Blade Length Research Articles

The effect of swallow guano application on the growth of mustard plants (Brassica juncea L.)

This study aims to determine the effect of giving swallow guano on the growth of mustard greens (Brassica juncea L.) using the dose that produces the best growth of mustard greens (Brassica juncea L.). This type of experimental research used a completely randomised design (CRD), X0 (control), X1 (122 grams), X2 (245 grams) and X3 (490 grams) each with 6 repetitions. The population in this study were all mustard plants with a total sample of 24 plants. Parameter measurements performed consisted of plant height, leaf length, leaf width, number of leaves and fresh weight. The data analysis technique was descriptive analysis and the BJND advanced test was carried out for analysis of variance. The results of the descriptive analysis of mustard plant growth from the 22nd HST measurement to the 40th HST experienced an increase in the graph with treatment X2 (245 grams) giving the best treatment for measuring plant height parameters, namely 40.63 cm, leaf length 25.81 cm, leaf width 16.06 cm, the number of leaves is 9.8 and the wet weight is 149.5 grams. The results of the analysis of variance from the 22nd HST to the 40th HST obtained the results of Fhit > Ftab. The results of the BJND HST test showed that treatment X2 (245 grams) gave a real treatment of measuring the parameters of plant height, length, width, and number of leaf blades and wet weight, compared to treatments X1 (122 grams) and X3 (490 grams).

Characterization of frost-tolerant plum genotypes (Prunus domestica L.) in Nishabur region, Iran: a morphological and phenological assessment following natural spring frost event

BackgroundThe Nishabur region in Iran is an ancient hub for plum production, home to numerous seedling orchards and indigenous plum varieties. In 2020, an evaluation was conducted in the primary plum-growing zones of Nishabur following a harsh spring frost. Forty-one plum genotypes and local varieties capable of bearing fruit after frost incidents were selected for further examination. These plum selections were evaluated based on 60 morphological, pomological, and phenological traits related to flowers, fruits, and trees, in accordance with the UPOV (2020) plum descriptor.ResultsAmong the 41 genotypes evaluated, 35 exhibited high yields, demonstrating their potential as viable options for cultivation in frost-prone areas. The highest coefficient of variation (39.45%) was observed in the fruit color. Several genotypes demonstrated acceptable pomological traits. The genotype ‘Kh.Da.cv.04‘ has the highest values in terms of fruit weight (56.2 g), fruit width (46 mm), and fruit length (61 mm). Significant positive correlations were found between fruit length and leaf length and fruit weight and leaf blade length. Factor analysis revealed that fruit weight, size, and leaf length are the most influential factors, accounting for 52% of the total variance. In the principal component analysis (PCA), genotypes were clustered into four main groups, with ‘Kh.Da.s.02’ and ‘Kh.Da.cv.04’ positioned at the positive end of the second axis, separate from the other genotypes. Cluster analysis indicated that these genotypes, along with ‘Ha.Bokh.cv.30’, formed distinct clusters, considerably distant from the other genotypes, which were grouped into four main clusters.ConclusionsThis research highlights the presence of frost-tolerant genotypes and varieties with suitable environmental adaptability in the Nishabur region, demonstrating relatively acceptable diversity. These genotypes hold potential for breeding and germplasm conservation purposes.

An efficient automated measurement method for aero-engine fan blade geometric parameters

The length of aero-engine fan blades usually exceeds 1 m, making contact-based coordinate measuring machines (CMM) costly and time-consuming. To enhance measurement efficiency and accuracy, we developed a large-field flexible measurement system. We propose the system calibration method using a standard sphere as the reference and taking the turntable axis into account. A model-driven path planning and multi-view data fusion (MVDF) strategy was introduced to enhance efficiency and reduce misalignment due to the robotic arm’s lower positioning accuracy. To improve cross-sectional data sorting and thinning, we proposed an adaptive threshold synchronous sorting and noise suppression method. Additionally, we developed algorithms for chord length and maximum thickness extraction to streamline the process. Experiments show improved accuracy for blade thickness (0.092 mm) and chord length (0.096 mm).

Energy-resolved neutron imaging study of a Japanese sword signed by Bishu Osafune Norimitsu

Our research focuses on elucidating the crystallographic structure of Japanese swords in a nondestructive manner using the neutron imaging instrument RADEN at the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex (J-PARC). We developed an analysis method combining wavelength-resolved Bragg-edge imaging and wavelength-selective neutron tomography with a new strategy and applied it to an approximately 45-cm blade length Japanese sword signed by Bishu Osafune Norimitsu. Computed tomography was performed, and the three-dimensional analysis captured the characteristic internal structure of Kobuse. Kobuse is the most famous steel-combining structure of Japanese swords, where an outer steel with high-carbon content (Kawagane) covers a core steel with low-carbon content (Shingane). The crystallite size distribution obtained through Bragg-edge analysis could consistently explain the internal structure of two steels observed in neutron tomograms. Our nondestructive imaging revealed deep hardening, forming a wavy pattern more than 5 mm from the cutting edge.

Wave exposure influences kelp morphological and biomechanical phenotypic plasticity

Despite global and local declines in kelp ecosystems, luxuriant kelp beds persist at the Eastern Shore Islands (ESI) in Nova Scotia, Canada. Kelp beds in other regions of Nova Scotia were defoliated as the invasive bryozoan Membranipora membranacea and warming temperatures weakened kelp tissues and enhanced erosion and dislodgment. We propose that the high wave exposure at the ESI causes morphological and biomechanical phenotypic plasticity of kelp tissues. We compared differences in morphology and mechanical properties of the kelps Laminaria digitata and Saccharina latissima across 3 sites with different wave exposures, and differences in mechanical properties across blade lengths. Both species showed morphological plasticity; higher wave exposure resulted in longer and thicker stipes and thicker blades with increased branching. The mechanical properties of L. digitata showed increased breaking stress (strength) and strain (extensibility) with higher wave exposure, whereas S. latissima did not show mechanical plasticity with increasing exposure. For both species, blades were weaker but more extensible at the meristem and stronger but less extensible near the distal end of the blade. Larger and stronger kelp from high-exposure areas may promote the persistence of kelp beds in the ESI despite local stressors.

Numerical investigation on boiling crisis characteristic of a 7-rod HCF assembly in hexagonal lattice

Helical cruciform fuel (HCF) has the advantages of larger heat transfer area, enhanced coolant mixing and self-supporting, which contribute to increasing power density and safety margins. Compared with the square lattice configuration, the hexagonal arrangement of HCF assembly is more compact, which can help achieve a higher power density. In this paper, the flow characteristics and heat transfer behaviors of HCF in hexagonal lattice were predicted at high and low vapor quality during boiling crisis based on Eulerian two-fluid model. The influence of twist pitches and cross-sections of the fuel rod on heat transfer efficiency and fuel temperature was also studied. The cross-flow intensity changed periodically with a 30° cycle at low vapor quality, and did not fluctuate periodically at high vapor quality, which decreased with the increase of flow resistance. The highest heat flux of HCF rod was the at the blade root and the lowest was at the blade tip, and the maximum to average heat flux ratio was about 1.8. The peak vapor fraction and temperature occurred at leeside side of the fuel rods. The increase of the twist pitch reduced the critical heat flux (CHF), and the increase of blade length enhanced the non-uniformity of heat flux distribution. During boiling crisis, the maximum temperature of the fuel was lower than the phase transition temperature of U-50 wt%Zr alloy, which means the cladding meltdown caused by boiling crisis will occur before phase transition of the fuel.

Structural dynamic characteristics of vertical axis wind and tidal current turbines

Vertical axis turbines have received great attention in both offshore wind and tidal current energy communities considering their advantages of economic design and unidirectional operation. However, their commercialization process is rather slow compared with the development of horizontal axis turbines due to technical challenges resulting from higher loads from unsteady aero/hydrodynamic forces, centrifugal forces and gravity of the structures. These are mainly because, while the inherent unsteady tangential pulls and fatigue loads intensify the structural vibration, aggravating structural safety and fatigue life, the relationship between the geometric parameters and the structural responses of blades remains unclear. Therefore, in order to clarify this issue, in this study, we focus on the modal and transient analysis of vertical axis turbines using multi-body dynamics, geometrically exact beam theory and detached eddy simulation. We find that the natural frequency of the rotor is directly related to the ratio of blade length and arm length. The effect of arms cannot be ignored in the structural analysis of the turbine. Moreover, an increase of blade length intensifies the deformation and vibration of the turbine’s structure, making the turbine more prone to fatigue failure. This article is expected to extend the existing knowledge of wind and tidal current turbines and provide a reference for choosing proper design parameters and developing suitable-capacity vertical axis turbines.

Twist and chord optimization using the linearization method on the taper blade of a micro-horizontal axis wind turbineTwist and chord optimization using the linearization method on the taper blade of a micro-horizontal axis wind turbine

The research aims to optimize the geometry of taper blade profiles for the Horizontal Axis Wind Turbine (HAWT) to improve aerodynamic performance and minimize fabrication complexity. The study used blade linearization as an optimization method for identifying a desirable twist (β) and chord (Cr). This approach enhances accuracy and boosts computational efficiency. It simplifies the optimization process by reducing complexity. In contrast, traditional nonlinear methods are slower and more resource-intensive due to complex aerodynamic interactions. The best β and Cr distributions were found by linearization with elements 1 and 10 of the blade length and positions 5%, 15%, 25%, 35%, 45%, 55%, 65%, 75%, 85, and 95% of the blade elements. The linearization results were used to determine the optimum performance of the HAWT design using simulation. The optimal blades for HAWT were fabricated and their performance evaluated under real wind conditions. The linearization of the 45% twist and chord of elements 1 and 10 provided the best blade shape. Optimized twist and chord yielded HAWT performance with the Cp of 45% to 47% at rotational speeds of 200–900 rpm and wind speeds of 2–10 m/s. Twist and chord optimization increased the Cp from 39.71% to 46.43% with a rotational speed of 550 rpm at a wind speed of 6 m/s, as well as the maximum mechanical power from 424.28 watts to 500.35 watts at a wind speed of 10 m/s. The result from real wind conditions showed that manufactured HWAT produced an average electrical power of 294.19 watts at a rotational speed of 590.66 rpm. These results demonstrate that the optimized design approach presents a close match and is still reasonable in comparison to practical conditions.

Numerical Simulation and Model Test on Pressure Fluctuation and Structural Characteristics of Lightweight Axial Flow Pump

In order to explore the relationship between the hydraulic performance, pressure pulsation, and structural characteristics of lightweight axial flow pumps, this paper takes the axial flow pump as the research object and analyzes pressure pulsation and structural characteristics by changing the blade length and thickness to realize the lightweight design of the axial flow pump impeller. Compared with the initial scheme (Scheme 1), the mass of the impeller is reduced by 17.2% (Scheme 2) and 29.9% (Scheme 3), respectively. The lightweight axial flow pump (Scheme 2 and Scheme 3) has a lower pressure pulsation amplitude at the impeller outlet monitoring point under large flow conditions. After the lightweight design of the axial flow pump impeller, the blade becomes shorter, the mass becomes lighter, and the cavitation performance will become worse. The maximum equivalent stress of Scheme 2 and Scheme 3 is increased by 2.8% and 31.9%, respectively, compared to Scheme 1. The maximum deformation of Scheme 3 increased by 27% compared to Scheme 1. This research can provide guidance for the lightweight optimization design of the axial flow pump.

An integrative taxonomic revision of the Chaerophyllum hirsutum complex (Apiaceae) using morphological and molecular markers

Background and aims – Chaerophyllum hirsutum represents a complex of taxa with varying treatments and ranks across floras. Using both morphometric and molecular markers, we assessed the robustness of C. hirsutum, C. elegans, C. villarsii, and C. villarsii var. cicutariiforme. Material and methods – Ten morphometric variables and two ratios were calculated. Based on the sequencing of six plastomes, the rps16 intron was selected as the more variable region and sequenced on a broader sampling. Additionally, we also sequenced the nrDNA internal transcribed spacer 2 (ITS2) using Illumina technology to obtain intra-individual allelic diversity. Key results – Morphologically, the most easily differentiated taxon was C. elegans, especially using the number of subterminal umbels. The distinction between C. hirsutum and C. villarsii was rather clinal, but is mainly based on the degree of carpophore division. Finally, C. villarsii var. cicutariiforme was less easily distinguishable from the three others, but partly using the carpophore length and the total length of basal leaf blade. The cpDNArps16 clearly distinguished C. elegans from the three other taxa of the complex, which rather showed a geographical pattern of cpDNA diversity. The nrDNA ITS2 partially distinguished C. villarsii from the other taxa, without distinction of C. elegans. Conclusions – The present study supports the species differentiation of C. elegans based on both morphology and chloroplast genome. Furthermore, C. villarsii var. villarsii and C. villarsii var. cicutariiforme could potentially be recognized as distinct varieties within C. hirsutum. This will need to be confirmed by future studies using a larger sampling size and more comprehensive markers, covering a broader portion of the nuclear genome.

A Physiological Analysis of Desiccation Stress in the Green Tide Species Ulva stenophylloides and Ulva uncialis in the South Pacific

Global green tide blooms of the Ulva genus have been increasing due to human activities, with mass accumulation in Algarrobo Bay, Chile, causing ecological and social issues. In this area, five Ulva species were previously identified, with Ulva stenophylloides dominating across seasons and intertidal zones; Ulva uncialis was the second most abundant, mainly in winter. In this study, we tested the hypothesis that U. stenophylloides is more tolerant to desiccation than U. uncialis, explaining its dominance in the upper intertidal zone. Based on in vitro cultures, we assessed the impact of desiccation stress on weight, blade length, cellular activity, and lipoperoxide levels. In U. uncialis, desiccation treatment caused a decrease in weight; conversely, in U. stenophylloides, both control and desiccation treatments caused a slight decrease in weight. No significant differences (p > 0.05) in blade length or lipoperoxide levels as a function of culture time were detected in the control and desiccation treatment groups for both species. Furthermore, desiccation had no negative effects on the cellular activity of either species. Although the observed weight changes suggest that U. uncialis is more desiccation-tolerant than U. stenophylloides under the experimental conditions, the cellular activity and lipoperoxidation indicate high desiccation tolerance in both species, which partly explains their intertidal dominance.

Evaluation of the diversity of the morpho-agronomic characteristics of Corchorus olitorius L. cultivars developed in Saudi Arabia

Corchorus olitorius is considered a crop with high nutritional value. The C. olitorius crop is cultivated in many regions of Saudi Arabia. There is a lack of research on genetic diversity among these varieties. This work aimed to evaluate the diversity in the morphological characteristics of KSA jute germplasms and compare them to international germplasms. This study included 8 local jute germplasm seeds collected in Saudi Arabia and 16 international jute germplasm seeds from Asia, Africa and the USA. Twenty-one quantitative and qualitative characteristics of the jute samples from the stem, leaves, and fruits were evaluated. These characteristics were evaluated using many reliable statistical methods, such as multivariate analysis and one-way analysis of variance (ANOVA). Morphological traits, especially plant height, days to 50% flowering, leaf blade length, leaf blade width, leaf petiole length, pod pedicel length, pod length, pod width, number of pods per plant and leaf area, significantly differed among the jute samples. This is the first study to compare local jute germplasms in the KSA to international, to provide important information on their morphological diversity. This information can be used in crop improvement and conservation programs.

The impact of extreme wind conditions and yaw misalignment on the aeroelastic responses of a parked offshore wind turbine

As global energy demands rise and the urgent need to reduce carbon emissions, offshore wind energy technology has evolved rapidly, becoming a vital component of the world’s energy portfolio. However, offshore wind turbines face new challenges due to complex marine environments. Under extreme conditions such as strong winds and yaw misalignment, parked wind turbines exhibit complex aerodynamic and structural responses that significantly differ from those in normal operating conditions. These responses, crucial to the integrity and safety of wind turbines, demand thorough analysis. This article presents an in-depth aeroelastic analysis of a parked 5 MW offshore wind turbine using a sophisticated and precise numerical model. It explores the impacts of incoming wind speed and yaw misalignment on the aerodynamic loads and structural behaviors of the wind turbine. The findings indicate that gravity plays a significant role in blade structural responses for a parked wind turbine. Additionally, higher wind speeds elevate aerodynamic forces, leading to more pronounced fluctuations in root forces and tip deflections. The increase in wind speed triggers and exacerbates high-frequency edgewise vibrations of the blade, further leading to fluctuations and instability in the loads. The study also reveals that yaw misalignment causes the AOA changes significantly over time, and generates intermittent fluctuations in lift and drag, leading to extra blade vibrations with the maximum amplitude exceeding 10% of the blade length. This research enhances the current understanding of the operational safety of offshore wind turbines, particularly under extreme conditions. It aims to provide valuable insights and guidance for researchers and developers in designing and monitoring the performance of offshore wind turbines, ensuring their resilience and efficiency in challenging environments.

Damage evolution simulation and lifetime prediction for composite blades under continuous droplet impacts

Offshore wind power generation is a promising technology in renewable energy applications due to its high reserves of wind energy in sea areas. To improve the energy transformation efficiency, the blade length of the offshore wind turbines has become larger and larger, and it has made rain erosion be one of the most frequent failures during the turbine operation. As the natural rainfall is stochastic in spatial and time domains, it is difficult to depict the damage evolution process caused by rain impact exactly. Therefore, regular and continuous droplet impact simulation and experiments present an alternative methodology for this issue. With the composite structure of the blade and deformability of the liquid droplet in consideration, a fluid solid interaction model will be established to investigate the impact response and subsequent damage evolution. In which, the Smooth Particle Hydrodynamics (SPH) model is utilized to depict the constitutive relationship within the droplet, and Finite Element Method (FEM) is used to construct the Representative Volume Element (RVE) model of the blade leading edge. The impact process is simulated first to obtain the impact pressure distribution at the contact center and velocity field in the droplet. Furthermore, the stress wave propagation in the blade multilayer structure can be analyzed. Owing to the multiaxial fatigue feature of the continuous droplet impact, the continuum damage mechanics is integrated with the fatigue criterion and the Jump-in-Cycle procedure is used to simulate the high-cycle fatigue process. The damage factor distribution on the blade coating surface and its influence on mechanical properties are analyzed. Thereafter, the droplet impact fatigue life can be accumulated based on Miner’s linear rules. The theoretical achievements are validated by experimental data provided by Rain Erosion Testing (RET), which shows a good agreement between each other. As a result, V-N curves and D-N curves, i.e. quantitative relationship between droplet falling conditions and impact fatigue life, are established. The achievements in this study can provide an effective tool for rain erosion mechanism analysis and life prediction in industrial applications.

MORFOMETRIK LAMUN DI ZONA INTERTIDAL PERAIRAN PANTAI DESA ADMINISTRATIF MALAKU KECAMATAN SERAM UTARA KABUPATEN MALUKU TENGAH

Background: Seagrass is an angiosperm flowering plant that can grow well in coastal environments. Seagrass is a one seed plant that has roots, stems, rhizomes, leaves, flowers, fruit and seeds. Differences in substrate type, environmental conditions and nutrient content can influece the existence of seagrass species and their morphometric shapes.This research aims to determine the morphometric of seagrass in the intertidal zone of coastal waters of Malaku Administrative Village, North Seram Sub-district Methods: Sampling used a roaming survey method in the intertidal zone of coastal waters of Malaku Administrative Village. The research data were analyzed descriptively based on the results of species identification, observations and measurements of the segrass morphological structure. Results : The type of seagrass found in the intertidal zone of the coastal waters of the Malaku Administrative village is Cymodocea serulata, Cymodocea rotundata, Halophila ovalis, Halophila minor, Halodule pinifolia, Halodule uninervis, Thalassia hemprichii, and Syringodium isoetifolium. Morphometric forms of seagrass include : Root length ±3cm-16,5cm. Rhizome distance ±1cm–4,5cm. leaf blade length ± 2,4cm-15cm. The shape of the leaf blade is flat, oval, cylindrical, serrated at the tip of the leaf and small in length. Leaf width ±0,2cm-1cm, seagrass stand heigth ± 3-19,3cm. Conclusion: From the research results obtained, it can be concluded that the intertidal zone of the coastal wters of the malaku administrative village are 8 (eigth) types of seagrass and have morphometric structure that vary in size.

Ecometrics demonstrates that the functional dental traits of carnivoran communities are filtered by climate.

Terrestrial carnivorans, with their diverse diets and unique adaptations such as the carnassial tooth, offer insights into the connections between functional traits and the climatic and environmental conditions they inhabit. They shed light on functional trait-environment relationships at the highest trophic levels across a broad range of environmental conditions. In this study, we evaluate the relationship between relative blade length (RBL) of the lower carnassial tooth, a key dietary adaptation among terrestrial carnivorans for slicing and grinding food items, and climate. We propose RBL as an ecometric trait and test the hypothesis that community-level RBL is correlated with climate and mediated by environmental effects on food availability. Our findings show that communities with higher mean and broader variance of RBL are typically located in warmer and wetter climates, suggesting a relationship between carnivoran dietary diversity and climate. Conversely, communities with a lower mean and narrower variance of RBL predominantly occupy cooler, drier places. This indicates that community-level carnivoran dietary traits have the potential to serve as indicators of environmental conditions. Given the robust fossil record associated with carnivorans, we also show how RBL can be used as a proxy for reconstructing paleoclimates by examining trait change at seven sites in North America to estimate changes in temperature and precipitation over time in relation to changes in carnivoran community assembly. Understanding the nature of trait-environment relationships can help us anticipate biological impacts of ongoing environmental change and the geographic regions at the greatest risk of ecological disruption.

Heritability and Genetic Advance Studies on Fruit Yield and It’s Attributes Traits in Brinjal (Solanum melongena L.)

The present investigation was conducted at the Main Vegetable Research Station, Anand Agricultural University, Anand during the period of 2023-2024. The experimental material comprised twelve generations viz., P1, P2, F1, F2, B1, B2, B11, B12, B21, B22, B1S and B2S of four families involving eight diverse cultivars of brinjal (Solanum melongena L.) used to study the heritability and genetic advance of brinjal for yield and shoot and fruit borer incidence. The experiment was laid out in a compact family block design with three replications. Higher magnitude of heritability along with a higher value of genetic advance as per cent mean was estimated for day to first flowering in family 2, plant height in family 1 and family 4, leaf blade length in family 4, leaf blade width in family 2, fruit length in all families, fruit girth in family 3 and 4, fruit weight in all families expect to family 2, fruits per plant in family 2, fruit yield per plant in all families expect family 4 and shoot and fruit borer incidence in family 2 which suggested preponderance of additive gene effect. The higher value of heritability coupled with the higher value of genetic advance shows higher selection efficiency, permitting plant breeders to efficiently select individuals or groups of individuals. In crops like brinjal, high narrow sense heritability estimates are particularly beneficial for developing enhanced varieties through the fixation of additive gene effects.

Analysis of Flow Field Characteristics in the Three-Phase Jet Fire Monitor Head

To enhance the jet performance of the three-phase jet fire monitor (TPJFM), an analysis was conducted on the internal flow field (IFF) characteristics of the monitor head. Using the volume of fluid method, the impact of key structural parameters, such as the powder-pipe bending angle and the supporting blade length, on the turbulent kinetic energy (TKE) of the IFF, the velocity distribution uniformity at the nozzle outlet, and the pressure drop (PD) between the inlet and outlet of the internal flow field, was analyzed. The study revealed that increasing the bending angle of the powder pipe will lead to a significant improvement in the uniformity of velocity distribution in the IFF. Extending the supporting blade length helps reduce the average TKE at the nozzle outlet but has a minimal impact on the velocity distribution uniformity and the PD between the inlet and outlet. Reasonable design of the distance between the supporting blades and the bending section of the powder pipe can improve the IFF characteristics, reducing local pressure losses and peak TKE. The research results can effectively improve the IFF characteristics, enhance jet performance, and provide theoretical basis and technical support for the design and optimization of the TPJFM.

Numerical Investigation on the Influence of Turbine Rotor Parameters on the Eddy Current Sensor for the Dynamic Blade Tip Clearance Measurement.

Eddy current sensors are increasingly being used to measure the dynamic blade tip clearance in turbines due to their robust anti-interference capabilities and non-contact measurement advantages. However, the current research primarily focuses on enhancing the performance of eddy current sensors themselves, with few studies investigating the influence of turbine rotor parameters on the measurements taken by these sensors for dynamic blade tip clearance. Hence, this paper addresses this gap by using COMSOL Multiphysics 6.2 software to establish a finite model with circuit interfaces. Additionally, the model's validity was verified through experiments. This model is used to simulate the voltage output of the sensor and the measurement of dynamic blade tip clearance under various rotor parameters. The results indicate that the length and number of blades, as well as the hub radius, significantly affect the sensor voltage output in comparison to rotation speed. Furthermore, we show that traditional static calibration methods are inadequate for measuring dynamic blade tip clearance using eddy current sensors. Instead, it is demonstrated that incorporating rotor parameters into the calibration of eddy current sensors can enhance the accuracy of dynamic blade tip clearance measurements.

Heat transfer enhancement of solar collector tube enhanced by swirling flow

Heat transfer capability was one of the key factors that restricted the collecting efficiency of the parabolic trough collector tube. In this paper, a swirl-enhanced solar collector tube with a cyclone inserted at the inlet of the metal tube was purposed to improve the heat transfer capability of the collector tube. The cyclone induced a swirling flow and improved the convection inside the tube, thereby enhancing the heat transfer capacity of the tube. The advantage of the cyclone tube was not changing the structure and processing technology of the original heat collector tube. A numerical model was established to study the flow and heat transfer characteristics of the cyclone tube using Ansys CFX software. The results demonstrated that the swirling flow was over a distance exceeding 1 m and the fluctuations in turbulent kinetic energy was within a distance of approximately 0.2 m. The heat transfer capacity was significantly enhanced within this 0.2 m region and the maximum normalized Nusselt number reached 2.81. Finally, the influences of the blade length and the blade numbers on the heat transfer capability were researched. Results showed that cyclone with short blades and more blades resulted in better enhancing effects.