Performance Analysis Of Turbine Research Articles

Probabilistic analysis of lateral behaviour of offshore wind turbine monopile considering uncertainties of geological model and loads

Due to the complex geological, meteorological and hydrological conditions, along with the limited availability of field measurements, multiple uncertainties are related to the performance analysis of the offshore wind turbine. The main sources of uncertainty are the geological model and the environmental loads. However, the geological model uncertainty and loads uncertainty were often characterized separately in previous studies. To this end, this article proposes a novel framework for the coupled characterization of the geological model and loads uncertainties. With this new framework, the geological model is generated using a conditional random field method, in which the stratigraphic and geo-properties uncertainties are characterized simultaneously. Next, environmental parameters are considered as random variables, and the cross correlation between different environmental parameters is captured with the Pearson correlation coefficient. Then, multiple realizations of the geological model and these of environmental parameters are sampled with Monte Carlo simulation. With these generated realizations as inputs, the monopile foundation performance could then be analyzed probabilistically considering uncertainties of the geological model and loads. To demonstrate the effectiveness of the new framework, a case study of an offshore site in Taiwan is conducted. Further, a comparative study is performed to quantitatively reveal the influence of different uncertainty sources on site characterization and monopile behaviour assessment, through which the superiority of the presented framework is demonstrated.

Conceptual Design and Analysis of Small-Scale Wind Turbine for Household Usage in Malaysia

Wind energy is a valuable renewable resource that holds great potential for generating electrical power through wind turbines. However, there is a lack of practical and cost-effective small-scale wind turbines designed specifically for household usage. This study aims to address this need by focusing on the design and performance analysis of a small-scale vertical Darrieus wind turbine tailored for household applications in Malaysia. The objective is to propose an optimized turbine design that maximizes energy conversion efficiency. Computational fluid dynamics (CFD) simulations using ANSYS Fluent software are conducted to evaluate the turbine's performance, with the power coefficient (Cp) calculated at various tip speed ratios (TSR). Two 3D designs with different blade configurations are developed using SolidWorks for the CFD simulations. The findings from this study contribute to the design optimization and performance evaluation of vertical Darrieus wind turbines, providing a sustainable and viable alternative for residential energy needs. This research addresses the pressing demand for clean and affordable energy solutions in Malaysia and supports the transition towards renewable sources.

Performance analysis of a novel small-scale radial turbine with adjustable nozzle for ocean thermal energy conversion

Ocean thermal energy is acknowledged as one of the most promising ocean renewable energy sources in low latitude sea areas. In the ocean thermal energy conversion system, the turbine plays a significant role, and it is responsible for converting the working medium enthalpy into the shaft output power. The present study is focused on the performance analysis of a novel radial inflow turbine with an adjustable nozzle in the OTEC system in order to adapt to the changing operating conditions of the turbine, which vary with the change in seawater temperature. At the design point, the predicted overall isentropic efficiency is 86.5%, and the shaft output power is 15.3 kW, slightly higher than the expected 15 kW. Furthermore, a parametric study is performed, respectively, for the nozzle vane stagger angle and the nozzle-impeller radial clearance to explore the favorable geometric parameters for different conditions. The turbine’s overall efficiency increases slightly with deceasing nozzle-impeller radial clearance, and the variation of the nozzle vane stagger angle is much more influential on the turbine shaft power and overall efficiency. The optimum stagger angle point moves from 32° to 36° gradually with the increase in nozzle-impeller clearance. Finally, the feasibility of an adjustable nozzle for the turbine under off-design conditions was verified by combining the radial clearance and nozzle stagger angle.

Performance analysis of small steam turbine in high back pressure heating unit

In view of the change of the operation mode of the small steam turbine of the high back pressure modified unit, the performance evaluation formula of the small steam turbine and the feed water pump is given. Through the performance test, the performance indexes of the small steam turbine and the feed water pump set are obtained, and the detailed data analysis is carried out. It is found that the modified small steam turbine and the feed water pump set do not meet the design requirements. The analysis of the test results, found the reasons for the performance is not up to the standard, and gave the next step.

Numerical Simulation and Analysis of Hydraulic Turbines Based on BIM for Sustainable Development

Hydropower is considered to be an important way to achieve the sustainable development goal of human progress. The performance of turbines is very important to the safety and stability of hydropower stations. Most of the hydraulic turbine performance studies only use Computational Fluid Dynamics (CFD) for performance simulation, lacking the integration of Building Information Modeling (BIM) technology and CFD. Therefore, a performance analysis model of a Francis turbine based on BIM was put forward in this paper. The BIM software OpenBuildings Designer CONNECT Edition Update 10 was used to build the hydraulic turbine model, and then the BIM model was transferred to the CFD numerical simulation platform ANSYS through the intermediate format conversion. In the ANSYS environment, the numerical simulation of different working conditions was carried out with the help of Fluent 2021 R1 software. The numerical simulation results show that the fluid velocity gradient in the volute was 2~3 m/s under the three working conditions, which was relatively stable. The water flow could progress the guide vane mechanism at a higher speed, and the drainage effect of the volute was better. There were some negative pressure areas at the back of the runner blades and the inlet of draft tube, and the negative pressure value was as high as −420,000 Pa and −436,842 Pa under maximum head conditions, which were prone to cavitation erosion. It is proven that BIM supported the hydraulic turbine performance analysis and provided a geometric information model for hydraulic turbine CFD numerical simulation, meaning that the performance analysis model based on BIM is feasible. This study can expand the application value of BIM and provide guidance for the study of hydraulic turbine numerical simulation using BIM technology in combination with CFD methods.

Comparative energy performance analysis of micro gas turbine and internal combustion engine in a cogeneration plant based on biomass gasification

With a view to replacing fossil fuels, biomass electricity generation worldwide has grown from 509 TWh in 2015 to 685 TWh in 2021 and an upward trend is expected for the next years. It is about dispatchable, low-emission power to complement generation from variable renewables. Although modern bioenergy is considered a stable and carbon-neutral source, there is a need to boost the efficiency of the Biomass-to-Energy (BtE) conversion technologies. Accordingly, in this modeling study, attention was drawn to biomass gasification for heat and power, with a special focus on the prime mover characterization for distributed generation. An internal combustion engine (ICE) and a micro gas turbine (mGT), having the same nominal capacity of about 240 kWel when fueled by natural gas (NG), were inserted into a two-way biomass gasification chain and hence fed by clean syngas deriving from a downdraft gasifier. Simulations of the main components of the thermal power plant (gasifier, syngas cleanup, power island) were validated against data available in the published literature and in technical sheets, for specific operating conditions. The next step was to evaluate the overall performance of the entire BtE chain in terms of electrical, thermal, and total efficiency, both at full and part load, in order to highlight the pros and cons of each generator, in a twofold perspective. The last goal was to simulate a load following strategy, for two typical cold and hot days. The results of the thermodynamic analysis indicate that ICE is better performing than mGT, in the simulated context where the power demand from the grid ranges from 80 kWel to 190 kWel, with an ambient temperature between 2 and 35 °C. ICE provides the best performance in CHP mode, with a total efficiency of 62–69%.

A control-oriented model for floating wind turbine stability and performance analysis

A well-designed floating turbine controller should lead to small power fluctuations while keeping the system stable. Floating wind turbines can experience instability when operating above rated wind speed, due to the blade pitch controller. This phenomenon, known as negative aerodynamic damping, is the reason why a controller needs to be re-designed for floating applications. One solution is to de-tune the blade pitch controller and make it slower than the floater pitch motion. This solution, although simple, reduces the controller’s ability to react to changes in the inflow and results in large power fluctuations. A more sophisticated approach involves an additional loop feeding back the fore-aft nacelle velocity to the blade pitch or generator torque. The choice of gains, however, is not trivial. This work proposes a control-oriented model derived from first principles to investigate different controller configurations in terms of both stability and turbine performance. The linear model with seven degrees of freedom (six rigid-body motions and drivetrain) is formulated analytically and coupled with the controller. The linear formulation allows us to investigate stability via eigenvalue analysis and performance via frequency-domain response, thus bypassing the need for time-domain simulations. Parametric studies with thousands of different controller configurations can be completed in a matter of minutes.

Performance analysis of a single-cylinder type steam turbine with a capacity of 3.5 mw using enthalpy drop method

The performance capability of the steam turbine under factory conditions will experience changes that can be caused by operating or environmental factors. Therefore, it is necessary to analyze the performance of the steam turbine during the actual condition so that it can be compared with the performance of the steam turbine from the manufacturer using mass and energy balance equations on HP heater #1 and deaerators and iteration methods. The research was conducted by looking at the phenomena that occur in the steam turbine using mathematical models and theories when the unit operates according to the heat balance design parameters. Feedwater flow from the calculation of the iteration method based on the equation of the water heater obtained a value of 17,961.58 kg/h. The performance steam turbine experienced a decrease in efficiency with a value for isentropic efficiency of 72.73% down 6.54% from the design value of 79.27% and thermal efficiency of 26.88% down 1.75% from the design value of 28.64%. Meanwhile, the steam rate value of 5.03 kg/kWh increased by 0.44 kg/kWh from the design value of 4.59 kg/kWh, and the turbine heat rate of 3198.83 kcal/kWh, an increase of 196.08 kcal/kWh from the design value of 3002.75 kcal/kWh.

Performance analysis of spherical-shaped Darrieus hydrokinetic turbine for an in-pipe hydropower system

The present study aimed to explore the applicability of Darrius hydrokinetic turbine (HKT) curbed inside a closed conduit, i.e., in-pipe hydropower system. Six numbers of 3- and 4-bladed Spherically shaped Darrieus HKTs (SDHKT) were designed having various diameters. Numerical analysis was performed in ANSYS CFX to calculate performance parameters, viz. coefficient of power (CP) and coefficient of torque (Ct), to get an idea of possible power production. Numerical analysis was conducted by varying fluid flow from 0.5 to 2.0 m/s with an increment of 0.5 m/s. Blockage ratios (BR) were maintained as 0.705, 0.796, and 0.893 for an 0.080 m (nominal) diameter pipe. The results were validated with experiments at 1.0 ± 0.2 m/s flow velocity. It was found that CP increased with the blockage ratio. In general, the performance of the 4-bladed SDHKT was found better than the 3-bladed SDHKT. However, the performance of 3- and 4-bladed SDHKTs at a BR of 0.796 were considered for further analysis due to operational constraints. It was observed that overall CP increased with fluid velocity but with less proportionate. Pressure drops across the turbine increased with increased TSR and fluid flow velocities inside the pipe.

Performance Analysis of Hydrokinetic Turbine Using Shroud Ratio Comparison under Yaw Misalignment Condition

This research aims to analyze the performance of hydrokinetic turbines under yaw misalignment conditions using descriptive statistical methods on coefficient of power (Cp) data. Tests were conducted at water velocities of 0.7, 0.9, and 1.1 m/s for three types of turbine shrouds consisting of turbines without shrouds, turbines with two different types of shrouds, at yaw angles from 0° to 25° with 5° intervals. The study concludes that the performance of each turbine type is significantly influenced by the combination of water flow velocity and yaw angle. The diffuser type has the highest Cp value at every yaw angle, but its performance decreases with increasing yaw angle. The Blade type has poorer performance compared to the diffuser at every yaw angle and has the best performance at a combination of 1.1 m/s velocity and 5° yaw angle. Meanwhile, the shroud type has more stable performance and is not greatly affected by variations in velocity and yaw angle. Based on the analysis of changes in average Cp values with changes in yaw angle at V 0.7 m/s, all three turbine types experienced an increase in Cp value at a yaw angle of 5, with the shroud experiencing the most significant increase. At V 0.9 m/s, the diffuser and shroud types were able to maintain their average Cp values at every yaw angle, while the blade type decreased with increasing yaw angle and experienced a significant decrease at a yaw angle of 25. At V 1.1 m/s, the diffuser and blade types experienced a decrease in performance with every increase in yaw angle, but the shroud type was able to maintain the same Cp value and even experienced a significant increase at a yaw angle of 5.

Assessing the Feasibility of Gravitational Vortex Turbines for Sustainable Energy Production in Remote Hilly Areas of Bangladesh

This research paper presents a comprehensive study of the design, optimization, and performance analysis of a gravitational vortex water turbine for small-scale hydropower applications in the Chittagong Hill Tracts of Bangladesh. The urgent need for cleaner and more efficient energy sources to address global energy challenges drives the development of innovative renewable energy solutions. The proposed turbine harnesses the power of gravity-induced water flow to efficiently convert rotational energy from a water vortex into electrical energy. The research employs advanced computational fluid dynamics (CFD) analysis using ANSYS Fluent to investigate the intricate flow behavior and velocity distribution. Through CFD calculations, the study provides valuable insights into the turbine's performance, allowing for optimization of its design parameters. The influence of blade numbers on turbine efficiency contributes to a better understanding of the turbine's operational characteristics. The paper discusses the advantages of decentralized energy systems and emphasizes the potential of gravitational vortex turbines for small-scale hydropower projects. It highlights the importance of mathematical analysis and performance results, further supported by the CFD analysis, demonstrating the turbine's capabilities. The power outputs achieved by the turbine align with or surpass the potential power capacities of identified small hydro sites, reinforcing its viability as a clean and reliable energy solution. While the research findings showcase the turbine's potential, it emphasizes the need for further feasibility studies and site-specific assessments to ensure successful real-life implementation. The study underscores the significance of utilizing advanced computational techniques in developing efficient and environmentally friendly hydropower solutions. The findings offer lessons for researchers, engineers, and policymakers for cleaner and more sustainable energy sources.

Performance and Loss Analysis of a Small-Scale Supercritical CO2 Turbine

The supercritical carbon dioxide (S-CO2) power cycle is widely applicable to the utilization of multigrade heat sources due to its high efficiency and compact structure, in which the turbine is critical to the performance of the system. In this study, the operation pattern and output performance of an S-CO2 axial turbine with a design power scale of 10 kW power are investigated by experiments and numerical simulations. The loss mechanisms and distributions are analyzed using numerical simulations and loss models. The results show that the turbine output power and efficiency are at 9.66 kW and 36.6% at the designed condition and the output performance depends on the pressure ratio and rational speed. In addition, the flow field distribution reveals that the flow separation phenomenon occurs leading to loss, with the tip clearance loss being the most significant. Furthermore, the loss model validated in this paper is proven to be competent enough to fulfill the prediction of the loss distribution under different operational conditions, which could be very promising in the design of an S-CO2 axial turbine.

Power Performance and Response Analysis of a Semi-Submersible Wind Turbine Combined With Flap-Type and Torus Wave Energy Converters

Abstract An integrated offshore wind and wave energy system is an attractive concept in areas with abundant wind and wave energy resources. The sharing of supporting platform and facilities, e.g., mooring systems, offers significant cost savings. This will effectively lower the levelized cost of energy (LCOE). In the present study, a conceptual design consisting of a braceless semi-submersible floating horizontal axis wind turbine (FHAWT), three flap-type wave energy converters (WECs), as well as a torus (donut-shaped) point absorber-type WEC is proposed. The flap-type WECs harvest wave energy through the flap motion caused by oscillating wave surge, while the torus WEC absorbs wave energy generated from its heaving motion. The absorbed mechanical power of the power take-off (PTO) systems is calculated based on linear damping forces and the motions of the WECs relative to the supporting platform. Hydrodynamic interaction between the WECs and the supporting platform is considered by including the coupling terms in the added mass and potential damping coefficient matrices. A fully coupled aero-servo-hydro-elastic numerical model of the concept is constructed. The feasibility study of the concept is carried out using time-domain simulations. Only operational environmental conditions are simulated based on simultaneous wind and wave hindcast data of a selected offshore site. The effects of the WECs on the wind turbine, platform motions, and WEC power take-off are examined. Based on the power performance of WECs, recommendations are also provided for optimum power absorption.

Advanced Methods for Wind Turbine Performance Analysis Based on SCADA Data and CFD Simulations

Deep comprehension of wind farm performance is a complicated task due to the multivariate dependence of wind turbine power on environmental variables and working parameters and to the intrinsic limitations in the quality of SCADA-collected measurements. Given this, the objective of this study is to propose an integrated approach based on SCADA data and Computational Fluid Dynamics simulations, which is aimed at wind farm performance analysis. The selected test case is a wind farm situated in southern Italy, where two wind turbines had an apparent underperformance. The concept of a space–time comparison at the wind farm level is leveraged by analyzing the operation curves of the wind turbines and by comparing the simulated average wind field against the measured one, where each wind turbine is treated like a virtual meteorological mast. The employed formulation for the CFD simulations is Reynolds-Average Navier–Stokes (RANS). In this work, it is shown that, based on the above approach, it has been possible to identify an anemometer bias at a wind turbine, which has subsequently been fixed. The results of this work affirm that a deep comprehension of wind farm performance requires a non-trivial space–time comparison, of which CFD simulations can be a fundamental part.

Multivariate Data-Driven Models for Wind Turbine Power Curves including Sub-Component Temperatures

The most commonly employed tool for wind turbine performance analysis is the power curve, which is the relation between wind intensity and power. The diffusion of SCADA systems has boosted the adoption of data-driven approaches to power curves. In particular, a recent research line involves multivariate methods, employing further input variables in addition to the wind speed. In this work, an innovative contribution is investigated, which is the inclusion of thirteen sub-component temperatures as possible covariates. This is discussed through a real-world test case, based on data provided by ENGIE Italia. Two models are analyzed: support vector regression with Gaussian kernel and Gaussian process regression. The input variables are individuated through a sequential feature selection algorithm. The sub-component temperatures are abundantly selected as input variables, proving the validity of the idea proposed in this work. The obtained error metrics are lower with respect to benchmark models employing more typical input variables: the resulting mean absolute error is 1.35% of the rated power. The results of the two types of selected regressions are not remarkably different. This supports that the qualifying points are, rather than the model type, the use and the selection of a potentially vast number of input variables.

The design, construction and performance analysis of a portable vertical axis wind turbine (VAWT) generator

The increase demand for electric power, high consumption and little power station capacity has caused to reduce supplying hours of electricity in Iraq. Furthermore high bills prices especially in rural areas and cities faraway from electricity-generating power stations. In addition to the increase in pollution due to the use of fossil fuel sources. All those obstacles have led to the search for cheap, clean and renewable energy sources. In this research, wind turbine model operates at a low wind speed and high efficiency was achieved. The model was located and studied in Tikrit city where wind power need to be consumed. Here, the vertical turbine with an area of 0.49 m2 was designed and then it was placed at least 8 meters above the ground without any disturbances within 100 meters in any direction. The system was observed to start rotating with wind speed of 1.5 m/s. However, the best turbine cycles per minute were 68 was obtained at wind speed of 6.6 m/s and the system torque was 60 N.m. Finally, 75 watts of power was produced from a multipurpose generator that was designed to run a single battery. and was used (Neodymium magnet), and also operated at low speed.

Investigation of the turbine performances in the case of dual usage of Savonius wind turbines

In this study, the turbine performances of Savonius wind turbines were investigated in the case of dual usage. While implementing the dual use of the Savonius wind turbine, a flat plate deflector was placed in front of the turbines to increase the turbine performance. The effects of design parameters such as the geometric dimensions of this flat plate placed in front of the turbines and the geometrical placement position on the turbine performance were investigated. In this direction, the flat plate prevented the negative torque that occurs during the operation of the turbines. Hence, the plate guided the wind to the turbine blade, which generated positive torque. The numerical analyses made in this study were confirmed by the previous literature study. The performance values of single, dual, and flat plate dual Savonius wind turbines were analyzed using the numerical analysis method, the accuracy of which was proven by the experimental data. It was determined that the similarity between the experimental result and the numerical result was approximately 0.3%, especially in the maximum power coefficient values. The computational fluid dynamics (CFD) program ANSYS Fluent was used for turbine performance analysis. With this design study, the maximum power coefficient ( Cp) was obtained around 0.17 with a single Savonius wind turbine, while the maximum power coefficient ( Cp) was obtained around 0.24 with a flat plate dual Savonius wind turbine. As a result, the power coefficient obtained with a single Savonius wind turbine increased by 42% in the flat plate dual Savonius turbine system when compared to the power coefficient of the single Savonius wind turbine. Thus, it was determined that the power coefficient obtained with a single Savonius wind turbine in the flat plate dual Savonius turbine system increased by 42% compared to the power coefficient of the single Savonius wind turbine.

Performance analysis of a vertical axis wind turbine using computational fluid dynamics

Vertical axis wind turbines (VAWTs) have gained popularity in the last few decades due to their numerous advantages when deployed in urban areas. Despite this, Vertical axis wind turbines have complex aerodynamics, dynamic stall, hence lower performance. Low/zero starting torque, noise, visual impact, as well as blade safeness are further hurdles when they are fitted into the physical environment. Due to these pertinent issues that comes to play in a vertical axis wind turbine, the current investigation explores an augmented vertical axis wind turbine (AVAWT) having a rotor and a stator. The outcome of the study highlighted the effect of mesh density and the type of turbulence model selected in the determination of the forces being exerted on the blade using computational fluid dynamics. Investigation into the effect of time steps showed lesser effect of this parameter on the performance of the blade computationally. The newly developed augmented turbine blades improved the output power by 1.35 times in comparison to an open rotor. The shape for the conical surface and the stator blade impacted the performance as well. Furthermore, it was deduced that there was higher dynamic stall for scenarios where the tip speed ratios were lower. The study showed the importance of the stator in a vertical axis wind turbine in ensuring that the incoming wind attains some acceleration as well as creating a lower pressure outlet but overall aids in the improvement of the power and torque coefficients by more than 36%.

Performance analysis of dual-stage vertical axis hydrokinetic turbine (VAHT) with azimuth variation at open canal hydrokinetic power plant

For several decades, the use of hydropower generation using hydrokinetic turbines has grown rapidly, aiming to get energy alternatives and reduce the dependency on fossil energy. Despite it has low efficiency, the vertical axis hydrokinetic turbine (VAHT) has been used to utilize hydro energy and has a promising result. A previous study had stated that the utilization of cascaded blade enhances the performance of VAHT. However, this technology produces fluctuating torque and power during its rotation. Hence the dual-stage VAHT is proposed to overcome this issue to improve VAHT’s efficiency. This research analyzes the dual-stage VAHT’s performances by variating its inter-stage azimuth of 45°, 60°, 75°, and 90°. For each stage, there is six blades that attach at three arms. The computational fluid dynamics (CFD) simulation is employed as its capability to provide in-depth information regarding flow phenomenon, force, and torque. This simulation has proven that the dual-stage configuration has an impact on reducing torque fluctuation of VAHT and show that different of inter-stage azimuth angle brings to different torque fluctuation pattern. The average torque value produced by the new turbine with variations in shift between stages of 45°, 60°, 75° and 90° is 10,119.21 Nm, 10,656.13 Nm, 10,490.31 Nm, and 10,457.3 Nm, respectively.

Evaluation of meteorological measurements made on the nacelle of wind turbines in cold climate

Operating wind turbines in cold climate leads to several challenges not encountered in regular climates such as frequent icing. These challenges are amplified by the difficulties associated with accurately quantifying icing without specialized instrumentation. Typically, the performance of wind turbines is monitored by comparing the turbine active power to the available power based on the wind speed measured on the nacelle. However, multiple other factors not related to cold climate can also lead to a reduction of turbine performance. Applying a temperature threshold under which ice accretion is deemed to be able to impact turbine performance is a popular tool to reduce the influence of these other factors. Currently, there is no generally accepted threshold temperature value. Using large data sets from 3 different wind farms equipped with different wind turbine models, this topic was investigated. Following this analysis, it has been found that the optimal strategy to define icing events is to consider that ice may remain on surfaces only if a minimal temperature of 1 °C in the previous 2-h window is observed. This strategy is supported by a temperature bias analysis, a turbine performance analysis and 3 case studies. An ice sensor can also be an efficient strategy to accurately identify icing events. Previous studies raised doubts on the accuracy of ice measurements made on a wind turbine nacelle due to the different conditions experienced by the blade tips. To verify this claim, the present paper provides comparisons of icing periods, defined by the wind turbine performance method, to the detection of an ice sensor installed on the nacelle. It was found that the start of 71 of the 74 identified icing events coincided with ice detection on the nacelle. The three remaining events were minor and could not be linked to the incapacity of detecting ice on the nacelle. In conclusion, sensitive nacelle-based sensors should be considered as suitable options for ice detection on wind turbine nacelle.