Gas Turbine Compressor Research Articles

Numerical Investigation of the Influence of Air Contaminants on the Interfacial Heat Transfer in Transonic Flow in a Compressor Rotor

Atmospheric air is a commonly used working fluid in turbomachinery. The air typically contains a certain amount of suspended solid particles, as well as water in the form of vapor or droplets. In the current paper, we focus on the numerical modeling of humid air transonic flow in turbomachinery. In this paper we demonstrate a rarely considered, but as presented herein important influence of air humidity, pollution and liquid water content on the performance of the first stage of the gas turbine compressor and turbofan engine fan (NASA rotors 37 and 67). We also discuss the impact of the interfacial heat transfer associated with steam condensation or water evaporation on the distribution of stagnation parameters at the rotor outlet, the rotor performance, and flow conditions, as well as losses. Results demonstrate the impact of the number of pollution particles and water droplets on the compression process in the analyzed rotors, especially on the Mach number distribution in the blade-to-blade channel. In this paper we highlight that the air pollution and liquid water content, together with such physical phenomena as steam condensation or water droplets evaporation, exert a significant influence on work parameters, losses and efficiency, and thus should be considered in high-velocity airflow simulations.

Vibration characteristics of cracked compressor blades with different materials

Aiming at the influence of different material properties on the vibration characteristics of cracked gas turbine compressor blades, the vibration characteristics of cracked compressor blades with three different materials were studied by numerical calculation. The first order bending vibration of a cracked cantilever beam was simplified to a single degree of freedom system. The breathing crack stiffness model was introduced to change the elastic modulus and other parameters of the material. The fourth-order Runge-Kutta method and fast Fourier transform were used to obtain the cantilever beam vibration characteristic diagram, and the relationship between the material properties and the structural vibration was analyzed. The results show that the elastic modulus of the material is proportional to the stiffness, and the stiffness of the material affects the vibration displacement response of the cantilever beam, and the larger the stiffness is, the smaller the vibration displacement is.

Mean-line model development for off-design performance prediction of transonic axial compressor of an industrial gas turbine based on computational fluid dynamics database

In this work, a mean-line model with the row-by-row stacking scheme is developed to simulate the off-design operation of a multi-stage transonic axial compressor of an industrial gas turbine. A database of computational fluid dynamics (CFD) simulation results validated with the field data is generated at different rotating speeds and pressure ratios by using CFD simulation tools and available detail geometry of the studied compressor. The compressor characteristic parameters including inlet/exit blockage factor, deviation angle parameter, rotor temperature and pressure coefficients, and the pressure loss of the stator for all stages, plus variable inlet guide vane, are extracted from CFD simulation results. Based on analytical/empirical relations in the literature, a generic formulation for the characteristic parameters is defined as a function of airflow parameters such as inlet Mach number, inlet flow angle, and velocity ratio. Since the accuracy of this type of model depends on the formulated characteristic parameters, and due to the error propagation potential of the sequential stacking solutions, a multi-objective optimization program is developed to specify the coefficients and exponent values of the generic formulations. The functionality of characteristic curves versus airflow parameters for different compressor rows is comprehensively investigated. The comparison between the results of the mean-line model and CFD simulations shows the high accuracy of the model. The developed model can be used in applications such as condition monitoring of in-service gas turbines, studying the effects of rescheduling the variable stator vanes, and investigating the wet compression process.

Heat Transfer, Thermal Stress and Failure Inspection of a Gas Turbine Compressor Stator Blade Made of Five Different Conventional Superalloys and Ultra-High-Temperature Ceramic Material: A Direct Numerical Investigation

Heat Transfer, Thermal Stress and Failure Inspection of a Gas Turbine Compressor Stator Blade Made of Five Different Conventional Superalloys and Ultra-High-Temperature Ceramic Material: A Direct Numerical Investigation

Structural and Thermal Analysis of F Class Gas Turbine Compressor Blade

In this study, the structural and thermal analysis of the final stage compressor rotor blades, which are currently used on-site, is performed by using the ANSYS program. For that reason, a 3D model of the existing compressor blade has been done. Later on, this model was transferred to the ANSYS program and analyzed. In the analysis, the parameters formed in the blade geometry were determined. By creating a design geometry with the selected parameters, the stress of the existing blade under operating conditions was examined. All external parameters in this study were taken from an F-class gas turbine operating under real field conditions. The stresses of the obtained values in different regions on the blade were examined. This study is also a reverse engineering study and the effects of real field conditions on the compressor blades have been analyzed.

Soft open points based load restoration for the urban integrated energy system under extreme weather events

With frequent occurrences of extreme natural disasters such as typhoons in urban integrated energy systems (UIES), it is of great significance to cope with different kinds of disturbances. This paper proposes a load restoration method under typhoon weather for urban distribution and natural gas networks based on soft open points (SOP). Firstly, the typhoon wind speed model is introduced and the line fault rates of distribution networks under typhoons are calculated. Secondly, the gas turbine and electric-driven compressor are considered as the coupling units of the integrated electric–gas energy system, and related models are constructed. The fault analysis method of the natural gas network is proposed considering the faults in the distribution network lead by typhoons. Thirdly, SOP installed in the distribution network with the V/f control mode is applied to restore electrical loads and provide voltage support for the loads on the fault side. After that, the loads of the gas network could also be restored because of the restoration of the coupling units. Optimal energy flow is applied to determine the output of the power and gas sources, coupling units and also the loads to be restored. Finally, the fault rate of each line under typhoon disaster is analysed and the correctness and effectiveness of the resilience improving method based on SOP are verified with test systems UIES E33-G14 and UIES E123-G48.

Effect of compressive residual stress on wear resistance of IGT25+ gas turbine compressor blades made of 1.4923 steel

Effect of compressive residual stress on wear resistance of IGT25+ gas turbine compressor blades made of 1.4923 steel

DIAGNOSTICS OF THE OPTIMAL OPERATING MODES OF GAS TURBINE COMPRESSOR STATIONS BASED ON THE ANALYSIS OF TECHNOLOGICAL PROCESSES

The article is dedicated to the analysis of the influence of the seasonally changing ambient temperature on the technological parameters of the compression process at a gas turbine compressor station for the transportation of natural and associated gas collected from oil and gas fields by an offshore subsea gas pipeline. As a result of the analysis, indicators of suction and discharge pressure, compressor capacity, ambient temperature during the summer and winter months were collected at each stage of a multi-unit two-stage compressor station. The indicators were divided into intervals, the number of measurements in the interval was determined, and graphs of the dependence of the number of measurements on the average value of the interval were built. As a result of the analysis of the graphs, the complex influence of technological parameters and ambient temperature on the performance of gas turbine compressors was evaluated. To compare the results and study the effect of the parameters on the operating mode and efficiency of the compressor station, the numerical value of the criterion as the ratio of the maximum number of measurements to the average value of the corresponding interval for each parameter was calculated. For both 1st- and 2nd-stage compressors, the value of this criterion for productivity was found to be almost twice as low in winter compared to summer. For this reason, there is a need to develop measures that can ensure the operation of the compressor station in the optimal operating mode. As a result of the analysis, it was found that in the 1st stage gas turbine compressors, due to increase of the inlet pressure, which is a positive factor for the compressor, by 16.4% (from 58 psi to 67.5 psi) in summer compared to winter, and due to the increase of the outlet pressure, which is the negative factor, by 0.9% (from 285 psi to 288 psi) and an increase in ambient temperature of 36o F (from 42o F to 80.5o F), the productivity is decreased by 15.2% (from 40.15 MMSCFD to 34.05 MMSCFD) to). In 2nd-stage gas turbine compressors, due to no change of the inlet pressure, which is a positive factor for the compressor, in summer, compared to winter (273 psi in both cases), and due to the decrease of the outlet pressure, which is a negative factor, by 0.2% (from 807.5 psi to 805.5 psi. ) and an increase in ambient temperature of 36o F (from 42o F to 80.5o F), productivity decreased by 10.1% (from 49.05 MMSCFD to 44.05 MMSCFD). Thus, 10.1% of the 15.2% decrease in the productivity of gas turbine compressors in the summer season is due to the increase in ambient temperature, while the remaining 5.1% is due to the organization of technological processes. Taking into account this factor in the field, the selection of the correct technological mode in the gas transportation system allows to prevent the loss of large amounts of gas. Taking into account the design features of gas turbine compressor units, it is concluded that the 10.1% decrease in productivity in the 2nd stage gas turbine compressors in the background of the constant no-change of compressor inlet and outlet pressures in summer and winter is due to automatic decrease in RPM of gas turbines from nominal 15000 cycles/min and thus the decrease of the power of gas turbines due to the overload in summer. Considering the fact that each turbine consumes 30,000 m3 of fuel gas per day, the 360,000 m3 gas per day for fuel at the station is taken from the outlet of the 2nd stage gas turbine compressors, and these turbines are overloaded, the fuel gas is considered to be taken from another source. By feeding all the turbines of the station from the outlet of the 1st stage compressors, it is possible to reduce the load on the interstage collector of the station, increase the productivity of the 1st stage compressors and direct the gas compressed by the 2nd stage compressors to the whole outlet pipeline. As a result of this technological operation, an additional 200,000-250,000 m3 of gas per day can be transported through the compressor station. This technique is recommended for multivariate analysis of various technological processes. As a result of the study, a technological scheme was proposed for increasing the productivity of a gas turbine compressor station by 3-4% by changing the source of fuel gas extraction. Keywords: gas turbine, compressor, natural gas pressure, ambient temperature, productivity, fuel gas, statistical method.

Retrofittable Solutions Capability for Gas Turbine Compressors

The increasing introduction of renewable energy capacity has changed the perspective on the operation of conventional power plants, introducing the necessity of reaching extreme off-design conditions. There is a strong interest in the development and optimization of technologies that can be retrofitted to an existing power plant to enhance flexibility as well as increase performance and lower emissions. Under the framework of the European project TURBO-REFLEX, a typical F-class gas turbine compressor designed and manufactured by Ansaldo Energia has been studied. Numerical analyses were performed using the TRAF code, which is a state-of-the-art 3D CFD RANS/URANS flow solver. In order to assess the feasibility of lower minimum environmental load operation, by utilizing a reduction in the compressor outlet mass-flow rate, with a safe stability margin, two different solutions have been analyzed: blow-off extractions and extra-closure of Variable Inlet Guide Vanes. The numerical steady-state results are compared and discussed in relation to an experimental campaign, which was performed by Ansaldo Energia. The purpose is to identify the feasibility of the technologies and implementation opportunity in the existing thermal power plant fleet.

Пример использования компрессора газотурбинного двигателя, освоенного в производстве и имеющего хорошие характеристики, в проекте новых изделий

The development of a new gas turbine engine requires a lot of time and money spent on the design and testing its compressor, which has been shown as the most complex and time-consuming assembly unit of the engine. This article examines the potential application of the industry-developed engine compressors in the designs of a new turbojet engine and a gas turbine compressor. The comparative analysis of the ideal cycles of an augmented turbojet engine and a turbojet engine with a high-temperature combustor is made. The advantage of the turbojet engine with a high-temperature combustor configuration over the augmented turbojet engine configuration is shown. The high rates of jet-pipe gas velocity make a turbojet engine with a high-temperature combustor suitable for supersonic cruise products.

Thermal studies of big sheep horn as thermal barrier coating (TBC) material for gas turbine compressor blade

This research focuses on the decomposition temperature of a large sheep horn from Haveri District, Karnataka, India, which is 302.9?C. It also demonstrates the possible use of large sheep horn in the aerospace industry. It can be utilised as a Thermal Barrier Coating (TBC) in high-pressure compressor blades of jet engines. Because of its poor thermal conductivity and specific heat capacity, it is a superb insulator, and temperatures throughout the TBC take around 10 minutes to match.

Influence of blade vibrations on aerodynamic performance of axial compressor in gas turbine: Direct numerical simulation

Flutter instability because of the blade vibrations is a major problem in axial compressor cascades. This paper investigates the effects of blade oscillations on aerodynamic performance and turbulent flow characteristics of modern gas-turbine compressors. Highly accurate direct numerical simulations (DNS) are performed based on the spectral-hp element method to predict the flow instabilities, pressure fluctuations and vortex generation on the surface of the compressor blades by considering all complex physical parameters at different vibration frequencies (0 < f < 8.28 Hz). The main novelty of this study is to consider the aeroelastic vibrations of the compressor blades in DNS analysis. The novel proposed method enables the detailed analysis of complex structure fluid interactions, which cannot be obtained using other methods such as RANS models. The simulations revealed that the blade oscillations have a huge impact on the vortex generation and laminar separation bubble on the suction side of the blade. Moreover, the amplitude of unsteady pressure distribution is greater at 90% span, with the phage angle deviating between 100° and 350°. Strong fluctuations are observed at the centre of the wake region of the vibrating blade cascade. These fluctuations are activated by the flow disturbances resulting from the blade oscillation. Moreover, intense pressure fluctuations happen in the wake region of the oscillating compressor blade compared with the stationary one. The separating point occurred 8.28% sooner on the suction surface of the vibrating blade with k = 0.4 (Xsep/C = 0.288) compared to the stationary blade with Xsep/C = 0.314.

Gas Turbine Compressor Configuration Analysis for Production and Efficiency Optimization at PT Saka Indonesia Pangkah Ltd.

Gas Turbine Compressors are used by Saka Indonesia Pangkah Ltd. in upstream oil and gas facilities either to boost hydrocarbon products to downstream facilities or to lift liquid hydrocarbon as a common artificial method. As production rate declining leads to gas supply deficiency to the compressors, the operating point move to surge line away from the best efficiency point. Gas feed shortage affecting the compressor’s performance which contributed to head and flow capacity. This condition is then calculated and simulated using UNISIM Design Simulator to get optimum configuration results. The simulation was performed at the same gas turbine shaft power output of each compressor. Two cases of centrifugal compressors configuration with different functions and performance are studied. Due to process dynamic conditions, constraint parameter is considered as per desired operating point. This paper also analyses techno-economic aspects between individual and serial pipelines arrangement of the two compressors by evaluating operational data and design calculation. Subsequently, this study produces assessment observations associated with the compressor performance both in individual and serial configuration and eventually analyses the rate of fuel consumption in the gas turbines as the main driver. The case study shows serial arrangement between MPC-1 and GLC with same gas turbine shaft power as individual configuration can reduce fuel consumption up to 47 kg/hr. It saves as much as USD 7,569.96 per day at low demand and USD 7,569.96 at high-demand cases.

ANALYSİS OF THE İMPACT OF PHYSİCAL AND CHEMİCAL FEATURES OF THE NATURAL GAS TO THE PARAMETERS OF THE GAS TRANSPORT SYSTEM

Definition of the technological regimes of the natural gas transportation system is co-related with the physical and chemical features of the gas. The results of the chemical analyses of gas in the gas turbine compressor station are laid out in the article: various levels of changes of the composition of gas at various points are described. Technological losses of gas are determined, as the result of change in its specific weight in the process of compression, cooling down and separation at the compressor station. Gas losses in the sub water main gas pipelines are analyzed. Changes of the content of the gas carbonate in the composition of the gas are analyzed, its degradation alongside the pipeline and existence of the CO2 in the composition of the low-pressure oil associated gas is described in comparison with the high-pressure natural gas, which is 3,8 times more. The problems, caused by the presence of the gas carbonate in the composition of the natural gas, are highlighted. The physical properties of natural gas are characterized by its specific gravity, temperature, pressure, volume and other parameters, and chemical properties by its composition, stability of gas-forming components. It should be noted that the physical and chemical properties of gas vary within certain limits, depending on the time, both on the reservoir and on the same reservoir. Therefore, in order to regulate the parameters of the gas transportation system, it is necessary to periodically examine and take into account the physical and chemical properties of the gas. Keywords: Natural gas, carbon dioxide,compressor station, gas pipeline, gas well.

Comparative analysis and forecasting of isentropic efficiency of gas turbine compressor with ARIMA, VAR, NARNN and ANFIS approaches

It is extremely important to monitor the status of gas turbine to ensure its safe and reliable operation. In this work, the variation trend of isentropic efficiency of compressor is analysed based on the measured data of F-class heavy-duty gas turbine in practical industrial application. The actual measured data of F-class heavy-duty gas turbine includes the data under start-stop and unstable working conditions, which cannot be directly used for calculation and analysis. To solve this problem, the data selection rules are designed and determined according to the operating conditions of gas turbine to select the data under effective working state. The isentropic efficiency of compressor is calculated based on the selected data. Then the forecasting effects of four forecasting methods on the variation trend of isentropic efficiency of compressor are studied. Four indexes, namely, symmetric mean absolute percentage error (SMAPE), mean absolute percentage error (MAPE), root mean square error (RMSE), and similarity (SIM) values are utilized to evaluate the forecasting accuracy. The research results indicate that the Adaptive Neuro-Fuzzy Inference System (ANFIS) method has better forecasting effect than Autoregressive Integrated Moving Average (ARIMA), Vector Autoregression (VAR) and Nonlinear Autoregression Neural Network (NARNN) for this F-class heavy-duty gas turbine. Through the ANFIS method, the SIM up to 96.77%, the SMAPE and MAPE are less than 0.1, and the RMSE is only 0.1157. Therefore, the ANFIS method is suitable for forecasting the isentropic efficiency of this F-class heavy-duty gas turbine compressor.

A gas turbine thermal performance prediction method based on dynamic neural network

In order to ensure safety and reliability of energy transportation, it is necessary to understand and predict the performance of the gas turbine components. A prediction frame of the gas turbine compressor isentropic efficiency is established using the neural time series theory based on the Dynamic Neural Network. In order to obtain appropriate parameters for the network, a validation set is introduced to generalize the model. The compressor isentropic efficiency can be predicted based on the suggested model which provides an effective technical mean for the early warning of gas turbine performance. The experiment verified that the performance calculation model and the isentropic entropy efficiency prediction model based on the neural time series are effective.

Study of pitting corrosion under actual operating conditions of a first stage compressor blade

In this study, pitting corrosion was investigated numerically and experimentally under actual operational conditions of a gas turbine compressor. First, the samples cut from a blade made of Custom 450 stainless steel were exposed to different corrosion times in a 3.5 wt% NaCl solution. After the creation of pits in the samples, the dimensions of the corrosion pits were measured using a 3D profilometer device. The stoichiometry equations governing the corrosion of the Custom 450 alloy in a chloride solution were extracted and applied to the models. The results of this simulation were validated by comparing the depth of the simulated pits and the experimental samples. Subsequently, simulation was conducted for 48 months on a compressor having pits. There is a good agreement between the simulation results and the results obtained from the Turbo machine laboratory of the Texas A&M University. In addition, pits grew under the influence of corrosion, joined together, and made an equivalent pit.

Dependence of thermogasodynamic parameters of operation of a helicopter gas turbine engine on its operation and dust in the atmosphere

By scanning the blades of the impeller and the guide devices of the full-scale compressor of the helicopter gas turbine engine, a solid-state design model of the compressor with a tunable geometry in the height of the blades was developed. The empirical dependencies of the values of nonlinear wear of the blade of the 1st stage of the compressor on the operating time and the concentration of dust in the air are presented. A block diagram of the procedure for calculating the characteristics and parameters of a helicopter gas turbine compressor is presented. When calculating the flow in the gas–air path of the compressor, the numerical solution of the Navier–Stokes equations averaged by Reynolds, the finite element method in combination with the establishment of patterns of erosive wear of the blades depending on the operating conditions of the engine is used. Mathematical dependencies of the thermogasodynamic parameters of the helicopter gas turbine compressor operation on its operating time and the dustiness of the atmosphere are obtained using modeling. The obtained results can be used in the development of a methodology for automated monitoring of the wear condition of the compressor blades of a helicopter gas turbine engine according to its thermogasodynamic parameters, applied to various climatic operating conditions.

Forced Response Excitation Due to the Stator Vanes of Two and Three Compressor Stages Away

Abstract State-of-the-art axial compressors of gas turbines employed in power generation plants and aero engines should have both high efficiency and small footprint. Thus, compressors are designed to have thin rotor blades and stator vanes with short axial distances. Recently, problems of high cycle fatigue (HCF) associated with forced response excitation have gradually increased as a result of these trends. Rotor blade fatigue can be caused not only by the wake and potential effect of the adjacent stator vane, but also by the stator vanes of two, three, or four compressor stages away. Thus, accurate prediction and suppression methods are necessary in the design process. In this study, the problem of rotor blade vibration caused by the stator vanes of two and three compressor stages away is studied. In the first part of the study, one-way fluid structure interaction (FSI) simulation is carried out. To validate the accuracy of the simulation, experiments are also conducted using a gas turbine test facility. It is found that one-way FSI simulation can accurately predict the order of the vibration level. In the second part of the study, a method of controlling the blade vibration is investigated by optimizing the clocking of the stator vanes. It is confirmed that the vibration amplitude can be effectively suppressed without reducing the performance. Through this study, ways to evaluate and control the rotor blade vibration are validated.

Development of an accelerated test for pitting corrosion of CUSTOM 450 by rDHM

Abstract A key application of CUSTOM 450 alloy is in the construction of gas turbine compressor blades. The study of pitting corrosion can prevent the failure of many gas turbine compressor blades. In this study, a reflective digital holography microscopy method was employed to investigate the growth of pitting corrosion in depth. To this end, a constant potential of 350 mVSCE in a 3.5 wt.% NaCl solution was applied to the specimen. The generated pits were simulated in three dimensions, and it was indicated that pitting corrosion rate was decreased as time passed. Comparing the obtained experimental data with the data gathered from the real industrial environment surrounding a compressor installation, an accelerated test was proposed. By the proposed accelerated test, it is possible to produce a pit similar to the one that will be initiated and propagated at any time in the future in real conditions.