scholarly journals Investigation of the Combined Effect of Variable Inlet Guide Vane Drift, Fouling, and Inlet Air Cooling on Gas Turbine Performance

Entropy ◽  
2019 ◽  
Vol 21 (12) ◽  
pp. 1186 ◽  
Author(s):  
Muhammad Baqir Hashmi ◽  
Tamiru Alemu Lemma ◽  
Zainal Ambri Abdul Karim
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Thermal Efficiency ◽  
Guide Vane ◽  
Inlet Guide Vane ◽  
Air Cooling ◽  
Turbine Performance ◽  
Surge Margin ◽  
Performance Deterioration ◽  
Variable Inlet Guide Vane

Variable geometry gas turbines are susceptible to various malfunctions and performance deterioration phenomena, such as variable inlet guide vane (VIGV) drift, compressor fouling, and high inlet air temperatures. The present study investigates the combined effect of these performance deterioration phenomena on the health and overall performance of a three-shaft gas turbine engine (GE LM1600). For this purpose, a steady-state simulation model of the turbine was developed using a commercial software named GasTurb 12. In addition, the effect of an inlet air cooling (IAC) technique on the gas turbine performance was examined. The design point results were validated using literature results and data from the manufacturer’s catalog. The gas turbine exhibited significant deterioration in power output and thermal efficiency by 21.09% and 7.92%, respectively, due to the augmented high inlet air temperature and fouling. However, the integration of the inlet air cooling technique helped in improving the power output, thermal efficiency, and surge margin by 29.67%, 7.38%, 32.84%, respectively. Additionally, the specific fuel consumption (SFC) was reduced by 6.88%. The VIGV down-drift schedule has also resulted in improved power output, thermal efficiency, and the surge margin by 14.53%, 5.55%, and 32.08%, respectively, while the SFC decreased by 5.23%. The current model can assist in troubleshooting the root cause of performance degradation and surging in an engine faced with VIGV drift and fouling simultaneously. Moreover, the combined study also indicated the optimum schedule during VIGV drift and fouling for performance improvement via the IAC technique.

scholarly journals Gas turbine efficiency and ramp rate improvement through compressed air injection

2020 ◽  
pp. 095765092093208 ◽  
Author(s):  
Kamal Abudu ◽  
Uyioghosa Igie ◽  
Orlando Minervino ◽  
Richard Hamilton
Keyword(s):  
Gas Turbine ◽  
Guide Vane ◽  
Injection Rate ◽  
Inlet Guide Vane ◽  
Heavy Duty ◽  
Part Load ◽  
Surge Margin ◽  
Rate Improvement ◽  
Heavy Duty Gas Turbine ◽  
Variable Inlet Guide Vane

With the transition to more use of renewable forms of energy in Europe, grid instability that is linked to the intermittency in power generation is a concern, and thus, the fast response of on-demand power systems like gas turbines has become more important. This study focuses on the injection of compressed air to facilitate the improvement in the ramp-up rate of a heavy-duty gas turbine. The steady-state analysis of compressed airflow injection at part-load and full load indicates power augmentation of up to 25%, without infringing on the surge margin. The surge margin is also seen to be more limiting at part-load with maximum closing of the variable inlet guide vane than at high load with a maximum opening. Nevertheless, the percentage increase in the thermal efficiency of the former is slightly greater for the same amount of airflow injection. Part-load operations above 75% of power show higher thermal efficiencies with airflow injection when compared with other load variation approaches. The quasi-dynamic simulations performed using constant mass flow method show that the heavy-duty gas turbine ramp-up rate can be improved by 10% on average, for every 2% of compressor outlet airflow injected during ramp-up irrespective of the starting load. It also shows that the limitation of the ramp-up rate improvement is dominated by the rear stages and at lower variable inlet guide vane openings. The turbine entry temperature is found to be another restrictive factor at a high injection rate of up to 10%. However, the 2% injection rate is shown to be the safest, also offering considerable performance enhancements. It was also found that the ramp-up rate with air injection from the minimum environmental load to full load amounted to lower total fuel consumption than the design case.

Triaxial Gas Turbine Performance Analysis for Variable Power Turbine Inlet Guide Vane Control Law Optimization

2018 ◽  
Author(s):  
Tao Wang ◽  
Yong-sheng Tian ◽  
Zhao Yin ◽  
Qing Gao ◽  
Chun-qing Tan
Keyword(s):  
Gas Turbine ◽  
Working Conditions ◽  
Guide Vane ◽  
Inlet Guide Vane ◽  
Control Law ◽  
Inlet Guide Vanes ◽  
Turbine Performance ◽  
Turbine Inlet ◽  
Power Turbine ◽  
Vane Angle

This paper proposes an inlet guide vane control law optimization technique for improving the off-design working condition thermal efficiency of triaxial gas turbine. Gas turbine dynamic and steady component-level simulation models are established in MATLAB/SIMULINK via Newton-Raphson algorithm based on component characteristic maps. After validating the models against experimental data and Gasturb software, they are applied to determine the effects of guide vane angle on gas turbine performance parameters. High Efficiency Mode (HEM) is utilized to adjust the power turbine inlet guide vanes to enhance the gas turbine efficiency and decrease the specific fuel consumption under off-design working conditions on account of the above gas turbine overall performance analysis results. The optimal angles of power turbine inlet guide vanes for various working conditions are acquired based on the steady gas turbine model as-established. HEM enhances the gas turbine’s thermal efficiency without exceeding its temperature or rotational speed constraints. The Radial Basis Function (RBF), a three-layer, feedforward neural network, is employed to fit the optimal guide vane angles and establish the corresponding relationship between the angles and various working conditions by system identification. The control strategy and gas turbine dynamic simulation model are tested in MATLAB/SIMULINK to verify their effects on gas turbine performance. The guide vane angle is found to significantly influence the gas turbine operating parameters, and HEM to effectively optimize gas turbine performance even within unpredictable atmospheric environment and working conditions.

Effects of Intake Air Cooling Performance Improvement on a Two-Shaft Laboratory-Scale Gas Turbine Unit

2007 ◽  
Author(s):  
Hussain Al-Madani ◽  
Teoman Ayhan ◽  
Omar Al-Abbasi
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Thermal Efficiency ◽  
Performance Test ◽  
Second Law ◽  
Inlet Temperature ◽  
Air Cooling ◽  
Ambient Conditions ◽  
Proposed Model ◽  
Compressor Inlet

The present study deals with the thermodynamically modelled two-shaft gas turbine system consisting of a cooling unit at the compressor inlet. The system is used to investigate the generated power, thermal efficiency and second law efficiency. The parametric study using this model shows effect of ambient conditions, compressor inlet temperature, and pressure ratios on power output, thermal efficiency and second law efficiency. Theoretical results using the proposed model show that when the compressor inlet temperature is decreased by some kind of cooling systems, the net power output and thermal efficiency increases up to 30% and 23%, respectively. Also, the second law efficiency of the proposed system increases in compression to the specified reference state. It shows that the proposed model is thermodynamically viable. A comparison of the performance test results of the model and the experimental results are in good agreement. The results provide valuable information regarding the gas turbine system and will be useful for designers.

Gas Turbine Operation Offshore: On-Line Compressor Wash at Peak Load

2003 ◽  
Author(s):  
Elisabet Syverud ◽  
Lars E. Bakken ◽  
Kyrre Langnes ◽  
Frode Bjo̸rna˚s
Keyword(s):  
Gas Turbine ◽  
Field Test ◽  
Power Output ◽  
Peak Load ◽  
Economic Factors ◽  
Absolute Accuracy ◽  
Key Factors ◽  
Turbine Performance ◽  
Performance Deterioration ◽  
On Line

On-line compressor wash is discussed for a RB211 compressor driver running at peak load at the Statoil Heidrun offshore platform. The oil field’s economy is directly linked to oil production; however, the production rate is limited by driver and gas compressor capacity. From this perspective, the power output and gas turbine uptime become decisive economic factors. The economic potentials related to successful on-line washing are given. This work is based on a series of trials with on-line compressor washing over a two-year period. Results include effect of different on-line washing procedures and washing fluids. The field test campaign has shown no significant improvements with on-line compressor washing at peak load. Understanding the gas turbine performance deterioration is of vital importance. Trending of its deviation from the engine baseline (datum maps) facilitates load-independent monitoring of the gas turbine’s condition. Peak load turbine response to compressor deterioration is analyzed. Instrument resolution and repeatability are key factors that sometimes are more important than absolute accuracy in condition trending. As a result of these analyses, a set of monitoring parameters is suggested for effective diagnostics of compressor degradation in peak load operation. Avenues for further research and development are suggested as our understanding of the deterioration mechanisms at peak load remains incomplete.

Influence of Variable Geometry Transients on the Gas Turbine Performance

2011 ◽  
Author(s):  
Joa˜o Roberto Barbosa ◽  
Franco Jefferds dos Santos Silva ◽  
Jesuino Takachi Tomita ◽  
Cleverson Bringhenti
Keyword(s):  
Gas Turbine ◽  
Guide Vane ◽  
Pressure Ratio ◽  
Research Work ◽  
Combined Cycle ◽  
Inlet Guide Vane ◽  
Variable Geometry ◽  
Gas Generator ◽  
Turbine Performance ◽  
Blade Geometry

During the design of a gas turbine it is required the analysis of all possible operating points in the gas turbine operational envelope, for the sake of verification of whether or not the established performance might be achieved. In order to achieve the design requirements and to improve the engine off-design operation, a number of specific analyses must be carried out. This paper deals with the characterization of a small gas turbine under development with assistance from ITA (Technological Institute of Aeronautics), concerning the compressor variable geometry and its transient operation during accelerations and decelerations. The gas turbine is being prepared for the transient tests with the gas generator, whose results will be used for the final specification of the turboshaft power section. The gas turbine design has been carried out using indigenous software, developed specially to fulfill the requirements of the design of engines, as well as the support for validation of research work. The engine under construction is a small gas turbine in the range of 5 kN thrust / 1.2 MW shaft power, aiming at distributed power generation using combined cycle. The work reported in this paper deals with the variable inlet guide vane (VIGV) transients and the engine transients. A five stage 5:1 pressure ratio axial-flow compressor, delivering 8.1 kg/s air mass flow at design-point, is the basis for the study. The compressor was designed using computer programs developed at ITA for the preliminary design (meanline), for the axisymmetric analysis to calculate the full blade geometry (streamline curvature) and for the final compressor geometry definition (3-D RANS and turbulence models). The programs have been used interatively. After the final channel and blade geometry definition, the compressor map was generated and fed to the gas turbine performance simulation program. The transient study was carried out for a number of blade settings, using different VIGV geometry scheduling, giving indication that simulations needed to study the control strategy can be easily achieved. The results could not be validated yet, but are in agreement with the expected engine response when such configuration is used.

Thermodynamic Analysis of Gas Turbine Performance With Different Inlet Air Cooling Techniques

2012 ◽  
Author(s):  
Ana Paula Pereira dos Santos ◽  
Claudia Regina de Andrade
Keyword(s):  
Relative Humidity ◽  
Gas Turbine ◽  
Mass Flow Rate ◽  
Air Temperature ◽  
Flow Rate ◽  
Power Output ◽  
Inlet Temperature ◽  
Air Cooling ◽  
Turbine Performance ◽  
Unit Energy

For geographic regions where significant power demand and highest electricity prices occur during the warm months, a gas turbine inlet air cooling technique is a useful option for increasing output. Inlet air cooling increases the power output by taking advantage of the gas turbine’s feature of higher mass flow rate, due the compressor inlet temperature decays. Industrial gas turbines that operate at constant speed are constant-volume-flow combustion machines. As the specific volume of air is directly proportional to the temperature, the increases of the air density results in a higher air mass flow rate once the volumetric rate is constant. Consequently, the gas turbine power output enhances. Different methods are available for reducing compressor intake air temperature. There are two basic systems currently available for inlet cooling. The first and most cost-effective system is evaporative cooling. Evaporative coolers make use of the evaporation of water to reduce the gas turbine inlet air temperature. The second system employs two ways to cool the inlet air: mechanical compression and absorption. In this method, the cooling medium flows through a heat exchanger located in the inlet duct to remove heat from the inlet air. In the present study, a thermodynamic analysis of gas turbine performance is carried out to calculate heat rate, power output and thermal efficiency at different inlet air temperature and relative humidity conditions. The results obtained with this model are compared with the values of the condition without cooling herein named of Base-Case. Then, the three cooling techniques are computationally implemented and solved for different inlet conditions (inlet temperature and relative humidity). In addition, the gas turbine was performed under different cooling methods applied for two Brazilian sites, the comparison between chiller systems (mechanical and absorption) showed that the absorption chiller provides the highest increment in annual energy generation with lower unit energy costs. On the other hand, evaporative cooler offers the lowest unit energy cost but associated with a limited cooling potential.

Gas Turbine Transients With Controlled Variable Geometry

2012 ◽  
Author(s):  
João Roberto Barbosa ◽  
Cleverson Bringhenti ◽  
Jesuíno Takachi Tomita
Keyword(s):  
Gas Turbine ◽  
Transfer Functions ◽  
Guide Vane ◽  
Pressure Ratio ◽  
Inlet Guide Vane ◽  
Time Interval ◽  
Variable Geometry ◽  
Validation Data ◽  
Jet Engine ◽  
Surge Margin

A small 5-kN thrust gas turbine, designed and manufactured having in mind a thorough source of validation data, serves as basis for the study. The engine is an uncooled turbine, 5:1 pressure ratio axial flow compressor, delivering 8.1 kg/s air mass flow, whose control is made by a FADEC. Cold runs of the jet engine version have already been completed. The engine characteristics are being developed using the technology indicated in the paper. Accelerations and decelerations from idle to full power in a prescribed time interval and positive surge margin are the limitations imposed to the control system. In order to accomplish such requirements, a proportional, integral and derivative (PID) has been implemented to control the variable geometry transients, which proved to drive the engine to the required operating points. Compressor surge is avoided during accelerations or decelerations, imposing operation limits to the surge margin. In order to simulate a jet engine under transient operation, use was made of high-fidelity in-house developed software. The results presented in the paper are related to the compressor inlet guide vane (VIGV) transients. The engine transient calculations were predicted with the IGV settings varying with time, and the results are being used for the initial calibration of the transfer functions for the real time control.

scholarly journals Effect of the Reynolds Number and Clearance Flow on the Aerodynamic Characteristics of a New Variable Inlet Guide Vane

Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 172
Author(s):  
Hengtao Shi
Keyword(s):  
Reynolds Number ◽  
Guide Vane ◽  
Three Dimensional ◽  
High Growth ◽  
Aerodynamic Characteristics ◽  
Inlet Guide Vane ◽  
Separation Region ◽  
Clearance Flow ◽  
New Type ◽  
Variable Inlet Guide Vane

Recently, a new type of low-loss variable inlet guide vane (VIGV) was proposed for improving a compressor’s performance under off-design conditions. To provide more information for applications, this work investigated the effect of the Reynolds number and clearance flow on the aerodynamic characteristics of this new type of VIGV. The performance and flow field of two representative airfoils with different chord Reynolds numbers were studied with the widely used commercial software ANSYS CFX after validation was completed. Calculations indicate that, with the decrease in the Reynolds number Rec, the airfoil loss coefficient ω and deviation δ first increase slightly and then entered a high growth rate in a low range of Rec. Afterwards, a detailed boundary-layer analysis was conducted to reveal the flow mechanism for the airfoil performance degradation with a low Reynolds number. For the design point, it is the appearance and extension of the separation region on the rear portion; for the maximum incidence point, it is the increase in the length and height of the separation region on the former portion. The three-dimensional VIGV research confirms the Reynolds number effect on airfoils. Furthermore, the clearance leakage flow forms a strong stream-wise vortex by injection into the mainflow, resulting in a high total-pressure loss and under-turning in the endwall region, which shows the potential benefits of seal treatment.

Accommodation of Multi-Shaft Gas Turbine Switching Control Gain Tuning Problem to IGV Position

2021 ◽  
Author(s):  
Yujia Ma ◽  
Liu Jinfu ◽  
Linhai Zhu ◽  
Qi Li ◽  
Huanpeng Liu ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Guide Vane ◽  
Optimization Procedure ◽  
Switching Control ◽  
Inlet Guide Vane ◽  
Multi Objective ◽  
Control Gain ◽  
Controller Gain ◽  
Compressor Inlet ◽  
Comprehensive Indicator

Abstract This article aims to discuss the influence of compressor Inlet Guide Vane (IGV) position on gas turbine switching control system gain tuning problem. The distinction between IGV and normally reckoned working conditions is differentiated, and an improved double-layer LPV model is proposed to estimate the protected parameters under various IGV positions. Controller gain tuning is conducted with single and multi-objective intellectual optimization algorithms. Simulation results reveal that normally used multi-objective optimization procedure is unnecessary and time-consuming. While with the comprehensive indicator introduced in this paper, the calculation burden can be greatly eased. This improvement is especially advantageous when tuning work is carried out under multiple IGV positions.

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