A triple-bladed dual-stage savonius-alike hydrokinetic turbine system

Abstract

The system comprises hydrokinetic turbine units (102) placed in an aquatic environment; a propeller (104) positioned on a rotor shaft (106), wherein the propeller comprises triple-blade stages (108) positioned at an angle of 120-degrees and are coaxially aligned and the vertical shaft is enforced co-centrically; and a ball bearing (110) installed on a plate frame supports the turbine's shaft to promote support and smooth rotation of the plurality of triple-blade stages during the turbine's operation in the water current; rifling vanes (112) to cause the water entering the forward entry section to spin like a vortex; front pre-spin vanes (114) to prevent items from entering the forward entrance portion and to cause rotation of the water entering the forward entrance portion; a gate (118) to decrease / increase the depth of water by altering the discharge; centrifugal pumps (120) to deliver the water to the open flume; and a second pump (122) to increase water velocity while altering the rate of discharge.

Description

[0001] A TRIPLE-BLADED DUAL-STAGE SAVONIUS-ALIKE HYDROKINETIC TURBINE SYSTEM

[0002] FIELD OF THE INVENTION

[0003] The present disclosure relates to a triple-bladed dual-stage Savonius-alike hydrokinetic turbine system with end plates and blade overlapping at low flow stream conditions.

[0004] BACKGROUND OF THE INVENTION

[0005] Energy is an important factor that impacts the nation's social and economic growth. Due to industrialization and urbanization in developing and developed regions, per capita energy consumption is surging day by day. Due to increased dependability on energy, the surge in global energy demand, fuel consumption-based environmental threats, and fossil fuel costs, the renewable energy demand has grown rapidly in recent years. Hydropower can be an efficient, predictable, and green source of energy from freely flowing water streams, of which an economically valued option is hydrokinetic energy. The principle of hydrokinetic energy conversion is based on the conversion of water's kinetic energy from freely flowing water in a river, irrigation canals, manmade channels, flumes, etc., into hydropower in micro and pico-scales. This method has great potential for generating hydropower from ultra-low or zero head and low flow speeds. A common technique for converting hydrokinetic energy from low flow speeds is Savonius hydrokinetic turbine (SAHT). This technique offers a novel and inventive method for producing electricity in low-velocity flow reserves. In addition, it is a mechanical device that primarily employs a drag effect mechanism. With SAHT blades, the self-starting technique is flawless. It features a very simple blade profile when compared to more complex airfoil-based designs, such as Darrieus-type turbines.

[0006] The fundamental problem with SAHT is its low efficiency, despite the turbine design is simple and that several inventive variations have previously been developed. The fundamental challenge is to make drag production by SAHT more effective by increasing the water contact area on its blades and simultaneously reducing the negative pressure effect on its blades. The problem is addressed by many researchers in the form of changing the semicircular blade profiles with elliptical, twisted, and semi-circular profiles with multiple blades, using end plates, deflectors, poly-staging of Savonius rotors, etc. Researchers investigated the double gap flow guides of a 0.5 m diameter Savonius turbine at various angular orientations between 45 and 90 degrees. A model with a 75° angle and 75 mm length displayed a maximum gain in the coefficient of performance of 12.24% at a tipspeed ratio of 1 and a water velocity of 0.4 m / s. The impact of a twisted blade on a vertical-axis Savonius rotor with direct discharge flow capability was investigated. The results demonstrate that a twisted Savonius turbine with a conical shaft exhibits an 18% increase in power coefficient and a 31% increase in discharge flow rate compared to a straight-shaft Savonius wind turbine. Researchers created a unique blade curvature to enhance the functionality of the standard Savonius rotor. The revised blade profile was designed using a section of an S1048 airfoil as a model. It was shown that at a tip speed ratio of 1, the modified blade profile can increase the standard design's peak power coefficient by 14%. Tapered and standard Savonius blades for the production of hydrokinetic power are examined. The outcome indicated that the tapered turbine-based blade boosted the performance of a conventional turbine by 5%. To assess the performance of the turbine with delta blades and a sweep angle leading edge, researchers conducted an experimental analysis. This study was conducted in an irrigation channel with a constant water current velocity of 0.86 m / s. The greatest value of Cpwas 0.184, and the numerical results showed that the sweep angles in the leading edge have a significant impact on the turbine's efficiency.

[0007] It has been found that a two-stage rotor had improved flow control at higher flow speeds, reaching a maximum Cpof 0.104. Some numerical simulations have been conducted for five different hybrid SAHT configurations using end plates with varying Savonius blade helicity values in the range of 0°-180°. Savonius blade helicity of 45° was shown to have a maximum power coefficient of 0.208, corresponding to a TSR of 0.9 and an in-stream water velocity of 0.5 m / s. A new model was developed using the NACA series Savonius blade profile along with end plates as investigated. From the numerical study, it has been found that the power coefficient reaches 0.25 with TSR 1.52 for the lowest upstream velocity measured (0.33 m / s). It has been numerically investigated the performance of the Savonius turbine using helical blades with end plates. The results revealed that both upper and lower-end plates enhance the power coefficient to more than 36% when no end plates are used. It has been experimentally evaluated the performance of a double-stage Savonius turbine using end plates and the maximum Cp and CT are found to be 0.104 and 0.166, respectively at the same TSR 0.626. Researchers performed an experimental analysis with 20% overlap in the Savonius water turbine attached with end plates by varying flip radius. The results reported that a maximum power coefficient (Cp) of 0.116 is obtained at a flip radius of 42 mm.

[0008] One of the researchers used deflectors as augmentation devices in the instance of wind application to enhance the power performance of a triple-bladed traditional Savonius turbine. With a coefficient of performance (Cp) of 0.183, the deflector augmentation increased the Savonius turbine's capacity to self-start and generate more power. Additionally, the researchers studied how to increase power performance by adjusting the longitudinal-position ratios of the deflectors. The maximum Cp, 0.26, was achieved by the turbine. The researcher combined deflector plates and their blade twist in Savoniu' design and performed its experimental approach in an irrigation channel. Three deflector concepts are examined by 3D-based CFD modeling to increase its effectiveness. The design achieved a higher Cpof 0.166 by using a deflector. In rural locations, it was more efficient to generate electrical energy in river streams, water channels, and tidal streams. The Savonius turbine efficiency was also increased by utilizing several other augmentation techniques, including the use of a porous deflector, wind booster, circular windscreen, fluid direction controller, and nozzle duct. In a recent study, the researcher found that using cross-stream vertical water thrust via a gap between its stages might increase fluid pressure on a dual blade, dual-stage SAHT's Cpat low tip speed ratios. The vertical velocity gradient is expected to provide additional pressure on the blades through the gap between its stages. It has been found that these flow physics led to an improvement in the performance of vertical axis co-axial wind turbines.

[0009] From the foregoing literature survey, it can be seen that many have attempted to improve the drag production on the Savonius blades by channelizing positive pressure on the blades through blade design modifications, adding more blades, reducing negative blade pressure using deflector pates, bounding the flow between two end plates to increase pressure on the blades, circulating the flow through overlap, multi-staging to magnify the fluid pressure, etc. However, nobody attempted to combine the contributions of multi-staging, end plates, flow through overlap, and additional water thrust between its stages through a gap for enhancing the SAHT performance at low flow speed conditions, although some researchers used multi-staging, end plate, and overlapping together. The performance of a dual-blade, dual-stage Savonius-alike turbine was shown to be strongly influenced by the gap between the stages of the SAHT. The design of a triple-blade, dual-stage end-plated SAHT with varying gap distances between its stages and overlapping has not yet been investigated. Implementing cross-stream vertical water thrust on more blades and having maximum fluid interactions due to end plates and overlapping may further improve the performance of such SAHT for application in low-flow stream reserves, where it is anticipated that the blade tip speed ratio will be low. The applicability of such SAHT in various low flow speeds and brake load conditions (when linked to a turbo-generator) may be constrained by the fact that water flow speed larger than 0.6 m / s and brake load more than 1000 g were not explored in that study. Additionally, the impact of loads on the functionality of a multi-bladed SAHT has not before been studied. The torque and power performances of such SAHT in a specific range of low flow speeds under the dynamic action of braking loads and stage clearance are also only sparsely studied.

[0010] In view of the foregoing discussion, it is portrayed that there is a need to have a triple-bladed dual-stage Savonius-alike hydrokinetic turbine system.

[0011] SUMMARY OF THE INVENTION

[0012] The present disclosure seeks to provide a triple-bladed dual-stage Savonius-alike hydrokinetic turbine system. The Savonius-like hydrokinetic turbine (SAHT) is a simplistic drag-based system to harness hydro energy from low-flow stream deposits. There is an evaluation challenge to improve its drag production and hence its efficiency, which can be achieved by increasing the water contact area on its blade surface and reducing negative pressure on the blades. Out of the already explored solutions, nobody attempted to combine the contributions of multi-staging, the gap between its stages, end plates, and blade overlapping for grooming its performance at low flow speed and tip speed conditions. In this study, the performance of a triple blade dual stage SAHT configuration with end plates and 15% blade overlapping is examined in a water channel with a range of stage gap (0 to 20 mm), low flow speeds (0.45 to 0.65 m / s) under applied brake loads (100 to 1500 g). The results demonstrate the turbine produces more torque as the brake load rises, reaching its maximum hydrodynamic torque (0.084 Nm) at the highest load of 1250 g. It also researched how precisely the turbine performs under various design and off-design scenarios. The stage clearance of 5 mm, turbine brake load of 1250 g, tip speed ratio of 0.259, and free-stream flow speed of 0.55 m / s yield the maximum coefficient of performance (0.087), which is higher than a few of the available designs under low tip speed ratios. The current experimental inquiry is carried out on a triple-blade doublestage along with end plate SAHT. Under various low-stream speed conditions of 0.45-0.65 m / s, brake load conditions of 100-1500 g, overlapping of 15%, and gap distances of 0.0-20.0 mm, the SAHT performance through a water channel is examined. This lower and higher limit of the flow speed range is being studied to quantify the torque and power behavior of the current SAHT design. Further, to provide useful performance insights, detailed turbine performance under various design and off- design scenarios is explored.

[0013] In an embodiment, a triple-bladed dual-stage Savonius-alike hydrokinetic turbine system is disclosed. The system includes a plurality of hydrokinetic turbine units placed in an aquatic environment, each of which has a shroud with a front entry section and a rear exit portion.

[0014] The system further includes a propeller positioned on a rotor shaft within the shroud, wherein the propeller comprises a plurality of triple-blade stages positioned at an angle of 120 degrees from one another on a vertical shaft, wherein the plurality of triple-blade stages are coaxially aligned and the vertical shaft is enforced co-centrically. A ball bearing installed on a plate frame supports the turbine's shaft to promote support and smooth rotation of the plurality of triple-blade stages during the turbine’s operation in the water current, wherein the circular cross-section shaft of 0.014 m diameter is used to attach the turbine's entire blade assembly. The system further includes a plurality of rifling vanes disposed on a shroud's inner surface to cause the water entering the forward entry section to spin like a vortex.

[0015] The system further includes a plurality of front pre-spin vanes placed close to the front entrance section to prevent items from entering the forward entrance portion and to cause rotation of the water entering the forward entrance portion.

[0016] The system further includes a plurality of rear pre-spin vanes placed next to the turbine units' rear departure section.

[0017] The system further includes a gate attached at the outlet to decrease or increase the depth of water by altering the discharge, wherein the gate is having a selectively blockable pathway with an open and closed position.

[0018] The system further includes a plurality of centrifugal pumps disposed to deliver the water to the open flume, wherein the height, width, and length of the open flume are 0.505 m, 0.9 m, and 12 m, respectively.

[0019] The system further includes a second pump connected to the gate to increase water velocity while altering the rate of discharge.

[0020] An object of the present disclosure is to produce power at flow rates higher than 0.55 m / s, allowing for better operational flexibility with a wider range of tip speed ratio.

[0021] Another object of the present disclosure is to increase pressure on the blades and improve performance.

[0022] Another object of the present disclosure is to develop a triple-bladed, twin-stage, and end plate Savonius hydrokinetic turbine that may be erected in very low stream flow reserves (flow speed less than 0.55 m / s) to operate it as a torque generator.

[0023] Yet another object of the present invention is to deliver an expeditious and cost-effective dual-stage, triple-bladed, end-plated Savonius-like hydrokinetic turbine (SAHT) at 15% blade overlapping.

[0024] To further clarify the advantages and features of the present disclosure, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail in the accompanying drawings.

[0025] BRIEF DESCRIPTION OF FIGURES

[0026] These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read concerning the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

[0027] Figure 1 illustrates a block diagram of a triple-bladed dual-stage Savonius-alike hydrokinetic turbine system in accordance with an embodiment of the present disclosure;

[0028] Figure 2 illustrates (a) Three views of the triple-bladed dual-stage Savonius turbine: (a) the actual view with the stage gaps; (b) the top view of the turbine; and (c) the front view of the turbine in accordance with an embodiment of the present disclosure; Figure 3 illustrates (a) Three views of the triple-bladed dual-stage Savonius turbine: (a) the actual view with the stage gaps; (b) the top view of the turbine; and (c) the front view of the turbine in accordance with an embodiment of the present disclosure;

[0029] Figure 4 illustrates the measurement device (a) Arrangement of the rope-brake dynamometer in upstream velocity (b) ADV probe positioning in an upstream location and (c) Spring Balance in accordance with an embodiment of the present disclosure;

[0030] Figure 5 illustrates a layout view of the open flume in accordance with an embodiment of the present disclosure;

[0031] Figure 6 illustrates the intensity of turbulence with RMSE of 0.15% at various stream-wise distances from the turbine in accordance with an embodiment of the present disclosure;

[0032] Figure 7 illustrates Velocity distribution near the side walls of the water channel- (a) left sidewall at mid-layer and (b) right sidewall at mid-layer in accordance with an embodiment of the present disclosure;

[0033] Figure 8 illustrates Torque, power, Cp and TSR variations with different brake load conditions for flow speed of 0.55 m / s with clearances of (a) 0.0 mm, (b) 5.0 mm, (c) 10.0 mm, (d) 15.0 mm, and (e) 20.0 mm in accordance with an embodiment of the present disclosure;

[0034] Figure 9 illustrates distributions of (a) Power, (b)Hydrodynamic torque, (c) Cp, and (d) TSR at 1250 g brake load condition against the flow speeds for the studied stage clearances in accordance with an embodiment of the present disclosure;

[0035] Figure 10 illustrates variations of maximum Cp for the studied stage clearances at optimal brake load against TSR for flow speeds (a) 0.45m / s, (b) 0.55 m / s, and (c) 0.65 m / s in accordance with an embodiment of the present disclosure;

[0036] Figure 11 illustrates Variations of maximum Cp for optimal gap conditions and brake load against TSR for the flow velocities 0.45 m / s, 0.55 m / s, and 0.65 m / s in accordance with an embodiment of the present disclosure;

[0037] Figure 12 illustrates a Comparison of Cpvs TSR between the present SAHT in accordance with an embodiment of the present disclosure;

[0038] Figure 13 illustrates Table 1 depicts Instruments Specifications in accordance with an embodiment of the present disclosure;

[0039] Figure 14 illustrates Table 2 depicts experimental results (at 5 mm clearance and 1250 g load) in accordance with an embodiment of the present disclosure;

[0040] Figure 15 illustrates Table 3 depicts a comparison with the existing literature in accordance with an embodiment of the present disclosure;

[0041] Figure 16 illustrates Comparison of maximum CT against TSR for flow velocity 0.55 m / s in accordance with an embodiment of the present disclosure; and

[0042] Figure 17 illustrates the comparison of Cpvs TSR between the present SAHT, Khan et al., and Shashikumar et al. in accordance with an embodiment of the present disclosure.

[0043] Further, skilled artisans will appreciate those elements in the drawings are illustrated for simplicity and may not have necessarily been drawn to scale. For example, the flow charts illustrate the method in terms of the most prominent steps involved to help to improve understanding of aspects of the present disclosure. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

[0044] DETAILED DESCRIPTION: To promote an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

[0045] It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be restrictive thereof.

[0046] Reference throughout this specification to “an aspect”, “another aspect” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, appearances of the phrase “in an embodiment”, “in another embodiment” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

[0047] The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such process or method. Similarly, one or more devices or sub-systems or elements or structures or components proceeded by "comprises...a" does not, without more constraints, preclude the existence of other devices or other sub-systems or other elements or other structures or other components or additional devices or additional sub-systems or additional elements or additional structures or additional components.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The system, methods, and examples provided herein are illustrative only and not intended to be limiting.

[0049] Embodiments of the present disclosure will be described below in detail concerning the accompanying drawings.

[0050] Referring to Figure 1, a block diagram of a triple-bladed dual-stage Savonius-alike hydrokinetic turbine system is illustrated in accordance with an embodiment of the present disclosure. System 100 includes a plurality of hydrokinetic turbine units (102) placed in an aquatic environment, each of which has a shroud with a front entry section and a rear exit portion.

[0051] In an embodiment, a propeller (104) is positioned on a rotor shaft (106) within the shroud, wherein the propeller (104) comprises a plurality of triple-blade stages (108) positioned at an angle of 120 degrees from one another on a vertical shaft, wherein the plurality of triple-blade stages (108) are coaxially aligned and the vertical shaft is enforced co-centrically.

[0052] In one embodiment, a ball bearing (110) is installed on a plate frame to support the turbine's shaft to promote support and smooth rotation of the plurality of triple-blade stages (108) during the turbine’s operation in the water current, wherein the circular cross-section shaft of 0.014 m diameter is used to attach the turbine's entire blade assembly.

[0053] In an embodiment, a plurality of rifling vanes (112) is disposed on a shroud's inner surface to cause the water entering the forward entry section to spin like a vortex.

[0054] In an embodiment, a plurality of front pre-spin vanes (114) is placed close to the front entrance section to prevent items from entering the forward entrance portion and to cause rotation of the water entering the forward entrance portion.

[0055] In an embodiment, a plurality of rear pre-spin vanes (116) is placed next to the turbine units' rear departure section.

[0056] In an embodiment, a gate (118) is attached at the outlet to decrease or increase the depth of water by altering the discharge, wherein the gate (118) is having a selectively blockable pathway with an open and closed position.

[0057] In an embodiment, a plurality of centrifugal pumps (120) is disposed to deliver the water to the open flume, wherein the height, width, and length of the open flume are 0.505 m, 0.9 m, and 12 m, respectively.

[0058] In an embodiment, a second pump (122) is connected to the gate (118) to increase water velocity while altering the rate of discharge.

[0059] In another embodiment, the turbine's blades are fabricated using aluminum sheets with 0.0015 m thickness in a cylindrical shape with a cross-section of a semi-circle having a chord length of 0.14 m.

[0060] In another embodiment, the height of one stage of the Savonius-like hydrokinetic turbine (SAHT) is 0.085 m with a diameter of 0.26 m, end plate diameter of 0.286m, and total height is 0.17 m, and thus the height-to-diameter ratio is 0.64, wherein the turbine's highest coefficient of performance (Cp) is attained at an aspect ratio of 0.7 for Savonius blades, wherein the SAHT is completely submerged inside an open flume such that the optimum attainable water depth is 0.24 m and the possible maximum discharge is 91 1 / s in the channel and the depth of water is decreased or increased by altering the discharge using the gate (118) at the outlet.

[0061] In another embodiment, the three centrifugal pumps (120) are deployed to deliver the water to the open flume, i.e., pump 1 (15 hp), pump 2 (20 hp), and a 25 hp pump is connected to the facility, which is used to cause water velocity increase while altering the rate of discharge.

[0062] In another embodiment, a storage water tank is placed under the ground, and using pumps, water is passed to the open flume, wherein the channel with the attained highest water velocity is 0.65m / s that is measured using a first Acoustic Doppler Velocimeter (ADV), in which the functions of the meter at a single point is utilized for measuring the speed of water from 0.03m / s to 2.5m / s, wherein sampling is done at the rate 0.09-49Hz. In another embodiment, a second ADV is interfaced with a plurality of sensors in the slender head and three receiver arms, wherein the transmitter is applicable for flow speed calculation in a significant space from the slender head.

[0063] In another embodiment, a non-contact type digital tachometer calculates the blade speed (rpm) of the turbine, which is further transferred by the ADV through a connected computer interface.

[0064] In another embodiment, a forward entry section of each of the plurality of hydrokinetic turbine units (102) is stabilized in the direction of current flow by a plurality of stabilizers extending from an external surface of the shroud.

[0065] In another embodiment, the shroud is having a rear exit section and a middle section that is tapered inward about the forward entry section, wherein a plurality of rifling vanes (112) produced on the shroud's inner surface cause the water entering the forward entry section to spin like a vortex and a plurality of front pre-spin vanes (114) positioned close to the forward entrance portion, aligned with the plurality of rifling vanes (112) to cause rotation of water entering the forward entrance portion and prevent objects from entering the forward entrance portion.

[0066] In another embodiment, at least two counter-revolving vertical turbine rotors are coupled to the turbine, each of which has a low solidity and includes a shaft attached at least at the top section of the turbine. In one embodiment, a top hub with three upper arms are proximate to the shaft's top portion. In one embodiment, a bottom hub with three lower arms is proximate to the shaft's bottom portion, wherein the triple-blade stages (108), each of which is attached to a lower arm of a set of three lower arms and an upper arm of a set of three upper arms.

[0067] Figure 2 illustrates (a) Three views of the triple-bladed dual-stage Savonius turbine: (a) the actual view with the stage gaps; (b) the top view of the turbine; and (c) the front view of the turbine in accordance with an embodiment of the present disclosure. The triple-blade dual-stage SAHT along with the end plate with different clearances between the stages from 0-20 mm are considered for experimental investigation and different views for the turbine blade setup are given in Fig.2 (a-c). The triple-blade stages (108) are positioned at an angle of 120 degrees from one another on the vertical shaft. Here, the turbine's blades are created using aluminum sheets with 0.0015 m thickness, which is cylindrical with a cross-section of a semi-circle having a chord length of 0.14 m. The height of one stage of the SAHT is 0.085 m with a diameter of 0.26 m, an end plate diameter of 0.286m, and a total height is 0.17 m, and thus the height-to-diameter ratio is 0.64. For Savonius blades, the turbine's highest Cp is attained at an aspect ratio of 0.7. Therefore, this current design adheres to the accepted design aspect ratio for the SAHT. A circular cross-section shaft of 0.014 m diameter is used to attach the turbine's entire blade assembly.

[0068] Figure 3 illustrates (a) Three views of the triple-bladed dual-stage Savonius turbine: (a) the actual view with the stage gaps; (b) the top view of the turbine; and (c) the front view of the turbine in accordance with an embodiment of the present disclosure. A ball bearing (110) installed on a plate frame is used to support the turbine's shaft to provide support during the turbine’s operation in water current. In the developed turbine, the experiments have been performed in a completely submerged condition for the SAHT inside an open flume (made in India). The height, width, and length of the open flume are 0.505 m, 0.9 m, and 12 m, respectively. In the channel, the optimum attainable water depth is 0.24 m and the possible maximum discharge is 91 1 / s. Based on the need, the depth of water can be decreased or increased by altering the discharge using a gate (118) at the outlet. The experimental setup and schematic diagram of the test system are represented in Fig.3 (a-b). Consequently, three centrifugal pumps (120) are utilized to deliver the water to the open flume, i.e., pump 1 (15hp, made in India), and pump 2 (20 hp, made in India). Depending upon the needs; a separate 25 hp pump is connected to the facility, which is used to cause water velocity increase while altering the rate of discharge.

[0069] Figure 4 illustrates the measurement device (a) Arrangement of the rope-brake dynamometer in upstream velocity (b) ADV probe positioning in an upstream location and (c) Spring Balance in accordance with an embodiment of the present disclosure. The necessary water is kept in the water tank for circulation; the storage water tank is situated under the ground, and using pumps, water is passed to the open flume. In this, the channel the attained highest water velocity is 0.65m / s that is measured using a device known as the Acoustic Doppler Velocimeter (ADV) of Son Tck / YSi Inc. Generally, this instrument is described as the current meter, in which the functions of the meter at a single point is utilized for measuring the speed of water from 0.03m / s to 2.5m / s. In addition, sampling is done at the rate 0.09-49Hz. Moreover, a 16 MHz micro ADV is additionally deployed, which is prepared by several sensors in the slender head and three receiver arms. The used transmitter is applicable for flow speed calculation in a significant space from the slender head. Furthermore, the created device can operate with 1% accuracy and can deliver the data through a connected computer interface. A non-contact type digital tachometer (make-systems) calculates the blade speed (rpm) of the turbine at an accuracy of 1%. In the present system, the designed triple-blade dual-stage SAHT with an aspect ratio of 0.64 is investigated for different clearance between the stages. Using the free- stream velocity of water (V), the maximum water power (Pmax) is calculated using eq. (1)

[0070] Where ‘ / / represents the density of water, and ‘A’ is swept area of the turbine. The turbine’s torque (r) based on the load applied with the help of a dynamometer arrangement based on rope-brake is computed by eq. (2).

[0071] Where Laand Rsrepresent the applied load and residual spring balance reading, respectively, SR denotes the shaft radius, which is measured in m, and the utilized nylon string diameter is denoted as dn swhich is measured in m. The power extracted from the SAHT is calculated by eq. (3). where ‘co’ is the angular velocity of the turbine in rad / s. The coefficient of performance (Cp) is the ratio of the maximum water power to the power derived from the turbine as stated by equation (4) as- The tip speed ratio (TSR) of the turbine is one of the key elements for the flow velocity effect in the free stream on the rotational rate of the turbine, and it is computed by eqn. (5).

[0072] In addition, the turbulence intensity Tintenumeration is one of the essential parameters, and it is computed for the flow at any specific positions that are expressed in eq. (6).

[0073] Where, Q'. R'. and S' denote the velocity changes in the x, y, and z directions, respectively. Generally, the incident free-stream velocity and the calculated turbulence intensity are inversely linked. For the stability of the free-stream flow in the channel, placing the turbine in the right place within the channel is essential so that turbulence intensity can be kept minimum. In the present case, the entrance, where a significant amount of water supply is continuously maintained by using two pumps, is located 9.4 m from the turbine. Here, the turbulence intensity is found to be minimal compared to that at the entrance (0.15%), which is in the acceptable range. Therefore, the flow of water is stabilized before striking the designed turbine blades. Furthermore, the blockage effect is also assessed, such that the blockage ratio (J3) is the ratio of the frontal area of the turbine (H x D) to the cross-sectional area of the channel (He x Wc), which is expressed in eq. (7).

[0074] Where H is the height of the turbine blade, D is the diameter of the turbine, Hcdenotes the channel height, and Wcdenotes the channel width. The obtained blockage ratio is 21.38 % and the corrections in blockage are mainly required for above 30% blockages according to Alexander and Holonia. As free-stream velocity changes with various depths of water, hence the water current velocity is computed in different turbine layers, which is counted from the bed level. In this, the computed water depth is specified as 0.07 m, 0.09 m, as well as 0.14 m, where, using an ADV probe, the flow speed is measured that is connected to a computer interface for the recording of data. In the channel, the average water velocity ranges from 0.45 m / s to 0.65 m / s, and the water-free surface is 0.02 m beyond the top edge of the blades. The velocity information is received from the probe settings at 0.2 and 0.25 m from the turbine axis, and its average value is taken into account. Both upstream and downstream regions go through the same process. To ensure the measurement's repeatability, six numbers of test readings are recorded. In addition, the occurrence of an error during experiments due to uncertainties and voltage fluctuations is measured to ensure a simple data recording process and data reduction; thus, the precise value of collected data is measured. The rope brake dynamometer arrangement, ADV probe positioned in an upstream location, along with a picture of the spring balance is shown in Fig.4 (a-c).

[0075] Figure 5 illustrates a Layout view of the open flume in accordance with an embodiment of the present disclosure. The open flume layout with various measurement points is shown in Fig.5, i.e., upstream of the turbine, along the x-axis, as from side walls to the center line. The velocity distributions are measured in a gap of 5 cm when the ADV probe is positioned at various points within a distance of 30 cm to 60 cm upstream of the turbine.

[0076] Error analysis

[0077] The measuring instruments have some assignable errors, which are analyzed while performing the experimental system. The instrumental errors are computed by Eq. (8)

[0078] Where .v represents the total percentage error, XTm denotes the error in the tachometer, / .ADV represents the error in ADV, and .SB is the error in spring balance. The error values for Cp, as well as torque (r), are computed with the use of an uncertainty approach when executing the experiments. The maximum error in Cpis computed using Eq. (9), and the torque error is computed by Eq. (10)

[0079] Specifications of the instruments used in the test design are shown in Table 1. The overall uncertainty related to the calculated values of Cpand torque (r) is estimated to be 8.5% and 5.7%, respectively, based on this data and Eqn. (9) and (10).

[0080] Figure 6 illustrates the intensity of turbulence with RMSE of 0.15% at various stream-wise distances from the turbine in accordance with an embodiment of the present disclosure.

[0081] Experimentation outcomes

[0082] The experimental outcomes are discussed in terms of preliminary test conditions and primary experimental findings.

[0083] Preliminary test conditions

[0084] The liquid flow in the channel should have the least amount of turbulence possible. As shown in Fig. 6, the observed flow speed is monitored in steps of 5 cm between 5 cm and 60 cm from the axis of the turbine to estimate turbulence intensities using Eq. (6) in the upstream direction. The measured turbulence intensity values are shown in Figure 6. The ADV probe detected the mean velocities as well as the fluctuating components along the three directions at each of the stream-wise points. The turbulence intensity variations' root mean squared (RMS) error comes out to be 0.15%, which is considered to be acceptable. Further observation reveals that as distance (5 cm to 60 cm) increases in the upstream direction, the turbulence intensities gradually drop from 0.98% to 0.87%, indicating streamlined water flow in the vicinity of the turbine site. Due to the interaction of the rotating turbine with the entering flow, it is anticipated that the amount of turbulence near the turbine position will rise. Figure 7 illustrates Velocity distribution near the side walls of the water channel- (a) left sidewall at mid-layer and (b) right sidewall at mid-layer in accordance with an embodiment of the present disclosure. Before starting the major trials, it is critical to reduce how much the turbine functioning is impacted by the channel's sidewall. To evaluate flow uniformity about a fixed flow speed of 0.55 m / s in the free stream, the mid-water layer (21 cm), or mid-axis of the turbine, is used. The distributions of flow speed that result across the turbine are therefore examined. When seen about the left sidewall, the various locations towards the center of the channel are shown on the x-axis to reflect distinct cross-stream positions; the same positions are recorded when viewed about the right sidewall (see Fig. 5). It is noted that the velocity profiles at the mid-layer, as illustrated in Fig. 7, are largely uniform. Figure 7(a) and (b) show that, with root mean squared errors of 0.04% and 0.03%, respectively, the average water speed at the mid layer (21 cm) is approximately 0.31 m / s towards the leftward and rightward borders of the channel from the turbine axis. The main tests are then carried out after seeing this homogeneity in average water speed, and the results are described in the next section.

[0085] Figure 8 illustrates Torque, power, Cp and TS variations with different brake load conditions for flow speed of 0.55 m / s with clearances of (a) 0.0 mm, (b) 5.0 mm, (c) 10.0 mm, (d) 15.0 mm, and (e) 20.0 mm in accordance with an embodiment of the present disclosure.

[0086] Primary Experimental findings

[0087] The primary test is carried out to ascertain the SAHT's performance under the regarded values of the parameters supplied to the channel after the preliminary experiments described above demonstrated the consistency of the experimental settings. The tests are carried out in the examined open flume at a range of low free-stream speeds (0.45 to 0.65 m / s) and under a range of braking load conditions (100-1500 g). The five various arrangements of the triple-blade Savonius-like turbines have clearance requirements ranging from 0.0 mm to 20.0 mm. The performance measures for the turbine are torque (T), turbine power (P), coefficient of performance (Cp), and turbine tip-speed ratio (TSR).

[0088] Study of brake load on turbine performance

[0089] Figure 8 depicts the fluctuations in torque, power, Cp, and TSR as a function of load (1 GO- 1500 g) for a low flow speed of 0.45 m / s. Regardless of stage clearance, the torque grows monotonically as the brake load rises to its maximum of 1500 g. However, as the load rises to 1250 g, the turbine can still generate a system (or power), but as the load rises to 1500 g, it starts to lose efficiency. This is because as the load is increased beyond 1250 g, the turbine system, and performance are reduced as a result of the decrease in turbine rpm and, consequently, TSR. Thus, regardless of flow rate and stage clearance, TSR steadily falls as the load increases. To accept heavier loads on the blades, the blade speed must decrease. According to Fig. 8, the variation patterns of power, torque, and Cp are closely associated types with the fewest disparities between their variations for the examined low flow speed of 0.45 m / s. At all stage clearance circumstances for this low flow speed, the turbine torque curve is below the power curve until the brake load is raised to 1250 g. As a result, the preferred load on the current turbine, which may make it operate like a motor, cannot be kept below 1250 g. As a result, at a stage clearance of 5.0 mm, a turbine brake load of 1250 g, and a flow rate of 0.55 m / s, the highest turbine torque of 0.084 N-m is produced. In terms of clearance variation, all parameter variations get better as the clearance between the stages rises to 5.0 mm; however, as clearance rises above 5.0 mm up to 20.0 mm, the same variations get worse. These patterns are in line with observations that are previously reported that are comparable. The bypassing of flow -through clearance with an increase of the same beyond 5.0 mm may be the probable cause.

[0090] Figure 9 illustrates distributions of (a) Power, (b)Hydrodynamic torque, (c) Cp. and (d) TSR at 1250 g brake load condition against the flow speeds for the studied stage clearances in accordance with an embodiment of the present disclosure. In the examined clearances and low flow velocity condition of 0.45 m / s for a 1250 g brake load, which may be thought of as the ideal brake load for maximum Cp, it is discovered that the SAHT has greater power performance. As shown in Figs. 9(a) through (d), the results of the measurement parameters (Prot, T, Cp, and TSR) at 1250 g load for all gap distance conditions have now been obtained by plotting against three flow velocities (0.45, 0.55, and 0.65 m / s). This is done to ascertain how flow speed impacts the turbine's hydrodynamic torque at the ideal braking load of 1250 g. For all clearance settings, Figure 9(a) shows that the turbine power output increases as flow speed increases to 0.55 m / s. When the flow rate is 0.55 m / s and there is 5 mm of space between the two stages, the SAHT runs at its maximum turbine power output of 0.172 W. The change in torque and TSR further on can be used to understand why turbine power becomes invariant to the rise in flow speed beyond 0.55 m / s at higher stage clearances (15.0 mm and 20.0 mm). Figure 9 (b) demonstrates that, for the ideal brake load of 1250 g, torque increases as flow speed increases to 0.55 m / s, then decreases as flow speed increases further. However, with higher stage clearances of 15.0 mm and 20.0 mm, the torque monotonically decreases with the increase in flow speed starting at 0.45 m / s, which has a negative effect. This is because when water pressure on the SAHT's blades is too high, water bypasses the SAHT through its stage clearance, flow speed is increased (resulting in a loss of volumetric discharge), and all of these factors reduce torque. According to Fig. 9(c), for stage clearances of 0.0 mm, 5.0 mm, and 10.0 mm, Cp rises to a flow speed of 0.55 m / s before dropping; however, for higher clearances of 15.0 mm and 20.0 mm, it declines monotonically in line with the same trend of torque variation. As shown in Fig. 9(d), similar trends are observed for TSR, with an increase in flow speed for low values of stage clearance. TSR values, on the other hand, tend to climb consistently from 0.45 m / s to 0.65 m / s at higher clearances of 15.0 mm and 20.0 mm, which is the polar opposite of the torque variation, which tends to decrease with increased flow speed (see Fig. 9b). The pressure-velocity coupling that occurs as blade pressure decreases with increased clearance (due to bypassing of flow and loss of discharge) may be the cause of this increase in TSR. As a result, the tangential speed of the blades may increase, increasing the TSR values. This indicates that a higher stage clearance TSR improvement results in a higher turbine rotational rate. The power of the turbine is unaffected by greater flow speed beyond 0.55 m / s even though torque declines with flow speed at higher stage clearance due to the combined effects of torque and TSR.

[0091] Thus, when the results are thoroughly analyzed as described above, the advantages of retaining stage clearance 5.0 mm and brake load 1250 g become evident. Table 2 provides a summary of the effective values of T, Prot, Cp, and TSR for 1250 g brake load and 5.0 mm clearance about the investigated flow speeds (0.45, 0.55, and 0.65 m / s) to emphasize this point. All of the SAHT's quantifiable performance metrics are listed in this table 2.

[0092] Figure 10 illustrates variations of maximum Cp for the studied stage clearances at optimal brake load against TSR for flow speeds (a) 0.45m / s, (b) 0.55 m / s, and (c) 0.65 m / s in accordance with an embodiment of the present disclosure. The fluctuations of the SAHT's maximum Cp at optimal brake load (1250 g) against the combination of stage clearance, end plates, overlapping 15%, and TSR for flow speeds of 0.45 m / s, 0.55 m / s, and 0.65 m / s are shown in Figures 10(a) through (c), respectively. Under various working situations, it displays the highest Cp that may be achieved, which represents the SAHT's ultimate performance attributes. In actuality, Fig. 10 displays the entire collection of performance traits in both design and off-design scenarios. The maximum Cp(0.087), which is attained for the design condition of 5.0 mm stage clearance and 0.55 m / s flow speed at a TSR of 0.259, is displayed in Fig. 10(b). The same figure also illustrates the other off-design performance parameters, i.e., those that do not correspond to the 0.55 m / s flow speed and 5.0 mm stage clearance. The current turbine blades' size, swept area, and clearance distance (5.0 mm) can accept maximum flow rates of up to 0.55 m / s and loads of up to 1250 g, allowing water to exert the most possible force on the blade. However, as the clearance rises even further, the water flow goes past without affecting the blades.

[0093] Figure 11 illustrates Variations of maximum Cp for optimal gap conditions and brake load against TSR for the flow velocities 0.45 m / s, 0.55 m / s, and 0.65 m / s in accordance with an embodiment of the present disclosure. Figure 11 represents the variation of maximum Cp with different TSR values at a 5mm gap. The benefit of maintaining a 5 mm gap between the triple-bladed two stages of SAHT with overlapping and joined end plates is clearly shown by a critical analysis of these results. Table 2 summarizes the effective values of T, Proctor, Cp, and TSR for the examined flow velocity circumstances (0.45, 0.55, and 0.65 m / s) at 1250 gm brake load and 5.0 mm gap spacing to emphasize the same. It has been found that the hydrodynamic torque reduces as flow velocity rises from 0.45 m / s to 0.65 m / s, while the mechanical power initially rises for flow velocity up to 0.55 m / s before falling. While the highest power of 0.172 (W) is reached at a flow velocity of 0.55 m / s, the maximum hydrodynamic torque of 0.084 N-m is attained at that same speed. The Cp and TSR exhibit a similar trend to the turbine power, and at a flow velocity of 0.55 m / s, they reach their maximum values of 0.087 and 0.259, respectively.

[0094] Figure 12 illustrates a Comparison of Cpvs TSR between the present SAHT in accordance with an embodiment of the present disclosure. The coefficient of performance of the present experimental study has been compared with some of the existing literature wherein different numbers of blades and stages along with end plates are used, as detailed in Table 3. The comparative study of the present system with that of the literature has been undertaken by considering the same range of flow speed (0.03-0.9) m / s and similar turbine diameter (DT) and aspect ratio range (0.4-0.9). The present findings show that with more plurality of blades (3 blades) and with comparable DTand aspect ratio, for a dual stage having stage clearance of 5.0 mm and flow speed of 0.55 m / s, the maximum coefficient of performance (0.087) close to the other reported works (Table 3) can be obtained using the present design of the SAHT.

[0095] Figure 13 illustrates Table 1 depicts Instruments Specifications in accordance with an embodiment of the present disclosure.

[0096] Figure 14 illustrates Table 2 depicts experimental results (at 5 mm clearance and 1250 g load) in accordance with an embodiment of the present disclosure.

[0097] Figure 15 illustrates Table 3 depicts a comparison with the existing literature in accordance with an embodiment of the present disclosure.

[0098] In addition, the system is also compared with the experiments conducted by Salleh et al. and Shashikumar et al., having similar turbine design with dual blades, which is visualized in Fig.l l. From the plot, it is observed that the maximum Cpfor the present case (0.087) is higher than the same (i.e. 0.084) obtained. Moreover, TSR (0.259) at the maximum Cpfor the former is also higher than the same (i.e. 0.1) for the latter. Furthermore, the operating range of TSR for the present design is much wider (i.e. improved range of operation for the triple blade design) compared to its counterpart dual blade design of Salleh et al. and Shashikumar et al.

[0099] In an alternate embodiment, a semi-circular blade profile along with a combination of different stages and deflectors may be added to further increase pressure on the blades and improve performance. a) another feature i.e. the gap between the stages may be added. In our system, the gap or the space between the stages is found to be useful in raising the performance of SAHT at low flow speeds. The gap between the stages is used to allow flow control across the height direction of the SAHT, which is quite possible due to the velocity gradient in the vertical direction. Such a gap between the two stages is also found to be useful for the performance of the SAHT at a very low flow speed i.e. less than 0.5 m / s. Precisely, the flow speed is quite low, which is in the range of 0.45 m / s to 0.65 m / s. For such a low flow speed condition, our system has developed a better SAHT compared to some of the existing Savonius hydrokinetic turbines. b) So, the method, involving the contribution of the combination of blade overlapping, space, and end plates, has developed a better SAHT design for the application in such a low range of flow speed conditions.

[0100] Finally, it has been noticed that multi-bladed Savonius hydrokinetic turbines with end plates and overlapping are already developed, but the contribution of the gap between stages along with the other features is an innovative solution for SAHT for low flow speed conditions. Thus, the above may be read carefully, and the above points are for your perusal, please.

[0101] In this study, a unique two-bladed, two-stage, overlapping and end plates Savonius-akin- hydrokinetic turbine (SAHT) with stage clearance (0-20 mm) is constructed, and its performance is experimentally tested at a variety of stage clearances (0.0-20.0 mm), 15% overlapping, and low flow rates (0.45-0.65 m / s) under different brake load scenarios (100-1500 g). As a result, the following conclusions are drawn:

[0102] The SAHT produces more power and torque under low stage clearance (5 mm) as the brake load rises, reaching maximum hydrodynamic torque (0.056 Nm) at the highest load of 1250 g for flow velocity of 0.55 m / s.

[0103] It is discovered that 5 mm is the appropriate stage clearance for the two-bladed two-stage SAHT. It is discovered that 1250 g is the perfect brake load for maximizing the turbine's performance.

[0104] At the same stage, clearance of 5.0 mm, turbine brake load of 1250 g, tip speed ratio of 0.248, and free-stream speed of 0.55 m / s, the SAHT generates its highest coefficient of performance, which is 0.058.

[0105] The highest torque coefficient obtained at the same stage, clearance 5.0 mm, turbine brake load of 1250 g, tip speed ratio of 0.248 is 0.055.

[0106] When compared to the two-bladed, double-stage SAHTs previously studied, the coefficient of performance is either improved or matched when operated under a low operating tip speed ratio.

[0107] The current two-bladed, two-stage, overlapping, and end plates Savonius hydrokinetic turbine may be set up to produce power at a flow velocity of 0.55 m / s or more, allowing for better operational flexibility. To further increase pressure on the blades and improve performance, future work may add modification of semi-circular blade profile along with a combination of different stages and deflectors.

[0108] Figure 16 illustrates the comparison of maximum CT against TSR for flow velocity 0.55 m / s in accordance with an embodiment of the present disclosure. Figure 16 shows the variations of maximum torque coefficient (CT) for the SAHT running at optimal brake load (1250 g) against TSR for flow velocity of 0.55 m / s. It shows the maximum attainable CT (which is the ultimate torque performance characteristics of the SAHT) under different operating conditions. The maximum CT (0.055) is obtained for the design condition of 5.0 mm stage clearance and 0.55 m / s flow velocity at a TSR 0.248. The present turbine blades can accommodate maximum flow velocity up to 0.55 m / s and load up to 1250 g as per its size, swept area, and clearance distance (5.0 mm), which allows water to produce maximum thrust on the blade.

[0109] Figure 17 illustrates the comparison of Cpvs TSR between the present SAHT, Khan et al., and Shashikumar et al. in accordance with an embodiment of the present disclosure. In addition, the present study is also compared with the experiments conducted by Khan et al. and Shashikumar et al., having similar turbine design with two blades, which is visualized in Fig. 17. From the plot, it is observed that the highest Cp in the current study (0.058) is higher than the same (i.e. 0.029) obtained by and almost the same as obtained by within the similar range of operated tip speed ratio.

[0110] The drawings and the forgoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, orders of processes described herein may be changed and are not limited to the manner described herein. Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all of the acts necessarily need to be performed. Also, those acts that are not dependent on other acts may be performed in parallel with the other acts. The scope of embodiments is by no means limited by these specific examples. Numerous variations, whether explicitly given in the specification or not, such as differences in structure, dimension, and use of material, are possible. The scope of embodiments is at least as broad as given by the following claims.

[0111] Benefits, other advantages, and solutions to problems have been described above about specific embodiments. However, the benefits, advantages, solutions to problems, and any componcnt(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature or component of any or all the claims.

Claims

CLAIMS1. A triple-bladed dual-stage Savonius-alike hydrokinetic turbine system, the system comprises: a plurality of hydrokinetic turbine units (102) placed in an aquatic environment, each of which has a shroud with a front entry section and a rear exit portion; a propeller (104) positioned on a rotor shaft (106) within the shroud, wherein the propeller (104) comprises a plurality of triple-blade stages (108) positioned at an angle of 120 degrees from one another on a vertical shaft, wherein the plurality of triple-blade stages (108) are coaxially aligned and the vertical shaft is enforced co-centrically; and a ball bearing (110) installed on a plate frame supports the turbine's shaft to promote support and smooth rotation of the plurality of triple-blade stages (108) during the turbine’s operation in the water current, wherein the circular cross-section shaft of 0.014 m diameter is used to attach the turbine's entire blade assembly; a plurality of rifling vanes (112) disposed on a shroud's inner surface to cause the water entering the forward entry section to spin like a vortex; a plurality of front pre-spin vanes (114) placed close to the front entrance section to prevent items from entering the forward entrance portion and to cause rotation of the water entering the forward entrance portion; a plurality of rear pre-spin vanes (116) placed next to the turbine units' rear departure section; a gate (118) attached at the outlet decrease or increases the depth of water by altering the discharge, wherein the gate (118) is having a selectively blockable pathway with an open and closed position; a plurality of centrifugal pumps (120) disposed to deliver the water to the open flume, wherein the height, width, and length of the open flume are 0.505 m, 0.9 m, and 12 m, respectively; a second pump (122) connected to the gate (118) to increase water velocity while altering the rate of discharge.

2. The system as claimed in claim 1, wherein the turbine's blades are fabricated using aluminum sheets with 0.0015 m thickness in a cylindrical shape with a cross-section of a semi-circle having a chord length of 0. 14 m.

3. The system as claimed in claim 1, wherein the height of one stage of the Savonius-like hydrokinetic turbine (SAHT) is 0.085 m with a diameter of 0.26 m, end plate diameter 0.286m and total height is 0.17 m, and thus the height-to-diameter ratio is 0.64, wherein the turbine's highest coefficient of performance (Cp) is attained at an aspect ratio of 0.7 for Savonius blades, wherein the SAHT is completely submerged inside an open flume such that the optimum attainable water depth is 0.24 m and the possible maximum discharge is 91 1 / s in the channel and the depth of water is decreased or increased by altering the discharge using the gate (118) at the outlet.

4. The system as claimed in claim 1, wherein the three centrifugal pumps (120) are deployed to deliver the water to the open flume, i.e., pump 1 (15 hp), pump 2 (20 hp), and a 25 hp pump is connected to the facility, which is used to cause water velocity increase while altering the rate of discharge.

5. The system as claimed in claim 1, wherein a storage water tank is placed under the ground, and using pumps, water is passed to the open flume, wherein the channel the attained highest water velocity is 0.65m / s that is measured using a first Acoustic Doppler Velocimeter (ADV), in which thefunctions of the meter at a single point is utilized for measuring the speed of water from 0.03m / s to 2.5m / s, wherein sampling is done at the rate 0.09-49Hz.

6. The system as claimed in claim 1, wherein a second ADV is interfaced with a plurality of sensors in the slender head and three receiver arms, wherein the transmitter is applicable for flow speed calculation in a significant space from the slender head.

7. The system as claimed in claim 1, wherein a non-contact type digital tachometer calculates the blade speed (rpm) of the turbine, which is further transferred by the ADV through a connected computer interface.

8. The system as claimed in claim 1, wherein a forward entry section of each of the plurality of hydrokinetic turbine units (102) is stabilized in the direction of current flow by a plurality of stabilizers extending from an external surface of the shroud.

9. The system as claimed in claim 1, wherein the shroud is having a rear exit section and a middle section that is tapered inward about the forward entry section, wherein a plurality of rifling vanes (112) produced on the shroud's inner surface cause the water entering the forward entry section to spin like a vortex and a plurality of front pre-spin vanes (114) positioned close to the forward entrance portion, aligned with the plurality of rifling vanes (112) to cause rotation of water entering the forward entrance portion and prevent objects from entering the forward entrance portion.

10. The system as claimed in claim 1, wherein at least two counter-revolving vertical turbine rotors are coupled to the turbine, each of which has a low solidity and includes: a shaft attached at least at the top section of the turbine; a top hub with three upper arms proximate to the shaft's top portion; a bottom hub with three lower arms proximate to the shaft's bottom portion; and wherein the triple-blade stages (108), each of which is attached to a lower arm of a set of three lower arms and an upper arm of a set of three upper arms.

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