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The problem of energy shortages is still a global problem which is especially felt in developing countries whose residents live in villages, which still require the development of more efficient energy sources. The problem of meeting the availability of electricity in rural areas by utilizing water energy as new and renewable energy is a long-term goal in this research. The goal is to obtain the value of the turbine power from the turbine design which is designed to later be able to fulfill a picohydro scale power plant. The current research on kinetic turbines is a combination of two types of waterwheels, which have a vertical axis (overshot turbine and pusher turbine). Most water turbines have fixed blades. In this research, the target of the novelty is a kinetic turbine with a vertical shaft which has a hinged blade. Hinged blades are blades that can move when the flow of water hits the blades, so that on one side of the turbine it will reduce negative torque and on the other hand it will increase turbine rotation. The results of the research that became the target were to obtain a turbine design that has more optimal turbine power and efficiency, compared to a turbine that has a fixed blade, so that this externally hinged blade kinetic turbine can contribute to the provision of rural electrical energy. The optimum value in this study is the number of blades 10 and turbine power 59.01 Watt.

This study introduces a novel fault recognition methodology for turbine faults through symmetric trigonometric fuzzy and neutrosophic cross entropy measures (FCEM and NCEM) consequently. After knowing the nethermost (lowest) and uppermost (highest) energy bounds of each real fault conditions, the energy interval ranges are constructed and then transformed into the form of single valued neutrosophic (SN) sets. Thereafter, the proposed symmetric trigonometric cross -entropy measures are deployed to recognize faults of turbine. The nethermost FCEM and NCEM values between familiar and unfamiliar fault conditions indicates that the unfamiliar fault condition is closer to the familiar one. The applicability of the proposed methodology is validated by taking into consideration the example of fault diagnosis of turbine. The repercussions of this study yield that the proposed symmetric trigonometric FCEM and NCEM cannot only recognize optimal fault, they can also provide meaningful and remarkable fault information. A comparison of the underlying FCEM and NCEM (based on SN sets) with the enduring cosine measures (based on vague sets) conclude that the latter sets may hide some fruitful fault information., when experimented under sensitive and intuitive criteria and thus resulting an incomplete fault evaluation criterion

The current experimental study looks at how the limiting current density is approached on using rotating 2-stage 4- blade flat turbine promoters to improve mass transfer coefficient in an open electrolytic cell. The mass transfer data are obtained at microelectrodes fixed on the cell wall and electrode support using an electrochemical method. The electrolyte was equimolal in potassium ferricyanide, potassium ferrocyanide and excess sodium hydroxide. The mass transfer coefficients were calculated using limiting current data from a diffusion-mediated electrode reduction reaction at the microelectrodes attached to the electrode supports. The limiting current technique has been particularly chosen in view of its accuracy, simplicity, negligible chemical polarization, and absence of any physical change to the reacting surface even after long exposure. The effects of geometric parameters such as turbine diameter (0.05-0.09 m), blade width (0.005-0.015m), turbine rotational speeds (250-1250 rpm) and electrolyte velocity (0.567x10-3 to 7.93x10-3 m/s) were investigated. The mass transfer coefficients were increased by the turbulence created by rotation of the promoter turbines. The mass transfer correlation was formed in terms of dimensionless numbers: Schmidt number (Sc), Sherwood number (She), rotational Reynolds number (Rer), and flow Reynolds number (Ref).

Through the multi-body coupling between the components in the numerical calculation, the self-adaptive yaw motion of the power flow turbine is realized. Specifically, the changes of launching dynamic performance in different yaw structure combinations (different rod length, different tail chord length, different tail limiting Angle and rotation axis position) are investigated. The results show that under the same operating conditions, the turbine efficiency of the optimized structure combination is increased by 1.05 % and the yaw speed is increased by 16.7 %. Then, the influences of different tip immersion depth and wave period on thrust coefficient and efficiency coefficient of turbine at free liquid surface are compared. The conclusion is that the turbine efficiency is increased by 0.8 % when the tip depth is 0.21D compared with that without free liquid surface. When the wave period is 1.3, the turbine efficiency is increased by 1.4 % compared with that without free liquid surface. The results show that the selection of appropriate structure combination and installation depth is of great help to turbine efficiency and yaw speed during the yaw process of turbine power flow unit. • Changing the position and limiting angle of the tail wing rotation axis can affect the yaw speed of the turbine device. • Modifying the length of the tail boom and tail chord can alter the yaw speed and efficiency of the turbine apparatus. • Different blade tip immersion depths under free liquid surface and wave periods can change the efficiency of the turbine device. [ABSTRACT FROM AUTHOR]

Enhancements in propulsion systems have played a key role in promoting aircraft fuel efficiency, which serves to achieve global decarbonization goals. In particular, investigation by decoupling individual components of the whole engine explicitly provides insight about improvement potential. In this study, stage-based exergetic assessments of the turbomachinery components such as compressor and turbine for a large turboprop engine used in military cargo aircraft are performed for five different flight cases. As a novelty, a new index called specific irreversibility ratio (SIR) showing irreversibility per unit power is established. In this regard, exergy efficiency of compressor changes from 86.6 % to 96.3 % throughout the 14 stages whereas for whole compressor, it is measured as 89.3 %. On the other hand, exergy efficiency of gas turbine changes from 92.5 % to 91.8 % throughout 2 stages whereas, for power turbine, it varies from 89.1 % to 89.7 % throughout 2 stages. Moreover, SIR of air compressor diminishes from 12.94 % to 4.26 % throughout 14 stages whereas those of gas turbine and power turbine increase from 8.17 % to 8.84 % and from 11.52 % to 12.58 % along with two stages, respectively. As for effect of flight cases, exergy efficiency of whole compressor changes by 2 % whereas those of gas and power turbines vary by 0.2 % and 0.5 %, respectively throughout flight cases. However, improvement potential rate of air compressor experiences a change between 23.81 kW and 58.19 kW whereas it varies between 27.31 kW and 50.74 kW for gas turbine and between 26.24 kW and 36.23 kW for power turbine. It could be inferred that variation of exergetic metrics throughout stages is more apparent in comparison with those of flight cases. The methodology improved in this study could help in understanding stage-based efficiency of turbomachinery components at on-design and off-design conditions. • Stage-based exergetic metrics for turboprop at dynamic flight. • Specific irreversibility ratio is showing irreversibility per unit power. • Stage-exergetic metrics is more apparent in comparison with flight phases. [ABSTRACT FROM AUTHOR]

Due to its insular condition, Gran Canaria operates an isolated energy system that requires high self-sufficiency in energy generation and that covers its energy need, 3,327,872.76 MWh/year. The future integration of the Chira-Soria Pumped Hydroelectric Power Plant, scheduled for 2030, is expected to radically transform the energy dynamics of Gran Canaria's electricity system, facing different challenges and opportunities. Challenges include the need for greater flexibility due to growing renewable energy sources, going from 381,000 MW of renewables today to an increase of more than 750,000 MW, environmental commitments, and the operation must address potential operational constraints related to downstream hydrological effects. On the other hand, the opportunities lie in the ability of the reversible hydropower plant to provide balancing services during off-peak hours, improving the integration of intermittent energy sources such as wind and solar power, in addition, the Pumped Hydroelectric (PHES) technology is recognized as mature and efficient for large-scale energy storage, contributing significantly to the integration of renewable energy sources. Implementing innovative approaches such as integrating Big Data into construction projects can also improve efficiency and decision-making in the project delivery process. This facility will facilitate energy storage through the pumping of water at high levels, allowing it to be subsequently turbined in periods of high demand, which will be essential to improve the management and efficiency of the island's energy system. This energy demand will be studied, which follows certain patterns according to the day of the week and, continuing with the line of research established in previous works, a detailed analysis of the existing system, simulation and algorithmic optimization of the integration of the Chira-Soria Pumped Hydroelectric Power Plant into the energy system of Gran Canaria in the year 2023 will be carried out, providing the expected results of such optimal integration by differentiating the demand patterns of each day of the week, previously establishing these annual representative days. [ABSTRACT FROM AUTHOR]

The results of profile loss measurements, including trailing edge flow details, are presented for the flow of an organic vapor through a linear turbine cascade. The so-called VKI-I blade profile from the open literature was chosen for the cascade, and the working fluid was NOVEC 649. Pitot probes and hot-wire anemometry were employed to measure the flow field up and downstream of the cascade. Details of the unsteady flow caused by the trailing edge of the blades and the turbulent spectrum were investigated using hot-wire anemometry. The new organic vapor flow results were compared with the literature data obtained for air and with the prediction of conventional literature loss models. It was found that, under certain thermodynamic conditions, specific traditional loss models can reasonably predict organic Rankine cycle (ORC) turbines’ profile loss. Still, significant deviations between the loss models and the experimental data can also occur.

In this paper, we propose a data classification and analysis method to estimate fire risk using facility data of thermal power plants. To estimate fire risk based on facility data, we divided facilities into three states—Steady, Transient, and Anomaly—categorized by their purposes and operational conditions. This method is designed to satisfy three requirements of fire protection systems for thermal power plants. For example, areas with fire risk must be identified, and fire risks should be classified and integrated into existing systems. We classified thermal power plants into turbine, boiler, and indoor coal shed zones. Each zone was subdivided into small pieces of equipment. The turbine, generator, oil-related equipment, hydrogen (H2), and boiler feed pump (BFP) were selected for the turbine zone, while the pulverizer and ignition oil were chosen for the boiler zone. We selected fire-related tags from Supervisory Control and Data Acquisition (SCADA) data and acquired sample data during a specific period for two thermal power plants based on inspection of fire and explosion scenarios in thermal power plants over many years. We focused on crucial fire cases such as pool fires, 3D fires, and jet fires and organized three fire hazard levels for each zone. Experimental analysis was conducted with these data set by the proposed method for 500 MW and 100 MW thermal power plants. The data classification and analysis methods presented in this paper can provide indirect experience for data analysts who do not have domain knowledge about power plant fires and can also offer good inspiration for data analysts who need to understand power plant facilities.

The propulsion system for an aircraft is one of its most crucial systems; therefore, its reliable work must be ensured during all operational conditions and regimes. Modern materials, techniques and methods are used to ensure this goal; however, there is still room for improvement of this complex system. The proposed manuscript describes a progressive approach for the mechanical properties prediction of the turbine section during jet engine operation using an artificial neural network, and it illustrates its application on a small experimental jet engine. The mechanical properties are predicted based on the measured temperature, pressure and rpm during the jet engine operation, and targets for the artificial neural network are finite element analyses results. The artificial neural network (ANN) is trained using training data from the experimental measurements (temperatures, pressure and rpm) and the results from finite element analyses of the small experimental engine turbine section proposed in the paper. The predicted mechanical stress by ANN achieved high accuracy in comparison to the finite element analyses results, with an error of 1.38% for predicted mechanical stress and correlation coefficients higher than 0.99. Mechanical stress and deformation prediction of the turbine section is a time-consuming process when the finite element method is employed; however, the method with artificial neural network application presented in this paper decreased the solving time significantly. Mechanical structural analyses performed in ANSYS software using finite element modeling take around 30–40 min for one load step. In contrast, the artificial neural network presented in this paper predicts the stress and deformation for one load step in less than 0.00000044 s.

The article considers some issues of choosing the gas temperature at the inlet of a liquid rocket engine turbopump turbine. The turbine is one of the key elements of the engine and its operability depends on the gas temperature. In addition, the turbine inlet gas temperature determines its power and main parameters of the engine chamber pressure and thrust. The higher turbine inlet gas temperature, the higher the chamber pressure and the better engine performance. The permissible temperature of the turbine structure is determined by the required safety margins and durability of the turbine rotor blades. For expendable engines, the safety margin is determined by the material short-term strength at maximum gas temperature. For reusable engines with a long service life, the safety factor is determined by the material long-term strength. The article presents the main factors affecting the choice of the generator gas temperature. It shows that one of the main factors is the non-uniformity of the temperature field at the turbine inlet. The choice of maximum admissible temperature is determined not so much by the engine schematic with the afterburning of oxidizing or reducing generator gas, but by the strength and durability of the structure with account of the influence of temperature factors.

Project Description:  The objective is to generate 500 MW of power for 8 hour periods. This would be enough to supply 325,000 homes annually in the San Diego area. A new upper reservoir will be constructed above the existing San Vicente Reservoir and connected by an underground pipe containing a reversible pump-turbine system. Energy produced by the system will be stored during off-peak hours and sold during peak hours. Tasks Completed:  Project research and analysis, Determination of criteria for upper reservoir, Selection of candidate sites using topography, Calculation of upper reservoir volume Faculty Adviser:   Richard Trembath, Trembath Consulting, Inc.

Wind is an important renewable energy source. The majority of wind farms in Pakistan are installed in Jhimpir, Sindh Wind Corridor. At this location, downstream turbines encounter upstream turbines', wake, decreasing power output. To maximize the power output, there is a need to minimize these wakes. In this research, a method is proposed to maximize the power output using a Genetic Algorithm (GA). Hub heights and inter-turbine spacing are considered variables in this method. Two wind farms located at Jhimpir, Sindh, namely, Second and Third Three Gorges Wind Farms (TGWFs), have been analyzed. Three different cases are considered to maximize the power output. In Case 1, thesame hub heights and inter-turbine spacing without wake effects are considered. In Case 2, the same hub heights and inter-turbine spacing with wake effects are considered. In Case 3, variable hub heights and inter-turbine spacing with wake effects are considered. The results revealed that TGWFs, with variable hub heights and inter-turbine spacing, produce more power output. It is also revealed that the increase in power output, in the case of two different hub heights, is greater in comparison to three different hub heights. Eventually, the proposed method may help in the layout optimization of a wind farm. [ABSTRACT FROM AUTHOR]

With the extensive application of renewable energy generation, thermal power units are required to participate in peak-regulating operations. The mode of steam distribution significantly influences the economy when the steam turbine operates at a low load. The turbine unit's governing valve characteristics and steam distribution modes are studied in this paper, and the optimal sliding pressure operation curve is derived. Firstly, the theoretical model of the governing stage and the governing valve is derived, and the reliability is verified with field data. Secondly, the overall simulation model of the turbine unit is established, and the turbine off-design performance is analyzed with variable main steam pressure. Finally, the advantages and disadvantages of the three steam distribution modes are discussed thoroughly. The steam distribution modes and optimal main steam pressures are analyzed. The results show that a precise composite sliding pressure operation scheme is recommended, and a sliding pressure operation mode is adopted under 470 MW and constant pressure operation for others. [ABSTRACT FROM AUTHOR]

To reduce carbon dioxide emissions into the environment, the energy sector develops oxygen-fuel energy cycles. One of the most promising cycles is the Allam cycle that features the highest efficiency of electricity generation among all others. One of the main elements of an oxy-fuel energy cycle is a high-temperature carbon dioxide turbine. The turbine's working fluid and coolant consist predominantly of carbon dioxide at a supercritical pressure. Currently, there are no recommendations in the literature for the design of carbon dioxide turbines for an oxy-fuel energy system (OFES) operating according to the Allam cycle; therefore, there is a need to study the influence of parameters of the flow path of carbon dioxide turbines on its efficiency and overall performance. In this paper, we have presented the results of one-dimensional calculations of a flow path of the carbon dioxide turbine for the Allam cycle with a capacity of 300 MW, with an initial temperature and pressure of 1100 °C and 30 MPa, and an outlet pressure of 3 MPa. The study was carried out by varying the rotor speed, the reactivity level and the average diameter. Based on the results of one-dimensional calculations, we have found that the highest efficiency of the turbine flow path is achieved at a speed of 471 rad/s, a reactivity of 0.5, and an average diameter of 1.1 m for the first stage. [ABSTRACT FROM AUTHOR]

A rim seal is often used to prevent the ingress of high-temperature gas into the turbine disk cavity and protect the turbine disk from damage. Based on the overlapping rim seal (Seal-A), this paper proposes two more composite sealing structures (Seal-B and Seal-C) to show the effects of a deep cavity in the static disk and a modified platform in the rotating disk. Three-dimensional unsteady Reynolds-averaged Navier–Stokes equations and the shear stress transfer (SST) k-ω turbulence model were used to reveal the flow field characteristics and the sealing efficiency. The results show that the rotor–stator interaction plays a dominant role in the sealing outlet pressure, and the sealing efficiency in the outflow area obtained by the transient calculation is lower than that of the steady-state calculation. The rise in the cooling air flow enhances the reverse vortex in the sealing cavity, and the disk cavity's sealing efficiency is also improved. When the cooling air flow ratio increases from 0.6% to 1.8%, the sealing efficiency at the high radius increases by 30%. The shape of the deep cavity produces a new return vortex at the lower part of the sealing cavity, which improves the sealing efficiency. The shark nose platform in Seal-C aggravates the gas ingress at the sealing outlet but improves the sealing efficiency at the sealing cavity. In general, compared with Seal-A, the sealing efficiency of Seal-B and Seal-C is increased by 13.5% and 10%, respectively, at a cooling air flow ratio of 0.6%. [ABSTRACT FROM AUTHOR]

Preparation of rotating machinery oil system plays very important role in commissioning process and defines if commissioning process of the turbine brings some troubles. Moreover, future maintenance and operation is very much affected if oil system clean liness is underestimated and machine commissioned without following complex cleaning procedure. Only standard displacement flush is not effective when system is corroded, where Varnish is agglomerated, pipe assembly done on site with lack of proper care. However, high machine availability and zero breakdowns is nowadays the main goal in every industry sectors! How to restore heavily corroded and Varnished turbine oil system after 10 years out of operation will be presented in this presentation. [ABSTRACT FROM AUTHOR]

Ceramic Catalytic Turbine (CCT) Technology is expected to become an important means to reduce vehicle emissions, especially during engine warm-up. In this paper, catalytic reaction was numerically simulated in 3D for a CCT on a gasoline engine during the warm-up period. The results showed that turbulence in the turbine promotes catalytic activity; CCT starts to significantly affect exhaust pollution since turbine inlet temperature of 550 K; the conversion efficiency of harmful gas in exhaust rises sharply when turbine inlet reaches 575–625 K; when the inlet temperature is about 720 K, the conversion efficiencies of C3H6, CO, and NO reach 23.7%, 21.1%, and 15.5%, respectively. Meanwhile the gas temperature is increased by about 30 K at turbine outlet. In addition, during the process of numerical modeling and calculation, it is found that minor change in boundary layer thickness has a negligible impact on the simulation. However, an extremely thin boundary layer will cause computational divergence. The intensity of catalytic reaction can influence the convergence of numerical calculation, while the moving average of the catalytic reaction with the turbine inlet temperature, in return, can reveal the catalytic light-off process. [ABSTRACT FROM AUTHOR]

The gravitational water vortex turbine is presented as an alternative for electric power generation for both low head and water flow conditions, additionally it is easy and low cost to implement and maintenance. However, the experimentally reported efficiencies motivate the scientific community to develop new geometries in order to improve its performance. First, it is not clear how the efficiency of the turbine is obtained and second, not all studies report it. The turbine is mainly made up of a tank, the rotor and the electric generator. The geometry of the tank is important because it stabilizes the fluid and in this component that the generation of the vortex is induced, which determines, added to other factors like tank geometry and runner, the global efficiency of the turbine. The primary purpose of this study is to compare numerically the torque generated at six (6) geometrical configurations of the basin inlet channel for Gravitational Vortex Turbine (GVT) with a Savonius rotor. The study was developed in ANSYS® CFX, where a transient state VOF model was configured with a BSL K-ω turbulence model and a discretization a discretization of the control volume made in the ICEM module. The highest torque was 0.553 Nm at 25 rpm for the trapezoidal curved inlet channel geometry, increasing the efficiency respect to the conventional Square inlet channel of the 2.73 %. The increase of tangential velocity contributes positively to the vortex generation, and consequently, an increase in torque is obtained. On the other hand, the design of the rotor considerably affects the performance of the GVT, where it may or may not take advantage of the kinetic energy of the vortex. [ABSTRACT FROM AUTHOR]

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Purpose: We investigate the use of TURBINE, a 3D radial‐Cartesian acquisition scheme in which EPI planes are rotated about the phase‐encoding axis to acquire a cylindrical k‐space for high‐fidelity ultrahigh isotropic resolution fMRI at 7 Tesla with minimal distortion and blurring. Methods: An improved, completely self‐navigated version of the TURBINE sampling scheme was designed for fMRI at 7 Telsa. To demonstrate the image quality and spatial specificity of the acquisition, thin‐slab visual and motor BOLD fMRI at 0.67 mm isotropic resolution (16 mm slab, TRvol = 2.32 s), and 0.8 × 0.8 × 2.0 mm (whole‐brain, TRvol = 2.4 s) data were acquired. To prioritize the high spatial fidelity, we employed a temporally regularized reconstruction to improve sensitivity without any spatial bias. Results: TURBINE images provide high structural fidelity with almost no distortion, dropout, or T2* blurring for the thin‐slab acquisitions compared to conventional 3D EPI owing to the radial sampling in‐plane and the short echo train used. This results in activation that can be localized to pre‐ and postcentral gyri in a motor task, for example, with excellent correspondence to brain structure measured by a T1‐MPRAGE. The benefits of TURBINE (low distortion, dropout, blurring) are reduced for the whole‐brain acquisition due to the longer EPI train. We demonstrate robust BOLD activation at 0.67 mm isotropic resolution (thin‐slab) and also anisotropic 0.8 × 0.8 × 2.0 mm (whole‐brain) acquisitions. Conclusion: TURBINE is a promising acquisition approach for high‐resolution, minimally distorted fMRI at 7 Tesla and could be particularly useful for fMRI in areas of high B0 inhomogeneity. [ABSTRACT FROM AUTHOR]

Micro turbojets are used for propelling radio-controlled aircraft, aerial targets, and personal air vehicles. When compared to full-scale engines, they are characterized by relatively low efficiency and durability. In this context, the degraded performance of gas path components could lead to an unacceptable reduction in the overall engine performance. In this work, a data-driven model based on a conventional artificial neural network (ANN) and an extreme learning machine (ELM) was used for estimating the performance degradation of the micro turbojet. The training datasets containing the performance data of the engine with degraded components were generated using the validated GSP model and the Monte Carlo approach. In particular, compressor and turbine performance degradation were simulated for three different flight regimes. It was confirmed that component degradation had a similar impact in flight than at sea level. Finally, the datasets were used in the training and testing process of the ELM algorithm with four different input vectors. Two vectors had an extensive number of virtual sensors, and the other two were reduced to just fuel flow and exhaust gas temperature. Even with the small number of sensors, the high prediction accuracy of ELM was maintained for takeoff and cruise but was slightly worse for variable flight conditions. [ABSTRACT FROM AUTHOR]

In the era of high energy demand caused by rapid population growth, renewable energy is required in the energy mix for the sustainability of both human and industrial development. This paper investigates the potential of extracting heat energy from abandoned oil and gas wells for electricity production. Four wells located in the Niger Delta were considered. Each well has its properties and steam flow rates. The geothermal reservoir was modeled as a liquid-vapor-dominated system at in situ reservoir conditions. The fluid temperature in the reservoir was determined to be 170oC in the reservoir. Equations describing geothermal resource potentials, energy flow in a wellbore, and gross electrical power production using turbines were presented. A Single-flash turbine system was used because steam was produced in the reservoir. MATLAB software was used in the simulation of the heat transfer process. The results showed that the geothermal energy corresponding to the reservoir considered was 2.45 x 1012 Joules. The electricity production result showed that there was a reduction in gross electrical power output due to an increase in sink temperature, while the relationship between gross electrical power output and separator temperature was such that there was an initial increase in gross electrical power output due to an increase in separator pressure until an optimum point was reached wherein further increase in separator pressure progressively decreased the value of the gross electrical power output. The optimum separator temperatures for well 1, well 2, well 3, and well 4 were 120oC, 120oC, 110oC, and 105oC respectively at a sink temperature of 45oC. Because of the high reservoir pressure used, the separator pressure was higher than the actual reservoir pressure. Proper understanding of heat flow which enables accurate estimation of heat production is necessary to maximize heat extraction from the reservoir. The simulation conducted reveals that geothermal resources holds great potentials for electrical energy generation and should be put to developmental use in Nigeria as a means to increase the total power generation and increase the portion of renewables in Nigeria energy value chain. [ABSTRACT FROM AUTHOR]

The construction, rehabilitation and re-licensing of hydropower stations must nowadays fulfill strict demands for fish protection, particularly those related to enhanced turbine passage survival rates of downstream migratory species. In an analogy to the efficiency curves of a water turbine represented on a hill chart, the bio-hill chart introduced herein depicts the relationships between the operating conditions (i.e., discharge and head) and the potential survival rate of migratory fish passing through the turbine. The bio-hill chart applies over the entire operating range of the machine, which is a step forward with respect to previous works that determined hydraulic-biological evaluations for only a few operating points. The elaboration of a bio-hill chart involves two steps: (i) the calculation of turbine flows for each operating point and (ii) the corresponding evaluation of fish friendliness. The flow conditions are determined via computational fluid dynamics simulations. The calculation of fish friendliness relies on modelling approaches to determine mortality risks associated with collision on rotating blades and rapid decompression. We thoroughly describe the process to elaborate the bio-hill chart for juvenile salmonid species, as well as its implementation in a Kaplan turbine. The bio-hill chart represents a first approximation for determining those operating conditions that may mitigate fish mortality risks (i.e., maximize fish friendliness) and for quantitatively establishing the inevitable trade-off that exists between the hydraulic and environmental demands of hydropower generation. [ABSTRACT FROM AUTHOR]