Turbine Size Research Articles

Выбор оптимальных газодинамических параметров радиально-осевых турбин при их совместной работе с поршневыми двигателями внутреннего сгорания

The study of radial-axial (centripetal) turbines is important for science and technology. They are widely used in the refrigeration industry, internal combustion engines, and power engineering, both in the form of auxiliary units and in autonomous power units. The article offers a method for selecting the gas-dynamic parameters of the centripetal turbine in order to obtain the highest efficiency and the best size of the turbine. The increased manufacturability of the turbine is provided due to the absence of a straightener at the outlet of the impeller and the use of straight blades in the impeller. The dependence of the efficiency of a centripetal turbine on the profiles of the blades and the radial dimensions of the nozzle apparatus and the impeller, as well as on the length of the impeller blades is investigated. Considering the recommended optimal parameters, the calculation of a pulsed centripetal turbine operating in conjunction with a four-stroke piston internal combustion engine is performed.

On wind turbine power fluctuations induced by large-scale motions

Our current understanding on the dynamic interaction between large-scale motions in the approaching turbulent flow and wind turbine power is very limited. To address this, numerical studies of a small-scale three-bladed horizontal axis wind turbine with cylinders placed in front of it to produce energetic coherent structures of varying scale relative to the turbine size have been carried out to examine the temporary variations of the turbine power. The predicted spectra reveal a strong interaction between large-scale turbulent motions generated by cylinders and the instantaneous turbine power. More specifically, it shows how the large dominant turbulent scales of incoming flow affect the spectral characteristics of turbine power, i.e, determining the level and trend of the turbine power spectrum. Comparisons reveal that there are two critical frequencies recognisable in the turbine power spectrum: the first one, close to the turbine rotational frequency, above which the coupling of upstream flow and turbine power disappears; the second one, identified for the first time and related to the dominant large-scale motions which dictate the level and trend of the turbine power spectrum. This study also shows that the strong scale-to-scale interaction between the upstream flow and turbine power reported previously does not appear at high Reynolds numbers.

The influence of carbon-glass blade structure on the performances of the whole wind turbine

ABSTRACT The ever-increasing size of wind turbines has given rise to a need for design of the carbon-glass hybrid blades. From the perspective of extreme loads, aero-elastic characteristics and cost, this study investigates the influence of carbon-glass blade structure on the performances of the whole wind turbine. With an integrated tool for analyzing ultimate loads and deformations of wind turbine components, the structural optimization model for the carbon-glass hybrid blade was built, and the new structural blade was optimized. By using a quantitative cost model, the performance of the wind turbine equipped with the optimized blades was analyzed; it shows that the use of glass-carbon hybrid materials and the reasonable structural design can effectively reduce the loads and deformation of the blade in the edge-wise and torsional directions. The use of carbon fiber will increase the manufacturing cost of the blade, but from an overall perspective, the cost of the whole wind turbine will have a slightly reduction of 0.8%.

Relative energy production determines effect of repowering on wildlife mortality at wind energy facilities

Abstract Reduction in wildlife mortality is often cited as a potential advantage to repowering wind facilities, that is, replacing smaller, lower capacity, closely spaced turbines, with larger, higher capacity ones, more widely spaced. Wildlife mortality rates, however, are affected by more than just size and spacing of turbines, varying with turbine operation, seasonal and daily weather and habitat, all of which can confound our ability to accurately measure the effect of repowering on wildlife mortality rates. We investigated the effect of repowering on wildlife mortality rates in a study conducted near Palm Springs, CA. We controlled for confounding effects of weather and habitat by measuring turbine‐caused wildlife mortality rates over a range of turbine sizes and spacing, all within the same time period, habitat and local weather conditions. We controlled for differences in turbine operation by standardizing mortality rate per unit energy produced. We found that avian and bat mortality rate was constant per unit of energy produced, across all sizes and spacings of turbines. Synthesis and applications. In the context of repowering a wind facility, our results suggest that the relative amount of energy produced, rather than simply the size, spacing or nameplate capacity of the replacement turbines, determines the relative rate of mortality prior to and after repowering. Consequently, in a given location, newer turbines would be expected to be less harmful to wildlife only if they produced less energy than the older models they replace. The implications are far‐reaching as 18% of US and 8% of world‐wide wind power capacity will likely be considered for repowering within ~5 years.

Wind power costs driven by innovation and experience with further reductions on the horizon

AbstractThe costs of wind power have declined to levels on par with or below those of conventional sources in many parts of the world. Wind power has become one of the fastest‐growing sources of new electricity generation. We take stock of wind power cost evolution over the past 20 years, review methodologies commonly used for cost assessment, discuss the potential for continued cost reduction, and identify anticipated cost and value drivers. Our scope includes both onshore and offshore wind technologies. We draw from a vast body of literature on these topics to highlight key trends, approaches, and limitations. Furthermore, we discuss strategies for wind power assets to enhance their marginal economic value to the broader power system and consumers. We identify a myriad of factors that are expected to influence the future cost and value of wind power, including siting, project scale, turbine size, operational synergies, commodity prices, advancements in turbine technologies, enhanced management of the wind resource, and novel control technologies that provide value for the electricity grid. Because the common methods for forecasting future costs each have their own strengths and weaknesses, we find the best insights are elicited from a combination of methods. Overall, researchers and analysts anticipate further sizable cost reductions for onshore and offshore wind. Midrange forecasts for levelized cost of energy in 2050 are generally between $20 and $30/MWh for onshore wind and $40 and $60/MWh for offshore wind, a reduction to approximately half of today's levels. Optimistic forecasts anticipate these levels as early as 2030.This article is categorized under: Wind Power > Economics and Policy

A multi-objective artificial electric field optimization algorithm for allocation of wind turbines in distribution systems

This paper presents wind turbine allocation in distribution systems to reduce active power loss and voltage deviations using a multi-objective Artificial Electric Field Algorithm (MOAEFA). The proposed method is a mathematical algorithm which is suitably capable to find optimal solutions based on the Pareto solution set using a fuzzy decision-making method. The proposed problem is implemented on 10, 33 and 69 bus IEEE radial distribution networks. The installation location, size and power factors of wind turbines are determined optimally using the MOAEFA method. Single and multi-objective allocation problem of wind turbines is implemented using AEFA, GWO, PSO and MOAEFA, MOGWO, MOPSO methods. The obtained the results of AEFA method achieves less power loss and voltage deviations compared to the conventional GWO and PSO methods. Moreover, the results of multi-objective fuzzy allocation show that there is a compromise between single-objective results and MOAEFA method provides better performance given the loss power and voltage deviation reduction in distribution networks. Furthermore, MOAEFA method has found a better voltage profile in the allocation of wind turbines in the distribution network compared to the other methods. The performance comparison between MOAEFA method and the previous methods given in the literature verifies the superiority of the MOAEFA method.

Microdebrider Assisted Inferior Turbinoplasty: The Evaluation According to the Pathological Causes of Hypertrophied Turbinates

Background: Hypertrophied inferior turbinates are the frequent cause of nasal obstructions.Microdebridoris one of recent advances in technology used for reduction of hypertrophied turbinate to improve nasalbreathing.Objective: To evaluate and compare the effectiveness of microdedrider assisted inferior turbinoplasty onnasal breathing, turbinate size and complications according to the pathological causes.Patients and Method: Aprospective case study of 45 patients with chronic nasal obstruction andhypertrophied inferior turbinates underwent microdebrider assisted tubinoplasty. At Salah-eldeen GeneralHospital and private practice in salah-eldeen governorate, Iraq. During the peroid from June 2016-June2018. The patients were classified according to the cause of turbinate hypertophy and follow up at 1,3,and 12 months post operatievly for nasal bereathing and turbinate size.Results : The preoperative turbinatesize was grade III (48.5%) and grade IV (51.5%). At 1,3,and 12 months post operatively, the grade I andII was (87%). (90%), and (84%) respectively better in compensatory hypertrophy. The subjective patient’ssatisfaction grade I(relieved) and II(improved)) at 1,3, and 12 month after surgery was (100%) (97%) and(89%) respectively more satisfaction with compensatory hypertrophy.Conclusion: The therapeutic success of microdebrider turbinoplasty for improvement of nasal obstructionand turbinate size, according to the causes . In early postoperative period was almost equal,but long-termfollow-up (one year) found it was greater in compensatory hypertrophy and chronic rhinosinusitis andless in allergic and nonallergic rhinitis. There is no significant association between the cause of turbinatehypertrophy and type of complications.

How could operational underwater sound from future offshore wind turbines impact marine life?

Offshore wind farms are part of the transition to a sustainable energy supply and both the total numbers and size of wind turbines are rapidly increasing. While the impact of underwater sound related to construction work has been in the focus of research and regulation, few data exist on the potential impact of underwater sound from operational wind farms. Here, we reviewed published sound levels of underwater sound from operational wind farms and found an increase with size of wind turbines expressed in terms of their nominal power. This trend was identified in both broadband and turbine-specific spectral band sound pressure levels (SPLs). For a nominal power of 10 MW, the trends in broadband SPLs and turbine-specific spectral band SPLs yielded source levels of 170 and 177 dB re 1 μPa m, respectively. The shift from using gear boxes to direct drive technology is expected to reduce the sound level by 10 dB. Using the National Oceanic Atmospheric Administration criterion for behavioral disruption for continuous noise (i.e., level B), a single 10 MW direct drive turbine is expected to cause behavioral response in marine mammals up to 1.4 km distance from the turbine, compared to 6.3 km for a turbine with gear box.

Post-operative clinical and radiological assessment after submucosal resection of inferior turbinate and partial inferior turbinectomy

ABSTRACT Background: Hypertrophied inferior turbinates, commonly caused by allergic rhinitis, cause nasal obstruction. Aim of this study: This study aimed to evaluate nasal patency following submucosal resection of the inferior turbinate as a mucosa and bone-preserving method for reducing the size of the hypertrophied inferior turbinate, in comparison with the traditional method (partial inferior turbinectomy). Patient and methods: This study was performed on patients with moderate to severe turbinate hypertrophy, selected from our ear, nose, and throat outpatient clinic, during March 2018 to March 2020. Patients were divided into GROUP I (n = 40; 25 males and 15 females), subjected to microdebridement submucosal turbinoplasty, and GROUP II (n = 40; 22 males and 18 females), subjected to traditional partial inferior turbinectomy. Result: There was a statistically significant decrease in mean nasal obstruction scores and a significant increase in nasal cavity space distance at three levels of the inferior turbinate after 6 months (P < 0.05),. Rhinorrhea and sneezing decreased significantly in both groups after 6 months (P < 0.05), but there was no significant difference between the groups in terms. There was significantly more post-operative bleeding, Crustations, and atrophic rhinitis in the GROUP II than in GROUP I in patients subjected to the traditional partial turbinectomy. Conclusion: These results highlight the superiority of microdebridement to traditional turbinectomy for the management of chronic nasal obstruction, as it demonstrated the highest efficacy and least complications.

Field testing of multi-variable individual pitch control on a utility-scale wind turbine

The ongoing increase in size of modern wind turbines creates the demand of better control algorithms to counteract the increased loads acting on them. Individual blade pitch control (IPC) algorithms to alleviate blade loads are becoming a crucial part of current wind turbine control systems. The state-of-the-art individual blade pitch load reduction controller mostly relies on multiple single-input single-output (SISO) designs. This approach, however, constrains the achievable bandwidth of the controller as relevant couplings in the dynamics are ignored. These couplings become more pronounced for bigger turbines. Model-based multiple-input multiple output (MIMO) control designs can be used to account for these couplings and hence reduce loads for future, larger turbines. In this article we present the results of an intensive field test campaign of an H∞-design based MIMO IPC. This controller is designed for and tested on the utility-scale 2.5 MW Clipper Liberty research turbine operated by the University of Minnesota. The article guides the reader through the turbine’s open loop dynamics, the IPC design and the relevant implementation steps on the turbine. Finally, the developed H∞-based IPC is compared using experimental field data against no IPC (collective blade pitch control) and a classical IPC based on decoupled SISO loops.

Effect of Growth in Turbine Size on Rotor Aerodynamic Performance of Modern Commercial Large-Scale Wind Turbines

In this study, the impact of growth in turbine size on aerodynamic rotor performance of modern commercial large-scale wind turbines was investigated. For this examination, three different commercial large-scale wind turbines of models VESTAS V80-2MW, V90-3MW, and V126-3.3MW operating on three existing onshore wind farms were selected. In order to determine the effects of turbine size growth on aerodynamic rotor performance, turbine power output P, turbine power coefficient, Cp, turbine rotational speed, Ω, thrust force, T, tip speed ratio, λ, and flow angle, ϕ, values obtained from these turbines were compared at the same magnitude of free-stream wind speeds, U∞. The results reveal that decreasing specific power decreases the rated output wind speed of the wind turbines; hence, the reduction in the rated output of wind speed contributes to the tendency of higher power capacity. Moreover, it was determined that the enlargement in the turbine size has a profound influence on the parameters that affect the performance of the turbine such as rotational speed, Ω, thrust force, T, tip-speed ratio, λ, and flow angle, ϕ. For instance, higher thrust loads and tip-speed ratios were acquired for the turbines having a larger rotor diameter which results in better aerodynamic efficiency of the turbine.

Joint sizing and placement of battery energy storage systems and wind turbines considering reactive power support of the system

The probabilistic and intermittent output power of Wind Turbines (WT) is one major inconsistency of these Renewable Energy Sources (RES). Battery Energy Storage Systems (BESS) are a suitable solution to mitigate this intermittency by smoothening WT's output power. Although the main benefit of BESSs mentions as peak shaving and load-shifting, but in this research, it will verify that optimal placement and sizing them jointly with WTs can lead to more benefits like compensating the required system's reactive power support from WTs. The reactive power size of WTs and BESSs will be derived from the result of the joint sizing and placement in this study, as well as their active power output to meet the load demand. This can facilitate WTs and BESSs contribution to cover the system's required reactive power and their participation in the reactive power market and ancillary services. This paper also proposes new cost functions for both WTs and BESSs and minimizes their cost while ensuring minimal total loss (active and reactive) in the power distribution system. This can benefit both WTs' and BESSs' owners as well as system operators. Suitable placement and sizing of the WTs and BESSs can also improve the load bus voltage profiles, which can benefit the end-users, and will verify using the proposed optimization by different case studies on the 33 bus distribution system. The results of case studies ascertain the consistency of the proposed formulation for placement and sizing BESSs and WTs jointly, as well as other benefits to the power system, the power plant owners, and system operators.

Structural design and optimization of a series of 13.2 MW downwind rotors

The quest for reduced LCOE has driven significant growth in wind turbine size. A key question to enable larger rotor designs is how to configure and optimize structural designs to constrain blade mass and cost while satisfying a growing set of challenging structural design requirements. In this paper, we investigate the performance of a series of three two-bladed downwind rotors with different blade lengths (104.3-m, 122.9-m, and 143.4-m) all rated at 13.2 MW. The primary goals are to achieve 25% rotor mass and 25% LCOE reduction. A comparative analysis of the structural performance and economics of this family rotors is presented. To further explore optimization opportunities for large rotors, we present new results in a root and spar cap design optimization. In summary, we present structural design solutions that achieve 25% rotor mass reduction in a SUMR13i design (104.3-m) and 25% LCOE reduction in a SUMR13C design (143.4-m).

Comprehensive Bird Preservation at Wind Farms.

Wind as a clean and renewable energy source has been used by humans for centuries. However, in recent years with the increase in the number and size of wind turbines, their impact on avifauna has become worrisome. Researchers estimated that in the U.S. up to 500,000 birds die annually due to collisions with wind turbines. This article proposes a system for mitigating bird mortality around wind farms. The solution is based on a stereo-vision system embedded in distributed computing and IoT paradigms. After a bird’s detection in a defined zone, the decision-making system activates a collision avoidance routine composed of light and sound deterrents and the turbine stopping procedure. The development process applies a User-Driven Design approach along with the process of component selection and heuristic adjustment. This proposal includes a bird detection method and localization procedure. The bird identification is carried out using artificial intelligence algorithms. Validation tests with a fixed-wing drone and verifying observations by ornithologists proved the system’s desired reliability of detecting a bird with wingspan over 1.5 m from at least 300 m. Moreover, the suitability of the system to classify the size of the detected bird into one of three wingspan categories, small, medium and large, was confirmed.

The potential of CSP plants for remote communities in the MENA region

The present work aims to investigate the load-following capability of a tower-based CSP plant assumed to cover a high fraction (90%) of the power demand of a mid-size remote community. The design of a CRS requires the determination of several variables (number of heliostats, layout arrangement, tower height, receiver dimensions) depending on the solar field size and the site location. In this paper, a two-step optimization procedure is presented. A preliminary optimization is carried out to define the solar field configurations minimizing the budget costs for a range of receiver thermal design powers (from 300 MWth to 1000 MWth). The second optimization, based on annual simulation, selects the storage tank volume, the steam turbine rated power, and the actual reflective area (number of mirrors) capable to cover 90% of the power demand at minimum cost. The analysis is carried out for two load profile and two locations in Egypt. The load profile, compared to the solar radiation availability, determines the relationship between tank capacity and turbine size. The level of radiation has the strongest impact on the oversizing of the solar field and levelized cost of electricity.

Effect of septoplasty on inferior turbinate hypertrophy

Background Septal deviation is usually associated with compensatory hypertrophy of the contralateral inferior turbinate. The current treatment of anterior septal deviation is septoplasty, but there is controversy about surgery for the hypertrophied inferior turbinate. Aim This study aims to determine the effect of septoplasty surgery alone on the size of inferior turbinate. Patients and methods This prospective study was done on 40 patients who attended ENT Department of Al-Zahraa University Hospital. This study was done in the period from September 2019 to September 2020. Their age ranged from 18 to 40 years. They had septal deviation on one side and inferior turbinate hypertrophy (ITH) on the opposite side. All of them underwent septoplasty without turbinate surgery. These patients were evaluated preoperatively and 6 months postoperatively by radiological (computed tomography), endoscopic examination, and nasal obstruction symptom evaluation questionnaire. Results Septoplasty alone significantly decreased the thickness of the medial mucosa of hypertrophied inferior turbinate by 1.03±0.74 mm (P=0.000) at the anterior part and decrease by 0.82±1.14 mm at the middle part (P=0.000), with no statistically significant decrease at the posterior part. Moreover, it also decreased the thickness of the lateral mucosa of turbinate by 0.31±0.25 mm (P=0.000) at the anterior part, decrease by 0.42±0.39 mm at the middle part (P=0.000), and no significant decrease at the posterior part. Insignificant change of conchal bone thickness on both sides was reported. Conclusion We conclude that septoplasty alone saves time and cost and avoids complications and sequelae associated with turbinectomy. This in turn improves quality of life, so it can be prescribed for patients with DNS with ITH mainly at anterior and middle segment soft tissue parts, but it is not enough for surgery of patients with ITH of posterior part or conchal bone.

Performance Investigation of a Novel Thermosyphon Based Trilateral Cycle Using Hydraulic Turbine for Power Generation Instead of Two-Phase Expander

The trilateral cycle (TLC) has been viewed as a promising technology for low grade heat to power conversion, while its application in reality is greatly limited by the low efficiency of two-phase expander and high volume flow rate at the expander outlet. This paper suggests a novel thermosyphon based trilateral cycle (TTLC), which uses hydraulic turbine for power generation instead of two-phase expander, avoiding problems in traditional TLC systems and also providing a chance for utilization of pump-as-turbine (PAT) technologies. The system performance of TTLC is theoretically investigated, and the results are compared with those of traditional TLC and ORC. It is found that the slip loss is the main contributor to the riser efficiency. The working fluids with smaller density ratio and specific heat are more suitable for TTLC. TTLC generates more power than TLC when the heat source temperature is less than 50 °C, and less power than TLC within the deviation of 10% for the heat source temperature in the range of 50-75 °C. Moreover, the volume flow rate at the turbine outlet of TTLC is only 2-17% of those for TLC and ORC, indicating a much smaller turbine size.

Large eddy simulations of wind turbine wakes in typical complex topographies

AbstractThere is a need to clarify the coupling characteristics of terrain‐induced wind fields and wind turbine‐induced wake in wind farm micrositing. However, research investigating the effect of hill shape on this interaction is lacking. In addition, during the optimization of the layout of the turbines over topographies, the flow behind the turbines should be predicted in a fast way. After obtaining the wake flow of the turbine mounted on flat terrain and the flow over the topographies, there are mainly two superposition methods to predict the turbine wake flow over the topographies. One is to add the wind deficit following the location with a vertical distance of the hub height (D‐line). The other is to add the wind deficit following the streamline starting from the turbine center (B‐line). It remains unknown to what extent these two superposition methods can be adopted. Therefore, the effects of hill shape, wind turbine size, and turbine location are investigated. When the wind deficit, obtained from modeling the wake flow of the turbine mounted on flat terrain, is superposed following B‐line, the results are overall better than those when following D‐line.

Application of hydro energy in small power supply systems

This paper provides an opportunity to increase the efficiency of use in low-pressure watercourse systems by determining the dimensions and design of the micro-hydroelectric power plant operating on low-pressure watercourses. It was found that the size of a micro-hydro water turbine depends on the flow rate of the water, the volume of water hitting the blade at a fixed time, and the depth of the water surface. As a result, a technological scheme of a micro-hydroelectric power plant operating on low-pressure water streams was developed.

Behavior study of prestressed concrete wind-turbine tower in circular cross-section

In this work, we sought to study the behavior of prestressed concrete wind-turbine tower in circular cross-section. The idea was to use Genetic Algorithm to obtain a structural optimization of the projected tower. Thus, a tower with the shape of a conical section was obtained, which minimizes the appearance of stress concentrations in the structure. The tower has a tapered profile to reduce the area subjected to wind thus lower the total weight and applied moment. It will also enhance the dynamic response of the tower and improve its overall stability. Steel tubular wind turbine towers are most widely utilized for wind turbines, however, the use of concrete material is becoming more attractive for wind towers because concrete towers are more stable for buckling failure. As the turbine size is growing and the towers are rising in height, steel towers are required to be sufficiently strong and stiff, consequently leading to high construction costs. Therefore, the prestressed concrete wind-turbine tower has a reduced construction cost compared to the steel tubular wind turbine towers or the self-supporting steel truss towers with a maximum height of 150 m. For this, Computer-Aided Engineering (CAE) tools were used and a 100 m prestressed concrete tower system for a wind turbine was optimized. It is concluded that the model met all the restrictions described and represents an economy in raw material and greater simplicity of design in relation to the octagonal model used for comparison. A new structural methodology was described for the study and application of prestressed concrete to replace the steel towers currently used.