Performance Of Cross-flow Turbine Research Articles

An experimental investigation of the performance of cross-flow turbine: impact of number of blades in runner

ABSTRACT This study examines a cross-flow turbomachine designed for power generation in areas with limited discharge and head availability, focusing on sustainability, affordability, and ease of operation. It investigates how varying the number of blades in the runner affects turbine performance while keeping other design factors constant. Testing runners with 8, 12, 16, 20, and 24 blades under identical conditions reveal consistent RPM variations across different blade numbers for various parameter combinations. The study identifies a 12-blade configuration as optimal for electrification projects at selected sites. Experimental validation using the Taguchi technique confirms the reliability of the findings. Additionally, the research explores the turbine’s performance under different nozzle tip elevations (18 cm, 16 cm, and 14 cm). The highest observed runner speed is 345 RPM for the 12-blade runner at an 8° angle of attack, with similar speeds recorded for the 24-blade runner under similar conditions.

Configuration blade shape for enhancement crossflow turbine performance by the CFD method

The pico scale crossflow turbine (CFT) is a prospect as an independent power plant for remote and rural areas because it has a stable efficiency range of 64 % to 79.5 % in high discharge fluctuation. An alternative to CFT performance enhancement is determining the upper blade configuration to increase lift force. Hence, this study investigates four configurations of the upper CFT blade: convex blade at the centre edge, convex at the trailing edge, convex at the leading edge and ordinary curvature. This research employs a computational fluid dynamics (CFD) method to visualise the flow field. The upper CFT blade configuration significantly affects its performance, and convex at the leading edge has higher performance than others. The performance related to each blade shape's specific speed is parabolic and expressed using empirical law. The empirical law recommends 4.88 as specific speed for designing a pico scale CFT.

Comparison of Crossflow Turbine Performance through Nozzle Position Variations Using ANSYS Simulation

The performance comparison of Crossflow turbines is greatly influenced by the position of the nozzle in the conversion of water energy into mechanical energy that occurs through the blades, runners, and shafts of Crossflow turbines. The study aims to directly examine the visualization of water fluid dynamics across the turbine runner blade and enhance the performance of the Crossflow turbine by varying the nozzle position. This study intends to investigate the impact of water flow dynamics and emission on the performance of Crossflow turbines with a combined horizontal-vertical nozzle position, specifically focusing on the magnitude of the number of turbine blades driven and the size of the runner blade area. The objective of investigating nozzle position variations in Crossflow turbines is to determine the specific nozzle position at which the turbine blade may efficiently extract maximum energy from the water flow, hence optimizing turbine performance. The research method using models made using CAD software is AutoCAD by exporting to IGES or IGS format to be compatible with ANSYS. The simulation of this research is with post-processing. There are three, namely making animations, making contours, and taking data to compare cross-turbine performance using variations in nozzle position. Crossflow turbine performance with horizontal nozzle position torque and turbine power is lower, and there is an increase in a vertical position. Then, the horizontal and vertical nozzle position is very good because the nozzle is more effective with maximum turbine performance, namely 13.811-watt turbine power 1,099 turbine torque at 120 rpm.

Comparison of Crossflow Turbine Performance through Nozzle Position Variations Using ANSYS Simulation

The performance comparison of Crossflow turbines is greatly influenced by the position of the nozzle in the conversion of water energy into mechanical energy that occurs through the blades, runners, and shafts of Crossflow turbines. The study aims to directly examine the visualization of water fluid dynamics across the turbine runner blade and enhance the performance of the Crossflow turbine by varying the nozzle position. This study intends to investigate the impact of water flow dynamics and emission on the performance of Crossflow turbines with a combined horizontal-vertical nozzle position, specifically focusing on the magnitude of the number of turbine blades driven and the size of the runner blade area. The objective of investigating nozzle position variations in Crossflow turbines is to determine the specific nozzle position at which the turbine blade may efficiently extract maximum energy from the water flow, hence optimizing turbine performance. The research method using models made using CAD software is AutoCAD by exporting to IGES or IGS format to be compatible with ANSYS. The simulation of this research is with post-processing. There are three, namely making animations, making contours, and taking data to compare cross-turbine performance using variations in nozzle position. Crossflow turbine performance with horizontal nozzle position torque and turbine power is lower, and there is an increase in a vertical position. Then, the horizontal and vertical nozzle position is very good because the nozzle is more effective with maximum turbine performance, namely 13.811-watt turbine power 1,099 turbine torque at 120 rpm.

Cycle-to-cycle variations in cross-flow turbine performance and flow fields

Cycle-to-cycle variations in cross-flow turbine performance and flow fields

Influence of the Downstream Blade Sweep on Cross-flow Turbine Performance

Because cross-flow turbines rotate perpendicular to their inflow, the blades encounter a continually fluctuating angle of attack and relative velocity that can lead to the unsteady, non-linear phenomenon of dynamic stall. Additionally, because of appreciable deceleration of the flow through the turbine rotor (induction), the relative velocity a blade experiences during the upstream portion of its cycle differs appreciably to that of the downstream portion. Both dynamic stall severity and turbine induction depend on the ratio of the blade tangential velocity to the inflow velocity - the dimensionless ”tip-speed ratio”. Consequently, the power generated by a blade varies substantially with tip-speed ratio and angular position. As the tip-speed ratio increases, the angle of attack range experienced by the blade decreases, dynamic stall weakens, and the relative velocity incident on the blade increases. In aggregate, this increases the amplitude of the performance peak in the upstream sweep and shifts the peak later in the cycle. In contrast, as the tip-speed ratio increases, power losses during the downstream sweep becomes increasingly detrimental to time-averaged turbine performance. Recent works, both experimental and computational, have investigated the near-blade hydrodynamics of cross-flow turbines in concert with performance measurements. However, despite the significance of the downstream sweep on performance, most attention has focused on the power generating phases.
 Here, we specifically investigate the impact of the downstream blade sweep on cross-flow turbine performance using a 1-bladed turbine (NACA 0018 foil). Because turbine torque is measured at the center shaft in our experiments, a one-bladed turbine allows us to isolate the performance contributions for the upstream and downstream sweeps (i.e., with a multi-bladed turbine, the torque contribution from each blade is ambiguous). Additionally, flow fields are investigated to understand the hydrodynamic mechanisms for the observed degradation in downstream performance at high tip-speed ratios. For this purpose, two-component, phase-locked, planar particle image velocimetry data is obtained inside the turbine swept area for two tip-speed ratios. We find that the average performance in the upstream sweep continues to increase beyond the optimal tip-speed ratio, with respect to time-averaged performance, of 2.5. In contrast, the average performance in the downstream sweep is net neutral until the optimal tip-speed ratio where it begins to decrease at a faster rate than the upstream performance increases. This indicates that the optimal tip-speed ratio is strongly influenced by the point at which the downstream sweep begins to consume appreciable power. These results highlight the importance of understanding hydrodynamics in the downstream sweep, where induction and upstream disturbances violate simple models to predict angles of attack and relative velocity. An improved understanding may suggest strategies to improve performance in the downstream sweep and increase optimal tip-speed ratios and performance of cross-flow turbines.
 
 
 
 

Study on Cavitation Occurrence Condition and Effect of Cavitation on Cross-flow Turbine Performance

Study on Cavitation Occurrence Condition and Effect of Cavitation on Cross-flow Turbine Performance

Effects of dimensionless parameters on the performance of a cross-flow current turbine

Cross-flow turbine performance is sensitive to multiple dimensionless parameters, including the Reynolds number, blockage ratio, and Froude number, based on both turbine submergence depth and overall channel depth. Here, we experimentally isolate the effects of each parameter. Turbine performance and free surface deformation were characterized in a recirculating flume at a baseline operating condition. Then, each parameter was independently increased by approximately 30% from the baseline case while all others were held roughly constant. Turbine performance, quantified by the power coefficient, was most sensitive to an increase in Reynolds number, followed by the blockage ratio and submergence depth Froude number. Increasing the channel depth Froude number had a negligible effect on performance. In contrast, increasing the channel depth Froude number caused the largest change in free surface deformation, and increasing the Reynolds number had a negligible effect on free surface deformation relative to the baseline case. Turbine performance changes are caused by a combination of blade hydrodynamics and strut losses, both of which are affected differently by each dimensionless parameter. These results suggest that each dimensionless parameter describes different fluid dynamics and that all four parameters should be considered during experimental design. Notably, we observe that turbine performance is sensitive to the submergence depth Froude number, a parameter that has not been previously explored in the archival literature.

Experimental study of Crossflow turbine under different operating conditions

In the present study, experiments were conducted to investigate the performance of Cross-flow turbines (CFT). A CFT runner with 16 degrees of angle of attack and a ratio of 0.67 inner to the outer diameter is selected for the experiment. The efficiency of the turbine was studied using a 3D printed runner with 30 blades at a constant head of 10m and varying rpm from 350 to 750 with an increment of 100 rpm and guide vane opening ranging from 10% to 100% with an increment of 10%. The results of the study indicate that CFT can be used effectively as it contains a flat curve that works well over wide flow conditions. CFT efficiency increases with increasing rpm to a certain point, after which it begins to decrease with increasing rpm.

Numerical investigations on performance improvement of cross flow hydro turbine having guide vane mechanism

ABSTRACT Cross-flow turbine is one of the leading turbines to harness the hydropower potential in micro-hydro power schemes. In spite of having a simple structure, low maintenance, and low initial investment, this turbine suffers the problem of low efficiency due to unguided flow in the runner cavity. In the present study, an attempt has been made to enhance the performance of cross-flow turbine by attaching hydrofoils shaped (symmetrical and unsymmetrical) guiding mechanism. The effectiveness of the placement of guide vane was examined numerically in terms of turbine efficiency and flow field distributions. The performance of the modified turbine was compared with the turbine having no guide vane. The position and placement angle of the guide vanes were also investigated to find the suitable position of the guide vane in the runner cavity. The turbine with symmetrical and unsymmetrical guide vane yields its maximum efficiency corresponding to vane angle of 55° and 45°, respectively, placed at the ‘right’ position (toward nozzle) for both types of guide vanes. The maximum efficiency of the turbine was observed as 80.1% and 79.9% corresponding to symmetrical and unsymmetrical guide vanes, respectively. Further, the flow field distribution inside the turbine runner and in the vicinity of the guide vane has been observed. It has been visualized that placement of the guide vane minimizes the water recirculation with the streamlined flow for smooth entry to the second stage of the runner. The reduction in turbulence and vortices generation results in the improvement of turbine efficiency for similar operating conditions.

Influence of Effective Head Variation on the Flow Field and Performance of Cross-Flow Turbine

Many small hydropower stations, which are run-off river types, use a cross-flow turbine because of its excellent partial load characteristics and low manufacturing cost. So far, there have been various studies to improve turbine performance. On the other hand, the flow field pattern is expected to be different with the variable effective head condition. Therefore, understanding the characteristics of flow field patterns and obtaining design guidelines for cross-flow turbines will improve the turbine performance and enlarge operating conditions. This study investigates the influence of the head on cross-flow turbine performance. This study used CFD analysis to evaluate the flow field pattern in the turbine with several head conditions. As a result, it is confirmed that the turbine shows a low degree of reaction. The first stage generates much torque by velocity head variation. The energy recovery rate at the second stage is changed with the head, which is a major reason for the change in turbine efficiency. The flow pattern around blades at the first stage varies with the head.

Simulation Study on Cross Flow Turbine Performance with an Angle of 20 ° to the Variation of the Number of Blades

Simulation Study on Cross Flow Turbine Performance with an Angle of 20 ° to the Variation of the Number of Blades

Study on the Application of Particle Image Velocimetry with Resin and Rhodamine B as Alternative Seeding Particles in Pico Hydro Cross Flow Hydro Turbine

One of the solutions to overcome the lack of electricity problem in rural area is Crossflow pico-scale hydropower. In improving cross-flow turbine performance, understanding fluid phenomena is needed. Particle image velocimetry (PIV) measurement is one of the methods used to visualize the fluid flow phenomena inside the turbine. Expensive price of seeding particle leads to find the solution for this PIV method. The objective of this study is to use a cheap seeding particle from cheaper materials, mainly resin and rhodamine B. Besides that, in this study, PIV measurement is compared to 2D computational fluid dynamics (CFD) with multiphase volume of fluid model. From the results, several phenomenon can be observed at both of the methods (PIV and CFD) such as separation in the blade tip. Therefore, this study showed that an inexpensive material resin and rhodamine B as a seeding particle has a potential and ability to represent flow inside pico-hydro cross-flow turbine.

Influence of Runner Shaft Diameter on Performance of Cross-flow Turbine with a Guide Wall and a Cylindrical Cavity

Influence of Runner Shaft Diameter on Performance of Cross-flow Turbine with a Guide Wall and a Cylindrical Cavity

Study on Hydraulic Performance of Cross-flow Turbine when the Cavitation Occurs

Study on Hydraulic Performance of Cross-flow Turbine when the Cavitation Occurs

Analysis of the Effect of Guide Vane Opening Variations and Total Blades on Cross Flow Turbine Performance Using Computational Fluid Dynamic

Indonesia is an agrarian country that continuously produces water, so it has the potential to develop a hydroelectric power plant. Computational Fluid Dynamic (CFD) application could be used to be an economical, quick, and efficient approach to improve the engineering design and turbine performance. This research aimed to find the effect of guide vane opening variations and total blades on cross-flow turbine performance using CFD simulation. This research used experimental modelling method with ANSYS program for turbine design with 22, 24, and 26 turbine blades and guide vane opening variations of 12°, 16°, 20°, 24°, and 36°. The data were collected by reviewing the simulation results after the numerical calculation process. The results showed that the cross-flow turbine performance was improving along with the increasing guide vane opening. The optimum turbine performance (power and efficiency) was obtained at 24° opening of guide vane and 26 total blades, producing 868.53 W power with 75.16% efficiency.

Analytical analysis of combined effect of interior guide tube and draft tube on cross flow turbine performance

Cross flow turbine is considered the most appropriate turbine in micro hydro range of small hydro plants. In this range, variation in flow in small streams is very high and cross flow turbines are inherently suitable for such sites. Further cross flow turbines are easy in fabrication and can be fabricated locally. However, the efficiency of cross flow turbine in comparison of other conventional turbines is inferior. It is therefore there is scope to improve its efficiency. Under the present study, theoretical investigation has been performed to improve the performance of cross flow turbine by providing an interior guide tube (having different shapes and different locations) and draft tube in cross flow turbine. The combined effect of interior guide tube and draft tube has been studied. A substantial improvement in efficiency about 3.35% has been totaled.

Effect of aspect ratio on cross-flow turbine performance

Cross-flow turbines convert kinetic power in wind or water currents to mechanical power. Unlike axial-flow turbines, the influence of geometric parameters on turbine performance is not well-understood, in part because there are neither generalized analytical formulations nor inexpensive, accurate numerical models that describe their fluid dynamics. Here, we experimentally investigate the effect of aspect ratio—the ratio of the blade span to rotor diameter—on the performance of a straight-bladed cross-flow turbine in a water channel. To isolate the effect of aspect ratio, all other non-dimensional parameters are held constant, including the relative confinement, Froude number, and Reynolds number. The coefficient of performance is found to be invariant for the range of aspect ratios tested (0.95–1.63), which we ascribe to minimal blade–support interactions for this turbine design. Finally, a subset of experiments is repeated without controlling for the Froude number, and the coefficient of performance is found to increase, a consequence of the Froude number variation that could mistakenly be ascribed to aspect ratio. This highlights the importance of a rigorous experimental design when exploring the effect of geometric parameters on cross-flow turbine performance.

Design and implementation of a crossflow turbine for Pico hydropower electricity generation

This study covered the design, implementation and performance evaluation of a crossflow turbine at various nozzle positions. The chosen blade material was analyzed using ANSYS for stress and deformation degree under the impact of hydraulic jets to ascertain its suitability while in operation. The shaft was analyzed under static and dynamic conditions using ANSYS in order to ensure a non-plastic deformation of the shaft at both conditions. The outcome of this analysis was employed in the harmonic response analysis of the runner shaft. Convergent tests were done for both the blade and runner shaft analysis. An experiment was designed for the evaluation of the crossflow turbine performance using optimal (custom) design tool of response surface methodology and 69 simulations/runs were obtained. The factors considered in the experimental design are: nozzle distance from the shaft, nozzle height and attack angle. The crossflow turbine was constructed using computed design values for all the machine's parts. The runner blades were positioned specifically at 28° outer blade angle and 90° inner blade angle. The turbine was tested under a water head and flow rate of 6.4m and 0.0042m3/s respectively. The shaft power and efficiency were evaluated using their respective formula. The responses were optimized in order to get the optimum position of the nozzle that would give the best performance of the responses using the two factor interaction (2F1) mathematical models in coded factors, developed for each of the response. The results obtained, proved that low carbon steel material was suitable for the turbine blading and the shaft is safe at both static and dynamic conditions since the induced stresses and deformations never exceeded the permissible range. Also, each of these considered nozzle positions had a significant effect on the responses with the nozzle height and attack angle having a combined effect on the performance of the turbine. The best turbine performance was obtained at lower angle of attack, nozzle distance very close to the runner shaft and at a nozzle height that will actualize greater energy impartation to the upper and lower blade profiles. The developed mathematical models for each response has higher correlation value, suggesting that the models are suitable for predicting the responses at the considered factor levels. An optimal nozzle distance, height and attack angle of 102mm, 413mm and 5° respectively, were obtained. At this nozzle position, the alternator gave an output of 35watts and 6V. When two voltage transformers were employed, it gave 200Volts AC. The turbine can be commercialized on large scale for greater output power using the determined optimal nozzle positions.

Implications of biofouling on cross-flow turbine performance

While biofouling is known to degrade the performance of marine energy conversion systems, prior experimental work has not explored this topic for cross-flow turbines. Here, we present experiments that investigate the impact of biofouling on turbine power output and structural loads. Using additive manufacturing, a three-dimensional scan of a barnacle was patterned onto the surface of turbine blades at three sizes and number densities, representing the progression from initial colonization to maturity. The impact of barnacles on turbine power output was found to be substantial and, for the most severe cases of fouling, the turbine does not produce power at any rotation rate. Conversely, barnacle fouling was found to have minimal impact on structural loading. To maintain generation capacity over extended periods, these results highlight the importance of antifouling coatings and proactive blade cleaning.