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Podded propeller (POD) has been developed recently as a new type of propulsion system. It is composed of a pod body, a propeller, and a strut. This propulsion system can save cabin space, reduce vibration of the main engine, increase propulsion efficiency, and improve the ship maneuverability. This study verifies the reliability of computational fluid dynamics (CFD) for calculating the hydrodynamic...
In this study, numerical investigations of flow characteristics of a pumpjet propulsor based on Computational Fluid Dynamics (CFD) method have been presented. The Zwart-Gerber-Belamri (Z-G-B) cavitation model based on the Reynolds Averaged Navier-Stokes (RANS) method is employed. The structured gird is applied. A four-blade skewed E779A propeller has been used to verify the numerical method. The comparison...
This paper presents the computational fluid dynamic (CFD) analysis of a horizontal axis tidal turbine assembly with 3 blades. The fluid flow over the turbine blades was analyzed by varying the pitch angle for low tide and high tide conditions for maximum power generation. A location, Great Bernera in the UK, has been selected for this purpose to analyse the real-time scenario. A 1.2MW tidal turbine...
The objective of this paper is to investigate the electromagnetic design aspects of a novel flux-switching motor-compressor with rotor poles designed as airfoils to perform compression. The proposed novel flux-switching motor-compressor is both an electric motor as well as an axial-flow compressor. Conventional motor-driven compressor system typically requires an electric motor and a gear box to connect...
VVER-1200 NPP (Nuclear Power Plant) is a 3+ generation Russian designed PWR (Pressurized Water Reactor). This type of NPPs will be built to increase the capacity of Paks NPP. In our paper the impact of the mixing vane of VVER-1200 spacers on the flow is examined. Distribution of velocity, temperature field and cross-flows are evaluated. For these investigations detailed calculation models have been...
Worldwide electric motor market is moving towards Premium/IE3, Super-Premium/IE4 and Ultra-Premium/IE5 efficiency classes. Therefore, motor manufacturers are constantly improving the overall design of three-phase asynchronous and synchronous motors and all the details with impact in the losses count, even if, individually, they just lead to efficiency gains of a fraction of a percentage point. In...
The main objective of this research is to optimize the diffuser design of Diffuser Augmented Wind Turbine (DAWT). Specifically, this study investigates the effect of different shapes of diffusers to develop the suitable diffuser parameter for the wind turbine power enhancement. For that purpose, two diffuser cases have been recommended as an effective design in increasing wind speed, using a validated...
Wind energy technology has seen steady growth in the energy market as a clean, renewable source of energy. This has brought attention to areas with moderate wind energy potentials. Darrieus type Vertical Axis Wind Turbines (VAWTs) allows capturing of this potential for energy production at a cost-effective scale. To improve the performance of these turbines their design needs to be modified. With...
This paper discusses the runner blade design of axial-flow hydraulic turbine type propeller using two different methods. The first method is considered with no-swirl flow at runner exit, while the second method with swirl flow at runner exit. The design results show that both methods produce the different stagger angle at each blade section of the runner blade. The numerical simulation was performed...
Computational fluid dynamics (CFD) is a simulation tool, that employs applied mathematics and powerful computer to model fluid flow situations to anticipate the mass, momentum and heat transfer and most favorable design in industrial processes. Turbine is a rotary engine actuated by the impulse or reaction of a current of fluid subject to pressure which is made with a series of curved vanes on a central...
In this paper are presented some analytical and numerical results regarding airfoil characteristics, lift coefficient improvement solutions and possible applications for airplane wing and helicopter blade. Starting from the general theory of aerodynamics and based on the CFD methods, the paper deals with the mathematical model of flow around an airfoil with a filed cavity, where a free rotational...
This paper introduces a tilted volute design for operation with a mixed flow turbine rotor. CFD results show an efficiency gain of up to 1.2% over the standard radial design at the highest tested turbine rotational speed. The efficiency gain was found to be the result of a reduction in separation from the blade suction surface. A reduction in the flow cone angle was also observed for the tilted housing,...
In the present work, ventilated disc brake rotors with variable diameter circular pillar configurations were analyzed to enhance the heat dissipation and obtain more uniform temperature distribution in the rotor. CFD code used in this work was validated with experimental results obtained by conducting experiments on a test rig. Experimental analysis was performed on existing taper radial vane (TRV)...
Magnus rotor is essentially a rotating cylinder that generates lift due to Magnus effect. The effect has been generating curiosity in a wide variety of fields ranging from sports to alternate energy. The wind turbine under investigation replaces tradition blades that have an airfoil cross-section, with such Magnus rotors. In this paper, Magnus wind turbines with three and five rotors have been analyzed...
Due to the manufacturing error, the worm deflection and other problems caused by the turbine rotor eccentricity, in the impeller vortex will cause the internal flow field of time pulsation, which leads to the additional flow excitation and noise. In this paper, the simulation of the centripetal turbine in eccentric rate stable condition, effect of rotor eccentricity on the exciting force, and the...
This paper presents a computational investigation into the effect of volute secondary flow structures on turbine inlet flow conditions. The steady state results show Dean type vortices exist early in the volute. As a result a substantial variation in absolute flow angle at the volute exit was observed. Pulsed flow simulations showed that the size and position of the secondary flow structures are time...
In the present study, a typical nozzle guide vane (NGV) is considered with twenty six rows of impingement holes combined with thirteen rows of film cooled rows for the flow analysis. The coolant mass flow variations in different rows of the film holes externally subjected to the hot main stream are obtained by making a three dimensional computational analysis of NGV. The analysis is performed with...
A numerical calculation method of Horizontal Axis Marine Turbine (HAMT) arrays is considered in this paper. For simulating the HAMT array, the author considered using fan and porous media for investigating the model. The mechanism of fan and porous media is able to attenuate energy and it reduce numerical efficiency. The fan model can be modeled without defining a blade shape in detail and it is possible...
Temperature effect on a free vibrating airfoil is investigated in this paper. Calculations are based on solving the Navier Stokes equations coupled to solid dynamic equations; the ALE formulation of RANS equations is applied. Turbulence is modeled by the SST k-ω model and the Flap/lead-lag motion is considered. Results show that high temperatures induce degradation of aerodynamic performances of the...
Rivers Water currents or flow in canals are considered as reliable source of power generation. Savonius rotors are considered suitable for power generation from water current. In this paper, an attempt has been made to develop a multi stage rotor with variable diameter of Savonius turbine in order to enhance the performance of Savonius rotor. This innovative multi stage Savonius rotor has been numerically...
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