Hydro Applications Research Articles

Design evaluation reviews on the savonius, darrieus, and combined savonius-darrieus turbines

The combination of Savonius and Darrieus turbines had been proposed with the aim to overcome the weaknesses and complement the strengths from each design. This paper gathers relevant information and provided an extensive review on the combined Savonius-Darrieus turbine for both wind and hydro applications. The paper initially reviews the experimental and computational methodologies utilized in previous research in design evaluation of the turbines. The self-starting capability and efficiency of both turbines were the main concern. Following this, investigations were conducted on the possibility of combining the advantages on the two turbines with respect on the design compactness, radius ratios, attachment angles and rotational velocities.

Rolling Turbines—Theoretical Considerations and Experimental Verification

Abstract Rolling turbines are fluid motors that may be used in pico hydro applications at very small hydraulic heads of below 1 m and can operate even with untapped (waste) water. The present study proposes a theory of their operation, based on the hydrodynamic stability of vortices. A solid body vortex may be transformed due to viscosity into a more stable potential vortex. Circulation generated in the vortex core is transmitted to a rotor. The rotor, which is the key element, performs a precession motion, rotating concurrently around its axis while processing around another (precession) axis. The mechanical power output is drawn from the precession motion via a shaft. The theoretical results were experimentally validated with three variants of the rotors: one truncated cone and two spherical rotors. It was concluded that the tested rolling turbines operate with an efficiency of 43% to 48% at a hydraulic head of between 0.5 and 1.6 m.

A Simplified Francis Turbine for Micro Hydro Application: Design and Numerical Analysis

Francis turbine is the most widely used type of hydro turbine due to its high efficiency and a wide range of operation. Despite its popularity in large scale power plants, the use of these turbines has not been yet realized for micro hydro applications. Considering the sustainability of micro-hydro power plants, the components of Francis turbine need some simplifications so that the manufacturing and operation of the turbine become more feasible. This study focuses on redesigning the turbine with simplifications in spiral casing and distributor along with investigating its effects on the performance of runner using CFD. Bovet method is used to obtain meridional dimension of runner while Bladegen feature of ANSYS 15.0 is applied to obtain the runner domain. Optimum design of the runner is obtained by analyzing the effect of parameters like wrap angle, lean angle, blade’s beta angle distribution and energy distribution on the runner’s performance. The velocity at the runner inlet is very low for micro Francis turbine which increases the dimension of spiral casing so dimension of spiral casing is made small by adjusting guide vane and stay vanes. A comparative study of conventional and simplified design is made based on pressure and tangential velocity distributions along spiral casing and distributor as well as on the performance of turbine. It is observed that the required reaction ratio and flow conditions can be obtained by combining the stay vanes and guide vanes. In addition, the proportion of combination depends on the magnitude of reaction ratio. It is found that the combining the stay vane and guide vane gives better result in best efficiency point however at other loading condition efficiency is lower which is due to improper stagnation.

Design of Francis turbine for micro hydropower applications

This study presents a Francis turbine designed for micro hydro application, using bovet approach of design and other general techniques, with some variations which make the manufacturing procedure relatively simpler. It also depicts the status of micro hydro in Nepal. Simplifications has been administered on runner, vane cascade and spiral casing. The study has been carried out under single flow condition, which is generally the case in micro hydropower, which divert a small portion of water from the main source, generally rivers or springs. The design procedure used for the design of each hydraulic components have been described in brief. The numerical study performed on the turbine have also been presented. Effects of simplifications administered on each component has been analysed. The small variation in efficiency due to simplifications administered has been justified for use in micro hydropower projects in view of the drop in efficiency caused due inaccuracies during manufacturing of turbine.

Experimental and numerical investigations on a new developed Savonius turbine for in-pipe hydro application

Due to limitation of energy resources, a large body of research activities has been turned to investigate potential alternative avenues to supply energy. In this regard, the renewable sources, which can provide the sustainable and cleaner energy production, have increasingly become attractive. Hydropower has the highest proportion of the renewable energy sources. Availability and high efficiency are the undeniable advantages of the hydro potentials. In this paper, hydro-energy extraction from pipelines by a new designed vertical axis turbine is studied experimentally and numerically. The turbine scheme is inspired by the Savonius rotor turbine, which includes two semicircular blades that is built by the 3D printer and installed vertically in a 100 mm transparent pipe. A sloped block is used just before the turbine blades to concentrate the flow and enhance the efficiency. In experiments, flow rate ranges from 2.7 × 10−3 m3/s to 7.3 × 10−3 m3/s and pressure drop that occurs through the turbine is less than 10.5 kPa. Numerical results show an acceptable agreement with experiments and assure that numerical method is reliable. Following successful validation, numerical studies are expanded, in order to study more details on the new turbine performance. According to the numerical results, the characteristic curves of the new turbine are depicted and described. In numerical simulation, for different turbine rotational speeds, the flow rate and the pressure difference examined are up to 12 × 10−3 m3/s and 30 kPa, respectively. Using the obtained results, investigations and studies are performed to describe turbine behavior under the effects of changing the clearance and flow field conditions. Finally, cyclic variations of turbine flow rate, torque and minimum pressure on the turbine blade are described by velocities streamlines. This approach might preform design improving for such a turbine.

Design of Spiral Casing of Francis Turbine for Micro Hydro Applications

Spiral casing is an important component of Francis turbine for even distribution of kinetic and potential energy of water so as to achieve the required reaction for better performance of the runner. Optimal design and analysis of spiral configuration is challenging, especially when the turbine is operating in a low head range due to the necessity of a large cross-sectional area of the casing to accumulate the large flow. The main objective of this study is to design the best configuration of cross section of spiral casing which have a very minimal pressure loss and can provide required inlet flow condition for stay vanes. For this, spiral casing configurations following free-vortex theory with different cross sections i.e. circular, trapezoidal and square are designed and analysed numerically. Pressure, radial and tangential velocity distributions are compared for different cross section of spiral casing suitable for micro hydro applications. Considering the ease of manufacturing, flexibility of dimension adjustments and comparable performance with that of the circular spiral casing, trapezoidal casing is found to be an appropriate alternative for such applications.

Effectiveness of Alkali Water Consumption to Reduce Blood Sugar Levels in Diabetes Mellitus Type 2

Background: Non-Communicable Diseases (NCDs) have become a public health problem, globally, regionally, nationally and locally. Non-Communicable Diseases (NCDs) that took a lot of attention was diabetes mellitus. In Indonesia diabetes mellitus is a serious threat to health development. Efforts developed to overcome the problems of diabetes mellitus type 2 is to apply four pillars of therapy namely education, nutrition therapy, physical activity and pharmacology. However, these efforts have not been able to achieve optimal results due to many obstacles encountered. One of the non-pharmacological treatments that can be utilized is to consume alkaline water to reduce blood sugar levels in diabetes mellitus type 2. Methods: The research design used was quasy experiment with pre-post control group design approach. The variables observed in this study were random blood sugar changes in people with diabetes mellitus type 2 prior to intervention and after intervention. Intervention is given over a period of 14 days. To measure the demand of drinking water on the respondents, the measurement was done using Water Drink Reminder - Hydro application. The alkaline water used in this study is alkaline water produced from Kangen Water Type SD501 Platinum Machine. Test analysis used is paired t test to determine the effectiveness of alkaline water consumption to decrease random blood sugar level of diabetes mellitus type 2. To know the difference of effectiveness of alkaline water consumption to decrease of blood sugar level, it uses one way anova test with significance value α: 0.05. Results: From result of the one way anova test with significance value α: 0.05, we have got significance 0.039. Since the significance probability value is 0.039 0.05, the research hypothesis is accepted which means that there is a significant difference in the level of random blood sugar of diabetes mellitus type 2 performed by using four kinds of intervention of alkaline water treatment (Alkali Water PH 7.0, PH 8.0, PH 9.5 and PH 9.5 and PH 11.5) for a period of 14 days. Conclusion: Support from health personnel and adherence to diabetes mellitus is required to utilize alkaline water as nonpharmacologic therapy to control blood sugar levels in people with type 2 diabetes mellitus. To achieve maximum results from nonfarmakologi therapy performed, people with diabetes mellitus type 2 should routinely consume antidiabetic drugs provided by health personnel and always strive for a healthy life.

Structural and Kinematic Features of a 2 DOF Speed Increaser for Renewable Energy Systems

The counter-rotating wind turbine is a relatively new concept of wind converter that contains two rotors placed on the same side or on both sides of the nacelle with the aim of increasing the wind energy conversion efficiency. As the rotors are rotating at a lower speed than the generator requires, the wind turbine usually contains a speed increaser to harmonize their running regimes. Similar counter-rotating systems are approached for hydro applications but they are still in the research phase.The paper proposes a novel concept of a 2 DOF speed increaser to be used in counter-rotating systems (wind or hydro). The structural and kinematic features of the 1 DOF and 2 DOF transmission running cases are presented in the paper. The differential transmission is further analyzed and the transmission functions and efficiency are established. Finally, conclusions regarding the use of 2 DOF transmissions in the renewable energy systems are formulated.

An experimental investigation of pump as turbine for micro hydro application

This paper presents the results of an experimental investigation of a centrifugal pump working as turbine (PAT). An end suction centrifugal pump was tested in turbine mode at PAT experimental rig installed in the Mechanical Engineering Laboratory of Universiti Tenaga Nasional. The pump with specific speed of 15.36 (m, m3/s) was used in the experiment and the performance characteristic of the PAT was determined. The experiment showed that a centrifugal pump can satisfactorily be operated as turbine without any mechanical problems. As compared to pump operation, the pump was found to operate at higher heads and discharge values in turbine mode. The best efficiency point (BEP) in turbine mode was found to be lower than BEP in pump mode. The results obtained were also compared to the work of some previous researchers.

Comparing recent views of public attitude on wind energy, photovoltaic and small hydro applications

As renewable energy projects have gradually been introduced in various forms and in many places around the world, public skepticism on these developments has emerged and siting decisions have, in several cases, been determined by intense conflicts and debate. In this context, the present study focuses on the assessment of the levels of public acceptability for existing and new renewable energy projects, namely wind farms, small hydro and photovoltaics (PVs), in a representative region of Southern Greece. A point of particular interest in this survey is the adverse environmental conditions and poor air quality existing in the area under investigation, resulting from the long-term operation of a lignite-based thermal power station. A postal, three-part survey has been conducted based on a representative sample of local inhabitants. According to the results obtained, high levels of acceptability for existing and new projects have been encountered for all technologies examined. Interestingly, better results concerned PV applications, with the positive trend towards new projects being illustrated by the high percentage of about 85%. Similarly, wind and hydro energy applications demonstrate high acceptability of the order of 80%. Furthermore, local habitants' experience on already operating renewable energy projects in the region has also designated their “tolerance” on the main environmental impacts of these technologies (visual, noise, land occupation etc.). However, this survey also reveals a specific minority of people that are opposed to renewable energy applications, either disregarding any environmental, social and financial benefits or just weighing benefits less heavily than the reasons of opposition.

Influence of the Blade Hub Geometry on the Performance of Low-Head Axial Flow Turbines

AbstractThe influence of geometric parameters, such as blade profile and hub geometry on axial flow turbines for micro hydro application remains poorly characterized. This paper first introduces a holistic theoretical model for studying the hydraulic phenomenon resulting from geometric modification to the blades. It then describes modification carried out on two runner stages, of which one has untwisted blades and the other has twisted blades obtained by modifying the inlet hub. The experimental results showed that the performance of the untwisted blade runner was satisfactory with a maximum efficiency of 68%. However, positive effects of twisted blades were clearly evident with an efficiency rise of more than 2%. This study also looks into the possible limitations of the model and suggests the extension of the experimental work and the use of computational tools to conduct a progressive validation of all experimental findings, especially on the flow physics within the hub region and the slip phenomena. T...

Experimental optimization of a free vortex propeller runner for micro hydro application

The turbine technology for low head application in the micro hydro range has been vastly neglected despite niche available in scattered regions of valley flows as well as in wastewater canals and other energy recovery schemes, where the available head does not exceed 2 meters. The goal of this study is to develop hydraulically optimized propeller turbines for the micro hydro range with a particular focus on ease of manufacture. This paper presents a wide range of geometrical optimization steps carried out on a propeller runner, whose blades have been designed using the free vortex theory, and operating with a gross head from 1.5 to 2 m and discharge of approximately 75 l/s. It further illustrates 3 stages of geometrical modifications carried out on the runner with an objective of optimizing the runner performance. These modifications comprised of changes to the tip angles (both at the runner inlet and exit) as well as the hub angles (at the runner inlet) of the runner blades. The paper also presents an interesting theoretical methodology to analyze the effects of each optimization stage. This method looks at the relative changes to shaft power and discharge at constant head and speed and gives wonderful insight as to how the internal parameters like Euler shaft work and runner hydraulic losses are behaving with respect to each optimization stage. It was found that the performance of the runner was very sensitive to changes to exit tip angle. At two levels of modification, the discharge increased in the range of 15–30%, while shaft power increased in the range of 12–45%, thus influencing the efficiency characteristics. The results of the runner inlet tip modification were very interesting in that a very significant rise of turbine efficiency was recorded from 55% to 74% at the best efficiency point, which was caused by a reduced discharge consumption as well as a higher power generation. It was also found that the optimization study on a propeller runner has reasonably validated the estimates of the free vortex theory despite small deviations. The final runner configuration demonstrated a maximum efficiency of 74% (±1.8%), which is very encouraging from the perspectives of micro hydro application. The paper concludes with recommendations of a series of optimization steps to increase the efficiency of the runner. It also recommends the attempt of Computational Fluid Dynamics both as a validation and optimization tool for future research on propeller runners.

A future application environment for BC Hydro's EMS

The paper reports on the results of a tailored collaboration project sponsored by BC Hydro and EPRI to review the state-of-the-art in EMS architectures addressing the necessary attributes of a modern EMS with respect to scalability, database and user interface openness, flexibility and conformance to industry standards, as well as to provide a migration path for the existing BC Hydro's EMS. This review was intended to assist BC Hydro in identifying functionality and standard requirements of future EMS procurements and a migration path for a future BC Hydro application program environment. The proposed migration path was prototyped to verify its prudence and applicability in providing an open architecture environment for EMS applications. The BC Hydro On-Line Voltage Stability Analysis (OLVSA) application developed by BC Hydro and Powertech Labs was chosen and integrated into the prototype.