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2 edition of performance of the Wells air turbine in oscillating flow conditions. found in the catalog.

performance of the Wells air turbine in oscillating flow conditions.

Oginga-Okumu Ombaka

performance of the Wells air turbine in oscillating flow conditions.

by Oginga-Okumu Ombaka

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Published .
Written in English


Edition Notes

Thesis (Ph. D.)--The Queen"s University of Belfast, 1984.

The Physical Object
Pagination1 v
ID Numbers
Open LibraryOL19799039M

Wave energy can be converted to the electrical energy by using a wave energy converter. The wave energy converter with oscillating water column (OWC) is one of the most promising devices because of its simple structure and easy maintenance. In this device, an oscillating water column due to the wave motion is used to drive an air column. An air turbine is used to convert the pneumatic energy Author: Manabu Takao, Kohei Yamada, Shinya Okuhara, M. M. Ashraful Alam, Yoichi Kinoue, Toshiaki Setoguchi. = turbine efficiency = density of air = solidity= c/s = angular velocity 1 Introduction The overall capture efficiency of any OWC WEC is critically dependent on the performance of the air turbine used to extract mechanical energy from the air flow generated by the moving free surface in the OWC chamber (Fig. 1). The air turbine must be of high.

The Wells turbine is a low-pressure air turbine that rotates continuously in one direction independent of the direction of the air flow. Its blades feature a symmetrical airfoil with its plane of symmetry in the plane of rotation and perpendicular to the air stream.. It was developed for use in Oscillating Water Column wave power plants, in which a rising and falling water surface moving in an. by fixing water flow rate at the turbine inlet and air suction flow rate at the valve A at the designed point. Table 1 shows the test result by the variation of air suction flow rate at the valve B. As the air suction flow rate at the valve B increases, output power of the test turbine increases as well, considerably.

The work presented here includes an experimental and numerical investigation of a prototype model of the wave energy converter. The turbine having five blades of variable chord lengths, twist angles, and constant thickness profile from hub to tip was simulated under similar flow as well as testing conditions, to predict the turbine : Paresh Halder, Hideki Takebe, Krisna Pawitan, Jun Fujita, Shuji Misumi, Tsumoru Shintake. Oscillating water column (OWC) devices, either fixed or floating, are the most common wave energy converter (WEC) devices. In this work, the fluid dynamic interaction between waves and a U-shaped OWC breakwater embedding a Wells turbine has been investigated through unsteady Computational Fluid Dynamic (CFD) simulations. The full-scale plant installed in the harbor of Civitavecchia (Italy) Author: Luana Gurnari, Pasquale G. F. Filianoti, Marco Torresi, Sergio M. Camporeale.


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Performance of the Wells air turbine in oscillating flow conditions by Oginga-Okumu Ombaka Download PDF EPUB FB2

Wells turbine is a self-rectifying airflow turbine capable of converting pneumatic power of the periodically reversing air stream in oscillating water column into mechanical energy.

This paper reports the computational analysis on performance and aerodynamics of Cited by: Wells turbine is a self-rectifying air turbine which is widely used in oscillating water column energy converter. The Wells Wells Turbine, Oscillating Water Column, Steady Characteristics, Stall performance under steady flow conditions is evaluated by, Turbine efficiency, Torque coefficient, Pressure drop coefficient File Size: KB.

in the case of Wells turbine drops rapidly at = because of stall and it increases with flow coeffi- cient after the stall point again.

of the impulse turbine. C slightly increases in the region of low flow coefficient. However, C. of the impulse turbine is considerably higher than that of Wells turbine after the stall point of Wells File Size: KB.

This paper describes the present status of the art on air turbines, which could be used for wave energy conversion. The air turbines included in the paper are as follows: Wells type turbines, impulse turbines, radial turbines, cross-flow turbine, and Savonius turbine.

The overall performances of the turbines under irregular wave conditions, which typically occur in the sea, have been compared Cited by: The Wells turbine is a reaction turbine and its blades rotate unidirectional by the alternating or oscillating axial flow of the air.

The turbine is connected to a generator and it produces. @article{osti_, title = {The Wells turbine in an oscillating air flow}, author = {Raghunathan, S and Ombaka,}, abstractNote = {An experimental study of the performance of a m diameter Wells self rectifying air turbine with NACA blades is presented.

Experiments were conducted in an oscillating flowrig. The effects of Reynolds number and Strouhal number on the performance of the.

When a Wells turbine is started from rest, the incoming relative flow will be at 90° to the rotor blades. According to the choice of the design parameters, the blades could be severely stalled and, consequentially, the tangential force Y will be small and the acceleration negligible.

In fact, if and when this situation occurs, the turbine may accelerate only up to a speed much lower than the. In order to improve the performance of a Wells turbine, the effect of guide vanes with various gaps between turbine rotor and guide vane has been clarified by model testing and numerical simulation.

The results have been compared with those of the case without guide vanes. It is found that the overall characteristics are considerably improved by the inlet guide by: 6. Wells turbine is the simplest and economical turbine for wave energy conversion.

In contrast, Wells turbine has inherent disadvantages such as poor starting characteristics, narrow operating range. WELLS TURBINE: The Wells turbine is one of the most suitable air turbines for energy conversion from oscillating air flow.

A schematic view of the OWC device with a Wells turbine is shown in Fig. The Wells turbine is an axial flow air turbine. It consists of. The paper describes an experimental investigation, and presents the results of the aerodynamic performance of a high-solidity Wells turbine for a wave power plant.

A monoplane turbine of m rotor diameter with guide vanes was built and tested. The tests were conducted in unidirectional steady by: tor load and the rotational speed.

Here the generated air flow is actively controlled by the 66 fans of the multi-fan wind tunnel in ONCT. Wind Turbines Performance in Steady Flow.

Power Coefficients of the Wind Turbines in Steady Flow. The power coefficients of wind turbine are defined by. P C AU, (1) where. P, A. and. Downloadable (with restrictions). Wells turbine concept depends on utilizing the oscillating air column generated over marine waves to drive a turbine.

As a matter of fact, previous researches on the performance analysis of such turbine were based on the first law of thermodynamics only. Nonetheless, the actual useful energy loss cannot be completely justified by the first law because it does Cited by: the increasing performance of the Wells turbine with size and illustrates the need for a high Reynolds number.

Experimental data will be put forward from the mounting of the turbine on a small-scale oscillating water column. The turbine is connected to a DC machine to act as the generator for the system.

Because the system. The turbine has low aerodynamic efficiency at higher flow rate and poor starting characteristics. In this paper, the characteristics of the hysteresis behavior of a Wells turbine for a wave energy conversion device under alternative axial flow conditions are by: 1.

The OWC converts the motion of the water waves into a bidirectional air flow, which in turn drives an air turbine. The bidirectional axial Wells turbine as a candidate for OWC power takeoff systems was the object of considerable research conducted in the last decades.

The vast majority of the investigations focused on the aerodynamic by: A Wells turbine is a self-rectifying air turbine which rotates in a single direction and extracts mechanical shaft power from such bi-directional air flow as in case of an OWC device [10].

There are many reports which describe the performance of the Wells turbine both at starting and running conditions. compact-type wind-lens turbine shows better performance the only rotor inthan sinusoidally oscillating velocity wind.

In order to make clear the relationship between flow field and the turbine performance, the specific flow fields are by PIV. In this paper numerical simulation is carried out using commercially available tool Fluent® to predict the performance of a Wells turbine in an oscillating water column wave energy convertor.

A wells turbine is the turbo machinery that rotates in same direction as the air flow through the turbine in either axial direction. The main aim of this investigation is to predict complex flow Cited by: 3. The Wells turbine Self-rectifying turbines are among the proposed solutions for an e cient and economical technique of converting the oscillating ow into an unidirectional rotary motion to drive the electric generator [16, Ch.

The Wells turbine is the rst concept of self-rectifying air turbine that have been designed [6].File Size: 2MB. K. Kaneko et al.[7] investigates the performance of the Wells turbine, an axial flow air turbine used for wave power conversion.

The Wells turbine has the benefit of not requiring rectifying air valves and can extract power at low airflow rate, when other turbines would be inefficient. But the.Analysis and performance comparison of an OWC wave power plant equipped with Wells and Impulse turbine s Eugénio V.

Corvelo Abstract The paper deals with numerical simulation on time domain of the performance of an OWC wave power plant equipped with two parallel electric turbo-generators sets equipped with Wells or with Impulse Size: KB.vertical duct to the fluctuating air motion across the turbine; - to analyse the performance of the Wells turbine under real, randomly varying sea conditions, that are most difficult to reproduce in laboratory.

The Wells turbine was a small monoplane turbine of m .