Turbine Test Research Articles

From Wind Turbines to Energy Islands: Wind as Model Power in Denmark

This article explains how the fluctuating, ever-changing elemental entity of wind is constructed as a stable renewable energy resource through a global wind energy infrastructural model promoted by the Danish wind energy industry. Examining Denmark’s project to build the world’s first “Energy Islands,” or offshore wind energy hubs, the article accounts for how wind is shaped into “energy” as a media environment, just as wind as medium and milieu shapes the infrastructural forms of wind power. The article thinks through wind with the elemental orientations of “matter,” “molecule,” “milieu,” and “medium,” as well as the mediated conditions of its legibility, to explicate the global wind infrastructural model as a multimodal elemental media assemblage. Wind’s ontological qualities as an infrastructural medium are transduced through apparatuses of environmental data, such as graphical “island” figures and models of landscape featured on promotional websites, wind turbine test sites, and wind atlases that are constructed with numerical data and statistical models. The article argues that the metonymic visibility and invisibility of wind energy infrastructural components enable the territorialization as well as deterritorialization of wind through the strategic projection and displacement of spatial boundaries and geographical situatedness. This extends the infrastructural scope of wind power across various scales, which also contributes to a milieu of geopolitical and economic speculation. Although wind energy is projected as a stable resource, it should be described as a speculative milieu of long-term projections, intermittent changes, and sudden crises, which renders the “Green Transition” an uncertain landscape of environmental futures.

Phantom Cooling Effects on Rotor Blade Surface Heat Flux in a Transonic Full Scale 1 + 1/2 Stage Rotating Turbine

Abstract An experimental and numerical investigation of phantom cooling effects on cooled and uncooled rotating high pressure turbine blades in a full scale 1 + 1/2 stage turbine test is presented. Objectives set to capture, separate, and quantify the effects of upstream vane film-cooling and leakage flows on downstream rotor blade surface heat flux. Multiple series of 1 + 1/2 stage rotating high pressure turbine tests were carried out in the Air Force Research Laboratory, Turbine Research Facility, at Wright-Patterson Air Force Base, Ohio. A non-proprietary research turbine was instrumented with high frequency double-sided thin film heat flux gauges custom made at AFRL. High bandwidth, time-resolved surface heat flux is measured on multiple film-cooled and non-film-cooled HPT rotor blades downstream of both film-cooled and non-film-cooled vane sectors. Upstream wake passing and heat flux is characterized on both rotor pressure and suction side surfaces, along with quantifying rotor phantom cooling effects from non-uniform first-stage vane film cooling and leakage flows. Fast response heat flux measurements quantify how rotor phantom cooling impacts the blade pressure side greatest. Measurements show upstream vane film-cooling alone can account for 50% of the rotor blade cooling effect in some instances, and even outweigh the rotor blade film cooling effect far from the blade showerhead holes. Added unsteady aero numerical simulation demonstrates how variations in inlet total temperature and incidence angle also contribute to the circumferentially non-uniform rotor heat flux. Results from this investigation aid modeling and design efforts in optimizing film cooling performance in real high-pressure turbine flow fields. Understanding the behavior of such non-uniform circumferential rotor phantom cooling effects can be critical to optimizing the efficiency, fuel consumption, range, and durability of advanced turbomachines.

Film Cooling and Thermal Performances of a Blade Tip Winglet Operated in an Annular Test Rig and a Test Gas Turbine Power Plant

Abstract This paper investigates the film cooling performances and thermal behavior of a blade tip winglet, which was initially investigated in a 1.5-stage experimental axial turbine facility and subsequently also tested in a gas turbine power plant. The adiabatic film cooling effectiveness was measured in the rotating 1.5-stage axial turbine facility, whereas in the gas turbine power plant, the tip winglet had active internal cooling coupled to the airfoil and winglet film cooling system. For both test facilities, the tip winglet consisted of several fan-shaped diffuser cooling holes, which were distributed in various regions of the tip winglet and airfoil. The pressure-sensitive paint method was employed to measure the film cooling effectiveness in the 1.5-stage test rig, which was conducted for two tip clearances and a range of blowing ratios. The tip winglet in the gas turbine test power plant was operated for a long duration and under various gas turbine steady-state and transient operating conditions. The blade and tip metal temperatures were measured with embedded thermocrystal sensors and thermocouples for a wide range of operating conditions. Measured local film cooling distributions from the 1.5-stage experimental turbine indicated that it was strongly dependent on the coolant blowing ratios but relatively insensitive to the tip clearances and coolant-to-hot gas density ratio. The measurements also indicated that there was reasonably good coverage of film cooling in large areas of the winglet cavity floor and pressure and suction side tip rims. Metal temperature measurements at various locations of the tip winglet from the gas turbine power plant tests, also indicated that the measured values were within the expected ranges of the predicted metal temperatures.

Evaluation of model precision and performance discrepancies in simulated vs. experimental testing of vertical axis wind turbines

The increasing global demand for clean and renewable energy has driven significant advancements in wind turbine technology. This paper explores innovative approaches to harnessing wind energy, with a particular focus on the deployment of vertical axis wind turbines (VAWTs) in urban environments and highways. By strategically positioning turbines along roadways, where wind generated by moving vehicles offers a reliable energy source, this study investigates the potential for integrating wind energy generation with existing infrastructure. The study compares the power generation of three VAWT designs—Giromill, Windside, and Helicoidal—through both physical prototypes and computational simulations. Utilizing 3D printing technology, scaled prototypes of each turbine were constructed and tested under controlled conditions in road separators to capture the wind generated by vehicular traffic. Computational Fluid Dynamics (CFD) software was used to simulate turbine performance under similar conditions. The primary objective is to evaluate the accuracy and error margin between physical tests and computational models, aiming to assess the feasibility of using CFD simulations as a predictive tool for real-world turbine performance. The results will contribute to bridging the knowledge gap in wind energy research, particularly in Colombia, by providing new insights into the comparative efficiency of experimental and simulated approaches. This work builds on previous studies related to wind turbine aerodynamics and 3D prototyping techniques, with a focus on urban wind energy harvesting solutions.

Comprehensive approach to static firing tests of micro gas turbine engines powered by liquid fuels

The paper presents test results on the combustion of liquid fuels in micro gas turbine engines (MGTE). A setup was designed and built to determine the following MGTE characteristics: thrust, inlet static pressure, compressor static pressure, compressor total pressure, combustor total pressure, turbine total pressure, turbine speed, and the air temperature at the inlet, inside the compressor, at the turbine outlet, and at the nozzle exit. Thermodynamic cycle analysis of MGTEs was performed in the operation mode providing the required thrust. Noise and vibration levels of the MGTE operation were measured using a noise and vibration analyzer. Concentrations of anthropogenic emissions (CO, CO2, NO, NO2, N2O, SO2, CH4, C3H8) were recorded using a set of sensors. The tests revealed consistent patterns in the variation of throttle characteristics, gas composition, noise, and vibration in different engine operation modes. The test results were processed to produce plots of the key MGTE characteristics. Recommendations were developed for testing new types of fuels in MGTEs.

Flow measurement in a wind tunnel with blockage screens

The small and medium-scale wind turbine development have been improved due to their adaptability in offshore and onshore localities for wind farm applications. Blockage effects caused by numerous impediments restrict the flow-field near the turbine and impact the turbine's performance. The testing and optimization of turbines in such conditions at laboratory-level are challenging due to the unavailability of customized wind tunnel configurations with blockage screens. The present work focuses on the design, development and evaluating aerodynamic performance of wind tunnel with and without blockage screens. A comprehensive design is established by evaluating losses in each section, uncertainties, velocity, forces, and turbulence intensity in the wind tunnel through the experimental analysis. The novel blockage screens are arranged to maintain 5 % and 10 % blockage percentage for wind velocity range of 2–14 m/s. The maximum velocity reduction with 5 % blockage is 41.40 % and this drop reaches to 67.84 % for 10 % blockage. Consequently, available wind power is seen to undergo a maximum reduction of 79.88 % and 96.67 %, respectively.

Experimental Investigation and Validation of Measured Wind Turbine Noise Characteristics using Standardized Technology

This paper aims in affirming the accuracy and consistency of acoustic noise assessment at an experimental and Grid Connected wind turbine. The experimental turbine is a three-bladed, upwind turbine located in the Tuticorin District of Tamil Nadu State in India. The measurement campaign was carried out during the noise measurement equipment by Brüel & Kjær (B&K) PULSE Wind Turbine Sound Power Determination system strictly in accordance with the IEC 61400-11 2012-11 AMDI 2018 Ed.3.1. The Experimental study deals in the measurement of total noise emitted from various wind turbine component and sub-systems, when the turbine is in ON condition. The background noise was obtained while the turbine is in OFF condition. The measurement data was obtained as per the above referred standards for wind speeds ranging from 7m/s to 13.5 m/s at 50m hub height. The measurement was also obtained simultaneously at 10m height above ground level for the wind speed ranging 6m/s to 8m/s during the windy season of September 2022. The measurement data both at turbine hub height and 10m level were obtained at the same atmospheric condition 26o C and 0.996atm and in a down wind direction. The other parameters like Aweighted sound pressure level, 1/3 octave band spectrum, electric power, and wind speed were also measured at both hub heights at 10m level. The measured parameters were compared with the PULSE Software output and in the process; it is concluded that the noise characteristic of the experimental wind turbine is less than 3dB at a distance of 66m in the down wind direction from the test turbine. The measured results were also validated from the PULSE software and the results show a close match.

Design and tests of a marine current turbine in low flow velocity

Marine current energy is recognized a promising energy source due to its inherent stability and high predictability. In the past decade, several milestones have been achieved in marine current turbine (MCT) research such as MeyGen and O2. However, compared with high-velocity currents, low velocity currents are more commonly distributed worldwide, which presents new challenges. The demand for low starting velocity and high efficiency necessitates some novel structure in the design of blade, power transmission, etc. To address these issues, taking a 50W MCT as research object, this paper firstly presents the MCT design of a new fan-shaped rotor configuration, a compact non-contact magnetic coupling, a low inertial power train and hollow-cup DC generator for easier starting. Furthermore, to realize the maximum power point tracking (MPPT) and sustainable power supply, the electrical system and its control strategy were designed. The hydrodynamic performance of the fan-shaped rotor was simulated and analyzed using CFD, and a simulation model of the electrical and control systems was constructed and tested to verify the performance. Finally, the tank and sea tests were respectively conducted to validate the performance of proposed MCT. The results indicate that the proposed MCT is capable of starting at velocities around 0.2 m/s and achieving a power coefficient (Cp) exceeding 0.4, making it well-suited for providing a continuous and stable power supply in areas with low flow velocities.

Impact of Blowing and Density Ratio on the Film Cooling and Heat Transfer in an Aggressive Turbine Center Frame

Abstract It was shown in the previous study that the aft purge flows from the last stage of the high-pressure turbine (HPT) have a significant film cooling potential in the downstream turbine center frame (TCF) (Jagerhofer et al., 2023, “Heat Transfer and Film Cooling in an Aggressive Turbine Center Frame,” ASME J. Turbomach., 145(12), p. 121012). The TCF is a stationary duct that guides the flow from the HPT outlet to the low-pressure turbine (LPT) inlet and is the third most thermally loaded engine component. This article investigates the impact of different purge-to-mainstream blowing and density ratios on the film cooling effectiveness and the heat transfer coefficient in the TCF. The experiments were conducted in a product-representative 1.5-stage HPT-TCF-LPT vane configuration under Mach-similarity in the Transonic Test Turbine Facility (TTTF) at TU Graz. The blowing ratio has been demonstrated to be the dominant parameter for purge film cooling in TCFs since HPT purge flows typically have very low momentum. Even at twice the nominal blowing ratio, no cooling film detachment was observed on the TCF hub or shroud surface. Varying the density ratio in the experimentally possible range delivered no significant differences in the results. With increasing purge blowing ratios, the film cooling effectiveness in the TCF increases as expected, but the heat transfer also intensifies due to the purge injection. The circumferentially averaged film cooling on the hub scales relatively well with an offset version of the well-known Hartnett correlation (Hartnett et al., 1961, “Velocity Distributions, Temperature Distributions, Effectiveness and Heat Transfer for Air Injected Through a Tangential Slot Into a Turbulent Boundary Layer,” ASME J. Heat Transfer, 83(3), pp. 293–305) that takes into account the ingress-induced premixing of the purge flow in the cavities.

Influence of Dilution and Effusion Flows in Generating Variable Inlet Profiles for a High-Pressure Turbine

Abstract The elevated flow temperatures and pressures exiting gas turbine combustors affect the efficiency and durability of the high-pressure turbine stage. Understanding the effects that result from the upstream dilution and effusion flow interaction in creating the combustor exit profiles is important to advancing gas turbines. Understanding how common combustor features, such as dilution jets and effusion cooling, interact based on computational predictions guided the design of a non-reacting profile simulator capable of producing a wide range of non-uniform temperature profiles representative of those entering high-pressure turbines. The mechanical design of a new simulator device, which will be experimentally tested in the future, is presented in this paper along with computational predictions of flow and thermal fields. The simulator was designed for modular installation into the Steady Thermal Aero Research Turbine (START), which is a continuous-duration, steady-state turbine facility that houses a single-stage test turbine. Features of the simulator included interchangeable liner panels with multiple rows of dilution jets and wall effusion cooling to study various hole diameters and patterns. The dilution jets generate elevated turbulence intensities and tailor the temperature profiles in the radial and circumferential directions. The air mass flow distribution and source flow temperatures are independently controlled. To aid in the simulator design, computational fluid dynamics (CFD) simulations using Reynolds-averaged Navier–Stokes modeling were conducted with a two-level Design of Experiments (DOE) approach to determine a number of engine-representative target profiles with temperature shapes that are mid-radius peaked, outer-diameter peaked, inner-diameter peaked, and uniform. A sensitivity analysis of the CFD DOE results determined which factors significantly affected the profile shape so that the target profiles could be produced. The analysis indicated that the main contributor to the temperature profile shape at near-wall vane radial span locations of 0–15% and 85–100% was the injection temperature of the effusion flow. The main contributor at radial span locations of 15–40% and 60–85% was the injection temperature of the third-row dilution jets, and at the mid-radius location of 40–60% vane radial span, the main contributor was the diameter of the first-row dilution holes.

Transient Shutdown Cooling Simulation of a Gas Turbine Test Rig Configuration Under Ventilated Natural Convection

Abstract A transient simulation of shutdown cooling for a gas turbine test rig configuration under ventilated natural convection has been successfully demonstrated using a coupled aero-thermal approach. Large eddy simulation (LES) and finite element analysis (FEA) were employed for fluid domain computational fluid dynamics (CFD) and solid component thermal conduction simulation, respectively. Coupling between LES and FEA was achieved through a plugin communicator. The buoyancy-induced chimney effect under the axially ventilated natural convection is correctly reproduced. The hotter turbulent flow in the upper part of the annular path and the colder laminar-type air movement in the lower part of the annulus are appropriately captured. The heat transfer features in the annular passage are also faithfully replicated, with heat flux of the inner cylinder reaching its maximum and minimum at the bottom dead centre (BDC) and the top dead centre (TDC), respectively. Agreement with experimental measurements is good in terms of both temperature and heat flux, and the result of the transient simulation for the shutdown cooling is encouraging too. In addition, radiation is simulated in the FEA model based on the usual grey body assumptions and Lambert?s law for the coupled computation. It has been shown that at the high power (HP) condition, the radiation for the inner cylinder is approximately 11% of its convective heat flux counterpart. The importance of radiation is thus clearly revealed even for the present rig test case with a scaled-down temperature setup.

Preface of the proceeding of 12th International Symposium on Current Research in Hydropower Technologies

Current Research in Hydropower Technologies, CRHT-XII conference is taking place at Kathmandu University every year since 2012. It is an annual event of Turbine Testing Lab, where researchers and students in the field of hydraulic turbines and hydropower technologies share their experiences and research outcomes in a common platform. The event used to take place among the Masters and PhD students of Kathmandu University and Norwegian University of Science and Technology. However, there has also been an active participation from researchers and students around the world who are engaged in the similar fields in recent times. The conference has now taken an international recognition, as the selected papers from this conference will be published in journal proceedings. This year in the conference, 37 papers were presented in the topics of hydraulic turbines and pumps, computational and experimental techniques, hydropower and other renewable energy technologies, as well as the problems of erosion and cavitations. This year, we also saw many papers in the field of fish migration, fish passing technologies in hydropower, tunnel engineering and EV technologies, which show the broad topics covered within the hydropower. After receiving comments from the presentations and a peer review process, 24 papers have been selected for publication in this proceeding. We hope that the papers will be beneficial for the researchers and students involved in the sector of hydropower. We would like to thank all the participants, organizing team and the technical committee for the valuable contributions to make this a successful event. Editors Sailesh Chitrakar, PhD (sailesh@ku.edu.np) Prajwal Sapkota (prajwal.sapkota@ku.edu.np)

Vibrational Analysis on Cooling Fan with Induced Mechanical Faults

Abstract This paper reports the investigation of different mechanical faults such as unbalanced loading, broken blades, and deformed blades induced in a fan using vibration analysis. The fan used in this study was a CPU cooling fan as a representation of a basic fan system giving an idea of vibration signatures when it is subjected to faults conditions. This study assists in developing the techniques of condition monitoring for the diagnosis of failures and faults in fan systems while logging the operating status and trend in performance. The investigation is carried out in the turbine testing lab using a Tri-axial accelerometer and a commercial Intel® CPU cooling fan consisting of 7 blades. The fan was run at different RPMs with normal and fault conditions like unbalanced loading conditions induced by adding mass of different weights, breakage of blades, deformation of blades, and holes in the blades. These faults are induced to simulate various mechanical faults that frequently occur in fan-based systems. The vibration data obtained from the accelerometer are filtered and the time series of acceleration values are plotted using MATLAB. For further analysis of data, the Fast Fourier Transform is done to evaluate the peaks of vibration signals in normal and fault conditions. Vibrational amplitude in fault conditions like Hole-2 has 4.5 times higher amplitude than normal and Cut-2 has 31.5 times higher amplitude.

An Investigation on Exhaust Pulse Characteristics of Asymmetric Twin-Scroll Turbocharged Heavy-Duty Diesel Engine

<div>The shape and energy distribution characteristics of exhaust pulse of an asymmetric twin-scroll turbocharged engine have a significant impact on the matching between asymmetric twin-scroll turbines and engines, as well as the matching between asymmetric twin scrolls and turbine wheels. In this article, the exhaust pulse characteristics of an asymmetric twin-scroll turbocharged engine was studied. Experiments were conducted on a turbine test rig and an engine performance stand to determine the operation rules of exhaust pulse strength, turbine flow parameters, turbine isentropic energy, and turbine efficiency. The results showed that the exhaust pulse strength at the inlets of both the small and large scrolls continuously decreased with the increase of engine speed. And the flow parameters at the inlets of the small and large scrolls exhibited a “ring” or “butterfly” shape with the change of expansion ratio depending on the pressure deviation of the extreme points at the troughs on both sides of the “secondary peak” of the exhaust pressure pulse, respectively. Besides, the distribution trend of turbine isentropic power was consistent with the trend of exhaust pressure pulse at the inlets of the small and large scrolls. Furthermore, when opening the balance valve, it caused the appearance of “concave” and “convex” features near the “main peak” and “secondary peak” of the turbine isentropic power pulses, respectively. Finally, as the engine speed increased, the fluctuation of turbine instantaneous efficiency gradually decreased. When calculating the instantaneous efficiency of the turbine, the influence of the rotor’s rotational inertia needs to be considered, otherwise, there may be a false phenomenon of exceeding 100% efficiency.</div>

Isothermal turbines − New challenges. Numerical and experimental investigations into isothermal expansion in turbine power plants

The efficiency of power plants with steam or gas turbines depends on the efficiencies of a thermodynamic cycle and devices implementing this cycle. In the case of high power outputs, we cannot expect a significant increase in the efficiency of individual devices. Therefore, what remains is to increase the efficiency of the implemented thermodynamic cycle − the complex Rankine cycle in the case of steam turbines or the extended Brayton cycle in gas turbine units. The efficiencies of these cycles depend on the hot reservoir temperatures, limited by the materials used. The solution seems to be the thermodynamic cycles with the highest efficiency within given temperature limits, the „generalized Carnot cycles”. About gas turbines, such a cycle is the Ericsson cycle. The most difficult element of this cycle is carrying out high-temperature expansion. So far, there is no literature data on a technical device implementing this process. In this article, we present a method for designing turbine nozzles for isothermal expansion and the results of experimental tests of the first isothermal turbine. In the case of gas microturbines with a regenerator, isothermal expansion can increase efficiency from 24% to 28% up to 36%. An increase in efficiency of several to a dozen percentage points is expected for Organic Rankine Cycle (ORC) turbines. Due to such significant increases in energy generation efficiency, an isothermal turbine may become a future solution for energy systems.

AERODYNAMIC IMPACT OF SECONDARY AIR INJECTION FLOWRATES ON THE MAIN ANNULUS FLOW FIELD FOR A TRANSONIC HIGH-PRESSURE TURBINE STAGE

Abstract In this study, the influence of secondary air blowing on the main annulus flow field of a transonic high-pressure turbine (HPT) was investigated experimentally and numerically. The experimental setup was a single-stage, unshrouded turbine with a blading consistent with modern HPTs. The entire testing campaign was conducted in a full annular, rotating, continuous turbine test rig at the Japan Aerospace Exploration Agency (JAXA), which realized the most faithful matching unrivalled of both the primary and secondary stream similarity parameters to reality. An elaborate secondary air system implemented in the hardware enabled it to mimic all the dominant coolant/purge streams representative of advanced hot sections: the full coverage film-cooling on stator and rotor airfoils, disk wheelspace purge air blown forward and aft of the rotor, and coolant injection through the over-tip casing. Detailed three-dimensional flow field measurements for various secondary air flowrates were performed by traversing a pneumatic thermometric combination probe downstream of the rotor. A complete set of numerical simulations was run concurrently with the testing to determine how well they captured the flow physics, particularly the interaction of the ejected secondary streams with the primary flow. The JAXA in-house code, UPACS, and its best practice settings, based on past verification and validation efforts, were employed and not intentionally tuned to better fit the data.

Development and Testing of a Gas Turbine Test Rig Setup for Demonstrating New Aviation Propulsion Concepts

To further increase efficiency and to significantly reduce climate impact in the aviation sector, new propulsion concepts must be developed. As full electrification in mid- and long-range aviation is impractical due to the low gravimetric energy density of batteries, new approaches must be developed. Therefore, the so-called hybrid electric ground demonstrator (HeBo), equipped with a Rolls Royce M250-C20B gas turbine is set up. The test rig serves as a development platform for various new gas turbine-based propulsion concepts for aviation, such as hybrid electric concepts or a novel cycle concept with steam injection to the combustor, which are described in this paper. The main focus of the work is on the experimental setup and the commissioning of the baseline test rig. This will place the test rig in the context of current research activities and serve as reference for subsequent research results.

Numerical Investigations of Flows and Heat Transfer in Turbine Disk Cavities

Abstract In gas turbines, the stator wells play a key role in the efficiency of the turbomachine. The research for performance gains requires a good understanding and an accurate modeling of the flows and heat transfers occurring in these areas. Within the framework of the European program main annulus gas path interaction (MAGPI) WP1, a two-stage axial turbine test rig provided an experimental database used to validate the computational fluid dynamics (CFD) models. The aim of this study is to setup a numerical methodology using the CFD solver ANSYSFluent to accurately predict the conjugate heat transfer in the stator well area. The validation of the methodology relies on thorough comparison of the results with the MAGPI WP1 experimental temperature/pressure measurements. A geometry with axial cooling injection through lock plate slot was chosen. A Reynolds-averaged Navier–Stokes (RANS) three-dimensional sectorized CFD model of the turbine with conjugate heat transfer was used. It includes main gas path, cavities with labyrinths, disks rotor, the casing, and the nozzle guide vanes (NGV). Mixing planes are placed between the static and rotating frames. Different influences (mesh, turbulence model, thermal boundary conditions, radial labyrinths clearances) were studied and compared with experimental data. As a baseline, the first calculations were performed with a cooling flowrate chosen so that hot gas ingresses from the main stream into the stator well cavity. Good agreements between predicted and measured temperatures/pressures were observed, especially in the vicinity of the stator well. Discrepancies were spotted at the first rotor hub endwall and at the upstream wheelspace and will be discussed. Two other cooling configurations were conducted, one with cooling air exiting from the disk rim cavity to the main gas path and the other with the lowest cooling flowrate and so the highest ingress. Finally, the turbine performance under nonadiabatic conditions has been evaluated with an appropriate efficiency definition.

Lessons learned from 10 years of wind tunnel tests on small wind turbines designed by students

This article discusses results from an international contest, open for university student teams (bachelor and master), involving the design, construction, and testing of small wind turbines in a large wind tunnel. The wind tunnel has an outlet of 2.85 x 2.85 m allowing a maximum rotor swept area of 2 m2 without significant tunnel effects. Both horizontal and vertical axis wind turbines are part of the competition. The turbines are evaluated by an external jury of industry experts based on criteria such as Annual Energy Production, cut-in wind speed, innovations, design, and sustainability. Although the contest has been initiated in 2013 with an educational focus, it has also evolved into a valuable database for scientific purposes by providing a decade worth of performance measurements for roughly 9-10 various turbine concepts each year. The collected data may serve as a unique validation resource for assessing the accuracy of design codes in modelling diverse turbine concepts thanks to detailed design reports with model descriptions accompanying each turbine (such turbine descriptions are often considered confidential for field measurements). The paper aims to explore the scientific value of this database by comparing calculations with measurements, offering explanations where possible, and reporting intriguing findings on unconventional concepts’ performance. Even though not all observations could be explained fully they provide food for thought. Recommendations are provided for both students to enhance their designs and for contest organizers to elevate the scientific value of the measurements in future contests.

Design of Pelton Turbine Test Stand in Plateau Environment

Abstract In recent years, with the continuous development of China’s hydropower projects, Pelton turbines are gradually being valued, and the focus of development has shifted from plain areas to plateau areas. Environmental impacts such as high altitude, water temperature, and high sediment content in the plateau area have caused serious interference to equipment that originally worked in a stable environment, for example, the failure of the cooperation between the parts of the turbine and the mutual seizure, the increased wear of the nozzle needle, the decrease of the flow rate and the water outlet speed of the nozzle, and the decrease of the air pressure in the plateau environment lead to the change of the flow state of the nozzle. In view of the above problems, this paper puts forward the design scheme of impulse turbine test-bed, using the method of changing specific speed to determine the basic parameters of impulse turbine unit, so as to eliminate the influence of plateau environment on the normal operation of turbine, obtain the efficiency condition of model experiment under low ambient pressure, and improve the operation efficiency and reliability of turbine unit.