Cristian Marius MIMIS


32-65 TESTE EXPERIMENTALE PE DISCUL BIPLAN AL VANEI FLUTURE

EXPERIMENTAL TESTS ON A BUtTERFLY

VALVE BIPLAN DISC

 

The paper present the obtained experimental results after laboratory tests on a butterfly valve biplane disc by using electrical resistive tensometry method. Measuring the variation of the sensor’s resistance through electrical methods is proportionally with its elongation and the deformation of the part of the butterfly valve disc. The measured elongations for three static loads applied on the valve disc are presented.

 

Keywords: deformations, biplane butterfly valve disc, tensometers electro-resistive

Cuvinte cheie: deformaţii, disc biplan vană fluture, tensometrie electro-rezisitivă

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32-62 APLICATII ALE METODELOR NUMERICE DE CALCUL ÎN ANALIZA COMPORTĂRII VANELOR FLUTURE BIPLANE

APPLICATIONS OF THE NUMERICAL METHODS IN ANALYZE THE BEHAVIOR OF BIPLANE BUTTERFLY VALVES

 

The paper presents the elongations obtained by numerical results on a butterfly valve biplane disc by using finite element method and these values were compared with elongations resulted from laboratory tests for three levels of water pressure applied upstream the biplane disc. The comparison between two methods to determine the elongation it shows that the finite element method applied to the disc can replace electrical resistive tensometry, to compute stresses and deformations for biplane butterfly disc on an industrial scale.

 

Keywords: finite element method, disc biplane specific strain

Cuvinte cheie: metoda elementelor finite, disc biplan, deformaţii specifice

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30-15 CERCETĂRI PRIVIND REABILITAREA PIESELOR PRIN ÎNCĂRCARE CU SUDURĂ

RESEARCH ON THE REHABILITATION OF PARTS
HARD SURFACING
The article presents a commonly used method for rehabilitation of parts
by welding load. The quality of rehabilitation is assessed by a set of
characteristics that give the reconditioned piece, the ability to meet the
necessary requirements, operating under normal conditions. Welding
instructions through material loading, are applied to the achievement of Francis
rotors type, on two components 1.4317 (GX4CrNi13-4)/SR EN 10213-2 cast
steel. These steels are ideal in terms of use conditions, where wear resistance
is really important, such as on hydraulic turbine components.
Keywords: rehabilitation, arc welded parts, charging by welding
Cuvinte cheie: reabilitare, piese sudate cu arc electric, încărcare prin
sudare

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29-74 ENEGIA DE DEFORMARE DIN DISCUL BIPLAN AL VANEI FLUTURE

STRAIN ENERGY IN A BUTTERFLY VALVE BIPLAN DISK
The papers present the strain energy that appears in a biplane disc of
the butterfly valve by using the numerical methods. Due to the eccentricities of
the biplane butterfly disc the obtained stresses and displacements are not
uniform in the whole structure of the disc. The study of the strain energy allows
us a qualitative evaluation of the energy distribution in the biplane disc when
external loads act on the upstream side of the disc.
Keywords: deformation energy, biplane butterfly valve disc, stresses,
strains
Cuvinte cheie: energie de deformare, disc biplan vană fluture, tensiuni,
deformaţii

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29-73 SUPRAFEŢE NEUTRE PENTRU DISCULUI BIPLAN AL VANEI FLUTURE

NEUTRAL SURFACES FOR BUTTERFLY VALVE BIPLAN DISK
Due to the eccentricities of the biplane disc of the butterfly valve, the
analysis of the directional stresses can be done by using the numerical
methods. The paper presents the neutral surfaces of butterfly valve biplane disc
obtained by numerical methods. The neutral surfaces are defined as surfaces
with directional stress of zero value or, those surfaces which delimit the passing
of the directional stresses from negative values to positive values.
Keywords: neutral surfaces, butterfly valve disc, tensions
Cuvinte cheie: suprafeţe neutre, disc vană fluture, tensiuni

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28-60 CERCETĂRI PRIVIND CALITATEA ÎMBINĂRILOR SUDATE DIN OȚEL TERMOREZISTENT

RESEARCH OF WELDED JOINTS HEAT-RESISTANT STEEL
Alloy and not alloy steels, with specified elevated temperature shall be prepared in accordance with SR EN 10216 – 2 + A2 – 2008 Standard. Structural examinations and mechanical tests performed on weld heat-resistant steels have shown the possibility of establishing, with some degree of certainty, the correlations between the type of microstructure and mechanical characteristics.
Solid solution hardening due to the presence of dislocations, the precipitating and foreign atoms from the network, represent a very important element to be taken into account in determining the structural and mechanical properties of heat-resistant alloy and not alloy steels wieldable.
Keywords: heat resistant steel, welded joint quality, mechanical stress, creep, ductility
Cuvinte cheie: oțel termorezistent, calitatea îmbinării sudate, solicitări mecanice, fluaj, ductibilitate

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27-50 OPTIMIZAREA FORMEI DISCULUI VANEI FLUTURE CU COEFICIENT DE REZISTENȚĂ HIDRAULICĂ DE 0,07

BUTTERFLY VALVE DISC SHAPE OPTIMISATION FOR HYDRAULIC RESISTANCE COEFFICIENT 0.07
The paper presents the optimization of butterfly valve disc shape to obtain hydraulic resistance coefficient 0.07 by numerical methods and by experimental measurements realized in Hydro-Engineering Co. Reşiţa. It is presented the test stand, the optimized butterfly valve disc model which measurements were made and the results of model tests. The results of model tests conducted by similarity criterion for butterfly valve with nominal diameter 4900 mm and nominal pressure of 170 mwc consists of determining the hydraulic resistance coefficient and consequently the flow coefficient and the determination of forces and moment coefficients, the coefficient of cavitation and vibration level.
Keywords: disc butterfly valve, hydraulic resistance coefficient, numerical analysis
Cuvinte cheie: disc vană fluture, coeficient de rezistență hidraulică, analiză numerică

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