Performance Characteristics Of Turbine Research Articles

An improved model for primary prediction of performance map for turbocharger radial turbine

In the contemporary landscape, possessing an intricate understanding of the performance characteristics of turbocharger radial turbine proves invaluable during engine development phases, to improve predictive capabilities of calculation codes and enhance the critical process of matching engines with turbochargers. This research deals with offering two precise yet straightforward analytical functions intended to generate comprehensive performance maps of turbocharger turbines. This is achieved through a refined adjustment of a preexisting analytical function, after introducing an inventive multiplication factor that aligns numerical calculations with experimental data to predict the turbine’s expansion ratio. Besides, a second analytical function forecasts the turbine’s thermo-mechanical efficiency by establishing a power balance equation between the turbine and supplied compressor map. The outcome of the developed model is compared with existing method on two distinct turbochargers, encompassing various rotational speeds. Additionally, a sensitive analysis aiming to detect the most important factors affecting our developed model while exploring it possible validity range for different thermodynamic parameters. The results indicate that the two functions yield reliable estimations of turbine performance, with maximum; root mean square error, R2, and mean absolute percentage error indices find around 9.47%, 0.993, and 9.03% for the turbine expansion ratio, and about 4.42%, 0.612, and 19.78% for efficiency prediction. This novel model enhances simulation accuracy while preserving user-friendliness and robustness based on the prerequisite of limited geometric and thermodynamic parameters at the turbocharger boundaries. Finally, the main advantages of the proposed model is its adaptability for the implementation in calculation codes, turbomachinery optimization strategies and assessments of the design and performance, addressing scenarios where the original turbine maps are rarely provided by turbocharger manufacturers.

Evaluating the impact of off-design CHP performance on the optimal sizing and dispatch of hybrid renewable-CHP distributed energy resources

The maturation of distributed energy resources (DER) has prompted the exploration of their deployment in commercial building applications due to their potential to supply energy at lower costs and emissions rates compared to centralized generation. While several software tools exist for evaluating the techno-economic potential of integrated renewable energy and combined heat and power (CHP) systems for distributed generation applications, many suffer from poor accuracy in capturing off-design (part load and changes in ambient air temperature and pressure) performance characteristics of microturbines, combustion turbines, or internal combustion engines. Thus, this paper presents a methodology for integrating these off-design characteristics in the mixed-integer linear program within REopt, a hybrid DER screening tool. The economic impact of the CHP off-design performance is observed through several application studies of various hybrid system configurations in different climates. Each study indicates how CHP off-design performance influences optimal sizing and dispatch decisions and therefore overall system economic value. We observe through case studies that modeling without the off-design effects, depending on the CHP prime mover and site, can result in Net Present Value predictions of hybrid systems that can be overoptimistic in frequently hot climates (up to 52 %), too conservative in frequently cold climates (up to 11 %), or unaffected (＋/−1 %) in temperate climates. Cases also highlight several advantages of hybrid systems relative to non-hybrid systems such as total economic value and the systems’ ability to mitigate potentially negative consequences attributed to off-design performance.

Wind turbine load optimization control and verification based on wind speed estimator with time series broad learning system method

AbstractWith the rapid development of wind power, the power performance and mechanical load characteristics of wind turbine are simultaneously considered and focused. Normally, wind turbine senses the incoming flow characteristics through the nacelle mounted anemometer, due to the inability to perceive the characteristics of wind speed in advance, the control strategy makes the wind turbine itself to be at a passive state during the operation process. In this paper, a wind turbine mechanical load optimization control strategy based on an accurate wind speed estimator with time series Broad Learning System Method (BLSM) is designed, simulated and also verified. Firstly, the basic control theory of the BLSM and also a mechanical load optimization controller is designed. Then the OpenFAST is used to conduct a full‐life cycle simulation comparison study on mechanical load characteristics of wind turbine before and after the implementation of the optimization control strategy. Finally, a field empirical mechanical load test is performed on the wind turbine, which is configured with BLSM mechanical load optimization control technology. The findings indicate that the implementation of this control strategy can significantly mitigate the ultimate and fatigue loads of wind turbines, particularly the fatigue loads of tower base tilt and roll bending moments, with a reduction rate of approximately 6.2% and 4.3%, respectively.

A comprehensive CFD investigation of tip vortex trajectory in shrouded wind turbines using compressible RANS solver

It is well known that a shroud placed around a wind turbine can increase its power coefficient, but it brings complex mechanisms by which the shroud alters the flow passing through the rotor. Such mechanisms impose numerical challenges, as the shrouded turbines present nonlinear behavior in the wake. This paper deals with a comprehensive analysis of tip vortex trajectory in shrouded wind turbines using Reynolds Averaged Navier–Stokes numerical solutions. The analysis includes aerodynamic performance and vortex characteristics of the whole wind turbine. The Multiple Reference Frame is used on a high-order unstructured compressible solver to study both, isolated and shrouded rotor. The NREL Phase VI Unsteady Aerodynamic Experiment rotor is used as a test case. The accuracy of results for wind speeds between 7 and 25 ms−1 is discussed. Overall, good agreement is achieved between the computed pressure distributions and the experimental reference values. At stalled blade, more efforts are needed to improve numerical solutions, especially for integrated load quantities. The vortex structure is examined, showing that shroud impacts tip vortex trajectory by the increase of the axial induced velocity at the rotor plane. This result, demonstrates that the classical Prandtl tip loss is not accurate for shrouded turbine analysis, and modern finite blade functions are needed. The influence of the flow conditions on the tip vortex trajectory, flow separation and shroud interaction are also discussed.

Aerodynamic performance analysis of a floating wind turbine with coupled blade rotation and surge motion

The unsteady aerodynamic characteristics and interference effects of a floating wind turbine are significantly influenced by the six-degree-of-freedom (6DoF) motions. In this paper, the computational fluid dynamics (CFD) method using the overset grid technique and the improved delayed detached eddy simulation (IDDES) model was adopted to investigate the effects of harmonic enforced surge motions on the aerodynamic performance and wake characteristics of wind turbines. The aerodynamic load coefficients including the constant term, damping coefficients (surge velocity-induced), and additional mass coefficients (surge acceleration-induced), were fitted by using the least squares method at different surge frequencies and surge amplitudes. The blade pressure distributions and wake characteristics were analysed in detail. The Ω ~ R of the third-generation vortex identification method was applied to visualize vortex evolution. The numerical results are evaluated against the data obtained by wind tunnel experiments, indicating an acceptable relative error of 3.45 % for the power coefficient, C p , at the rated tip speed ratio (TSR). The higher frequency and greater amplitude surge motions lead to more dramatic fluctuations for the power coefficient than the axial load coefficient. The neglect of the additional mass coefficient only results in an acceptable error. Furthermore, the mean damping coefficient is on average approximately 3.5 times the mean constant term coefficient for C p , approximately 1.5 times for C z . In terms of the blade pressure distributions and wake characteristics, a higher comprehensive induced velocity, V c , is induced to expand the wider high-pressure area and shrink the low-pressure area at the pressure surface. Meanwhile, toroidal vortex ropes were induced by surge motion. Besides, the surge motion at high frequency and greater amplitude positively impacts enhancing wake deficit recovery.

Influence of turbulent coherent structures on the performance and wake of a wind turbine

Wind energy in the atmospheric boundary layer serves as the primary source for energy absorption and structural load on wind turbines. However, the impact of turbulent coherent structures on the aerodynamic performance and wake characteristics of wind turbines has not been comprehensively evaluated. In this study, the proper orthogonal decomposition (POD) method is employed to assess the influence of turbulent coherent structures of varying scales on the aerodynamic performance and wake characteristics of wind turbines in the neutral atmospheric boundary layer. The results show that turbulent coherent structures are the main factor that determines the wind velocity fluctuation, aerodynamic performance and wake characteristics of wind turbine in the atmospheric boundary layer. When considering the 13th or lower order POD mode, the wind velocity fluctuation increases with the increase of energy content (more POD modes) of the turbulent coherent structures. When considering the first 19 POD modes, the dynamic loads and power of wind turbine fluctuate with high frequencies, the thrust fluctuates in an amplitude range between 2.4 % and 13.9 % around the mean value, and the power fluctuates from 4.5 % to 28.6 % of the mean value. When considering the first 40 POD modes, the average power generation of the wind turbine increases by 26 % compared to the case with no turbulent structures considered. The study of turbine wake shows that turbulent coherent structures can expand the wind turbine wake approximately to a width of 2.5D and a height of 3D (D is the diameter of the wind turbine), offset the wake approximately to 2D, and move forward the position of the wake vortex beginning to dissipation approximately to 7D behind the wind turbine. In addition, turbulent coherent structures can accelerate the wake velocity recovery by increasing the momentum exchange between the atmospheric boundary layer and wind turbine wake.

Teaching practice of wind turbine practical training based on virtual teaching platform

AbstractThe wind turbine components are bulky and costly. Undergraduate students majoring in wind power cannot achieve professional skills training in the laboratory. To deepen the understanding of wind turbine installation, a virtual simulation platform for the teaching exploration of wind turbine assembly practice course is developed. The goal of the platform is to build a virtual simulation installation process of each huge component of the wind turbine through the model, so that students can experience the experiential learning of the installation of the wind turbine, and experience the learning opportunities of the visualization of parts and the operability of the assembly process, so as to lay the foundation of wind power engineering practice for undergraduate students. The teaching of simulation working process based on wind turbine assembly process and performance characteristics is discussed. The results and questionnaires of students in three classes are counted. The teaching experiment shows that the average score of the experimental group is 4.5 points higher than that of the control group. This method can significantly improve students' interest in learning and academic performance, improve students' wind turbine assembly ability, and meet the actual needs of students majoring in wind power. The research shows that the platform can be effectively used as a practical teaching tool for wind power students.

Hydrodynamic Performance and Flow Field Characteristics of Tidal Current Energy Turbine with and without Winglets

In order to gain a more comprehensive understanding of the influence of winglets on the hydrodynamic performance and flow field characteristics of tidal current energy turbines, two different shapes of winglets are designed, and numerical simulation results for turbines with and without winglets are compared and analyzed. The results show that both shapes of winglets can improve the energy conversion efficiency, and the winglets with a cant angle (60°) are more effective than the flat (0°) winglets; the winglets transfer the tip vortices to the winglet tips and weaken the tip vortices, increase the pressure coefficients of the cross-section in the tip region, and inhibit the three-dimensional flow phenomenon in the tip region; the winglets will make the wake axial velocity deficit larger in the near-wake region, and with the axial distance increases, the axial velocity of the wake flow with winglets recovers faster than that without winglets; winglets can make the vortex pairing and breaking of the turbine tip vortex faster, which can also be observed by the change in the turbulent kinetic energy (TKE).

Multiobjective Optimization Study On the Aerodynamic Performance and Anti-Erosion Characteristics of a Single-Stage Dusty Flue Gas Turbine

Abstract Solid particle erosion of dusty energy recovery turbine blades has a great impact on the operating economics and safety of the unit. To mitigate the erosion of blade and improve the aerodynamic performance of the turbine, a multiobjective optimization method for turbine cascade based on the experimental design method, genetic algorithm and CFD multiphase flow simulation was developed. The optimization results show that the number of stator and rotor blades and the trailing edge angle at 50% blade span are the main parameters affecting the efficiency and blade erosion of the dusty turbine. By reducing the number of stator blades and the circumferential bending angle of the stator trailing edge, the impingement velocity and impingement probability of particles impinging on the stator trailing edge decrease by 7.5%~16.8% and 8.9%~46.2%, respectively. Additionally, compared with the original design, the flow separation loss and secondary flow intensity of the rotor cascade are suppressed by adjusting the load distribution and inlet attack angle of the rotor; thus, the turbine efficiency effectively improves by 2.28%. Meanwhile, the optimized blade reduces the particle impingement velocity and probability on the rotor leading edge, and the erosion condition of the rotor leading edge decreases by 70%.

Experimental and numerical investigations on the performance and wake characteristics of a tidal turbine under yaw

This paper presents an extensive examination of the wake characteristics and hydrodynamic performance of a 1:60 scale horizontal axis tidal stream turbine under yawed inflow conditions. Experimental investigations were conducted in a laboratory flume, while numerical simulations utilized the actuator line method and large-eddy simulation technique. The turbine was subjected to an inflow turbulence intensity of 6% and was tested at five different yaw angles (5°, 10°, 15°, 20°, and 30°). The findings demonstrate a substantial reduction in the power coefficient as the yaw angle increases, with a notable drop of 47.1% recorded at a yaw angle of 30°. Furthermore, numerical simulations of wake characteristics, including mean velocity and turbulence intensity, were examined and compared with measurements, yielding satisfactory agreement. The yawed wake flow exhibited asymmetrical distributions of mean velocity and deviations from the centerline. Additionally, distinct deformations of the yawed wake in the y-z cross sections were observed, indicating a discernible curled kidney shape that intensified with larger yaw angles. Moreover, interactions between the turbine wake and support structures affected the width and turbulence intensity of the near wake, introducing additional unsteadiness that accelerated wake recovery.

An experimental study to investigate the effect of pitch angle and wave characteristics on the performance of a horizontal axis tidal turbine

This study investigates the performance characteristics of a scaled-down three-bladed tidal turbine in a towing tank. The effects of pitch angle, electrical load, wave characteristics, and current velocity on turbine performance are examined. The experimental model, a 1:6 scale horizontal-axis tidal turbine with a rotor diameter of 1.15 m, is tested in the Strait of Khoran in Iran, selected based on tidal potential evaluation. After calibration and uncertainty analysis, experimental tests are conducted using the Taguchi method to optimize parameters and explore turbine performance in different conditions: current-only and wave-current interactions. Results demonstrate the direct relationship between power, momentum, thrust, rotor speed, and current velocity. Notably, power and momentum coefficients exhibit nonlinear (polynomial) variations at different tip speed ratios (TSRs). The presence of waves consistently enhances turbine performance compared to the no-wave mode, albeit with a lesser impact than other variable parameters. A pitch angle of 18.77° in the presence of waves yields a significant increase of up to 31.1% in power coefficient and up to 23.6% in momentum coefficient, compared to the no-wave mode. The optimal blade angle generally falls within the range of 30–35 mm, with 35 mm (18.77°) and 30 mm (22.72°) as the respective optimum pitch angles for wave-current interaction and the no-wave state. Optimal electrical load is achieved by setting Rheostat equal to 20 Ω, resulting in a remarkable 11% to 40% increase in system efficiency. In the upstream flow, the maximum power and momentum coefficients are observed as 0.219 and 0.033, respectively, at a TSR of 6.62 in the presence of waves with a dimensionless wave number of 3.43. Similarly, in the no-wave mode, the optimal power and momentum coefficients are obtained as 0.205 and 0.0286, respectively, at a TSR of 7.18. These findings highlight the significance of waves with a dimensionless wave number of 3.43.

Effect of solid particles on performance and erosion characteristics of a high-pressure turbine

Effect of solid particles on performance and erosion characteristics of a high-pressure turbine

Investigation on effect of anti-cavitation edge on performance and leakage vortex characteristics of tubular turbine for ocean power generation

Anti-cavitation edge directly affects turbine runner performance and clearance leakage flow. This paper takes a tubular turbine as the object of study and uses the numerical simulation method of SST-CC turbulence model based on rotation and curvature correction to study the effect of anti-cavitation edge thickness on the turbine internal flow patterns and the flow characteristics of tip leakage vortex under different conditions. The results show that the high-altitude bubble concentrated area on the blade suction surface is reduced after installing the anti-cavitation edges. Meanwhile, the leakage volume decreases by 13.28% under the optimal condition, and the maximum leakage decreases by 37.72% under the off-design condition. The raised structure of the anti-cavitation edge can effectively push the tip leakage vortex (TLV) away from the blade suction surface and destroy the original vortex structure; the strength of tip separation vortex (TSV) is obviously reduced. The energy loss increasingly reduces with the increase of anti-cavitation edge thickness, and the loss reduction value is greater in the off-design condition. The small negative helicity vortex at the draft tube wall surface disappears. The above research results provide a certain reference for the performance optimization of tubular turbine.

Numerical analysis on a self-rectifying impulse turbine with U-shaped duct for oscillating water column wave energy conversion

In this paper, a novel self-rectifying impulse turbine with U-shaped duct used for oscillating water column wave energy conversion is proposed. It has a pair of fixed, symmetrical and radial-flow guide vane rows, and an axisymmetric, U-shaped duct with increasing cross-sectional area from the rotor to the guide vane rows, therefore it is expected to be relatively simple, reliable and efficient. A three-dimensional (3D) steady-state numerical model and a fully transient model are established for the present turbine. These two models are validated by comparison with experimental results from the published works, respectively, and then used to investigate the steady performance and transient characteristics of the impulse turbine. Effect of the geometry of the guide vanes, the number of the guide vanes, and the hub-to-tip ratio on turbine performance under steady airflows and transient airflows are studied, and the difference between these two models in predicting turbine performance is discussed.

Aerodynamic performance and flow characteristics of a compressed air energy storage axial turbine with nozzle governing

There is pressure difference between the air storage device pressure and turbine inlet pressure of the compressed air energy storage (CAES) system. The throttling loss caused by pressure difference can be reduced by using a reasonable air distribution mode. In this paper, the mass flow rate, specific work and efficiency characteristics of axial turbine with chamber under two nozzle governing modes are studied. Compared with the throttle governing, for the optimal mode under rated mass flow rate, the average specific work of the turbine increases by 6.8 %, and the average total efficiency increases by 7.0 %. The flow field loss is mainly related to the decreased regulated pressure. As the regulated pressure decreases, there are expansion and mixing losses at the corresponding stator outlet, which reaches the maximum after the regulated nozzle is closed. Moreover, with the base pressure decrease, the flow in the passages tends to be uniform and the loss gradually decreases.

Performance Characteristics of Savonius Wind Turbines With Variations Air Gaps in Supporting the Development of Renewable Energy

<pre><strong><em>To overcome the occurrence of an energy crisis in the future, an innovation / invention of energy that is environmentally friendly and energy sources will not run out in the future. Energy sources that are environmentally friendly and their potential when developed is very large, one of which is energy sources derived from wind energy.</em></strong> <strong><em>This study aims to determine the effect of wind speed on the performance of wind turbines. To find out the performance characteristics of wind turbines with variations in air gaps. The research method begins with the design / design of the wind turbine, then continues the manufacturing stage, the assembling and installation stage, the testing of tools and analysis, the tests carried out include testing the performance characteristics of the wind turbine. The parameters measured in this study are rotation, torque as well as calculating the kinetic power produced, TSR and CP. The test results conducted showed that the 200 mm air gap Savonius wind turbine with a value of CP = 0.02480-0.15658 had optimum work at low wind speeds (4 m / s). Meanwhile, the 170 mm airborne Savonius wind turbine with a value of CP = 0.00593-0.14668 has optimum work at high wind speeds (8 m / s to 9 m / s). </em></strong></pre><p><strong><em>Keywords- wind turbine savonius, air gap, coefficent of power.</em></strong><strong><em></em></strong></p>

CFD analysis of gravity-fed drag-type in-pipe water turbine to determine the optimal deflector-to-turbine position

AbstractIn-pipe hydroelectric power generation is a relatively new clean energy power generation technology. This new clean energy technology has been identified to be feasible after successful commercial installation in different parts of the world. Several researchers worldwide have studied the optimal turbine type, the optimal number of blades in turbine, introduction of suitable deflector, etc. for this technology. However, the effect of the turbine's position relative to the upstream deflector on its performance has not been studied so far. This research encompasses a numerical study of the in-pipe hydroelectric power generation turbine to identify the optimal position of the turbine from the deflector. The study was performed for a 160-mm diameter pipeline and a 126-mm turbine height and aims to predict the behavior of larger diameter pipelines for commercial installation. The numerical study was performed for a hollow-type drag turbine at 6 different rotational speeds and 10 different turbine positions. The results suggest that the performance characteristics of drag-type turbine are erratic, thus leaving little space to draw a firm conclusion about the turbine's performance. However, there was an increase in pressure difference, head and available theoretical power with the increase in rotational speed for all the positions. It was also found that such turbines were generally more efficient at slightly higher rotational speeds, i.e. speed greater than 40 rad/s, and at about the distance of 0.65D (where D is the pipe diameter) between deflector's eye and turbine.Highlights: • Drag-type water turbines can significantly contribute to the production of clean energy. • We varied the turbine position and rotational speed to see how these parameters affects the turbine performance. • Computational fluid dynamics approach is used to study the behavior of turbine at different operating conditions.

Numerical study on aerodynamic performance and particle erosion characteristics of flue gas turbine

The 3-D numerical simulation method is coupled with erosion and particle rebound models based on the results of high temperature erosion tests to systematically study the gas-solid two-phase flow characteristics of a flue gas turbine for the first time. The aerodynamic loss characteristics of the flue gas-steam mixtures and particle erosion mechanism in the flue gas turbine cascade under design and non-design conditions are investigated. The results indicate that the mixing loss of cooling steam and gas, secondary flow loss, and separation loss significantly affect the entropy increment of the rotor cascade. The isentropic efficiency of the flue gas turbine under the design condition is 78.74%. The radial inflow of wheel cooling steam from the axial clearance has a radial impact and mixing effect on the mainstream flue gas, enhancing the generation and development of the secondary flow vortex in the rotor cascade. When the dimensionless cooling steam flow rate is reduced from 1 to 0.6, the isentropic efficiency of the flue gas turbine increases by approximately 0.9%. By contrast, when the dimensionless cooling steam flow rate increases from 1 to 2, the isentropic efficiency decreases by 0.42%. The erosion rate of the leading and trailing edges of the rotor is higher than those at other streamwise locations. The erosion of the rotor leading edge and the blade-tip trailing edge is caused by the high speed impact of particles above 10 ?m, while the erosion of the rotor root is caused by the grinding of 1-5 ?m particles carried by the secondary flow.

Numerical investigations on roof ventilator turbine performance characteristics using ANSYS

Rooftop wind turbine ventilators are natural air circulation systems that employ a rotating blade to remove stale air from a building, improving the indoor air quality and saving money in the process. The effectiveness of a roof ventilator turbine depends heavily on its construction. By varying the diameter of the turbine blades (500, 670, and 690 mm), this CFD study modeled and examined three distinct designs for wind-driven ventilation devices. This numerical analysis was further developed to compute the presentation of a rotating ventilator by analyzing the pressure, turbulence kinetic energy, and velocity of the airflow related with the ventilator at variant designs. To investigate the viability of a numerical approach to modeling the many aspects of a ventilator flow, a computational fluid dynamics (CFD) analysis was conducted utilizing the conventional k- turbulence model with the multiple reference frame meshing method. The proposed design of a 690 mm ventilator blade for a rooftop turbine was found to perform better than two alternative designs using computational fluid dynamics (500 and 670 mm turbine blade diameter). The trend lines appear to be in virtuous contract with formerly available data, signifying that mathematical modelling could be a useful and cost-efficient tool for the design, growth, and performance evaluation of a wind-driven rotational ventilation system in the future.

Study the effect of wind speed on the dynamic stall behavior of horizontal axis wind turbine performance characteristics during yaw misalignment using analytical approach

Study the effect of wind speed on the dynamic stall behavior of horizontal axis wind turbine performance characteristics during yaw misalignment using analytical approach