International Journal of Research ISSN NO: Volume 7, Issue XII, December/2018. Page No:830

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1 A SCHEMATIC STUDY AND APPROACH OF A KAPLAN TURBINE VARYING FLUID FLOW RATE BY USING CFD ANALYSIS B.Vamsi Krishna Branch: Thermal engineering Roll no:14351d2121 Dr.Samuel George institute of Engg & Technology, Markapur, Prakasam(Dist). D.Ramesh babu Assistant professor Department of mechanical engineering Dr.Samuel George institute of Engg& Technology, Markapur, Prakasam(Dist). ABSTRACT Fluid dynamics plays a critical role in many of the products that we encounter every day from obvious applications such as water treatment systems and auto and aircraft aerodynamics to boundarypushing. CFD analysis which enables product design and analysis in a virtual environment has revolutionized fluid dynamics by automating the solution, even for problems that are numerically large. By identifying physical forces and flow characteristics that are sometimes impossible to measure or gain insight into, CFD solutions can help a company dramatically improve time to market Kaplan Turbine is Reaction, Axial and adjustable Flow Turbine. In this Project modelling of Kaplan Turbine is done by assuming shaft diameter, runner diameter and profile of the blade in nx 8.0 parametric Software. Computational Fluid Dynamic Analysis is performed by importing the model into CFD Software Ansys Fluent by assuming Initial Boundary Conditions (i.e., inlet pressure and Velocity, by Fixing Blade Twist angle, and varying adjustable angle). Different CAD models are drawn and variation of flow parameters can be found along the (i.e. pressure and Velocity) in Ansys fluent Software. The above analysis is performed for different Blade twist angles. Suitable graphs are plotted between flow parameters. By this we will be in the position to judge, which angle is the most preferable one i.e., one which converts the whole pressure and velocity of the fluid into into useful shaft work. 1.0 INTRODUCTION Kaplan Turbine is an Axial Flow Reaction Turbine. The s are designed based on simplifying assumptions. But the actual flow inside the space is not as per assumptions and hence performance differs from design conditions. It is therefore, necessary to predict the actual performance before making prototype. The conventional method to predict the performance is testing of model, which is a model of prototype at reduced scale and fulfils the hydraulic similitude conditions. The model construction and testing is costly and time consuming when several modifications in the design are needed. The model testing may provide only global performance characteristics and it is difficult to get characteristics for individual component The rst known attempt to use an adjustable-blade is evidenced by a United States Patent issued to O.W. Ludlow in 1867 There were no water-control gates on the, and stationary guide vanes were used. Dr. Viktor Kaplan, of the Technische Hochschule in Vienna, was the rst to apply the idea by using the advantage of adjusting the blades and the gates simultaneously. Patent applications were led in Europe in 1913 and in the United States in 1914 The firrst large Kaplan is installed at Lilla Edet in the south of Sweden and the efficiency is up to 92.5%. This caused the attention in the Page No:830

2 commercial market and now Kaplan s are widely used in the world. Kaplan s are used for low head sites and compared to other s which have the range of heads between 10 to 1300 meters, Kaplan s have the lowest range of heads which are between 6 to 60 meters. In addition, Kaplan s usually have vertical shafts because this makes best use of the available head and makes installation of a generator more economical. 2.0 LITERATURE SURVEY [1] Huang, H., and Yan, Z the concept of pumped storage power plants, in the range of 50 to 100 MW, was evolved mainly in developed countries to manage the peak power requirements. In later years, chemical industries became another area for the application of PATs for energy recovery. Even in water supply networks identical applications of this technology were found. This background gave some momentum to a rich phase of research and then onwards, standard manufactured pumps were studied in mode. In later years, many more techniques were developed by many researchers The technology for the use of PAT for electrical power generation was not available earlier. However, advances in electrical machinery control technologies which allow the driving regulation with variable velocity, rotation sense and torque have created the possibility of the utilization of pumps working in inverse mode for power generation [2] Lipej, A., Tested many pumps in mode over the years and concluded that when a pump operates in a mode, its mechanical operation is smooth and quiet; its peak efficiency is same as in pump mode; head and flow at the best efficiency point (BEP) are higher than that in pump mode and the power output is higher than that the pump input power at its best efficiency. Various pumps which can be used as s for the power range of 1 kw to 1 MW are shown in Figure 2.1 It can be seen that multi stage radial flow pumps are suitable for high head and low discharge sites; whereas, axial flow pumps are appropriate in low head and high discharge range. Similar chart was also presented by Orchard and Klos (2009) (range: 5 to 750 kw). [3] Sueg-Young, Young-Ho, Developed a theoretical method of predicting performance of PAT on the basis of former research results, through theoretical analysis and empirical correlation which are given below. The effects of variations of pump specific speed and pump maximum efficiency on h and q were studied and observed that two pumps with same specific speeds may have different h and q. In the next step, a centrifugal pump was simulated in direct and reverse modes using commercial 3D Navier-Stokes computational fluid dynamics (CFD) code available in ANSYSCFX which has utilized a finite-element based finitevolume method for discretization of the transport equations. The comparison of proposed method with other two methods viz. Stepanoff (1957) and Sharma (1998), as shown in Figure 2.4, revealed that BEP characteristics predicted by the proposed method and CFD were more accurate than the other two methods. The slight difference between experimental and numerical results was found which may be attributed to the 23 negligence of leakage loss through balancing holes, mechanical loss caused by mechanical seal and bearings and the surface roughness value set on the machines surface. [4] Mittal Sushil Kumar developed a method called variable operating strategy (VOS) for the optimum design of PAT working under different operating conditions. The characteristic curves of seventeen different PATs rotating at different speeds were considered for the analysis. To create hydraulic variability, hydraulic and electric regulations were used. The hydraulic regulation system was consisted of series-parallel circuit with a PAT and two regulating valves. Whereas, for the electric regulation the PAT Page No:831

generator was connected with an inverter to change the rotational speed It was mentioned that, based on the performance curve of a single PAT, all the information needed for the application of VOS

3 generator was connected with an inverter to change the rotational speed It was mentioned that, based on the performance curve of a single PAT, all the information needed for the application of VOS can be obtained by the application of affinity law of turbo machines as mentioned in Eq. (2.6). The study revealed that, the performance curves predicted by affinity law and Suter parameters led to15% error in the evaluation of the head drop compared to experimental results. [5] Mulu B.G., Jonsson P.P Predicted the BEP of centrifugal pump running as using theoretical analysis based on area ratio method developed by The maximum efficiency of PAT was calculated as the ratio of net power output from the and the hydraulic power supplied at the inlet. The net power output was worked out by subtracting various losses in the (e.g. volute power losses, leakage losses, kinetic energy losses at the outlet, hydraulic losses and mechanical losses) from the gross power. A complete mini hydropower test rig established in the laboratory of University of Tehran, as shown in Figure 2.5, was used for the experimental verification of theoretical results. At BEP, the values of discharge number, head number, power number and efficiency predicted by theoretical methods were found to be 1.1%, 4.7%, 5.25% and 2.1% lower than that of corresponding experimental values. These deviations may be due to assumptions made in the evaluation of the volute and the impeller losses. The equation of maximum efficiency of PAT was derived. 3.0 METHODOLOGY The Kaplan Bulb evolved from the Francis, and allowed for a more efficient production of power in considerably lower head application scenarios that were not possible with the Francis. Kaplan Bulb s rotate very quickly, up to nearly four hundred fifty revolutions per minute. Larger Kaplan s have the potential to create enough hydroelectric power to power up to five million households a year. This is the equivalent of twenty million barrels of oil, or nearly ten million metric tons of carbon dioxide emissions. Together with its variable head, Kaplan can produce and output that ranges from a few KW up to 230 Megawatts. DESIGN OF KAPLAN TURBINE: Mainly the Kaplan is used to create the power from the low head s. Large flow rate is required from the Kaplan. The main purpose of the Kaplan is used to provide loading at large flow rates. The design of the Kaplan and Francis are very much similar. The water flow in the Kaplan is in the radial direction the flow is entered and exists axially. In the inlet of the guide vanes are fixed. We can see the passage in between the rotor and guide vane which the flow is in the radial direction. Initially the flow must be in radial direction but the radial direction is forced to move in the axial direction. We can observe the similarity in between the rotor and propeller of a ship. To the central shaft of the rotor blades are attached. With the help of moveable joints blades are connected to the shaft. The blades are rotated according to the water flow rate and the water head available. Compared to the other axial flow Turbines, the blades of the Kaplan are not planer. So they are designed with a twist along the total length so it allows rotation of the water flow at the inlet and leaves at the axial flow. Figure: Kaplan Turbine Page No:832

velocity variations can be found along the in this analysis.

differential equations of momentum and mass i.e. navier strokes equation.

By Varying Adjustable angle and blade twist angle, the cad models are draw and

Then results are plotted for pressure and velocity along the.

4 Figure: Blade Figure: Shaft Figure 3.5 Thickness used to thicken surface loft blade ANALYSIS AND RESULTS Pressure and velocity variations can be found along the in this analysis. In back ground the calculation is done by solving the second order degree differential equations of momentum and mass i.e. navier strokes equation. This variation can be found along the stream lines along the. By Varying Adjustable angle and blade twist angle, the cad models are draw and CFD analysis is performed on them. Then results are plotted for pressure and velocity along the. In the form of images as shown below, Different color indicates the level of pressure and velocity of water. ANALYSIS FOR TURBINE: Figure Assembly View of Kaplan Turbine Figure Pressure distribution of Figure Surface trim Page No:833

Figure Velocity distribution of 15-15 ANALYSIS FOR 15-45 TURBINE: Figure Velocity

Distribution of 15-45 ANALYSIS FOR 30-15 TURBINE: Figure Pressure Distribution of 30-15

conditions are applied in the above analysis software of ANSYS 14.5 for CFD.

5 Figure Velocity distribution of ANALYSIS FOR TURBINE: Figure Velocity Distribution of Figure Pressure Distribution of Figure Velocity Distribution of ANALYSIS FOR TURBINE: Figure Pressure Distribution of Pressure & Velocity Variation At the reference the design specifications and boundary conditions are applied in the above analysis software of ANSYS 14.5 for CFD. Thus the various results are analysed and output are discussed below: Fluent flow analysis of velocity on s Page No:834

Figure: Velocity flow analysis on 25% of turbo surface Figure: Velocity flow analysis on 50% of turbo surface Figure: Velocity flow analysis on 75% of turbo surface Fluent flow analysis of pressure

6 Figure: Velocity flow analysis on 25% of turbo surface Figure: Velocity flow analysis on 50% of turbo surface Figure: Velocity flow analysis on 75% of turbo surface Fluent flow analysis of pressure counters on s: Figure: Pressure Counter analysis on 25% of turbo surface CONCLUSION: The velocity flow and pressure counter with density of water kg/m3 is compared. The result shows that is the best to implement for power generation and safe to run with low cost and maintenance. When the blade angles were changed the increase in power and flow of velocity of the with more efficiency As compared with the Kaplan can generate 2.83Mw and Archimedean screw can generate 3.03Mwpower output. Thus the Archimedean screw as given as 83% efficiency In the present study, we discuss the procedure to carry out the CFD analysis of a Vertical Kaplan Turbine agreement. Hence, CFD can be consider as an efficient tool to analyze the Vertical Kaplan in early design stage for design optimization and later validate it with experiment test results. In future, experiment and CFD analysis would be further carried out at different part load and over load conditions in order to have a better understanding in a broader view. This variation can be found along the stream lines along the References: [1] Huang, H., and Yan, Z., "Present Situation and Future Prospect of Hydropower in China", Renewable and Sustainable Energy Reviews, Volume 13, pp , China, Page No:835

7 [2] Lipej, A., "Optimization Method for the Design of Axial Hydraulic Turbines", Proceedings of the Institution of Mechanical Engineers, Journal of Power and Energy, Volume 218, No. 1, pp , UK, [3] Sueg-Young, Young-Ho, 2013, "CFD Validation of Performance Improvement of a 500 kw Francis Turbine", Renewable Energy, Vol.54, pp [4] Mittal Sushil Kumar, 2012,"Effect of Runner Solidity on Performance of Elbow Draft Tube", Energy Procedia, Vol. 14 pp [5] Mulu B.G., Jonsson P.P., Cervantes M.J., 2012, ''Experimental Investigation of a Kaplan Draft Tube-Part I Best Efficiency Point'', Applied Energy, Vol. 93, pp [6] Krishnamachar P., 2009 CFD approach for design optimisation and validation for axial flow hydraulic, Indian Journal of Engineering and Material Science, pp [7] Prasad Vishnu, Khare Ruchi, Chincholikar Abhas, 2010, "Hydraulic Performance of Elbow Draft Tube for Different Geometric Configurations Using CFD", IIT Roorkee, India. [8] Muhammad Abubakar., Saeed Badshah., Modelling and Analysis of a very Low Head Kaplan Turbine Runner Blades for Rural Area of Punjab International Journal of Scientific & Engineering Research, Volume 5, Issue 7, July ISSN [9] Ajaz bashir janjua., muhammad shahid khalil., Blade Profile Optimization of Kaplan Turbine Using CFD Analysis Mehran University Research Journal of Engineering & Technology, Volume 32, No. 4, October, 2013 [10] Tarun Singh Tanwar., Dharmendra Hariyani., flow simulation (cfd) & static structural analysis (fea) of a radial international journal of mechanical engineering and technology (ijmet), Volume 3, Issue 3, September - December (2012), pp Page No:836

International Journal of Scientific & Engineering Research, Volume 6, Issue 8, August ISSN

International Journal of Scientific & Engineering Research, Volume 6, Issue 8, August-2015 232 Numerical Simulation for Unsteady Flow Analysis of Kaplan Turbine Vaibhav Chandrakar 1, Dr. Ruchi Khare 2