Rodica BĂDĂRĂU


32-41 STUDIUL EROZIUNII OȚELULUI USt 37-2 PRIN CAVITAȚIE VIBRATOARE

Erosion study of the Steel UST 37-2

by vibratory cavitation

 

The paper presents the results of the experiment cavitation vibrators, carried on carbon steel for general use UST 37-2, used in the manufacture of hydraulic turbine components, along the route of water flow into the turbine. Testing is performed on standard crystal vibrator device piezo ceramic of the Cavitation Laboratory of the University Politehnica Timisoara. OH12NDL comparison with standard steel and grey iron with pearlite structure shows that steel has low resistance to cavitation generated by the vibrator device, therefore not recommended in the manufacture of parts in areas of developed cavitation.                    Keywords: erosion, cavitation, carbon steel, average depth of erosion, erosion rate, vibrator device                   Cuvinte cheie: eroziune, cavitație, oțel carbon, adâncime medie de eroziune, viteza de eroziune, aparat vibrator

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32-15 INSERȚIA METALICĂ ÎN PALETA ROTORULUI DE TURBINĂ EOLIANĂ DE PUTERE MICĂ

THE INSERT OF METAL IN THE ROTOR BLADE OF

THE LOW POWER WIND TURBINE

 

Attachment of the wind turbine rotor blade is made by a metal structure, that provides a rigid mounting and precise positioning as accurate as possible to the calculated direction angle of incidence of the air flow relative to the blade profile sections. The mechanical strength at static load for the blade is within acceptable limits even without metal insert. In real operating conditions, the wind gusts have the effect of a dynamic load upon the blade and the base material, fiberglass reinforced polyester (FRP) is subjected to fatigue stressed. This leads to micro cracks in the resin and gradually reaches the blade breakage. Therefore the recessed fitting area of the blade, which is an aerodynamically inactive area, must have a metal structure with maximum adhesion to FRP of the blade structure. The shape of this structure, the way of insertion into the interior of the blade, the depth of penetration, are issues which will be discussed in this paper.

 

Keywords: insert of metal, blade, rotor, wind turbine, FRP

Cuvinte cheie: inserție metalică, paletă, rotor, turbină eoliană, PAFS

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30-05 DINAMICA MECANISMULUI CENTRIFUGAL DE PROTECȚIE LA SUPRATURARE A ROTORULUI DE TURBINĂ EOLIANĂ DE PUTERE MICĂ

DYNAMICS OF THE CENTRIFUGAL MECHANISM FOR
PROTECTION AT OVERSPEED OF THE LOW
POWER WIND ROTOR TURBINE
Rotor over speed protection for small wind turbine power requires a
mechanical system cheap and reliable as possible. This is because any electric
or electronic device depends on the electrical power source that disaster
becomes unavailable. Of these centrifugal mechanism is priced at acceptable
cost, but contains some subtleties of interpretation of the method of operation.
In this paper, we explain step by step the original solution of this mechanism
put in place for a 5 kW wind turbine.
After triggering centrifugal mechanism speed is reduced to 20 … 30
rev / min and the effect of centrifugal mechanism is greatly reduced. So that the
force of compressed spring plus aerodynamic torque blade in relation to spindle
axis, returns the mechanism to its original work position. For that to occur
slowly, return must be controlled by a hydraulic damper or a blockingunblocking
flag position for the rotor blades.
Adjusting ballast weight of centrifugal mechanism and the reliable
automatically operation of the whole system should be checked repetitively on
a trial endurance stand.
Keywords: wind turbine, force, torque, protection centrifugal
mechanism at over speed
Cuvinte cheie: turbină eoliană, forțe, momente, mecanism centrifugal,
protecţie la supraturare

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30-04 CINEMATICA MECANISMULUI CENTRIFUGAL DE PROTECȚIE LA SUPRATURARE A ROTORULUI DE TURBINĂ EOLIANĂ DE PUTERE MICĂ

KINEMATICS OF THE CENTRIFUGAL MECHANISM FOR
PROTECTION AT OVERSPEED OF THE LOW POWER WIND
ROTOR TURBINE
Rotor over speed protection for small wind turbine power requires a cheap
and reliable mechanical system as possible. This is because any electric or
electronic device depends on the electrical power source that becomes
unavailable in disaster conditions. Of these, centrifugal mechanism is priced at
acceptable cost, but contains some subtleties of interpretation of the operation
mod. In terms of kinematics, centrifugal mechanism is reduced to a crank and
connecting-rod assembly with sliding piece. This paper presents schematically
this mechanism and the elements that govern the movement of the sliding
piece: race, speed and acceleration.
The mechanism function is alternative to a crank angle range of α =
0°…45°. Sliding piece is operated offset from the sliding axis. The complexity
consists in the fact that each blade is attached to the single sliding piece
through a rod and a crank. Thus the three rotor blades rotate simultaneously by
the cumulated action of the centrifugal force that occurs due to the rotating
counterweights.
Keywords: wind turbine, slide race, speed, acceleration, crank and
connecting-rod assembly
Cuvinte cheie: turbină eoliană, cursa culisei, viteza, accelerația, mecanism
bielă-manivelă

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28-39 MECANISM CENTRIFUGAL DE PROTECȚIE LA SUPRATURARE A ROTORULUI DE TURBINĂ EOLIANĂ

PROTECTION CENTRIFUGAL MECHANISM OF
THE WIND TURBINE ROTOR AT OVERSPEED
The protection centrifugal mechanism at overspeed described in this paper is designed and made for a wind aggregate of 5 kW. This mechanism is a complex system, designed as an automatic mechanical system to react without electronic control. Only the returning to the initial state is controlled by the electronic system of automatic control of the wind turbine. The triggering of the centrifugal mechanism must be followed by the locking in its extreme position of the rotation of the blades. After locking, the speed is reduced to 20 … 30 rpm then, if weather conditions allow, it gives the command to unlock the centrifugal mechanism so the mechanism returns back to the normal working position.
Keywords: wind turbine, protection centrifugal mechanism at over speed, locking-unlocking device
Cuvinte cheie: turbină eoliană, mecanism de protecţie la supraturare, dispozitiv de blocare-deblocare

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28-38 STAND PENTRU TESTAREA MECANISMULUI CENTRIFUGAL DE PROTECȚIE LA SUPRATURARE A UNUI ROTOR DE TURBINĂ EOLIANĂ DE 5 kW

STAND FOR TESTING THE OVERSPEED PROTECTION CENTRIFUGAL MECHANISM OF A 5 KW
WIND TURBINE ROTOR
The testing stand is designed to check the rotor protection complex system of a wind aggregate of 5 kW at over speed. The planned complex system is designed as an automatic mechanical system to react without electronic control. Only the returning to the initial state is controlled by the electronic system of automatic control of the wind turbine. The stand checks triggering centrifugal mechanism when is achieved the maximum rotation speed initially prescribed. The triggering of the centrifugal mechanism must be followed by the locking in its extreme position of the rotation of the blades. After locking, the centrifugal speed is reduced to 20 … 30 rpm then, if weather conditions allow, it gives the command to unlock the centrifugal mechanism. An electric motor drives a cam which raises the locking pin so that the centrifugal mechanism returns back to the normal working position. The adjusting of the centrifugal counterweight of the centrifugal mechanism and the impeccable operation of the whole automatic system should be checked on the testing stand. The purposes of the tests are to adjust, check and improve the endurance of the mechanism.
Keywords: wind turbine, testing stand, protection mechanism at overspeed, locking-unlocking device
Cuvinte cheie: turbină eoliană, stand de probă, mecanism de protecţie la supraturare, dispozitiv de blocare-deblocare

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26-55 MODIFICAREA REZISTENȚEI LA CAVITAȚIE A BRONZULUI AMPCO 45 PRIN DIVERSE TRATAMENTE DE DURIFICARE

CHANGE THE BRONZE AMPCO 45 RESISTANCE TO CAVITATION BY VARIOUS HARDENING TREATMENTS
This paper presents of the micro hardness effect of the Bronze AMPCO 45 upon resistance to cavitation of erosion, generated to T2 device vibrating piezoelectric crystal, by the Cavitation Laboratory of the Polytechnic University of Timisoara. The micro hardness changing of the exposed surface to the cavitation, by volume heat treatment, laser reminting with three powers in pulse, and by thermal spray, followed by laser reminting, with two powers different in impulse. Research shows that resistance to cavitation erosion tends to grow exponentially with hardness. The greatest strength, namely the average penetration depth of erosion is recorded for the area covered with ceramic powders remitted with laser
Keywords: erosion by the cavitation, the cavitation, the average penetration depth of erosion, the hardness

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25-46 TESTAREA LA SARCINĂ STATICĂ DISTRIBUITĂ A PALETELOR DE TURBINĂ EOLIANĂ DE MICĂ PUTERE

TESTING AT DISTRIBUTED STATIC LOADS OF THE ROTOR
BLADES OF LOW POWER WIND TURBINES
This paper presents a study on distributed static load testing of 5 kW
wind turbine blades. There have been done tests at distributed static loads on
five blades of the rotor designed and installed in an Alba county site. It has also
been investigated the behaviour at the same load type and for the same blade,
using a finite element analysis method. There were drew conclusions about the
comparison of results obtained by the two methods.
Keywords: low power wind turbines, Finite Element Analysis, load,
stress
Cuvinte cheie: turbine de vânt de mică putere, paletă, metoda
elementelor finite, forţe aerodinamice, momente, tensiuni, rezistenţă mecanică
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19-62 CONSIDERAŢII PRIVIND AVARIILE PRODUSE LA ARBORII TURBINELOR BULB DE LA PORŢILE DE FIER II

CONSIDERETIONS CONCERNING THE DAMAGES
CREATED ON BULB TURBINES IRON GATES II
The paper presents the damages observed, after an important time of
running, on the shafts of hydraulic bulb turbines. The damages have taken the
form of multiple cracks, generated through fatigue stresses.
Keywords: application to fatigue, hydraulic tubine bulb, cracking, corrosion
Cuvinte cheie: solicitare de oboseală, tubine hidraulice bulb, fisuri,
coroziune

62 CONSIDERAŢII PRIVIND AVARIILE PRODUSE LA


24-38 CONSIDERAŢII PRIVIND CREŞTEREA PUTERII ŞI REDUCEREA ZGOMOTULUI PENTRU TURBINELE EOLIENE DE MICĂ PUTERE CU PALETE PREVĂZUTE CU WINGLET

CONSIDERATIONS ABOUT POWER INCREASING AND
NOISE REDUCTION FOR LOW POWER WIND TURBINES
WITH TURBINE BLADE WITH A WINGLET
The low power wind turbines are being designated for locations that
have as a characteristic a moderate wind regime. These are placed in the
proximity of human habitation, where is necesary to reduce the aerodynamic
noise. Adding a winglet bended towards upstream side to the existing blade
increase the force distribution on the blade and increase the produced power.
The winglet bended towards downstream side reduces the aerodynamic noise.
Cuvinte cheie: turbine de vânt de mică putere, zgomot aerodinamic,
capătul paletei, vizualizări în tunel aerodinamic
Keywords: low power wind turbines, aerodynamic noise, winglet,
visualizations in aerodynamic tunnel

38 CONSIDERAŢII PRIVIND CREŞTEREA PUTERII ŞI REDUCEREA ZGOMOTULUI PENTRU TURBINELE EOLIENE DE MICĂ PUTERE CU PALETE


21-53 ASUPRA VALORIFICĂRII ENERGIEI VÂNTULUI ÎN ROMÂNIA

SUR LA VALORIFICATION DE L’ÉNERGIE ÉOLIENNE
EN ROUMANIE
Réorientation des Etats membres de l’UE, dirigée par des énergies
propres, a déterminé les facteurs roumains, de décision, à reconsidérer leur
position sur l’allocation des fonds pour étudier et utiliser de l’énergie éolienne;
la Roumanie ayant l’un de les plus importants potentiel d’énergie éolienne en
Europe. À cet égard, l’ouvrage vient à présente des éléments importants sur le
potentiel de l’énergie de Roumanie, avec l’exemplification pour l’emplacement
de Sulina. Les données contenues dans l’ouvrage ayant conduit à la nécessité
de développer le secteur de l’énergie éolienne, comme source d’énergie
alternative de l’avenir.
Cuvinte cheie: vânt, energie eoliană, curbe de frecvenţă, agregate
eoliene
Mots-clés: courbes de fréquence de l’énergie éolienne du vent, du
vent, les agrégats

53 ASUPRA VALORIFICĂRII ENERGIEI


22-16 CONSIDERAȚII PRIVIND CRITERIILE DE EVALUARE A REZISTENȚEI MATERIALELOR LA EROZIUNEA PRIN CAVITAȚIE

This paper presents the using criterions to estimate the behavior and
cavitațional resistance of materials. The materials were testing in laboratory
installations. Also are analyses how can it apply and calculate.
Cuvinte cheie: cavitație, rezistență, criteriu, parametru, viteza de
eroziune cavitațională
Keywords: cavitations, resistance criteria, parameters, cavitational
erosion rate

16 CONSIDERAȚII PRIVIND CRITERIILE DE EVALUARE


22-13 CONSIDERAŢII PRIVIND ADAPTAREA MODELULUI PRANDTL PENTRU O TURBINĂ DE VÂNT DE MICĂ PUTERE

At low power wind turbines blade end is free. The paper shows the
negative influences of finite span on performance profiles. It is made a critical
analysis of application Prandtl model for finite span wing at low power wind
turbines. The paper introduces a new method for calculating certain
adjustments based on Prandtl model.
Cuvinte cheie: turbine de vânt de mică putere, modelul Prandtl,
anvergura finită, coeficient de portanţă, coeficient de rezistenţă, coeficientul de
portanţă indus şi coeficientul de rezistenţă indus.
Keywords: low power wind turbines, Prandtl model, scale finite lift
coefficient, drag coefficient, lift coefficient and induced drag coefficient induced

13 CONSIDERAŢII PRIVIND ADAPTAREA MODELULUI


22-7 CONTRIBUŢII ÎN CORELAREA PARAMETRULUI EROZIUNII CAVITAŢIONALE 1/MDPR CU PARAMETRII FUNCŢIONALI AI APARATULUI DE CERCETARE

Établir des relations pour permettre l`application des résultats des
testes d`érosion de la cavitation, d`un appareil a l`autre, représente une
continue préoccupation des chercheurs. À cet égard, l`ouvrage offre un model
de cet type de relation, mais qui, dans cette phase, permettre la corrélation
d`un petit nombre de matériaux, testé en Laboratoire de Machines
Hydrauliques de Timisoara, Gdansk et Michigan.
Cuvinte cheie: rezistența la cavitație, parametri aparat vibrator, relații
de corelare
Mots-clés: résistance à la cavitation, les paramètres des appareils
vibrants, des relations de corrélation

7 CONTRIBUŢII ÎN CORELAREA PARAMETRULUI