Blade Curvature Research Articles

The Rheological and Energy Study of the Blade Torsion Effect in a Vessel Stirred by Two- Blade Impeller

This work presents a comprehensive numerical study on the hydrodynamic behaviour and power consumption of a cylindrical vessel stirred by a two-blade impeller, employing the simulation by the RRF method (Rotation Reference Frame). The study focuses on addressing the issue of power consumption in the context of blade orientation referring to different values equal to α=15°, α=30°, α=45°, α=90°, α=135°, and α=180°. The primary objective is to identify a novel design that promotes effective fluid circulation and exhibits lower energy consumption compared to standard geometries. By employing the commercial CFD code ANSYS CFX 14.0, the research delves into the impact of fluid rheology and blade curvature on mixing efficiency. The validation of the results, achieved by comparing them with data from existing literature, demonstrated a satisfactory agreement. According to our obtained results, it has been observed that the energy consumption decreases when the blade orientation exceeds 90°. This study contributes valuable insights into both blade orientation and Reynolds number effects (ranging from 1 to 100 for laminar flow), with the ultimate goal of proposing innovative designs that optimize fluid mixing efficiency while minimizing the consumed energy.

Study on performance and structure optimization of self-priming pump based on response surface method

ABSTRACT This paper aims to improve the performance of a self-priming pump by optimizing blade geometry parameters, with the head and efficiency as the targeted objectives. Based on the Response Surface Methodology (RSM), the Computational Fluid Dynamics (CFD) were conducted to investigate the pressure distribution characteristics inside the pump chamber and the variations in pump performance parameters. By analyzing the internal pressure field of the pump, it is concluded that adjusting the blade curvature radius and the outlet angle can change the area and uniformity of the low-pressure zones within the fluid to improve the pump performance. The results show that the fitted regression equations indicate that the blade curvature radius and the blade outlet angle have a significant impact on pump performance, while the blade inlet angle has a relatively minor effect. When the outlet angle β 2 = 60 ∘ , the change of the inlet angle β 1 and the curvature radius R has basically no impact on the efficiency. The self-priming pump achieves its optimum performance when β 1 = 50.8 ∘ , β 2 = 52 ∘ and R = 84.9 mm. Compared to the original model, the optimized model’s head increases by 7.12%, H = 34.12 m; and the efficiency improves by 3.40%, η = 63.8.

Influence of Rotor Inflow, Tip Loss, and Aerodynamics Modeling on the Maximum Thrust Computation in Hover

Comprehensive rotorcraft simulation codes are the workhorses for designing and simulating helicopters and their rotors under steady and unsteady operating conditions. These codes are also used to predict helicopters’ limits as they approach rotor stall conditions. This paper focuses on the prediction of maximum rotor thrust when hovering (due to stall limits) and the thrust and power characteristics when the collective control angle is further increased. The aerodynamic factors that may significantly affect the results are as follows: steady vs. unsteady aerodynamics, steady vs. dynamic stall, blade tip losses, curvature flow, yaw angle, inflow model, and blade-vortex interaction. The inflow model and tip losses are found to be the most important factors. For real-world applications vortex-based inflow models are considered the best choice, as they reflect the blade circulation distribution within the inflow distribution. Because the focus is on the impact of aerodynamic modeling on rotor stall, the blade design and its flexibility are intentionally not considered.

The influence of blade curvature radius on the internal unsteady characteristics of a centrifugal pump

AbstractTo study the influence of the blade curvature radius on the flow‐induced vibration and noise of the centrifugal pump, the internal sound field of the IS 80‐65‐160 centrifugal pump was numerically calculated by adjusting the blade wrap angles to change the blade curvature radius. The RNG (Reynolds Time Average Simulation) turbulence model was selected for the numerical calculation of the centrifugal pump. The numerical simulation of the whole flow channel of the centrifugal pump was carried out using Ansys Fluent software, and the external characteristic curve of the centrifugal pump was obtained. The influence of different blade wrap angles on the internal pressure, velocity and Turbulent Kinetic Energy of the centrifugal pump was obtained. On the basis of the sound–structure coupling equation, the unsteady sound field of the centrifugal pump was calculated, and the time domain and frequency domain characteristics of the pressure pulsation at each monitoring point were obtained. The calculation results showed that the dynamic and static interference between the impeller and the volute tongue mainly caused the vibration of the centrifugal pump. By appropriately increasing the blade wrap angles, the pressure pulsation in the volute fluid domain could be effectively reduced. The vibration and noise test bench of the centrifugal pump was set up to verify the test. The experimental results showed that at the double‐blade frequency, the variation trend of the experimental value and the simulated value of the outflow flow‐induced noise of the centrifugal pump were consistent, which verified the accuracy of the sound field simulation calculation. When the blade wrap angle , it could effectively reduce the internal sound pressure level and the flow‐induced vibration and noise of the centrifugal pump. By adopting measures such as grid encryption at the position of the tongue, nonstationary calculation and comparison of different turbulence models, the accuracy of the calculation results of the internal flow field and sound field of the centrifugal pump is effectively improved, and the accuracy and reliability of the experimental results are ensured. The above research results had certain reference significance and application value for improving the working efficiency of centrifugal pumps and reducing flow‐induced vibration and noise.

3D CFD study of a DeepWind demonstrator at design, off-design and tilted operating conditions

Energy transition, towards increased renewables, demands for reliable, efficient, and innovative technical solutions, at acceptable cost. Wind energy conversion exhibits one of the greatest potential, mainly in off-shore deployment. Vertical-axis wind turbines are characterized by a reduced wave recovery and enhanced power output, which boost the installation of bigger capacity turbines, properly cluster to maximize the farm density. These two requirements entail deeper understanding of the wake physics and detailed description of the machine performance. A careful 3D CFD investigation, supported by experimental validation, is carried out to define the relevant flow mechanism of a lab-model, DeepWind demonstrator, in upright and tilted condition. The results show how the performance is varying along the span, and how it is affected by a skewed flow. The lower part of the machine benefits from combined effect of blade curvatures and rotor inclination. A thorough description of the complex vortical field complements the performance data, and provide useful considerations apt for promoting the design of future vertical-axis wind turbines, for floating off-shore applications. The performance parameters are then computed for a full-size rotor to show how the Reynolds effect play a relevant role in the machine aerodynamics of bigger capacity turbines.

PEMBUATAN PROTOTYPE PLTB TURBIN ANGIN SAVONIUS TIPE-U SUMBU VERTIKAL DENGAN SUDUT KELENGKUNGAN SUDU 135o MENGGUNAKAN SUMBER ANGIN BUANGAN EXHAUST KITCHEN

Bali is known as a tourism island for both local and foreign tourists, therefore there are many hotels, resorts and restaurants for tourists. In order to fulfill the Bali Clean and Green program, the Regional Government of Bali encourages tourism-related businesses, such as hotels, to construct sources of electricity from new renewable energy. The authors use waste energy in the form of exhaust wind from the kitchen exhaust fan in addition to using natural wind energy. Artificial wind is created when waste energy from exhaust fans is converted into a form that can be used to rotate or power a generator. Making a PLTB prototype with a vertical axis Savonius turbine with a blade curvature angle of 135 degrees is the goal of this research in order to increase the wind sweep area and obtain the highest output ratio. This study employed a quantitative methodology. This study was able to maximize the exhaust fan's wind speed, which was 5.84 m/s. The highest generator output value is at 2.93 vdc, 0.62 mmA, and 1.80 Watt for a 2-blade turbine and 40 ohm load, and at 3.22 vdc, 0.74 mmA, and 2.39 Watts for a 4-blade turbine and 40 ohm load.

A Simplified Optimization Model for Hydrokinetic Blades with Diffuser and Swept Rotor

The use of a diffuser in hydrokinetic turbines can improve the power coefficient. However, the risk of cavitation in the rotor blades increases. Studies suggest that backward-curved blades can reduce the axial load on the rotor and therefore prevent cavitation. Therefore, this work develops an optimization procedure applied to backward-curved blades in hydrokinetic turbines with diffusers based on the Blade Element Momentum Theory. The main contribution is to consider both the sweep effect and the presence of a diffuser in the optimization in an innovative way. We use a radial transformation function that adjusts the radial position considering the curvature of the blade during optimization under the effect of the diffuser. The results showed that the increase in blade curvature resulted in greater chord distributions and twist angles, especially at the blade tips. The Prandtl’s loss factor was not sensitive to sweep, but the linked circulation increased at the blade tips, suggesting an increased risk of cavitation. Depending on the sweep angle, the optimized blades were able to mitigate or avoid cavitation. In particular, a sweep angle of 30∘ eliminated cavitation. This study indicated that the proposed optimization can effectively prevent cavitation, showing satisfactory results.

Analyzing the impact of blade geometrical parameters on energy recovery and efficiency of centrifugal pump as turbine installed in the pressure-reducing station

Improving renewable energy efficiency has received great attention globally by increasing demand for energy supplies and air pollution issues. The Soft Pressure Regulation System (SPRS) as a potential technology provides the possibility of regulating pressure and energy recovery in pressure-reducing stations. Pump as Turbine (PAT) is a good choice for installation in Water Distribution Network (WDN) pipelines due to its availability and economic benefits, and it can play a key role in decreasing startup time and return on investment. In this paper, the performance of centrifugal PAT under WDN conditions has been numerically and experimentally evaluated, and simulation validation was performed, too. Analyzing the work conditions of the pressure reduction station shows that the hourly flow rate trend changes considerably based on end-user demand. A major portion of the SPRS's operation time occurs in off-design conditions of the PAT, and efficiency is drastically decreased considering the lack of flow control tools. The effect of blade inlet angle, blade warp angle, blade curvature, and change of these parameters simultaneously was investigated to increase the high-efficiency working range. Losses resulting from flow separation and formation of vortices are significantly decreased by simultaneous change of blade geometrical parameters in the range of design point and higher flow rates (Q ≥ 1.0QBEP). Since the highest frequency of flow rate based on statistical analysis occurs in this range, the total power generation of SPRS improves significantly. The PAT efficiency with the improved impeller at part-load condition (0.8QBEP), design condition (QBEP), and over-load condition (1.2QBEP) is improved by 0.83 %, 2.69 %, and 6.71 % in comparison with the original impeller, respectively.

Geometrically exact aeroelastic stability analysis of helicopter composite rotor blades in forward flight

In this paper, a sophisticated method for analyzing the geometrically exact aeroelastic stability of composite rotor blades in forward flight has been proposed. The unique advantage of the proposed method is to use the geometrically exact beam model with the updated Variational Asymptotic Beam Sectional analysis (VABS) for structural modeling to not only calculate the blade cross-sectional properties and blade spanwise deformations more accurately, but also take into account the effect of transverse shear deformation and blade initial twist and curvatures sophisticatedly. The Peters finite state airloads theory and the Peters-He finite state dynamic inflow model are coupled to calculate the three-dimensional unsteady airloads applied on the blade. The auto-pilot trim scheme is adopted to determine the blade pitch controls. The finite element spatial discretization method, the Newmark numerical integration method, the Newton-Raphson method and the moving-block analysis method are combined to solve the established geometrically exact aeroelastic equations and obtain the geometrically exact aeroelastic stability of composite rotor blades. The proposed method is validated by correlation with existing analytical results. The investigations show that the effect of transverse shear deformation on the aeroelastic stability of composite hingeless rotors in forward flight is non-negligible. Blade initial curvatures have significant effect on the aeroelastic stability of composite hingeless rotors in forward flight, which is not only related to the blade elastic couplings, but also to the advance ratio.

Design and Analysis of an Adaptive Dual-Drive Lift–Drag Composite Vertical-Axis Wind Turbine Generator

In this paper, based on the lift-type wind turbine, an adaptive double-drive lift–drag composite vertical-axis wind turbine is designed to improve the wind energy utilization rate. A drag blade was employed to rapidly accelerate the wind turbine, and the width of the blade was adaptively adjusted with the speed of the wind turbine to realize lift–drag conversion. The aerodynamic performance analysis using Fluent showed that the best performance is achieved with a blade curvature of 30° and a drag-type blade width ratio of 2/3. Physical experiments proved that a lift–drag composite vertical-axis wind turbine driven by dual blades can start when the incoming wind speed is 1.6 m/s, which is 23.8% lower than the existing lift-type wind turbine’s starting wind speed of 2.1 m/s. At the same time, when the wind speed reaches 8.8 m/s, the guide rail adaptive drag-type blades all contract and transform into lift-type wind turbine blades. The results show that the comprehensive wind energy utilization rate of the adaptive dual-drive lift–drag composite vertical-axis wind turbine was 5.98% higher than that of ordinary lift-type wind turbines and can be applied to wind power generation in high-wind-speed wind farms.

Optimising Highway Energy Harvesting: A Numerical Simulation Study on Factors Influencing the Performance of Vertical-Axis Wind Turbines

Vertical-axis wind turbines (VAWTs) are an innovative solution for energy harvesting, as they harness the power of the wind by enabling rotational motion around a vertical shaft situated on the ground. This paper deals with the design optimisation of VAWT systems for highway energy harvesting. The four design parameters, blade number, blade curvature angle, blade thickness and blade diameter ratio, have been investigated to find their respective optimalities for the enhanced energy efficiency of VAWT systems. Computational fluid dynamics (CFD) simulations are conducted in Ansys Fluent using a Banki turbine model created in Solidworks®, with a constant velocity inlet of 4 m/s and rotational speeds ranging from 0.5 to 3 rad/s. The simulations consider the placement of the turbine in the central reservation of a highway with a windshield for enhanced performance. From the results, it was observed that increasing blade thickness and blade number improve turbine performance, with maximum power coefficients achieved at specific tip speed ratios (TSRs). The optimal blade diameter ratio has been found to be approximately 0.75 for TSR values between 0.1 and 0.5, whilst a ratio of 0.83 gave the best performance at higher TSR values. Also, a blade curvature angle of 60 degrees has been found optimal for slow rotations, while 100 degrees yielded the highest power coefficient for faster rotations. The study could also highlight the significance of blade curvature angle variation, resulting in a notable 14% performance increase compared to the baseline. The geometric changes proposed in the study allow for greater power extraction from the same turbine footprint, leading to increased energy efficiency in VAWT systems.

Multidisciplinary robust optimization approach of fan rotors under structural constraints with blade curvature

The robust optimization approach is an important method to solve the problem of fans/compressors performance disparities caused by geometric tolerances. Nonetheless, since the optimum design of turbomachinery blades is multidisciplinary in nature, traditional robust optimization approaches that only consider aerodynamic performance may result in the blade strength exceeding their material limit. Therefore, it is necessary to investigate the multidisciplinary robust optimization approach (MROA) considering both aerodynamic and structural performance. For MROA, there is a big challenge of huge computation cost and runtime for the time-consuming high-fidelity CFD and FEM. In this paper, a new method to reduce the computation cost and runtime of MROA is proposed by using the blade curvature to approximate the evaluation of blade stress. Firstly, data mining by self-organizing mapping method is used to analyze and extract the constraint value of the blade curvature. And the blade curvature constraint value is used as a penalty function instead of the time-consuming high-fidelity FEM, which greatly reduces the computational cost and runtime of the multidisciplinary optimization. Then, Polynomial chaos Kriging (PCK) is then used as a surrogate model for uncertainty quantification (UQ) of aerodynamic performances, and one MROA based on the PCK model-based UQ method and the curvature constraints is developed. The proposed method is verified using a fan rotor as a case study. The results show that the maximum stress of the traditional optimization method was 453 MPa, which exceeded the yield limit of aluminum alloy (420 MPa). In contrast, the maximum stress of the method proposed in this paper was 343 MPa. In terms of aerodynamic performance, compared with the baseline, the mean efficiency of the traditional and the proposed method increased by 2.6% and 2.1%, with a variance reduced by 45.5% and 48.5%, respectively. Therefore, compared with the traditional robust optimization method, the proposed method reduces the maximum stress of the blade by 24.3% with almost the same improvement for aerodynamic performance means and disparities.

Effects of structural parameters of laidback fan-shaped hole on film cooling effectiveness on convex surface

To burden higher turbine inlet temperature, shaped holes are introduced to the film cooling of turbine blade. The structural parameters of shaped holes are the key variables for the cooling design. Relevant literatures conduct studies mainly on the flat surface, which excludes the influence of blade curvature. And their conclusions are inconsistent, appealing for further mechanism study. In this paper, the effects of structural parameters of laidback fan-shaped hole are experimentally investigated on a convex surface. Pressure sensitive paint technique is used to measure the adiabatic effectiveness. Three parameters, including forward expansion angle (0–12 deg), lateral expansion angle (2–20 deg) and length of the diffuser (2–14 mm), at five blowing ratios (0.5, 0.8, 1.0, 1.3 and 1.5) are tested. Numerical simulation is also employed to present the mechanism of jet-mainstream interaction. It is shown that, at the blowing ratio over 0.8, the optimal forward and lateral expansion angle lies in the medium range. Cooling effectiveness increases before the optimal value due to better film attachment but deteriorates after then due to coolant separation within the hole. In contrast, at the blowing ratio of 0.5, the results become different because the coolant attaches well enough that the change of the coolant dissipation rate appears more dominant. The competition of two factors, weaker kidney vortex entrainment and larger shear surface, leads to an unpredictable trend. Finally, suggestions are provided for the parameter selection on the blade suction surface. As a comparison, the same studies are numerically conducted on a flat surface. Distinctly, at high blowing ratio, the effectiveness increases monotonously without a drop at too large expansion because the absence of radial pressure gradient worsens jet attachment and magnifies the effect of promoting jet attachment.

Optimization of a novel impulse gas turbine nozzle and blades design utilizing Taguchi method for micro-scale power generation

This study is conducted to optimize the nozzle and blade of a compact non-combustion impulse gas turbine driven by the pressurized gas line with Computational Fluid Dynamics (CFD) approach and Taguchi method. For nozzle, throat diameter, nozzle inlet and outlet diameter and convergent-divergent length were investigated. Meanwhile, number of blades, blade radius, blade curvature angle, blade thickness and surface roughness were evaluated for blade. An L25 orthogonal array was chosen for both optimizations. Once optimized, the corresponding operating envelope was identified and compared against the original turbine. When operating at flow rate of 1.2MMSCFD and pressure of 69 bar, the turbine with optimized nozzle produces a maximum power output of 4383.59W at 5500 rpm, while with optimized blades produce 2058.64W at 5000 rpm. Combining optimized nozzle and blades produced 4928.64W at 6000 rpm. These produced powers are significantly higher than the original turbine maximum power of 1743.81W at 4500 rpm. This indicates potential performance enhancement of the turbine by optimizing its blade and nozzle geometry which is useful for its implementation on the offshore platform. To fully utilize this potential enhancement, the electric generator attached to the turbine shall be fine-tuned to have peak power at the optimum rpm band of the optimized turbine.

Cfd Analysis to Investigate the Effect of Leaned Rotor On the Performance of Transonic Axial Flow Compressor Stage

This paper describes the numerical study carried out to understand the impact of combination of forward and backward leaned rotor on the overall performance of a transonic axial flow research compressor of CSIR National Aerospace Laboratories (NAL), Bangalore. The analyses were carried out using commercial Computational Fluid Dynamics (CFD) solver Ansys-CFX. Initially CFD analysis was carried out for the baseline rotor configuration and validated the results with the experimental data. Then, three new configurations of combined Leaned rotors were modeled from the radially stacked baseline rotor by changing the circumferential curvature of original stacking line using three control points located at 0%, 50% and 100% of the blade span. Analyses were carried out for all the three configurations of modified geometries and the results were compared with the baseline configuration. The results revealed many interesting aspects which will be very useful for better understanding of the blade curvature effects on the shock and secondary losses within the transonic rotor. The discussions on the effect of combination of forward and backward leaned rotor and the consequent developments on the overall performance of the compressor are presented in detail in this paper.

Computational fluid dynamics investigations over conventional and modified Savonius wind turbines

Wind turbines are devices that convert the kinetic energy present in the wind into clean, sustainable, and effectively renewable energy that could be used to generate electricity. A Savonius wind turbine is a drag-based vertical axis wind turbine (VAWT) that is known to have low noise levels and good starting characteristics even at low wind speeds. Its disadvantage lies in its low efficiency or low coefficient of performance. Exploring ways to increase the coefficient of performance, numerical investigations were carried out on different modified Savonius VAWT configurations, having different curvatures, different overlap percentages, added mini blades, and fitted out with extended surfaces. These investigations were computationally executed on Ansys Fluent™ using the sliding mesh technique. Two-dimensional simulations, on a Bach blade curvature with zero overlap as well as a half-circle and a polynomial curvature with overlap, showed that for a wind speed of 5 m/s and a tip speed ratio of 0.8, the half-circle blade curvature having an overlap of 20% performs best, yielding the highest net (average) coefficient of moment, equal to 0.3065. Results also show that the addition of mini blades to this optimal configuration produces a slight improvement in the coefficient of moment. However, the addition of extended surfaces onto the blades caused the minimum coefficient of moment to be a substantial negative value and thus resulting in a much lower value for the turbine's average coefficient of moment.

Multi-objective optimization of a regenerative pump with S-shaped impeller using response surface methodology

Regenerative pumps can supply relatively high heads at low flow rates. On the other hand, regenerative pump impellers can be manufactured at a low cost due to their specific design. Although regenerative pumps perform with high heads at low flow rates, they have low nominal efficiency. This study aims to design and optimize a new S-shaped impeller. A conventional radial impeller was replaced with a new impeller to improve head and efficiency. The new S-shaped optimized impeller and the conventional radial impeller have been investigated numerically and experimentally. The design variables for the optimization process are blade number, thickness, and curvature. The Design of Experiments (DOE), the response surface methodology, and the Box Behnken design (BBD) have been utilized for optimization. The pump efficiency increased by 2.85% in single-objective optimization with efficiency as the objective. In addition, the efficiency increased by 1.67% in dual-objective optimization with head and efficiency as objectives. The casing pressure value was the same for dual-objective optimization and radial geometries. Single-objective optimization increased the pressure on the casing and ultimately raised the head amount.

Aerodynamic and structural multidisciplinary optimization design method of fan rotors based on blade curvature constraints

The optimization design of the actual fan/compressor rotors is a multidisciplinary problem. The aerodynamics and strength multidisciplinary optimization design of the fan/compressor rotors can improve the aerodynamic performance of rotors as much as possible under the condition of satisfying the structural strength requirements. However, the conventional multidisciplinary optimization of aerodynamics and structures will significantly increase the amount of computation cost and time period. Thus, it is difficult for conventional multidisciplinary optimization methods to be used in real-world engineering practices. In order to reduce the computational burden and time cost of the multidisciplinary optimization design, this paper firstly proposes a multidisciplinary optimization design method for rotors based on blade curvature constraints. In the optimization, the self-organizing map (SOM) method is applied to analyze and extract the constraint value of the blade curvature. And the blade curvature constraint value is used as a penalty function instead of the time-consuming high-fidelity FEM, which greatly reduces the computational cost and runtime of the multidisciplinary optimization. Besides, the Free-form deformation (FFD) method is adopted to realize the flexible deformation of the three-dimensional blade with the smallest number of design variables and polynomial chaos Kriging is used as a surrogate model for aerodynamic performance prediction in the optimization process. The method verification and mechanism analysis are carried out by studying a fan rotor. Data mining of FEM samples shows that, in the optimization design space, the maximum spanwise curvature of the blade is monotonically related to the maximum stress of the blade. And the maximum streamwise curvature, maximum spanwise slope, maximum streamwise slope, and maximum thickness of the blade have no related relationship with the maximum stress of the blade. Compared with the conventional multidisciplinary optimization design method based on the surrogate models of high-fidelity computational fluid dynamics (CFD) and finite element method (FEM), the time cost of the multidisciplinary optimization design method based on curvature constraints is reduced by 10 times, and the time cost of the multidisciplinary optimization is significantly reduced. The results show that, in terms of structural performance, the maximum stress of the aerodynamic optimization method without blade curvature constraints is 426 MPa, which exceeds the yield limit of aluminum alloy material (420 MPa), and the maximum stress of the multidisciplinary optimization design with blade curvature constraints proposed in this paper is 344 MPa. In terms of aerodynamic performance, the isentropic efficiency of the aerodynamic optimization method without blade curvature constraints and the method proposed in this paper are increased by 2.1% and 1.8%, respectively. Therefore, the proposed method reduces the maximum stress of the blade by 19.5% with little influence on the aerodynamic performance.

Development of a large-area curved Trench-MWPC 3He detector for the D16 neutron diffractometer at the ILL

The D16 instrument is a versatile cold-neutron diffractometer at the ILL. It has benefited from a number of upgrades over the years, such as the installation of a large-area 3He Multi-Wire Proportional Chamber (MWPC) in 2011. This detector has provided a resolution of 1 mm x 1 mm over an area of 32 cm x 32 cm. After 12 years of operation, it was replaced by a new curved detector which covers a wider solid angle while maintaining a high angular resolution. Its 86° horizontal angular coverage makes it possible to perform time-resolved experiments with a large q-range. This new detector is based on the Trench-MWPC detector technology developed at the ILL. In the D16 Trench-MWPC, 6 modules are mounted side by side in an 3He-filled curved vessel. Each module consists of 192 cathode blades positioned every 2 mm, and 192 anode wires spaced by 1.5 mm. The radius of curvature of the cathode blades is 1150 mm, providing a parallax-free resolution of 0.075°, horizontally along the 86° angular coverage of the 38 cm high detector. The various steps of the fabrication and mechanical inspection of the D16 Trench-MWPC detector modules and pressure vessel are presented, as well as experimental results obtained during the characterisation of the detector with neutrons.

Performance Comparison of Crossflow Turbine Configuration Upper Blade Convex and Curvature by Computational Method

A pico-hydro-type crossflow turbine (CFT) with an off-grid system configuration is a suitable option to increase the electrification ratio in remote or rural areas because it has a simple shape and can be applied in run-of-river conditions. Yet, a comprehensive study is necessary for the CFT to be applied to run-of-river conditions (low head and extreme fluctuation discharge), since this is categorized as an impulse turbine. One solution to optimize the CFT’s performance in this context is to increase the lift force. Hence, this study investigated the effect of the upper blade of the CFT with convex and curved configurations using the computational fluid dynamics (CFD) method. The CFD transient approach uses a moving mesh feature, and the solver is pressure-based in low-head conditions (5 m pressure). The CFD results and analysis of variance (ANOVA) calculation results from this study reveal that the upper CFT affects the performance of the turbine. The relationship of the CFT performance with the rotation and specific speed is parabolic. The express empirical law relation for performance to rotation is a four-order polynomial, and for performance to a specific speed, a three-order polynomial. Based on empirical laws, a CFT with a convex blade is recommended for conditions with low head and extreme fluctuation discharge since it has a wider range of specific speeds than a curved blade, propeller, or Kaplan, Pelton, or Francis turbine. Doi: 10.28991/CEJ-2023-09-01-012 Full Text: PDF