Turbine Model Research Articles

Evaluating the Impact of CO2 Capture on the Operation of Combined Cycles with Different Configurations

In order to reduce greenhouse gas emissions associated with power generation, the replacement of fossil fuels with renewables must be accompanied by the availability of dispatchable sources needed to balance electricity demand and production. Combined cycle (CC) power plants adopting post-combustion capture (PCC) can serve this purpose, ensuring near-zero CO2 emissions at the stack, as well as high efficiency and load flexibility. In particular, the chemical absorption process is the most established approach for industrial-scale applications, although widespread implementation is lacking. In this study, different natural gas combined cycle (NGCC) configurations were modeled to estimate the burden of retrofitting the capture process to existing power plants on thermodynamic performance. Simulations under steady-state conditions covered the widest possible load range, depending on the gas turbine (GT) model. Attention was paid to the net power loss and net efficiency penalty attributable to PCC. The former can be mitigated by lowering the GT air–fuel ratio to increase the CO2 concentration (XCO2) in the exhaust, thus decreasing the regeneration energy. The latter is reduced when the topping cycle is more efficient than the bottoming cycle for a given GT load. This is likely to be the case in the less-complex heat recovery units.

A CFD Study on High‐Thrust Corrections for Blade Element Momentum Models

ABSTRACTThis paper presents a reanalysis of four axial‐flow rotor simulation datasets to study the relationship between thrust and axial induction factor. We concentrate on high‐thrust conditions and study variations in induction factor and loads across the span of the different rotor blades. The datasets consist of three different axial‐flow rotors operating at different tip‐speed ratios and, for one dataset, also at different blockage ratios. The reanalysis shows differences between the blade‐resolved CFD results and a widespread empirical turbulent wake model (TWM) used within blade element momentum (BEM) turbine models. These differences result in BEM models underestimating thrust and especially power for axial‐flow rotors operating in high‐thrust regimes. The accuracy of BEM model predictions are improved substantially by correcting this empirical TWM, producing better agreement with blade‐resolved CFD simulations for thrust and torque across most of the span of the blades of the three rotors. Additionally, the paper highlights deficiencies in tiploss modelling in common BEM implementations and highlights the impact of blockage on the relationship between thrust and axial induction factors.

Active Energy Management for Enhanced Engine Transient Operations

Combat aircraft often require the engine to accelerate as fast as possible in response to the demand of maneuvering. The engine acceleration rate, however, is limited by the compressor surge constraint, which prevents more fuel addition that, otherwise, could provide for higher net shaft torque, and thus, faster acceleration. This paper examines the idea of using the electric starter/generator (ES/G) system to provide additional net shaft torque during this critical phase of acceleration. The idea is examined by simulations using a quasi-one-dimensional dynamic compressor flow model coupled with a lumped combustor–turbine model. A notional single-spool turbojet with a low overall pressure ratio is modeled and simulated. Simulation results suggest that an ES/G, when used as an electric-assist motor during acceleration, can help the engine to accelerate roughly 11, 48, and 70% faster compared to the case without ES/G participation, by using electric power roughly equivalent to 0.1, 1, and 3% of full-speed fuel combustion power, respectively. Furthermore, the respective increase in the acceleration rate leads to an additional 19, 80, and 113% of propulsion impulse, respectively (i.e., thrust integrated over time), during the first 5 s following the acceleration command.

Research on Key Technology of Wind Turbine Drive Train Fault Diagnosis System Based on Digital Twin

Fault diagnosis of wind turbines has always been a challenging problem due to their complexity and harsh working conditions. Although data-mining-based fault diagnosis methods can accurately and efficiently diagnose potential faults, the visibility is extremely poor. In this paper, digital twin technology is introduced into the fault diagnosis of wind turbine drive train systems, and a wind turbine drive train fault diagnosis method based on digital twin technology is proposed, which monitors and simulates the actual operating condition in real-time by establishing a digital twin model of the wind turbine drive train. In addition, an improved variational modal decomposition combined with particle swarm optimization least squares support vector machine (IVMD-PSO-LSSVM) fault diagnosis method is proposed, which not only improves the accuracy of fault diagnosis but also effectively shortens the diagnosis time and strengthens the response speed of the system. Finally, a digital twin system for condition monitoring and fault diagnosis of wind turbine drive trains is developed based on the Unity 3D platform. Experiments show that the proposed IVMD-PSO-LSSVM can accurately identify fault types with an accuracy rate of 99.1%, which is an improvement of 3.4% compared to before. The proposed digital twin model can be used for real-time monitoring of wind turbine vibration data and provide a more intuitive real-time simulation of the wind turbine’s operating status. This facilitates quick fault location and enables more accurate and efficient maintenance.

Takagi-Sugeno fuzzy sampled-data observer design for nonlinear permanent magnet synchronous generator-based wind turbine systems using auxiliary function-based integral inequality technique

This study focuses on designing the fuzzy sampled-data observer (FSDO) scheme for nonlinear permanent magnet synchronous generator (PMSG)-based wind turbine systems (WTS). The primary objective of this problem is to solve an unmeasurable state problem under the mismatched premise variables conditions among system, observer, and controller, respectively. To do this, firstly, the proposed wind turbine model is described in a Takagi-Sugeno fuzzy model due to the complex nonlinearities in PMSG-based WTS. Next, based on the measured output signals and sampled estimated states, the FSDO is designed to understand some unmeasurable state variables of the studied system. Then, a novel auxiliary function-based integral inequality (AFBII) is presented to approximate the integral quadratic terms related to sampling information. Thanks to the proposed AFBII technique and the introduction of slack variables, several new and less conservative stability requirements are derived in the formulations of linear matrix inequalities (LMIs) using the looped Lyapunov function. Finally, the simulation studies for the considered wind turbine model are validated numerically, and then some comparative results are provided to show the superiority and applicability of the theoretical observations.

Improving cross-axis wind turbine performance: A Lab-scale investigation of rotor size and blades number

Horizontal and vertical-axis wind turbines have long been used to generate electricity in open areas by utilizing horizontal wind flow. Under certain conditions, for example in multi-storey building areas, wind flows not only from horizontal but also vertical directions. Therefore, this research aims to develop a new turbine model known as a cross-axis to capture wind flow from horizontal and vertical directions around multi-storey buildings. Design, production, testing, and performance analysis are carried out in this project. The model is designed with a rotor diameter of 700 mm which has 5 vertical blades and 10 horizontal blades with a total height of 600 mm which is divided into two configurations, upper and lower. Performance analysis was carried out using a wind tunnel in a conditioned laboratory both in loaded and unloaded conditions. The output power of the wind turbine is measured using an electric dynamometer. The no-load test was applied to determine the time required to move from non-rotating to constant rotation at different speeds and horizontal blade angles. Meanwhile, the load test is used to determine the power coefficient at various speeds, horizontal blade pitch angles, and loads. The research results show that the time required to move from a non-rotating speed to a constant speed is influenced by the wind speed and the blade pitch angle. The power coefficient was also observed to be influenced by wind speed, blade pitch angle, and load. Furthermore, the shortest time to reach a constant rotation speed is around 20 seconds at a wind speed of 7.6 m/s and a blade pitch angle of 25°. The maximum power coefficient of the wind turbine was obtained at 5.2% at a wind speed of 7.6 m/s, blade pitch angle of 25°, and tip speed ratio of 0.5.

Characterizing lean blowout dynamics of DME/air premixed swirl flames in a gas turbine model combustor with and without confinement

This work investigates lean blowout (LBO) dynamics of dimethyl ether (DME)/air premixed swirl flames in a gas turbine model combustor with and without confinement. CH* chemiluminescence imaging and 2 kHz high-speed OH* chemiluminescence imaging are performed to capture the swirl flame macrostructures. Particle image velocimetry (PIV) and planar laser-induced fluorescence (PLIF) are used to visualize the flow fields and reaction zones, respectively. Compared to the unconfined flame, the addition of confinement results in the appearance of an outer recirculation zone (ORZ), variation in flame topology, enhanced overall heat release (HR) rate, increased turbulent kinetic energy (TKE), and extended LBO limits. Far from LBO, all flames are stabilized in the shear layer. Approaching LBO, the confinement enhances the flow vortex structures along the shear layers, which is associated with extinction at the flame base and shear layer. However, the unconfined flame is still stabilized in the shear layer due to the weaker flow vortex structures. Different extinction mechanisms during the LBO process are also discussed between the unconfined and confined flames. The unconfined flame suddenly leaves the inner shear layer (ISL) and recedes to the inner recirculation zone (IRZ) within about 100 ms before LBO. Abundant CH2O is transported into IRZ mainly by recirculation, which reduces the HR region area and give rise to LBO. For the confined flame, more and more cold reactants gather near the base plate and then are gradually brought into IRZ by ISL vortices, which makes the flame lift from the base plate and decrease the HR region area until LBO happens.

Research on three-dimensional wake model of horizontal axis wind turbine based on Weibull function

In wind turbine wake models, Gaussian models depend on multidimensional integration to ascertain the distribution of wake velocity deficits. These integrations, which often involve complex boundary conditions, significantly enhance the complexity of mathematical computations. Due to the difficulty of obtaining analytical solutions, numerical integration methods such as Monte Carlo or other numerical integration techniques are commonly employed. This study presents a three-dimensional wake model (3DJW) for horizontal axis wind turbines, utilizing the Weibull function to simplify wake deficit characterization instead of traditional Gaussian distribution methods. The 3DJW model considers wind shear effects and mass conservation laws to enhance predictions of vertical wake velocities. By integrating incoming wind conditions and turbine parameters, the model efficiently computes downstream wake velocities, improving computational efficiency. To enhance predictions in the ultra-far wake region, an improved three-dimensional Weibull wake model is proposed using the exponential fitting method. Validation through wind tunnel experiments and wind farm data demonstrates the model's accuracy in predicting wake deficits at the hub height, with relative errors in horizontal and vertical profiles mostly within 5% and 3%, respectively. The proposed model enables accurate and rapid calculation of wake velocities at any spatial location downstream, facilitating enhanced energy utilization and reduced costs.

Real-time hybrid test method for floating wind turbines: Focusing on the aerodynamic load identification

Since the development of floating wind turbine (FWT) shows a rapid trend towards larger capacity and larger rotor size, the traditional full-model basin test method has encountered limits. Especially the balance between the wind generation system (WGS) size and scale ratio of the model FWT system. Under such circumstances, the hybrid model test method provides the possibility to improve the FWT model test. In the hybrid model test method, the original physical model system is divided into physical subsystem and numerical subsystem, and the data acquisition and process module between the 2 subsystems plays an important role. In this paper, a framework of real-time hybrid test (RTHT) system is setup firstly, which combines physical model wind turbine and motion platform. The damping modification to the corresponding numerical code is applied to improve the motion calculation accuracy. Delay implementation is employed to avoid motion divergence. Then a simulation loop is setup in numerical environment to study the identification of aerodynamic load. The influence of identification accuracy to the RTHT result is analyzed. Lastly, the dual-accelerometer method of aerodynamic load identification is employed in the proposed RTHT system. Decay tests and irregular wave only tests are carried out to validate the aerodynamic load identification method. The capability and potential of the RTHT method of floating wind turbine model test is preliminary proved in the work of this paper.

Analytical Analysis of the Bladeless Rotor Turbine Design for Enhanced Performance

The growing desire for clean and efficient energy solutions has fueled considerable advances in turbine technology. This study proposed a conceptual approach to enhancing the performance of bladeless turbines using an analytical technique, and the analytical solutions bear a resemblance to the experimental setup for a fluid dynamics investigation of a rotor for real-flow effects. The Navier-Stokes equations for fluid flow in cylindrical coordinates were simplified to two-dimensional flow by ignoring axial direction and velocity, and direct integration was used in conjunction with series expansion solutions. The experiment data were used to verify the rotor's fluid dynamics analytical solutions. The model's result was compared to previously calculated solutions of the fluid dynamics of a disc rotor in a bladeless turbine. The disc turbine models were used to predict radial velocity, tangential velocity, pressure gradient, volumetric flow rate, rotor torque, shear stress on the inner and outer disc walls, and rotor efficiency. The model was validated using experimental data with an efficiency of 23.9%, the theoretical solution model was 34%, and the analytical efficiency was 24.3%. The efficiency comparison of the analytical solutions model to the theoretical solutions model revealed a substantial difference, however, the correlation between computed theoretical and analytical results is significant. Previous studies used computed solutions for models, but current analytical solutions outperformed them. The model's output will be valuable to engineers building the disc turbine. It demonstrates a strong link between the analytical and experimental research of the bladeless turbine.

A Nonlinear Hybrid Modeling Method for Pump Turbines by Integrating Delaunay Triangulation Interpolation and an Improved BP Neural Network

In order to solve the problem that the data processing accuracy of the characteristic curves is not high, which affects the accuracy of the simulation of variable-speed pumped storage units, this paper proposes a nonlinear hybrid modeling method for pump turbines by integrating Delaunay triangulation interpolation and an improved back-propagation neural network. Firstly, the improved Sutter transform is used to preprocess the original curve, and the convex hull of the transformed curve is calculated. With the unknown point inside the convex hull, Delaunay triangulation interpolation is used to model the transformed curve. With the unknown point outside the convex hull, the back-propagation neural network is first established based on the input and output, and then the initial weights and thresholds of the network are determined using the mind evolution algorithm to complete the modeling and simulation of the curve. Simulation results show that the proposed method fully integrates the high-precision features of interpolation and the powerful nonlinear fitting ability of the neural network, which greatly improves the efficiency and accuracy of pump turbine modeling.

RMSE POWER COEFFICIENT OF WIND TURBINES WITH INVERSE TOQUE-SPEED CONTROL

The Blade Element Momentum (BEM) method stands out among various turbine modelling techniques due to its integration of airfoil aerodynamics with momentum theory, allowing detailed force calculations on blade elements. While traditional methods like BEM and Wake Models are efficient for initial turbine design, advancements in computational power have enabled the use of Computational Fluid Dynamics (CFD) for more accurate simulations. Although these models are precise, they are computationally intensive, leading to the continued use of simpler empirical methods, such as the static power coefficient approach, in power system studies. Future research aims to validate and implement dynamic estimation models to account for wind variability and turbine control dynamics. Traditional constant torque-speed control strategies maintain a constant generator speed by using a fixed electromagnetic torque command and adjusting the pitch angle when wind speed exceeds the rated value. However, if the pitch control does not respond quickly enough, rotor acceleration can occur, leading to increased power beyond the generator’s rating. To mitigate this, the pitch control mechanism must react promptly to adjust the turbine's torque profile, ensuring convergence to the rated operating point and avoiding prolonged generator overload. To reduce the burden on the pitch-control system, an inverse torque-speed control approach is proposed, where the electromagnetic torque is dynamically adjusted based on real-time rotor speed data. This method aims to achieve rated power operation with improved responsiveness and reduced stress on the pitch-control mechanism.

Experimental modelling of a novel concrete-based 15-MW spar wind turbine

Physical model testing is a crucial step in the validation process of floating offshore wind concepts that can be used to contribute to the worldwide decarbonization objectives. It is also important to understand the coupled performance of all the sub-systems that conform to a floating wind concept: wind turbines, mooring systems or floating platform hydrodynamic responses. Few experimental tests had been conducted, and no real-time hybrid modelling had been performed in these tests. In this paper, an open-source experimental dataset is presented, and the dynamics of a concrete spar-based floating concept withstanding the IEA 15-MW Reference Wind Turbine are investigated. An experiment on a 1:55 scale concrete-based spar (WindCrete) at IHCantabria's ocean basin was developed by means of the hardware-in-the-loop technique under the COREWIND EU-H2020 project. The available data consist of the hydrodynamic characterizations and seakeeping tests with a total of 57 available datasets. The proper behaviour of the WindCrete platform and the designed mooring system is confirmed by the maximum motion values and accelerations below the established acceptance criteria defined. Moreover, this test program identifies the importance of the wind loads over the dynamic performance of the concept.

Numerical simulation study of cavitation characteristics of jet hydrofoil surface

To mitigate the adverse effects of cavitation on the performance degradation and chemical corrosion of hydraulic machines, a jet hydrofoil physical model based on the structure of a guide vane model of a high-pressure mixed-flow hydraulic turbine was established. A density correction turbulence model based on filters was adopted to numerically simulate the cavitation characteristics on the surface of the jet hydrofoil. The results demonstrate that when the jet speed is 12 m/s and the jet angle is −15°, the scheme exhibits the best cavitation suppression effect among all combinations of jet angles and speeds. Cavities near the jet structure are prematurely collapsed after being pressurized, and the cavitation suppression effect in the low-pressure area at the trailing edge is also satisfactory. The time-averaged bubble volume fraction reaches its minimum at 2.17%, with the time-averaged bubble volume fraction being 27.3% of the prototype hydrofoil. At flow speeds of 2.4 m/s and 7.2 m/s, small-angle jet fluid accumulated will stick to the closed cavities on the surface of the hydrofoil and cause them to rupture, while the jet fluid at the jet angle of 60° and speeds of 7.2 m/s and 12 m/s will directly cut off the bubbles.

Development of a mobile wind power plant for power supply to troops

The study examined the feasibility of using wind energy to supply energy to field military shooting ranges of the Armed Forces of the Republic of Kazakhstan. The object of study is a mobile wind turbine with a vertical axis of rotation. Theoretical studies have identified key factors influencing turbine modes and performance, which has led to the selection of optimal placement options. The proposed system took into account the power supply needs of troops in the field, with special attention to the energy-consuming equipment of field military shooting ranges as the main consumers. A comparative analysis has established the superiority of a mobile wind turbine with a vertical axis over traditional wind generators with a horizontal axis. The developed turbine design provides full coverage of the airflow regardless of direction, with an optimal blade angle of 60°. Theoretical studies included studying the airflow around the blade at different angles of attack, which provides insight into drag and lift. The basis for the development was the designed model of a mobile wind turbine, protected by a patent, characterized by mobility, sectionality and the ability to adapt to various environmental conditions. Its simple and compact design, combined with a vertical axis of rotation, ensures an uninterrupted power supply, especially at remote military installations and border areas. This research led to the development of a model for calculating the parameters of a mobile wind turbine suitable for powering troops in the field. The study demonstrates the potential of mobile wind power plants to significantly enhance energy reliability at military shooting ranges. The calculated results confirm the viability of mobile wind turbines in providing power support for shooting activities at these ranges

Commercial Small-Scale Horizontal and Vertical Wind Turbines: A Comprehensive Review of Geometry, Materials, Costs and Performance

The effective exploitation of renewable energy sources is one of the most effective solutions to counter the energy, environmental and economic problems associated with the use of fossil fuels. Small-scale wind turbines (converting wind energy into electric energy with a power output lower than 50 kW) have received tremendous attention over the past few decades thanks to their reduced environmental impact, high efficiency, low maintenance cost, high reliability, wide wind operation range, self-starting capability at low wind speed, limited installation space, reduced dependence on grid-connected power and long transmission lines, low capital costs, as well as the possibility to be installed in some urban settings. However, there are significant challenges and drawbacks associated with this technology from many different perspectives, including the significant discrepancy between theoretical performance data provided by the manufacturers and real field operation, that need to be investigated in greater depth in order to enable a more widespread deployment of small-scale wind turbines. In this review, a complete and updated list of more than 200 commercially available small-scale horizontal and vertical wind turbine models is provided and analysed, detailing the corresponding characteristics in terms of the number and material of blades, start-up wind speed, cut-in wind speed, cut-out wind speed, survival wind speed, maximum power, noise level, rotor diameter, turbine length, tower height, and specific capital cost. In addition, several scientific papers focusing on the experimental assessment of field performance of commercially available small-scale horizontal and vertical wind turbines have been reviewed and the corresponding measured data have been compared with the rated performance derived from the manufacturers’ datasheets in order to underline the discrepancies. This review represents an opportunity for the scientific community to have a clear and up-to-date picture of small-scale horizontal as well as vertical wind turbines on the market today, with a precise summary of their geometric, performance, and economic characteristics, which can enable a more accurate and informed choice of the wind turbine to be used depending on the application. It also describes the differences between theoretical and in-situ performance, emphasizing the need for further experimental research and highlighting the direction in which future studies should be directed for more efficient design and use of building-integrated small-scale wind turbines.

Efficiency Improvement of Darrieus Wind Turbine Using Oscillating Gurney Flap

In this work, a new model of Darrieus wind turbines with an oscillating gurney flap (OGF) is proposed. A detailed 2D computational fluid dynamics (CFD) investigation is carried out using ANSYS-Fluent 22.0 to assess the turbine performance. The OGF can alter its position between the upper and lower blade surfaces during the turbine rotation. Equations related to the combined motion are implemented through a user-defined function (UDF). The proposed model is validated where a good coincidence is achieved. The overset dynamic mesh method is used. It was found that a judicious synchronization of OGF and turbine blades creates beneficial vortex interactions, which correct the pressure distribution and lead to an overall improvement in the lift force. The magnitude of the improvement is highly dependent on the OGF length and the phase motion φ. The average torque coefficient Cm for the controlled case increased by more than 19% in comparison with the nominal case.

Fully Coupled Hydrodynamic–Mooring–Motion Response Model for Semi-Submersible Tidal Stream Turbine Based on Actuation Line Method

Fully Coupled Hydrodynamic–Mooring–Motion Response Model for Semi-Submersible Tidal Stream Turbine Based on Actuation Line Method

Effects of wall confinement on flame topologies and lean blowout characteristics of partially premixed DME/air flames in a gas turbine model combustor

Dimethyl ether (DME) is a promising alternative fuel for gas turbines, considering its renewable nature and potential for large-scale synthesis from CO2 feedstock. However, there are limited studies on the swirl combustion characteristics of DME, particularly regarding the stability performance. This work investigates the effects of wall confinement on flow, mixing, and lean blowout (LBO) characteristics of partially premixed DME/air swirl flames in a gas turbine model combustor. Flow and flame macrostructures are captured using particle image velocimetry and planar laser-induced fluorescence (PLIF) measurements, respectively. The results show remarkable differences in flame topologies between unconfined and confined flames, especially the formation of inner recirculation zone and outer recirculation zone. The LBO limits are measured over various Reynolds numbers and flame dynamics approaching LBO are captured using 10 kHz OH* chemiluminescence imaging. Unconfined flames have unexpectively lower LBO limits (∼0.4) than the LBO limits of confined flames (over 0.5). Approaching LBO, unconfined flames display a quiet blowout mode featuring swirling spiral blow-off behaviors. In contrast, confined flames exhibit a violent blowout mode featuring large-scale quasi-instability behaviors, including periodic events of local extinction, flame lift-off, and re-ignition. Based on the numerical simulations and simultaneous OH- and CH2O-PLIF measurements, the large discrepancy in the measured LBO limits between the two configurations is found to result from different re-ignition processes related to the low-temperature ignition before the final blowout. These findings highlight the crucial roles of wall confinement in determining the stable flame topologies, LBO characteristics, and mechanisms driving the LBO physics for partially premixed DME/air swirl flames.

Wind Potential Assessment for Songkhla, Thailand

The analysis and evaluation of wind energy projects are important to understand their economic and environmental suitability for installation and operation. Using wind data from the Meteorological Department, Used WAsP software for calculating, simulating, and analyzing the Annual Energy Production (AEP) and then applied it to calculate the Levelized Cost of Electricity (LCOE) of wind turbines installed in the Songkhla province area. The selected areas are suitable for all three models of wind turbines in the simulation. From the wind data analysis, wind direct was found that in the east sector (sector 4), there is the highest wind frequency at the wind station. The simulation results from Laem son-on area and Hua khao area show suitable mean wind speeds for wind farm installations. In the wind turbine simulation, three models were compared: Bonus 300 kW MkIII, Bonus 1.3 MW, and PowerWind 56 900 kW. At the Songkhla cape area, the positions with the highest AEP were 132.485 MWh, 344.419 MWh, and 332.597 MWh, respectively. Hua Khao area, the positions with the highest AEP were 225.284 MWh, 586.303 MWh, and 540.045 MWh, respectively. In the LCOE calculations for all model of wind turbines, at both Laem Son- On and Hua Khao locations, the most cost-effective wind turbine is the Bonus 300 kW. It has an LCOE of $142.43/MWh and $83.76/MWh, respectively. Therefore, the most cost-effective location is Hua Khao.