automation System ◽  
Model Free ◽  
Gas Pumping ◽  
Pumping Units

The purpose of the study is to analyze the prospects for the development of loading methods for gas turbines as well as to develop a mathematical model that adequately describes the real operating conditions of the loading system at various loads and rotation speeds. A comparative analysis of the most common methods and technical means of loading the shafts of a free turbine at gas turbine plants intended for operation as part of gas pumping units is presented. Based on the results of the analysis, the expediency of using the loading model “Free Power Turbine Rotor–Hydraulic Brake” as a load simulation is shown. Recommendations for the creation of an automation system for the load testing of power plants have been developed. Mathematical models and Hardware-in-the-Loop simulation models of power plants have been developed and tested. One of the most important factors that predetermine the effectiveness of the loading principle is the possibility of software implementation of the loading means using software control systems that provide the specified loading parameters of the gas turbine.

scholarly journals Impact of compressed air energy storage demands on gas turbine performance

2020 ◽  
pp. 095765092090627 ◽  
Author(s):  
Uyioghosa Igie ◽  
Marco Abbondanza ◽  
Artur Szymański ◽  
Theoklis Nikolaidis
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Engine Performance ◽  
Compressed Air ◽  
Design Stage ◽  
Simulation Code ◽  
Ratio Distribution ◽  
Stall Margin ◽  
Industrial Gas Turbines

Industrial gas turbines are now required to operate more flexibly as a result of incentives and priorities given to renewable forms of energy. This study considers the extraction of compressed air from the gas turbine; it is implemented to store heat energy at periods of a surplus power supply and the reinjection at peak demand. Using an in-house engine performance simulation code, extractions and injections are investigated for a range of flows and for varied rear stage bleeding locations. Inter-stage bleeding is seen to unload the stage of extraction towards choke, while loading the subsequent stages, pushing them towards stall. Extracting after the last stage is shown to be appropriate for a wider range of flows: up to 15% of the compressor inlet flow. Injecting in this location at high flows pushes the closest stage towards stall. The same effect is observed in all the stages but to a lesser magnitude. Up to 17.5% injection seems allowable before compressor stalls; however, a more conservative estimate is expected with higher fidelity models. The study also shows an increase in performance with a rise in flow injection. Varying the design stage pressure ratio distribution brought about an improvement in the stall margin utilized, only for high extraction.

Micro Gas Turbine With Ceramic Nozzle and Rotor

2005 ◽  
Author(s):  
Takayuki Matsunuma ◽  
Hiro Yoshida ◽  
Norihiko Iki ◽  
Takumi Ebara ◽  
Satoshi Sodeoka ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Turbine Rotor ◽  
Total Power ◽  
Inlet Temperature ◽  
Present System ◽  
Outlet Temperature ◽  
Micro Gas Turbine ◽  
Buffer Material ◽  
Inconel 713C

A series of operation tests of a ceramic micro gas turbine has been successfully carried out. The baseline machine is a small single-shaft turbojet engine (J-850, Sophia Precision Corp.) with a centrifugal compressor, an annular type combustor, and a radial turbine. As a first step, an Inconel 713C alloy turbine rotor of 55 mm in diameter was replaced with a ceramic rotor (SN-235, Kyocera Corporation). A running test was conducted at rotational speeds of up to 140,000 rpm in atmospheric air. At this rotor speed, the compression pressure ratio and the thrust were 3 and 100 N, respectively. The total energy level (enthalpy and kinetic energy) of the exhaust gas jet was 240 kW. If, for example, it is assumed that 10% of the total power of the exhaust jet gas was converted into electricity, the present system would correspond to a generator with 24 kW output power. The measured turbine outlet temperature was 950°C (1,740°F) and the turbine inlet temperature was estimated to be 1,280°C (2,340°F). Although the ceramic rotor showed no evidence of degradation, the Inconel nozzle immediately in front of the turbine rotor partially melted in this rotor condition. As a second step, the Inconel turbine nozzle and casing were replaced with ceramic parts (SN-01, Ohtsuka Ceramics Inc.). The ceramic nozzle and case were supported by metal parts. Through tests with the ceramic nozzle, it became evident that one of the key technologies for the development of ceramic gas turbines is the design of the interface between the ceramic components and the metallic components, because the difference between the coefficients of linear thermal expansion of the ceramic and metal produces large thermal stress at their interface in the high-temperature condition. A buffer material made of alumina fiber was therefore introduced at the interface between the ceramic and metal.

Thermodynamic Performance Analyses of Mixed Gas-Steam Cycle (1): Performance Prediction Method

1998 ◽  
Author(s):  
Kirk Hanawa
Keyword(s):  
Gas Turbine ◽  
Performance Prediction ◽  
Gas Turbines ◽  
Prediction Method ◽  
Design Stage ◽  
Inlet Temperature ◽  
Evaluation Tool ◽  
Operational Parameters ◽  
Mixed Gas ◽  
Linear Differential

There are various papers relevant to the improvement ideas of gas turbine cycles, which in general discuss only optimum one-point cycle analysis.*1,*2,*6 It is, accordingly, unclear whether such improvement concepts can be applied into existing gas turbines or not. It might be difficult to incorporate such ideas, in the case of yielding significant changes for operation modes. And it may be essential to assess improvement ideas, from view points of applicability to existing gas turbine models.*3 This paper introduces the performance analysis method of simplified small perturbation procedure, showing thermodynamic behaviors based upon the component characteristics, and resultant influences due to settled operation parameters, like ambient temperature & pressure, turbine inlet temperature, etc. The established method might be used as a rule of thumb for the performance prediction when introducing water and/or steam injection into GTs, where operational parameters’ changes are defined under multi-linear differential equations. This is easy to compile in the computer as Lotus 1-2-3 or Exel to evaluate whether every parameter is within the limit or not, offering very helpful performance evaluation tool for the conceptual design stage.

The Characteristics of Radial Turbines for Small Gas Turbines

2003 ◽  
Author(s):  
C. Rodgers
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Structural Integrity ◽  
Velocity Ratio ◽  
Turbine Rotor ◽  
Flow Coefficient ◽  
Cycle Performance ◽  
Radial Turbine ◽  
Auxiliary Power Units ◽  
Axial Turbines

Inward flow radial and mixed flow turbines are effectively utilized in both small gas turbine auxiliary power units (APU’s) and turbochargers, where moderately high levels of efficiency can be readily attained with simple cast components, less sensitive to blade end-gap clearances than axial turbines. This paper provides an overview of radial turbine performance characteristics for small gas turbine applications as basically influenced by specific speed, velocity ratio, exit flow coefficient, and rotor tip to exducer root mean square (RMS) diameter ratio. Since turbine rotor mass and inertia play important roles in structural integrity and engine acceleration characteristics, the importance of turbine velocity ratio selection upon rotor tip diameter, and cycle performance are discussed. The effects of rotor reaction on radial turbine flow versus pressure characteristics are examined pertinent to engine matching requirements. Engine transient performance is addressed, as influenced by turbine operation towards and beyond runaway conditions.

Aerodynamic Design and Numerical Investigation on Overall Performance of a Micro Radial Turbine With Millimeter-Scale

2009 ◽  
Author(s):  
Lei Fu ◽  
Yan Shi ◽  
Qinghua Deng ◽  
Zhenping Feng
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Micro Gas Turbine ◽  
Radial Turbine ◽  
Overall Performance ◽  
Low Reynolds ◽  
Exit Mach Number ◽  
Installation Technology

For millimeter-scale microturbines, the principal challenge is to achieve a design scheme to meet the aerothermodynamics, geometry restriction, structural strength and component functionality requirements while in consideration of the applicable materials, realizable manufacturing and installation technology. This paper mainly presents numerical investigations on the aerothermodynamic design, geometrical design and overall performance prediction of a millimeter-scale radial turbine with rotor diameter of 10mm. Four kinds of turbine rotor profiles were designed, and they were compared with one another in order to select the suitable profile for the micro radial turbine. The leaving velocity loss in micro gas turbines was found to be a large source of inefficiency. The approach of refining the geometric structure of rotor blades and the profile of diffuser were adopted to reduce the exit Mach number thus improving the total-static efficiency. Different from general gas turbines, micro gas turbines are operated in low Reynolds numbers, 104∼105, which has significant effect on flow separation, heat transfer and laminar to turbulent flow transition. Based on the selected rotor profile, several micro gas turbine configurations with different tip clearances of 0.1mm, 0.2mm and 0.3mm, respectively; two different isothermal wall conditions; and two laminar-turbulent transition models were investigated to understand the particular influence of low Reynolds number. These influences on the overall performance of the micro gas turbine were analyzed in details. The results indicate that these configurations should be included and emphasized during the design process of the millimeter-scale micro radial turbines.

scholarly journals Status of the Automotive Ceramic Gas Turbine Development Program: Year 3 Progress

1994 ◽  
Author(s):  
Takane Itoh ◽  
Hidetomo Kimura
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Performance Test ◽  
Development Program ◽  
Turbine Rotor ◽  
Maximum Speed ◽  
Inlet Temperature ◽  
Test Rig ◽  
Thermal Test ◽  
The Individual

Under the ongoing seven-year program, designated “Research and Development of Automotive Ceramic Gas Turbine Engine (CGT Program)”, started in June 1990. Japan Automobile Research Institute. Inc. (JARI) is continuing to address the issues of developing and demonstrating the advantageous potentials of ceramic gas turbines for automotive use. This program has been conducted by the Petroleum Energy Center (PEC) with the financial support of MITI. The basic engine is a 100 kW, single-shaft regenerative engine having a turbine inlet temperature of 1350°C and a rotor speed of 110,000 rpm. In the third year of this program, the experimental evaluation of the individual engine components and various assembly tests in a static thermal test rig were continued. Exhaust emissions were also measured in a performance test rig for an initially designed pre-mixed, pre-vaporized lean (PPL) combustor. A maximum speed of 130,700 rpm was obtained during hot spin tests of delivered ceramic turbine rotors, which was almost the same level as during cold spin tests. A dynamic thermal test including a centrifugal compressor, a ceramic radial turbine rotor and all the ceramic stationary hot parts was initiated.

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