Inlet Guide Vane Angle Research Articles

Model-based performance study of an industrial single spool gas turbine 9EA-GT by changing the inlet guide vane angle and modifying the compressor map

Model-based performance study of an industrial single spool gas turbine 9EA-GT by changing the inlet guide vane angle and modifying the compressor map

Investigation of inlet flow influenced on the first rotor flow instability at blade non-synchronous vibration state

Multistage axial compressor first stage rotor blades have occurred non-synchronous vibration (NSV). An experiment, including fluid and structure measurements, is adopted at the NSV occurred conditions to conduct a detailed investigation about NSV and rotating instability. The blade vibration stress was obtained from the strain gauges. High-frequency response two-hole pressure probes captured the flow characteristics at the inlet and outlet of the first stage rotor. NSV has a complex aerodynamic disturbance source. Wavelet and frequency spectrum analyses of pressure and blade stress results were utilized to determine the relationship between the blade vibration and the flow field. The inlet flow angle has been adjusted through the inlet guide vane (IGV) to reduce the vibration intensity. This paper revealed the aerodynamic origin behind this adjustment of IGV angle operation. The yaw angle and the axial direction March number at the first stage rotor inlet at different inlet guide vane (IGV) angles revealed the aerodynamic effect. Three operation points, including the maximum stress point and near surge point, are analyzed to broaden the cognition boundary of the NSV. The time and space characteristics of the rotating instabilities have been studied with the azimuthal mode analysis method. This research confirmed that the enlarged inlet incidence angle and the tip flow worsened caused the first stage rotor non-synchronous vibration in this multistage axial compressor. These experiments help find a straight relationship between the NSV and rotating instability.

Numerical study on the hydrodynamic performance and internal flow of an axial-flow pump with various inlet flow angles

In this study, numerical simulation was employed to predict the performance and internal flow characteristics of the inlet of an axial-flow pump by assigning an absolute flow angle to the inlet guide vane (IGV) trailing-edge flow. Further, the finite volume method based on the three-dimensional Reynolds-averaged Navier–Stokes equations was employed to discretize the governing equations. The shear stress transport model was used as the turbulence model, and an appropriate number of nodes were selected for the hexahedral grid system through a grid-dependency test. The performance curve and changes in the internal flow field were investigated based on the variation in the flow angle at the inlet of the axial-flow pump. These results can be used to establish an efficient operational plan by adjusting the IGV angle of IGV when installing a variable IGV for an axial-flow pump.

Development of flow and efficiency characteristics of an axial compressor with an analytical method including cooling air extraction and variable inlet guide vane angle

Development of flow and efficiency characteristics of an axial compressor with an analytical method including cooling air extraction and variable inlet guide vane angle

Design and off-design system simulation of concentrated solar super-critical CO2 cycle integrating a radial turbine meanline model

The proper design of a Concentrated solar power (CSP) plant and the associated thermal energy storage requires a careful analysis of the yearly expected irradiance and environmental conditions. System simulations based on accurate components models allow the prediction of the performance of the plant and the analysis of the components interactions. The simulations of various scenarios provide information that will help tuning the design of the components to improve the performance of the whole system at design and off-design conditions. In this paper, the focus is set on the radial turbine expander which is one of the most important component. Classical system simulation approaches use map based performance model for the turbine. This require to generate the performance map either with meanline models, CFD simulations or experiments. This is not very convenient when iterating on the system design and if the actual turbine does not exist yet. In this work, a meanline model for radial inflow turbine operating with real gas has been implemented in MODELICA language for the first time to the authors’ best knowledge. This turbine model has been coupled with the available CSP sCO2 Brayton cycle model in MODELON ThermalPower library. A parametric study on a virtual test bench show the turbine performances for various rotational speed and inlet guide vane angle. The study focus then on the performance prediction of on and off design of the system with a 8 MW turbine obtained with a simple preliminary design calculation. The investigations showed that for the varying load conditions in the solar plant system, an improved operating point has been identified by adjusting the rotational speed and the inlet guide vane angle. Future work will focus on the use such system model with multi objective meta heuristic optimization.

Optimal detailed design and performance assessment of natural gas pressure reduction stations system equipped with variable inlet guide vane radial turbo-expander for energy recovery

The turbo-expander system is utilized instead of the pressure regulator to avoid exergy destruction occurring in gas pressure reduction systems. However, due to the variation of natural gas input conditions such as mass flow rate, the sustainable performance of this technology is challenging. In this study, at first, the optimal system design of gas pressure reducing station equipped with radial expansion turbine is performed. It is based on economic and exergy analyses as well as considering geometric, fluid, thermodynamic constraints of components and the systematic constraints. To do so, detailed design models of main components including mean-line design model of radial turbine, mathematical model of heat exchanger and design model of fired heater are developed. Then, the annual proficiency of the optimal system in dynamic conditions was evaluated according to the strategies considered for having stable production. One of the solutions is to improve the turbine efficiency by adjusting the angle of nozzle blades regarding the changes in mass flow rate. Therefore, our developed mean-line off design model of the turbine is applied to adjust inlet guide vane angle in the off-design situation to improve continuous electricity generation. The results of the design section show that the exergy efficiency on this occasion can achieve up to a maximum of 40%. Compared with fix inlet guide vane (IGV), applying variable IGV improves efficiency of turbine up to 60% at off-design condition. The Levelized cost of electricity (LCOE) and payback period of selected optimal design are about 0.0236 $/kWh, and 4 years, respectively. It indicates that this technology could be the economic option compared to other power generation systems.

Combustion Tuning for a Gas Turbine Power Plant Using Data-Driven and Machine Learning Approach

Abstract Conventional physics-based or experimental-based approaches for gas turbine combustion tuning are time consuming and cost intensive. Recent advances in data analytics provide an alternative method. In this paper, we present a cross-disciplinary study on the combustion tuning of an F-class gas turbine that combines machine learning with physics understanding. An artificial-neural-network-based (ANN) model is developed to predict the combustion performance (outputs), including NOx emissions, combustion dynamics, combustor vibrational acceleration, and turbine exhaust temperature. The inputs of the ANN model are identified by analyzing the key operating variables that impact the combustion performance, such as the pilot and the premixed fuel flow, and the inlet guide vane angle. The ANN model is trained by field data from an F-class gas turbine power plant. The trained model is able to describe the combustion performance at an acceptable accuracy in a wide range of operating conditions. In combination with the genetic algorithm, the model is applied to optimize the combustion performance of the gas turbine. Results demonstrate that the data-driven method offers a promising alternative for combustion tuning at a low cost and fast turn-around.

Computational study on the performance improvement of axial-flow pump by inlet guide vanes at part loads

In order to investigate the influence of adjustable inlet guide vanes on the hydraulic performance of axial-flow pump and impeller, the axial-flow pump with different inlet guide vane adjustable angles was simulated based on the RNG k-e turbulent model and Reynolds time-averaged equations. The multivariate non-linear regression prediction model was established about the effect of adjustable inlet guide vane on the hydraulic performance of axial-flow pump based on the numerical simulation. The performance curves of axial-flow pump with different inlet guide vane adjustable angles were obtained by calculation, showing that the performance curve shifts towards larger flow volume in case the guide vanes are turned from positive to negative angle. With the increase of inlet guide vane positive angle, the optimum operating of pump is closer to smaller operating condition, but the hydraulic efficiency of pump is lower. The larger the flow is, the larger the decreasing amplitude of pump efficiency is. With the decreases of inlet guide vane negative angle, the higher hydraulic efficiency of pump increases first then decreases. The inlet guide vane angle affects the axial velocity distribution of the blade trailing edge.

Off-design performance improvement of twin-shaft gas turbine by variable geometry turbine and compressor besides fuel control

A novel procedure for finding the optimum values of design parameters of industrial twin-shaft gas turbines at various ambient temperatures is presented here. This paper focuses on being off design due to various ambient temperatures. The gas turbine modeling is performed by applying compressor and turbine characteristic maps and using thermodynamic matching method. The gas turbine power output is selected as an objective function in optimization procedure with genetic algorithm. Design parameters are compressor inlet guide vane angle, turbine exit temperature, and power turbine inlet nozzle guide vane angle. The novel constrains in optimization are compressor surge margin and turbine blade life cycle. A trained neural network is used for life cycle estimation of high pressure (gas generator) turbine blades. Results for optimum values for nozzle guide vane/inlet guide vane (23°/27°–27°/6°) in ambient temperature range of 25–45 ℃ provided higher net power output (3–4.3%) and more secured compressor surge margin in comparison with that for gas turbines control by turbine exit temperature. Gas turbines thermal efficiency also increased from 0.09 to 0.34% (while the gas generator turbine first rotor blade creep life cycle was kept almost constant about 40,000 h). Meanwhile, the averaged values for turbine exit temperature/turbine inlet temperature changed from 831.2/1475 to 823/1471°K, respectively, which shows about 1% decrease in turbine exit temperature and 0.3% decrease in turbine inlet temperature.

A 1D mean line model for centrifugal compressors with variable inlet guide vanes

This paper considers a 1D in‐line analytical model for centrifugal compressors with variable inlet guide vanes. A theoretical 1D model is developed to predict the effect of varying the inlet guide vane angle at different rotational speeds. An iterative algorithm is presented, which provides a fast and efficient method for evaluating the performance of the compressor under different operating conditions. The results from the analytical 1D model are presented and compared to full 3D CFD (computational fluid dynamics) simulations. The simulations validate the assumptions used in the 1D model and show good agreement between the two approaches over a range of vane angles. Qualitatively, both demonstrate the same trends as the vane angle and rotational velocities are varied. Quantitatively, the pressure ratio was found to agree within 8% and the temperature gain to within 15%. The 1D model was then modified to introduce a 5% loss in the diffuser and this was found to improve the 1D model predictions, with the pressure within 2% of the CFD value.

Performance improvement of an axial-flow pump with inlet guide vanes in the turbine mode

The axial pump operating in the pump-as-turbine mode is a practical and cost-saving alternative suitable for low-head pico hydropower in rural and remote areas that bypasses the need for expensive turbines. Their pump characteristics, however, indicate that efficiency is low in off-design flow rates. Using the computational fluid dynamics, the adjustable inlet guide vanes with five angles (±20°, 0°, ±10°) in front of the impeller of the axial pump have been redesigned and installed specifically to increase the operating range of high efficiency in the pump-as-turbine mode. To validate the simulation method, a prototype of the axial pump was built to measure in the pump mode the pump characteristics including head and efficiency. The results obtained show that the computational fluid dynamics calculated results are in qualitative agreement with the experimental data. In the pump-as-turbine mode, the adjustable inlet guide vanes were found to affect the performance of the axial pump. The most important aspect is that the adjustable inlet guide vanes widen the efficiency range if the inlet guide vane angle is adjusted for different flow rates. For the same situation with negative angles, the efficiency values at the BEP are higher than those with positive angles, where the efficiency around the angle − 10° is the highest. The main reason is that the direction of flow at the impeller-zone exit is guided by the adjustable inlet guide vanes to reduce the energy loss, which can be supported in the view of vector field and energy losses of different parts of pump.

Using inlet guide vane to improve load following ability of solid oxide fuel cell and gas turbine hybrid cycle

High efficiency and high reliability with low emission of solid oxide fuel cell make them one of the best choices for distributed generation systems. Furthermore, the gas turbine power generation systems are completely developed in recent decades. Hybrid cycle of SOFC and gas turbine gathers these points and introduces the highest possible efficient system for building heating and power. The behavior of this cycle can be studied from a model of fuel cell, gas turbine and balance of plant. For each component a model is developed and the performance of the overall system analyzed by integrating each model. Load variation for SOFC-GT hybrid cycle in residential application is very wide. To adjust the net power and choosing best operation point for SOFC-GT hybrid cycle, an inlet guide vane (IGV) is used in the inlet of the compressor. In this study by using a dynamic model, transient effect of IGV angle on performance of SOFC-GT hybrid cycle is investigated. Also this model can be used for designing a controller for safe operation of this cycle while satisfying constraints of the hybrid cycle. Results showed that by using IGV, the off-design performance of the SOFC-GT cycle is enhanced.

Experimental Evaluation on Performance of Novel Cross-flow Impulse Turbine for Water Stream in Hilly Areas of Pakistan

Hydropower plants play a key role in power sector. Pakistan is facing an acute energy crisis due to dependence on fossil fuels having economical as well as environmental consequences. Now-a-days, small hydropower is important in Pakistan due to its simplicity, efficiency and availability of hydro potential in this region. The present work includes designing of cross flow turbine and evaluating its performance parameters like tip speed ratio λ, power coefficient C p and constraints affected by inlet guide vane angle. The prototype is tested for different guide vane angle; that is 20.5°,25.5°,30.5°,35.5°,40.5° to find maximum efficiency of cross-flow turbine. Power coefficients C p for cross-flow turbine are calculated for different inlet guide vane angle and tip-speed ratios (TSR . This cross flow turbine has been designed for low head of 6 meter which would have theoretically generated the electricity of 10 kW. The experimental setup is tested at the hilly waterfalls region and its experimental and theoretical results are compared. The cross-flow turbine is capable of producing 8.9 kW electric power at the head of 6 m, flow rate of 0.21m 3 /s and channel flow speed is 10.84 m/s. The optimum efficiency of 89% is achieved when C p is 0.78 and TSR reaches 4.4 at the middle position when guide vane angle is 30.5 o .

Experimental and numerical analysis of the unsteady influence of the inlet guide vanes on cavitation performance of an axial pump

The effect of the inlet guide vanes on cavitation performance of an axial pump is investigated to assess the mechanism for cavitation in pumps and improve their cavitation performance. The effect of inlet guide vane angles on cavitation performance was assessed experimentally, and computational fluid dynamics was used to analyze the inner flow field of the axial pump and to probe the cavitation mechanism. The simulation results agree qualitatively with the experimental data, showing that cavitation performance is improved with positive inlet guide vane angles but hampered with negative ones. The cavitation performance itself is controlled by the cavitation volume, which first expands circumferentially when the net positive suction head decreases from a certain large value and then develops toward the axis radially after the net positive suction head reaches a certain value. This is when the cavitation performance deteriorates. Comparing cavitation volume for the critical net positive suction head as determined by two different methods, the method based on efficiency drop (NPSHeff.,1%) is found to be more suitable than that based on head drop (NPSHhead.,3%). Furthermore, the distribution of swirl is shown to be closely related to the distribution of cavitation, a feature that may be used to predict cavitation along the impeller.

고마력 터보 블로어의 최적 깃배치각에 관한 수치 예측

The turbo blowers having large power capacity are generally composed of the variable inlet guide vane, the impeller and the variable diffuser. In the present study, the effect of the stagger angles on the aerodynamic performances has been investigated by CFD methods. The design specifications of the reference model having 400kW power were given as 7.43kg/s of mass flow rate, 1.66 of pressure ratio with 12000rpm of impeller rotating speed. As the first simulation parameter, the diffuser vane angle was varied in the range of ±20 degree from the initial-design point. The inlet guide vane angles, as the second one, was changed in the range of ±40 degree from the initial-design point. The commercial Navier-Stokes solver, ANSYS-CFX, was applied to solve the three-dimensional unsteady flow fields inside the turbo blower. Through the numerical results, the desirable setting angles were proposed to fit the best performance to the variation of the operating conditions.

Experimental and numerical analysis of the unsteady influence of an inlet guide vane

The unsteady inlet guide vane (IGV)–impeller–diffuser interaction in a centrifugal compressor is investigated numerically and experimentally under different IGV prewhirl angles. The influence of IGV prewhirl angle on the flowfield and the unsteadiness of the impeller and diffuser are studied, and the mechanism of the unsteady IGV–impeller–diffuser interaction is explored. Results show that quite fair quantitative agreements are achieved between the predicted and measured flowfield. The IGV wake can decrease the unsteadiness on the impeller and diffuser, and the reduction of the unsteadiness caused by the IGV is a function of the IGV prewhirl angle. The unsteadiness in the diffuser with negative IGV angles is larger than that for positive prewhirl angles. The low-frequency oscillations inside the flowfield are induced by the IGV. When IGV prewhirl occurs, the basic frequency of the unsteady flow in the vaneless diffuser is mainly half of the blade passing frequency of the impeller. In practice, the IGV prewhirl angle can be adjusted to avoid unsteady vibrations in some off-design conditions, with reliability and performance improved simultaneously.

입구 안내익 영향으로 인한 원심 압축기 불안정성 연구

An experimental study on the performance and instability development characteristics of a centrifugal compressor equipped with an adjustable inlet guide vane has been performed with varying guide vane angles. The test was conducted at the design speed of 20,800 rpm for 6 guide vane angles : -30°, -20°, -10°, 0°, 10°, 20°, 30°. Unsteady pressures were measured using high-frequency pressure transducers at the inducer to investigate the instability phenomena such as rotating stall and surge inside the compressor. From the unsteady measurements, it is found that the transient process from rotating stall to surge was mainly affected by inlet guide vane angles. The results of the present study can be applied to the instability control of the centrifugal compressors using a adjustable inlet guide vane.

Investigation of the Swirling Flow in a Suction Pipe with Inlet Guide Vanes. Experimental Studies of the Swirling Flow in a Suction Pipe of a Centrifugal Compressor.

The swirling flow in a suction pipe with inlet guide vanes was experimentally studied. It was observed that the periodical pressure and velocity oscillations occurred when the guide vane angle was set at middle opening in a pipe in which a disk inserted downstream from the inlet guide vanes. The wall pressure and velocity distribution were measured in various conditions where the inlet guide vane angle and the disk position were changed. It was found that the velocity and wall pressure oscillations were strongly related to each other and that they proceed from upstream to downstream in a pipe with swirling. This phenomenon was considered to be induced by spiral vortices. An operating test showed that the similar phenomenon occurred in a centrifugal compressor suction pipe and a countermeasures to suppress the rotor whirling vibration was valid in which the inlet guide vanes were set adjacent to a compressor impeller.

An Experimentally Verified NOx Prediction Algorithm Incorporating the Effects of Steam Injection

A Perfectly Stirred Reactor model, kinetic rate data, and equilibrium adiabatic flame temperatures have been incorporated into a closed form NOx prediction algorithm. The algorithm accounts for combustor inlet parameters and steam injection. Combining this model with the operating map for the gas turbine allows prediction of NOx with variation in parameters such as inlet guide vane angle, ambient temperature, and load. If the actual values of the model input variables are measured, real time prediction of NOx emissions may be generated using a microcomputer. This signal may then be used as an input to NOx abatement systems such as Selective Catalytic Reduction. The semitheoretical technique is based upon the extended Zeldovich chain reaction kinetics for the production of NOx in the post-flame zone. The temperature and concentration of major product species in the post-flame zone are taken to be those appropriate to equilibrium. Steam injection and inlet effects enter the model through their influence on the abiabatic equilibrium flame temperature. Mixing effects are accounted for empirically.