Wyniki wyszukiwania - BazTech

1

Study of the state a Francis turbine

Żółtowski M., Żółtowski B., Castaneda L.

Polish Maritime Research

|

2013

|

nr 2

41--47

EN

This paper presents a methodology to evaluate the technical state of a Francis turbine by shaft rotor dynamic simulation. There are several rotor dynamic criteria that define the technical state of a turbo-machine. To feed the shaft rotor dynamic model this delivers the required information to accomplish the technical assessment. The numerical rotor dynamic model uses as input, the field forces obtained by the fluid-solid interaction analysis undertaken over the blades of the runner. The rotor dynamic numerical simulations allow to determinate the record-in-time of the displacements of any point along the shaft. This information is relevant for diagnosis tasks, because it is possible to decompose it spectrally and to estimate the severity of the vibrations. Comparing the results of the numerical model against those obtained from machines that operates under normal conditions, it is possible to determinate the technical state of the turbo-machine. This allows studying the stability of the turbine working on several operation ranges. A Francis turbine is a very complex machine that involves many physical phenomena of different nature. In this way, the hydraulic input forces needed by the rotor dynamic model should not be assumed but calculated directly from the fluid interaction over the turbine structure.

2

Study Of The Technical State Of A Francis Turbine By Rotor Dynamic Simulations

Żółtowski B., Castaneda Heredia L., Barbosa J.

Journal of Polish CIMAC

|

2009

|

Vol. 4, no 3

113-123

EN

This paper presents a methodology to evaluate the technical state of a Francis turbine by shaft rotor dynamic simulation. There are several rotor dynamic criteria that define the technical state of a turbomachine. To feed the shaft rotor dynamic model this delivers the required information to accomplish the technical assessment. The numerical rotor dynamic model uses as input, the field forces obtained by the fluid-solid interaction analysis undertaken over the blades of the runner. The rotor dynamic numerical simulations allow to determinate the record-in-time of the displacements of any point along the shaft. This information is relevant for diagnosis tasks, because it is possible to decompose it spectrally and to estimate the severity of the vibrations. Comparing the results of the numerical model against those obtained from machines that operates under normal conditions, it is possible to determinate the technical state of the turbomachine. This allows studying the stability of the turbine working on several operation ranges. A Francis turbine is a very complex machine that involves many physical phenomena of different nature. In this way, the hydraulic input forces needed by the rotor dynamic model should not be assumed but calculated directly from the fluid interaction over the turbine structure.

3

Part-Load Vortex in the Draft Tubes of Francis Turbines: Numerical Simulation and Investigations

White P., Stein P., Gentner Ch.

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

|

2008

|

nr 134

77-90

EN

At part-load operation the flow in the draft tube of Francis turbines develops an unsteady rotating flow pattern, the draft- tube vortex, which causes pressure pulsations. Previous CFD studies have shown that a reliable prediction of the complex vortex structure in a draft tube at part-load operation requires highly accurate numerical methods. This paper extends the earlier work with two extensive parallel transient CFD computations on very fine grids, including the interaction between guide vane, runner and draft tube and prediction of the cavitating vortex rope.

4

Teoretyczna analiza przepływu przez palisady hydraulicznych maszyn wirowych w ruchu turbinowym

Zieliński A.

Górnictwo Odkrywkowe

|

2006

|

R. 48, nr 7-8

183-186

PL

W Instytucie Konstrukcji i Eksploatacji Maszyn Politechniki Wrocławskiej opracowano algorytm i zestaw programów komputerowych służących do analizy i projektowania palisad maszyn wirowych. Zastosowano dwuwymiarowy model przepływu cieczy nielepkiej wykorzystując metodę osobliwości. Do oceny poprawności konstrukcji ułopatkowania i współpracy wirników częściowych zaproponowano m.in. wykorzystanie przedstawionych w przekroju merydionalnym obrazów zmiany krętu w palisadzie oraz tzw. sprawności teoretycznej będącej miarą straty wylotowej. Przedstawione wyniki dotyczą badania przepływu przez wirniki turbiny wodnej typu Francisa oraz pompy diagonalnej pracującej w ruchu turbinowym.

EN

An algorithm and computer programs for analysis and design of cascades of rotodynamic machinery have been developed in the Institute of Machine Design and Operation at Wrocław University of Technology. Two-dimensional model of in viscid fluid flow using the singularity method was applied. The diagrams of change of angular momentum in cascade, presented in meridional section, as well as so called theoretical efficiency, that is a measure of exit loss, were proposed for evaluation of designed rotor and interaction of elementary rotors. Presented results refer to testing of flow through the rotors of Francis turbine and of mixted flow pump operating in turbine mode.