Blade Length Research Articles

Optimization of a radial inflow turbine rotor with splitter blades based on entropy production theory and artificial neural network

The radial inflow turbine is the core component of the organic Rankine cycle, and the application of splitter blades is an effective way to reduce its flow loss. It is helpful to study the energy loss characteristics of radial turbines with splitter blades and the optimal geometrical parameters of splitter blades for further improving their aerodynamic performance. In this paper, an optimization framework based on the combination of back-propagation neural network and non-dominated sorting genetic algorithm II is developed. Considering the turbine efficiency as the objective, the geometric parameters of splitter blades, including relative length of the blade, relative distance of the leading edge, circumferential offset, and outlet angle of the blade, are optimized. In addition, the entropy production method is used to locate and quantitatively evaluate the energy loss of the radial turbine with the optimal splitter blades. The results indicate that the genetic algorithm optimized back-propagation neural network model can accurately predict turbine efficiency with a maximum deviation of 2.47 %. In addition, the optimal geometrical parameters of the splitter blade are related to the turbine geometry. In this case, the optimal splitter blade has a relative blade length of 0.639, a relative leading edge distance of 0.3, a circumferential offset of 0.442, and an outlet angle of 38°. Compared with the original turbine, the efficiency of the radial turbine with optimal splitter blades increases by 4.65 %. The total entropy production of rotor and turbine is reduced by 33.3 % and 44.1 % respectively by the installation of optimal splitter blades. Compared with the case without splitter blades, the turbine with the optimal splitter blades can achieve higher efficiency at a flow rate 40 % higher than the design value, and it expands the efficient working range of the turbine by 60 %. This work can provide guidance for the optimization design of radial inflow turbines.

Performance Analysis and Aerodynamic Design of Axial Flow Compressors

The main objective of the paper is to analyze theperformance of axial flow compressors and to generate asystematic design approach which enables to designsubsonic flow ones. In order to investigate the validity of this approach, the LP axial flow compressor of the RR SpeyMK511 turbofan engine is taken as an example. The designcalculations were based on thermodynamics, gas dynamics,fluid mechanics and empirical relations. The flow isassumed to be of two-dimensional compressible type withconstant axial and rotor blade velocities with a free-vortexswirl distribution. Design calculations includethermodynamic properties of the working fluid, number ofcompressor performance parameters such as, stagetemperature rise and number, flow and blade angles (bladetwist), velocity triangles and relative inlet Mach number atrotor blades tips as well as blades tip and hub diameters. Arepeated calculation is made to determine these parametersalong compressor stages. The variation of velocity whirlcomponents, air and blade angles, deflection and degree ofreaction from root to tip of the blades were also determined.The twist of the blades along the blade length is setaccording to the recommended values in order to obtainsmooth blade twist profile.

Pressure and Liquid Distribution under the Blade of a Basket Extruder of Continuous Wet Granulation of Model Material

This study explores the influence of blade design on the low-pressure extrusion process, which is relevant to techniques like spheronization. We investigate how blade geometry affects the extruded paste and final product properties. A model paste was extruded through a basket extruder with varying blade lengths to create distinct wedge gaps (20°, 26° and 32° contact angles). The theoretical analysis explored paste behavior within the gap and extrudate. A model material enabled objective comparison across blade shapes. Our findings reveal a significant impact of blade design on the pressure profile, directly influencing liquid distribution in the paste and extrudate. It also affects the required torque relative to extruder output. The findings of this study hold significant implications for continuous granulation, a technique employed in the pharmaceutical industry for producing granules with uniform size and properties. Understanding the influence of blade geometry on the extrusion process can lead to the development of optimized blade designs that enhance granulation efficiency, improve product quality, and reduce energy consumption. By tailoring blade geometry, manufacturers can achieve more consistent granule characteristics, minimize process variability, and ultimately produce pharmaceuticals with enhanced efficacy.

Exploring the Aerodynamic Effect of Blade Gap Size via a Transient Simulation of a Four-Stage Turbine

With the impact of size on low-pressure turbines (LPTs) increasing, the gap between the blades has shrunk, inevitably influencing the unsteady effects inside the turbine. In this study, the aerodynamic effect of the blade gap size is investigated using a compressible unsteady Reynolds-averaged Navier–Stokes (URANS) model on the basis of a four-stage LPT. Simulations are conducted in which the gap between the third-stage stator (S3) and rotor (R3) varies from 0.2 to 0.8 times the axial chord length of the R3 blade. The multi-stage environment reflects the complexity of real low-Reynolds flow fields. Computational fluid dynamics is used to analyze the flow field in detail. The results demonstrate that in the small-gap (AG-0.2) case, the turbulence kinetic energy (TKE) level of the S3 wake close to the R3 leading edge is four-thirds of that in the large-gap (AG-0.8) case. The higher intensity of the wake impacting on the blade results in a higher inverse pressure gradient in the rear part of the R3 suction surface, which increases the profile loss. However, the AG-0.2 case leads to fewer losses caused by the passage vortex in the hub area under the influence of the higher intensity of the wake.

Study on the Influence of Protuberance Amplitude on the Performance of Vertical Axis Wind Turbines

Abstract The performance of vertical axis wind turbine (VAWT) is mainly affected by the dynamic stall process of the blade. Inspired by the anti-stall performance of the humpback whale flipper, leading edge protuberances (LEPs) are applied to 2-blade VAWT. Based on computational fluid dynamics simulation method, the effects of LEPs amplitude on VAWT performance are investigated when blade tip speed ratio is 2.19. The results show that the larger the amplitude of the LEP, the lower the average power coefficient. When the number of protuberances is 3, the average power coefficient of the VAWT with a protuberance amplitude of 6.625mm is 1.8% higher than prototype blade. Considering the impact of increasing the chord length of biomimetic blades, the average tangential force coefficient of all biomimetic VAWTs decreases. The peak section performance of the bionic blade decreases significantly while the trough section performance increases significantly. The difference between the peak section and trough section of the LEPS plays an important role in improving the performance. This study provides a reference for the application of bionic protuberances in VAWTs.

Numerical investigation of the vortical structures in the near wake of a model wind turbine

It is well known that the vortex system in a horizontal axis wind turbine wake is highly relevant in terms of fatigue loads and performance of wind turbines located in the wake of other wind turbines. The breakdown process of tip vortices particularly influences the mixing process of the low-speed wake region with the undisturbed flow outside the wake. As a collaboration with the Technische Universität Berlin (TUB), a major goal in a joint research is to study the effects involved in tip vortex breakdown. TUB designed a model turbine that will be towed through a large water tank to analyse and to control the tip vortex decay. To accommodate the measurement equipment, the ratio of blade length to nacelle length is unconventionally small, leading to uncertainty regarding the effect on the breakdown of the tip vortex. Due to the dimensions of the model wind turbine the root vortex system and the nacelle wake are not comparable to former studies and should therefore be investigated in detail. To do so computational fluid dynamics, in particular delayed detached eddy simulations, are conducted for the model turbine with the compressible flow solver FLOWer and the two-equation Menter-SST turbulence model. Two simulations are conducted with and without the nacelle. The results indicate that the root vortices propagate downstream and interact with each other. Additionally, these vortical structures are also influenced by the geometry of the turbine nacelle which causes faster decay of the root vortices compared to a configuration without the nacelle. However, the root vortex breakdown does not influence the tip vortices as the turbulent intensity matches for the area where tip vortices are present. In short, this investigation shows that the influence of the nacelle geometry and root vortex system on the tip vortices is negligible. Thus, the model wind turbine designed by TUB is suitable for the investigation of tip vortices.

Development of a machine learning model for wind turbine fatigue and ultimate loads based on static loads

A machine learning model is trained on HAWC2 time-domain aeroelastic load simulations in order to provide a load surrogate model from static rotor loads input to lifetime wind turbine design loads, to be utilized in fast design loads evaluation for design optimization. The simulations are performed on the IEA-3.4-130-RWT with a range of design variations for tip-speed-ratio, pitch-ramp settings, and blade length scaling. The surrogate model is shown to provide accurate predictions of lifetime blade and turbine ultimate and fatigue loads for design variations within the training design space.

Altitude-dependent variations in some morphological and anatomical features of Anatolian chestnut

Morphological measurements of Anatolian chestnut (Castanea sativa Mill.) leaves were done within the borders of Abana district of Kastamonu province. The study was conducted using mixed (oak, beech, hornbeam, black pine, and yellow pine) medium (41% to 70%) and fully closed (71% to 100%) stands. Some leaf parameters, such as leaf blade width, petiole length, leaf blade length, leaf length, distance between lateral veins, teeth width, teeth length, the angle between the leaf base and the petiole, and the angle between the midrib and lateral veins, were measured. Moreover, stomata of the leaves picked up from precise altitudes were observed under a scanning electron microscope. The differences between fibre elevation, fibre wall thickness, elasticity coefficient, rigidity coefficient, Muhlstep rate, and Runkel ratio were found in the wood samples taken from different altitude zones. It was found that altitude did not affect leaf blade width, fibre length, fibre width, felting ratio, and lumen width. However, it was determined that altitude affected other studied characteristics.

Failsafe layer for wind turbine blades: Erosion protection of glass fiber composite through nanodiamond-treated flax composite top layer

Wind turbine blades are mainly made from E-glass fiber (GF) epoxy composites, because of their good ratio of strength to weight and costs. With the increase in blade length and tip speed, the problem of leading edge erosion is becoming more severe, reducing annual energy production and raising maintenance cost. It was recently shown that nanodiamond-treated flax fiber (FFND) composites have significantly less erosion than GF composites and could be an alternative for GF in the turbine blade aeroshells. However, FFND alone might not be suitable for manufacturing turbine blades at the large scale of modern wind turbines. Here, we show that a hybrid composite with a thin layer of only 1.5 mm of FFND on a GF base, can achieve the same superior results as bulk material FFND composite. In addition, we show and explain why aramid fibers, that are known for impact resistance, do not perform well as erosion protection. Our research shows the great potential of this technology to be implemented as a low-cost, lightweight skin layer on the leading edge. Acting as damage-tolerant failsafe layer, negligible ∼0.04% extra weight of the FFND could increase the blade’s base erosion resistance by a factor of 60±20 compared to plain GF, expanding the repair window, reducing costs, and enhancing reliability.

Individual architecture and photosynthetic performance of the submerged form of Drosera intermedia Hayne

Drosera intermedia grows in acidic bogs in parts of valleys that are flooded in winter, and that often dry out in summer. It is also described as the sundew of the most heavily hydrated habitats in peatlands, and it is often found in water and even underwater. This sundew is the only one that can tolerate long periods of submersion, and more importantly produces a typical submerged form that can live in such conditions for many years. Submerged habitats are occupied by D. intermedia relatively frequently. The aim of the study was to determine the environmental conditions and architecture of individuals in the submerged form of D. intermedia. The features of the morphological and anatomical structure and chlorophyll a fluorescence of this form that were measured were compared with analogous ones in individuals that occurred in emerged and peatland habitats. The submerged form occurred to a depth of 20 cm. Compared to the other forms, its habitat had the highest pH (4.71–4.92; Me = 4.71), the highest temperature and substrate hydration, and above all, the lowest photosynthetically active radiation (PAR; 20.4–59.4%). This form differed from the other forms in almost all of the features of the plant’s architecture. It is particularly noteworthy that it had the largest main axis height among all of the forms, which exceeded 18 cm. The number of living leaves in a rosette was notable (18.1 ± 8.1), while the number of dead leaves was very low (6.9 ± 3.8). The most significant differences were in the shape of its submerged leaves, in which the length of the leaf blade was the lowest of all of the forms (0.493 ± 0.15 mm; p < 0.001) and usually the widest. The stem cross-sectional area was noticeably smaller in the submerged form than in the other forms, the xylem was less developed and collaterally closed vascular bundles occurred. Our analysis of the parameters of chlorophyll fluorescence in vivo revealed that the maximum quantum yield of the primary photochemistry of photosystem II is the highest for the submerged form (Me = 0.681), the same as the maximum quantum yield of the electron transport (Me φE0 = 0.183). The efficiency of energy use per one active reaction center of photosystem II (RC) was the lowest in the submerged form (Me = 2.978), same as the fraction of energy trapped by one active RC (Me = 1.976) and the non-photochemical energy dissipation (DI0/RC; Me = 0.916). The ET0/RC parameter, associated with the efficiency of the energy utilization for electron transport by one RC, in the submerged plant reached the highest value (Me = 0.489). The submerged form of D. intermedia clearly differed from the emerged and peatland forms in its plant architecture. The submerged plants had a thinner leaf blade and less developed xylem than the other forms, however, their stems were much longer. The relatively high photosynthetic efficiency of the submerged forms suggests that most of the trapped energy is utilized to drive photosynthesis with a minimum energy loss, which may be a mechanism to compensate for the relatively small size of the leaf blade.

Verification of Euler–Bernoulli beam theory model for wind blade structure analysis

This paper presents a computational tool for analyzing the structural response of wind turbine blades using the advanced Euler–Bernoulli Beam theory. The objective is to achieve efficient computation of blade structural response under aerodynamic loading without sacrificing computational accuracy. This study involves the development of a Python-based computer program as a numerical tool, which utilizes inputs such as blade geometry and aerodynamic loading from Blade Element Momentum theory. The program outputs axially varying moments of inertia, spatial deflections of the blade, and stress distributions within the blade. The numerical tool is verified by comparing the results with both analytical solutions and far more time-consuming commercial finite element solvers. One of the key contribution of this research is the application of the polygon algorithm, which efficiently calculates the moments of inertia of web-stiffened turbine blades along the blade length. It is shown herein that this algorithm significantly reduces computational time while maintaining numerical accuracy as compared to the results obtained from commercially available finite element codes. The study confirms that the advanced Euler–Bernoulli beam theory, when combined with the polygon algorithm, is capable of accurately predicting the structural response of cambered and twisted wind turbine blades during the initial design phase.

Exploring the complexities of plant UV responses; distinct effects of UV-A and UV-B wavelengths on Arabidopsis rosette morphology

UV-B radiation can substantially impact plant growth. To study UV-B effects, broadband UV-B tubes are commonly used. Apart from UV-B, such tubes also emit UV-A wavelengths. This study aimed to distinguish effects of different UV-B intensities on Arabidopsis thaliana wildtype and UVR8 mutant rosette morphology, from those by accompanying UV-A. UV-A promotes leaf-blade expansion along the proximal–distal, but not the medio-lateral, axis. Consequent increases in blade length: width ratio are associated with increased light capture. However, petiole length is not affected by UV-A exposure. This scenario is distinct from the shade avoidance driven by low red to far-red ratios, whereby leaf blade elongation is impeded but petiole elongation is promoted. Thus, the UV-A mediated elongation response is phenotypically distinct from classical shade avoidance. UV-B exerts inhibitory effects on petiole length, blade length and leaf area, and these effects are mediated by UVR8. Thus, UV-B antagonises aspects of both UV-A mediated elongation and classical shade avoidance. Indeed, this study shows that accompanying UV-A wavelengths can mask effects of UV-B. This may lead to potential underestimates of the magnitude of the UV-B induced morphological response using broadband UV-B tubes.Graphical abstract

Control of separation flows of turbine-blade-tip turbines by splitter blades

Gas turbines cannot be directly reversed, and the astern operation of gas turbines still requires additional power transmission equipment to be achieved. To compensate for this deficiency, the application of turbine-blade-tip turbine in gas turbines was proposed. Turbine-blade-tip turbines have the characteristics of extremely low solidity and extremely high diameter-span ratio. Compared with conventional turbine blades, the capacity of turbine blades to restrain gas flow is greatly weakened, the separation flow is obvious when going astern, resulting in low efficiency. For the control problem of low solidity turbine-blade-tip turbines separation flow, a splitter blade control strategy is selected to suppress the separation flow. Adding a splitter blade between original rotor blades effectively improves the ability of rotor blades to restrain gas flow, significantly reduces separation phenomena, and significantly improves efficiency. As the axial chord length of the splitter blade shortens, the inhibitory effect on the separation flow decreases, and the ability of splitter blades to improve the efficiency gradually descends.

Feasibility study of geosynthetic vegetation substrate for hard-surface ecological restoration part 1: Development of designated vegetation

Current ecological restoration techniques often face challenges on steep and hard surfaces (e.g., concrete or rock surfaces) because of their reliance on soil as a vegetation substrate. Two geosynthetic-based ecological restoration techniques are proposed in which a geosynthetic material is used to replace the soil as a vegetation substrate on hard-surface slopes. In the first technique, vegetation is planted directly on a geosynthetic vegetation substrate (GVS), where the GVS provides water to the vegetation and room for the growth of vegetation roots. In the second technique, Hygrophila ringens is first planted on the GVS. This plant exhibits rapid growth initially and then dies after three months, creating a layer of humus over the GVS. Subsequently, herbaceous vegetation can grow over the GVS. The effectiveness of the GVS restoration technique was verified by conducting a one-year-long experimental study. During the experiment, vegetation such as Tall Fescue, Bermuda grass, bentgrass, Chinese holly, and Tifdwarf were grown on the GVS. Vegetation growth parameters such as blade length, biomass production, and species iteration were monitored with respect to the vegetation species and seeding density. The experimental results suggest that both ecological restoration techniques based on the GVS can successfully sustain vegetation on concrete slopes.

Maximisation the autonomous flight performance of unmanned helicopter using BSO algorithm

Abstract The usage areas of rotary or fixed wing unmanned aerial vehicles (UAV) have become very widespread with technological developments. For this reason, UAV designs differ in terms of aerodynamic design, flight performance and endurance depending on the intended use. In this study, maximising of the autonomous flight performance of the unmanned helicopter produced at Erciyes University using an optimisation algorithm is discussed. For this purpose, the input parameters of the dynamic model are chosen as blade length, blade mass density, blade chord width and blade twist angle of the unmanned helicopter and the proportional, integral, derivative gain coefficients of the lateral axis of the autopilot. The output parameters of the dynamic model are selected as settling time, rise time and maximum overshoot, which are autonomous performance parameters. The dynamic model consisting of helicopter and autopilot parameters is integrated into the back-tracking search optimisation (BSO) algorithm as an objective function. In the optimization process, where mean squared error (MSE) is used as the performance criterion, optimum input and output values were determined. Thus, helicopter and autopilot parameters, which are among the factors affecting autonomous performance, are taken into account with equal importance and simultaneously. Simulations show that the obtained values are satisfactory. With this approach based on the optimisation method, complex and time-consuming dynamic model calculations are reduced, time and cost are saved, and practicality is achieved in applications. Therefore, this approach can be an innovative and alternative method to improve UAV designs and increase flight performance compared to classical methods.

Research on the Effect of Thermal Coating Temperature on the Fatigue Performance of Wind Turbine Blade Bolts

The bolted connection of wind turbine blades is a bridge for transmitting blade loads. In recent years, with the rapid increase in blade length, the fatigue load at the blade root has also been continuously increasing. The bolt fatigue strength has always been a bottleneck in the interface design between blade and wind turbine hub. However, industry standards still hold conservative values for the S/N curve of bolt fatigue, and there are unclear requirements for thermal coatings, The S/N curves provided by the standards in different periods do not meet the actual processing requirements of bolts. In order to study the effect of thermal coating temperature on the fatigue performance of threads and provide a reasonable basis for the subsequent design of long blade bolt connections. Based on the actual processing technology of bolts, experiments were conducted on the S/N fatigue curves of thermal coated bolts at different temperatures. The experimental results prove that the slope of the inclined part of the low-temperature Dacromet test data and the fatigue strength under 2 million cycles are significantly higher than normal temperature Dacromet coated bolts. Low temperature Dacromet can effectively improve the fatigue strength of bolts.

Characterization based on colorimetry, physiology and sensory attributes among traditional jujube cultivars of Sindh, Pakistan

Jujube (Ziziphus spp.) fruit is attaining incredible attention in current global climatic changing scenario as the fruit has significant nutritional value but remained unexplored in past. Fifteen Jujube cultivars were selected at Jujube Research Station Tandojam, Sindh Pakistan, to exploit their morphological, physiochemical, color and sensory attributes. Measured traits like tee shape diverged as semi erect, erect and spreading whereas leaf shape was also found highly variable. Thorn attachment differed as cadoucous, partial and persistent and fruit shape was set as round, oblong, oval and ovate. Maximum leaf blade length was counted by Soofi sanghar (9.0cm) while lowest was found in Gola soghat (5.1cm). Maximum fruit mass was recorded in cultivar Late gola (31.57 g) whereas least was observed in Khirol mukkhri (5.63 g). Maximum stone weight was estimated in Early gola (10.55 g) whereas minimum was recorded in Khirol desi (6.4 g). Highest glucose level was observed in Soofi local (4.46 g 100 mL−1) while lowest glucose level was recorded in Khirol desi and Khirol Ratam (3.53g 100 mL−1). Best cultivars by appearance were Late gola and Early gola followed by Gola saffina, Gola soghat, Soofi sanghar and Soofi local. Findings of this study are useful for varietal improvement and to run successful breeding programmes. Commercially relevant features evaluated in this study are highly beneficial for jujube varietal identification and germplasm conservation

Hydrodynamic characteristics of a waterjet propulsion pump with front straight guide vane

ABSTRACT This research proposes a front straight guide vane (FSGV) to suppress pre-rotation before the waterjet pump, forming a double guide vane (DGV) with the rear guide vane (RGV). To verify its effectiveness, the hydrodynamic characteristics are studied numerically. The simulated external characteristic curve is consistent with the experimental result. The parameter optimisation of FSGV is processed. The result shows that FSGV can improve the adverse inflow pattern significantly and is beneficial to the hydrodynamic characteristics, and the propulsion performance is improved significantly with the increasing blade length and the axial gap. In addition, when the rotating speed is less than 3.29 times the design rotating speed, the influence on the cavitation performance by the DGVs in the impeller can be ignorable. However, the cavitation grows worse if the rotating speed increases far outweighing the design rotating speed, at which the propulsion pump never operates.

Modeling Design of Picohydro Power Generation System Using Crossflow Turbine

The goal of this project is to learn how to use a Crossflow turbine to create a Picohydro power plant system modeling. The manufacturing process, from design to evaluation, is the methodology employed. The turbine type utilized is a crossflow turbine, measuring 26 cm in outer diameter, 17.3 cm in inner diameter of the blade runner, and up to 35 pieces of blades. The calculations show that the distance between the blades is 2.3 cm, the blade length is 8.5 cm, the blade width is 4.4 cm, and the radius of curvature of the blade is 2.8 cm. The test results without load obtained the highest turbine rotation of 421 Rpm produces a voltage of 7.29 V before going through the boost converter.

Experimental cultivation of Neopyropia kitoi (Bangiales, Rhodophyta) for the establishment of a new marine crop in nori cultivation: A field experiment assessment of growth, pigments and free amino acids

To elucidate whether Neoporphyra kitoi strain OHN-1 has superior characteristics as a new marine crop in the nori farm setting, we compared OHN-1 and Neopyropia yezoensis f. narawaensis strain U-51 cultivated under identical conditions during the early nori season. We assessed the growth and the contents of photosynthetic pigments and free amino acids (FAAs), which affect the quality and taste of nori, between OHN-1 and U-51. The blade length of OHN-1 was found to be significantly longer than that of U-51, and OHN-1 exhibited high-yield characteristics. Notably, the blade thickness of OHN-1 was only slightly greater than that of U-51, despite the significant differences between the two strains. The contents of pigments and FAAs related to the taste were also higher in OHN-1 than in U-51. These results obtained with a N. kitoi cultivar demonstrated that N. kitoi has superior growth and quality characteristics in the nori farm setting. Thus, we concluded that N. kitoi could be used as a new marine crop for nori cultivation.