CFD Analysis on the Flat Runner Blades of Propeller’s Turbine under Low Head and Low Flow Condition

2014 ◽  
Vol 699 ◽  
pp. 437-442 ◽  
Author(s):  
Masjuri Musa Othman ◽  
Juhari Ab Razak ◽  
Mohd Farriz Bashar ◽  
Nor Salim Muhammad ◽  
Kamaruzzaman Sopian
Keyword(s):  
Flow Rate ◽  
Rural Areas ◽  
Fluid Dynamic ◽  
Water Flow Rate ◽  
Low Flow ◽  
Rate Condition ◽  
Low Head ◽  
Do It Yourself ◽  
Flat Profile ◽  
User Friendly

Hydropower is one of the most widely source to produce electricity for domestic houses as well as for industries around the world. However, for those off-grid settlements the pico-hydro scheme is more suitable due to its cost-effectiveness (less maintenance), clean, user-friendly and do not involved with huge construction works. Even the installation of this type of hydropower scheme is very simple as do it yourself (DIY) concept. One of the most popular pico-hydro turbines which have been implemented widely in rural areas until nowadays is propeller type or also known as axial turbine. Propeller turbine is selected because it is suitable to operate under low head with high flow rate condition. However, in this particular case, low head with low flow rate of water are the two main parameters which need to be considered. This is because during dry or drought season the water level of the rivers will become low and fluctuated, and this scenario affected the performance of the propeller turbine itself. In order to overcome this problem, the runner blades of the propeller turbine need to be redesigned to suit with this nature behavior. Therefore, in this study the runner blades with flat profile with few different angles and number of blades will be applied under 2 meters head. On the other hand, since the low flow is another parameter which needs to be focused therefore the value of the water flow rate has been set to 13 l/s. Analysis tools such as Computer Fluid Dynamic (CFD) is applied in this study in order to determine the most optimum results based from few selected parameters which has been mentioned. From the CFD’s final result, 3 blades with angle 300 was the best combination among the parameters involved.

scholarly journals A Novel Z-blade Reaction Type Turbine for Low Head Low Flow Water Condition

2020 ◽  
Vol 9 (3) ◽  
pp. 1370-1374
Keyword(s):  
Flow Rate ◽  
High Efficiency ◽  
Water Flow Rate ◽  
Low Flow ◽  
Practical Case ◽  
Hydro Power ◽  
Small Stream ◽  
Reaction Type ◽  
Water Condition ◽  
Low Head

This paper discusses the performance characteristics on efficiency and applicability of the test unit under low-head and low-flow condition for a novel Z-blade reaction type hydraulic turbine. Unlike large hydro power system, this technology’s superiority lies in the fact that it can harness electrical energy even from a small stream of water as energy sources and it does not poses any adverse environmental impact. This turbine was developed for an ideal and practical case which investigated applying the principal equations that were derived using the philosophies of conservation of mass, momentum, and energy. Assuming frictional losses factor or k-factor for different operating head, the relationship between rotor diameter, angular speed, flow rate, and power output was plotted and elaborated with allusion to the experimental data. Experiments were carried out at 5m head and below with the water flow rate less than 2.5L/sec, and it was evaluated against theoretical results. The turbine has a capability to achieve high values of rotational speed (up to 500 rpm) with minimal mass flow rate and high efficiency (up to 78%) at low head water condition (5m).

scholarly journals Parametric analysis on a simple design water reaction turbine for low-head low-flow Pico-hydro generation system

2021 ◽  
Vol 15 (3) ◽  
pp. 8356-8363
Author(s):  
Nurul Ashikin Mohd Rais ◽  
M. F. Basar
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Parametric Analysis ◽  
Water Flow Rate ◽  
Mass Conservation ◽  
Angular Speed ◽  
Low Flow ◽  
Pipe Diameter ◽  
Water Head ◽  
Low Head

This paper presents a parametric analysis of the outward flow reaction type turbine known as a Z-Blade turbine for low-head low-flow conditions. By applying the principles of mass conservation, momentum and energy, a nomogram was designed to investigate the theoretical performance characteristics. Based on the parametric analysis and the governing equations and experimental results, attempts have been made to prove that the mass flow rate, angular speed, centrifugal head, power output and efficiency respond dynamically to the water head, radius of the rotor, size of the PVC pipes and the nozzle exit area. A turbine with a 1” pipe diameter gives a higher performance compared to a 1/2” pipe diameter, and certainly the performances of both pipe sizes are improved when the supplied potential energy is increased. This innovative turbine has a maximum rotational speed at an optimum turbine diameter at 0.6m, accompanied by a point where there is a sudden reduction in the water flow rate, where previously the increment in the water flow rate was very high. This can shows from the outcome nomogram with 1” pipe diameter can perform 350 rpm speed with 1.48 L/sec water flow. The Z-Blade turbine has been examined and has shown good potential to be used for low-head (3m, 4m and 5m) and low-flow (less than 2.5 L/sec) conditions.

scholarly journals Optimization of Reaction Typed Water Turbine in Very Low Head Water Resources for Pico Hydro

2021 ◽  
Vol 90 (1) ◽  
pp. 23-39
Author(s):  
Mohd Farriz Basar ◽  
Nurul Ashikin M Rais ◽  
Azhan Ab Rahman ◽  
Wan Azani Mustafa ◽  
Kamaruzzaman Sopian ◽  
...  
Keyword(s):  
Flow Rate ◽  
Nozzle Exit ◽  
Water Flow Rate ◽  
High Water ◽  
Angular Speed ◽  
Low Flow ◽  
Substantial Impact ◽  
Static Water ◽  
Water Turbine ◽  
Low Head

The purpose of this research is to investigate the dominant parameters that influence the optimum performance of reaction typed turbine at very low water head. The concepts of conservation of mass, momentum and energy are utilised to explore performance characteristics using a graphical technique. Parametric analysis of the governing equation and experimental results were performed to show that the turbine diameter and nozzle exit area has a dynamic response to mass flow rate, angular speed, output power and efficiency. Depending on the nozzle diameter of (0.01 m, 0.006 m, and 0.008 m) and turbine pipe size with (diameter of 0.025 m and 0.015 m), six versions of prototype turbine Z-blade turbine were produced. All the turbines have been tested at 100 kPa static water pressures and below. According to a variety of experimental data for all types of turbines, the turbine diameter and nozzle exit area have a substantial impact on turbine performance, especially at high water heads. Despite differences in turbine length and nozzle exit area, more than 90 % of the pattern curves for rotational speed, water flow rate, and mechanical power were identical. Overall, the Z-blade turbine Type B outperforms, resulting in higher turbine efficiency at low head and low flow water condition.

Analysis of Triangular Microchannel Under Forced Convection Heat Transfer Condition for Laminar Flow Condition

2013 ◽  
Author(s):  
D. A. Kamble ◽  
B. S. Gawali
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Water Flow ◽  
Flow Rate ◽  
Heat Input ◽  
Water Flow Rate ◽  
Temperature Drop ◽  
Experimental Result ◽  
Rate Condition ◽  
Wide Range

Micro-convection is a strategic area in transport phenomena, since it is the basis for a wide range of miniaturized high-performance heat transfer applications. Surface area is one of the important parameter for high flux heat transfer in microchannel performance. This experimental study deals with heat transfer using triangular microchannel having hydraulic diameters of 321μm and 289μm. Experimentation is carried out for triangular microchannel set for different heat input and flow rate condition. Triangular microchannel are manufactured with EDM technology. Testing of microchannel under laminar flow is considered with different tip angle, spacing, and length of microchannels. The different microchannels made up of copper material with 29 microchannel each having three different sets of length of 50 mm, 70 mm and 90 mm respectively. Tip angles for triangular microchannel is varied 50 ° and 60 ° with width of 30 mm each respectively are analyzed numerically. Spacing between triangular microchannels is also varied and 300μm and 400μm are considered for the analysis. Water flow rate is considered laminar flow. The flow rate of water is varied from 0.0167 kg/sec to 0.167 kg/sce to carry away heat. It is observed that as hydraulic diameters increase the heat transfer coefficient decreases. As the heat input to microchannel increases from 10 Watt to 100 Watt the temperature drop across varies from 2° C to 22°C as water flow rate increases. The numerical analysis is done using computer C programming. Experimental result differ from theoretical for temperature drop with variation of 2°C to 5°C. It is also observed that in all triangular microchannels its geometry i.e. tip angle and hydraulic diameter are dominant parameters which influences on rate of heat transfer. With increasing channel depth, increases flow passage area therefore enhances heat transfer sufficiently. From experimentation a Nu number correlation is proposed with considering tip angle, length, spacing of microchannel and other related parameters.

CFD Simulation of Fine Particle Gravity Separation in Hindered-settling Bed Separators

2007 ◽  
Vol 2 (3) ◽  
Author(s):  
Y. K. Xia
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Fine Particles ◽  
Particle Density ◽  
Fluid Dynamic ◽  
Water Flow Rate ◽  
Fluid Motion ◽  
Feed Water ◽  
Hindered Settling

In the modeling of hindered-settling bed separators, the published separation mechanisms are based on differences of particle density and size distributions, without the details of the complexity of particles-liquid interactions. A fluid dynamic model for the separator is developed using the Euler-Lagrangian approach of Computational Fluid Dynamics (CFD). Fluid motion is obtained from solving the movement of liquid governing equations. The damping effect on flow patterns caused by the movement of particles resulting in liquid-particle coupling is included in the models. Effects of particle size, particle density compositions, feed rate, feed water flow rate, and upward fluidizing water flow rate, etc., are simulated in the 2-D separation model. Flow pattern effects on the separation of fine particles in the separators with center downward-flow and side cross-flow feed systems are investigated.

Effect of rotor–stator axial spacing on the pressure-rise performance and flow field in an axial pump

2018 ◽  
Vol 233 (6) ◽  
pp. 727-737
Author(s):  
Han Xu ◽  
Donghai Jin ◽  
Dakun Sun ◽  
Lin Du ◽  
Xingmin Gui ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Rate ◽  
Particle Image ◽  
Incidence Angle ◽  
Pressure Rise ◽  
Low Flow ◽  
Working Fluid ◽  
Rate Condition ◽  
Axial Pump ◽  
Image Velocimetry

In this paper, the effect of the rotor–stator axial spacing is investigated in an axial pump with the working fluid of water. The pressure-rise performance was tested at a range of flow rates. Results indicate that decreased axial spacing generates improved hydraulic head, especially when the flow rate is low. Particle image velocimetry measurement was performed and flow fields for five rotor phases were obtained in a low flow rate condition. Particle image velocimetry results demonstrate that the stator inlet flow is both affected by the wake of the rotor and the existence of the stator. As the axial spacing gets close, the incidence angle of the stator decreases and the flow separation on the suction side is restrained, and therefore the pressure rise ability is improved.

Effect of the Section Area of Volute in Low Specific Speed Centrifugal Pumps on Hydraulic Performance

2009 ◽  
Author(s):  
Xiang Zhang ◽  
Yang Wang ◽  
Jianhui Fu ◽  
Cui Dai ◽  
Caihong Wang
Keyword(s):  
Flow Rate ◽  
Low Flow ◽  
Centrifugal Pumps ◽  
Blade Angle ◽  
Rate Condition ◽  
Section Area ◽  
Impeller Outlet ◽  
Low Specific Speed ◽  
Specific Speed ◽  
Experimental Researches

The volute of low specific speed centrifugal pumps has a great impact on the performance of the pump in that the highest efficiency can only be achieved when the impeller is matched with a well-designed volute. At off-BEP conditions, the performance of pumps declines as a consequence of a mismatch between characteristics of the impeller and the volute. The section area is the most important factor of volute. Numerical simulations and experimental researches have been carried out on the routine-designed impeller and the non-overloading designed impeller (different impeller outlet blade angle between two types of impellers) in the hope of finding out the effect of the section area of volute on low specific speed centrifugal pumps. It has been found that the uneven flow rate on different volute sections caused by the backflow between volute and impeller is one of the reasons for the efficiency decline of pumps at off-BEP conditions, especially in the low flow rate condition. It has also been found that the routine-designed impeller is more easily affected by the section area of volute than non-overloading designed impeller.

The Effect of Impeller Cutback on the Fluid-Dynamic Pulsations and Load at the Blade-Passing Frequency in a Centrifugal Pump

2008 ◽  
Vol 130 (11) ◽  
Author(s):  
Raúl Barrio ◽  
Eduardo Blanco ◽  
Jorge Parrondo ◽  
José González ◽  
Joaquín Fernández
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Dynamic Load ◽  
Fluid Dynamic ◽  
Low Flow ◽  
Maximum Magnitude ◽  
Flow Rates ◽  
Numerical Predictions ◽  
Blade Passing Frequency ◽  
Radial Gap

A study is presented on the fluid-dynamic pulsations and the corresponding dynamic forces generated in a centrifugal pump with single suction and vaneless volute due to blade-volute interaction. Four impellers with different outlet diameters, obtained from progressive cutbacks (trimmings) of the greatest one, were successively considered in the test pump, so that the radial gap between the impeller and the volute ranged from 8.8% to 23.2% of the impeller radius. The study was based on the numerical computation of the unsteady flow through the machine for a number of flow rates by means of the FLUENT code, solving the 3D unsteady Reynolds-averaged Navier–Stokes equations. Additionally, an experimental series of tests was conducted for the pump with one of the impellers, in order to obtain pressure fluctuation data along the volute front wall that allowed contrasting the numerical predictions. The data collected from the numerical computations were used to estimate the dynamic radial forces and torque at the blade-passing frequency, as a function of flow rate and blade-tongue radial gap. As expected, for a given impeller diameter, the dynamic load increases for off-design conditions, especially for the low range of flow rates, whereas the progressive reduction of the impeller-tongue gap brings about corresponding increments in dynamic load. In particular, varying the blade-tongue gap within the limits of this study resulted in multiplying the maximum magnitude of the blade-passing frequency radial force by a factor of about 4 for low flow rates (i.e., below the nominal flow rate) and 3 for high flow rates.

scholarly journals Pore-Scale Simulations of Particles Migration and Deposition in Porous Media Using LBM-DEM Coupling Method

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 465
Author(s):  
Yanjie Zhou ◽  
Liping Chen ◽  
Yanfeng Gong ◽  
Shilin Wang
Keyword(s):  
Porous Media ◽  
Critical Velocity ◽  
Flow Rate ◽  
Shear Force ◽  
Particle Deposition ◽  
Moving Boundary ◽  
Low Flow ◽  
Rate Condition ◽  
Groundwater Source ◽  
Low Flow Rate

This paper studies the migration and deposition of suspended particles in porous media. This problem results from the fact that during the operation of a groundwater source heat pump, the recharging process will contribute to the impairment of soil permeability. A coupling lattice Boltzmann method, discrete element method and immersed moving boundary method were used to investigate the migration of particles in porous media. The DKT (Drifting, Kissing, Tumbling) phenomena were employed to validate our program. The coupled effects of concentration, flow rate and pH on the clogging mechanism of the porous media were analyzed. Results show that, due to the repulsive barrier between the particles and porous media, there is a critical velocity. At a low flow rate, the deposition ratio increases with the increase in velocity. Beyond the critical velocity, the deposition ratio decreases when the velocity increases due to higher shear force. Permeability impairment increases with the increase in concentration, especially in the low flow rate condition. Changes in pH mainly affect the repulsive barrier. For a low flow rate, the decrease in repulsive barrier greatly promotes the deposition of particles. Under the condition of favorable deposition, the increase in flow rate reduces the deposition phenomenon. Under the condition of unfavorable deposition, the lower flow rate condition has a lower deposition ratio. The process of particle deposition and the dynamic motion after deposition were observed such as particles gliding over the surface. Accumulated particles in the downstream form bridges and hinder fluid flow. At a high flow rate, strong shear force is more capable of destroying bridges and recovering permeability. Adsorbed particles glide on the surface of the grain and deposit in the downstream. This paper aims to help understanding of the micro-events of particle deposition and the clogging process.

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