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Metoda pomiaru składowych i zwrotu wektora prędkości przepływu płaskich

Socha K., Ligęza P.

Prace Instytutu Mechaniki Górotworu PAN

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2007

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Vol. 9, no. 1-4

79--86

PL

W pracy przedstawiono metodę pomiaru dwuwymiarowego wektora prędkości przepływu. Pomiar wektora wykonywany jest za pomocą sondy dwuwłóknowej z odczepami. Umożliwia ona pomiar wartości składowych wektora prędkości, jego kierunek oraz zwrot. W celu sprawdzenia skuteczności prezentowanej metody pomiarowej sondę przebadano dla prędkości z zakresu od 0.4 do 5m/s i różnego ustawienia sondy względem przepływu.

EN

Method of measurement of two-dimensional velocity vector are presented in this paper. Two-wire sensor with additional supports is used in this method. To determined effectivity of the presented method, probe was testing for flow velocities ranging from 0.4 to 5 m/s and for different positions of sensor.

2

Termoanemometryczne pomiary przepływu dwuwymiarowych z uwzględnieniem zwrotu

Socha K., Ligęza P.

Prace Instytutu Mechaniki Górotworu PAN

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2006

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Vol. 8, no. 1-4

25--35

PL

Pomiar dwuwymiarowych pól prędkości jest bardzo ważnym zagadnieniem metrologicznym między innymi w pomiarach wentylacyjnych, klimatyzacyjnych, technikach chłodzenia. Istotne jest nie tylko wyznaczenie wartości składowych prędkości, ale również określenie zwrotu przepływu. Jedną ze stosowanych metod pomiarowych jest termoanemometria, która w klasycznej formie umożliwia wyłącznie pomiar składowych wektora prędkości przepływu, bez uwzględnienia jego zwrotu. W pracy przedstawiono przegląd termoanemometrycznych metod pomiaru dwuwymiarowych pól prędkości. Omówiono metody umożliwiające wyznaczenie tylko wartości składowych wektora prędkości (sonda X) oraz metody wykrywające zwrot (anemometr pulsacyjny PWA, ruchoma sonda FHA). Na zakończenie przedstawiono nową metodę pomiarową, wykorzystującą dwuwłóknowy czujnik z odprowadzeniami na środku każdego włókna. Pozwala on na wyznaczenie wartości składowych oraz zwrotu wektora prędkości.

EN

Measurement two-dimensional field of velocity is very important metrological problem, especially in ventilation, air conditioning measurements, cooling technique. It is necessary not only determined value and direction but also sense of velocity vector. The paper outlines few hot-wire methods used to measurement two-dimensional field of velocity. Described methods enabled to determine only value components of velocity vector (X probe) and methods detecting sense of velocity vector (flying hot-wire anemometry, pulsed wire anemometer). In the article new measurement method, which use two-wire sensor is also presented. The additional supports placed in the middle of the each wire enable to determine sense of velocity vector.

3

Fluctuating flow of a third order fluid past an infinite plate with variable suction

Hayat T., Nadeem S., Pudasaini S. P., Asghar S.

Archives of Mechanics

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2003

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Vol. 55, nr 3

305-324

EN

The two-dimensional flow problem of a third order incompressible fluid past an infinite porous plate is discussed when the suction velocity normal to the plate, as well as the the external flow velocity, varies periodically with time. The governing partial differential equation is of third order and nonlinear. Analytic solution is obtained using the series method. Expressions for the velocity and the skin friction have been obtained in a dimensionless form. The results of viscous and second order fluids can be recovered as special cases of this problem. Finally, several graphs are plotted and discussed.

4

Calculations of the condensing water steam flows in turbine blade cascades

Wróblewski W.

Turbulence : international journal

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2000

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Vol. 6-7

209-223

EN

This paper describes modelling of two- and three-dimensional flows with homogeneous condensation. It needs a simultaneous solution of a differential governing equations (continuity, momentum and energy- equations) and differential equation of condensate formation. It was assumed that flow is inviscid, the velocity slip between the vapour and liquid droplets is neglected. The formation of the liquid phase is calculated using classical nucleation theory. Superheated and subcooled steam parameters are computed from a virial non-linear equation of state. The influence of correction methods and droplet growth models is discussed. The finite volume cell centred calculation method is used. The solution procedure is based on the upwind Godunov-type scheme adapted to the real gas problems. Presented algorithm is capable to investigate unsteady condensation phenomena in the flow. The computational results of the two-phase flow modelling with condensation through a turbine cascade are presented. For the turbine stator of the steam turbine the 3-D flow structure is described.

5

Theoretical analysis of the hydrodynamic characteristics of electrorheological fluid in a parallel duct flow

Shimada K., Nishida H., Yamaguchi T.

Applied Mechanics and Engineering

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2000

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Vol. 5, no 4

803-820

EN

Theoretical analysis was conducted of the hydrodynamic characteristics of the two-dimensional flow of electrorheological fluid between parallel plates by using the mechanical dynamic model proposed herein. The model includes the Voigt model and a slider. It can present four types of relations between shear stress and shear rate. The theoretical results were compared with the experimental data. The theoretical analysis explains the experimental results qualitatively. The qualitative tendency is the same for the four types of relations between shear rate and shear stress. Based on the theoretical results, velocity distribution of flow in four types of relations is not influenced by shear stress and shear rate. This finding differs from that for rotational flow around a rotating disk. The pressure difference depends on apparent viscosity. The local Reynolds number depends on the local velocity at a low given flow velocity and on the local kinematic viscosity at a high given flow velocity.