A Two-Dimensional Analysis of Unsteady Torque on Mixed Flow Impellers

1986 ◽  
Vol 108 (1) ◽  
pp. 26-33 ◽  
Author(s):  
Y. Tsujimoto ◽  
K. Imaichi ◽  
T. Tomohiro ◽  
M. Gotoo
Keyword(s):  
Flow Rate ◽  
Functional Form ◽  
Thickness Distribution ◽  
Rotational Velocity ◽  
Apparent Mass ◽  
Two Dimensional ◽  
Mixed Flow ◽  
Flow Surface ◽  
Two Dimensional Flow ◽  
Annular Cascade

A new method is given for the analysis of unsteady flows through mixed flow impellers under an assumption of a two-dimensional flow in a representative flow surface of revolution. The flow is mapped to one around a two-dimensional annular cascade. If the thickness of the impeller flow passage changes in a certain functional form, the flow can be represented by using a two-dimensional potential flow in the mapping plane. For impellers with such a thickness distribution, small sinusoidal and/or large transient fluctuations of flow rate and/or rotational velocity are considered. Special attention is paid to the unsteady torque on the impeller. The unsteady torque is divided into three components—quasisteady, apparent mass and wake, and the effects of the geometry of the flow surface on each component are discussed. Apparent mass torque coefficients are determined for fluctuations of flow rate and rotational velocity. Stability of torsional vibration and surging are discussed from energy considerations.

Measurements of Apparent Mass Torque Coefficients of Two-Dimensional Centrifugal Impellers

1986 ◽  
Vol 108 (4) ◽  
pp. 407-413
Author(s):  
Y. Tsujimoto ◽  
K. Imaichi ◽  
T. Moritani ◽  
K. Kim
Keyword(s):  
Angular Velocity ◽  
Flow Rate ◽  
Potential Flow ◽  
Rotational Velocity ◽  
Apparent Mass ◽  
Two Dimensional ◽  
Drag Torque ◽  
Mean Flow ◽  
Experimental Values

Apparent mass torque coefficients for fluctuations of flow rate and angular velocity are determined experimentally for two-dimensional centrifugal impellers. Nearly sinusoidal fluctuations of flow rate and angular velocity are produced by using crank mechanisms, and the resulting unsteady torque on the impeller is measured. The torque is divided into components in-phase and out-of-phase with the displacements. The in-phase components are used to determine the apparent mass coefficients. Drag torque coefficients are defined and used to represent the out-of-phase components. The tests are conducted under various frequencies and amplitudes of the fluctuations with zero mean flow rate and rotational velocity. The apparent mass torque coefficients are compared with theoretical values obtained under the assumption of a two-dimensional potential flow. The experimental values are 5 to 20 percent larger than the theoretical ones and no appreciable effects of the frequency and the amplitude are observed within the range of the experiments.

An Analysis of Unsteady Torque on a Two-Dimensional Radial Impeller

1982 ◽  
Vol 104 (2) ◽  
pp. 228-234 ◽  
Author(s):  
K. Imaichi ◽  
Y. Tsujimoto ◽  
Y. Yoshida
Keyword(s):  
Angular Velocity ◽  
Flow Rate ◽  
Velocity Fluctuation ◽  
Unsteady Flows ◽  
Apparent Mass ◽  
Two Dimensional ◽  
Wide Range ◽  
Mass Coefficient ◽  
Sinusoidal Flow ◽  
Three Components

Unsteady flows around radial impellers are analyzed by the use of singularity methods. Unsteady torque is given for transient and/or sinusoidal flow rate and/or angular velocity fluctuation. It is shown that the unsteady torque can be divided into three components—quasisteady, apparent mass and wake—and the nature of each component is discussed. As a result of separating the torque into these three components, it is shown that the wake component is usually smaller than the others. A gross estimate of torque fluctuation can be made easily by using the apparent mass coefficient given in the paper for logarithmic impellers covering a wide range of blade angles, blade numbers and impeller diameter ratios.

Compression of Viscoplastic Material Between Rotating Plates

2009 ◽  
Vol 76 (3) ◽  
Author(s):  
Sergei Alexandrov ◽  
Yeau-Ren Jeng
Keyword(s):  
Friction Surface ◽  
Thickness Distribution ◽  
Numerical Procedure ◽  
Equivalent Strain ◽  
Two Dimensional ◽  
Accurate Approximation ◽  
Viscoplastic Material ◽  
Equivalent Strain Rate ◽  
Two Dimensional Flow ◽  
Rotating Plates

An analysis is conducted of the two-dimensional flow of Bingham solids between two rotating plates. The maximum friction law is adopted at the plate surface. An asymptotic analysis of the solution is performed in the vicinity of the friction surface. Its results are used in a numerical procedure to obtain an accurate approximation of the solution near the friction surface. The through thickness distribution of velocities, the equivalent strain rate, and stresses is illustrated. Qualitative features of the solution are emphasized. The results are compared with the solution for rate-independent materials.

Miscible displacement in a Hele-Shaw cell at high rates

1999 ◽  
Vol 398 ◽  
pp. 299-319 ◽  
Author(s):  
E. LAJEUNESSE ◽  
J. MARTIN ◽  
N. RAKOTOMALALA ◽  
D. SALIN ◽  
Y. C. YORTSOS
Keyword(s):  
Flow Rate ◽  
Viscosity Ratio ◽  
Three Dimensional ◽  
Cylindrical Tube ◽  
Wave Theory ◽  
Vertical Displacement ◽  
Two Dimensional ◽  
Two Dimensional Flow ◽  
Diffusive Effects ◽  
Hele Shaw Cell

We study experimentally and theoretically the downward vertical displacement of one miscible fluid by another lighter one in the gap of a Hele-Shaw cell at sufficiently high velocities for diffusive effects to be negligible. Under certain conditions on the viscosity ratio, M, and the normalized flow rate, U, this results in the formation of a two-dimensional tongue of the injected fluid, which is symmetric with respect to the midplane. Thresholds in flow rate and viscosity ratio exist above which the two- dimensional flow destabilizes, giving rise to a three-dimensional pattern. We describe in detail the two-dimensional regime using a kinematic wave theory similar to Yang & Yortsos (1997) and we delineate in the (M, U)-plane three different domains, characterized respectively by the absence of a shock, the presence of an internal shock and the presence of a frontal shock. Theoretical and experimental results are compared and found to be in good agreement for the first two domains, but not for the third domain, where the frontal shock is not of the contact type. An analogous treatment is also applied to the case of axisymmetric displacement in a cylindrical tube.

Two-Dimensional Flow of Polymer Solutions Through Porous Media

1999 ◽  
Vol 2 (3) ◽  
pp. 251-262
Author(s):  
P. Gestoso ◽  
A. J. Muller ◽  
A. E. Saez
Keyword(s):  
Porous Media ◽  
Polymer Solutions ◽  
Two Dimensional ◽  
Dimensional Flow ◽  
Two Dimensional Flow

STUDY OF NON-ISOTHERMAL TWO-DIMENSIONAL FLOW OVER A SQUARE CYLINDER IMMERSED IN A CHANNEL

2019 ◽  
Author(s):  
Gabriel Machado dos Santos ◽  
Ítalo Augusto Magalhães de Ávila ◽  
Hélio Ribeiro Neto ◽  
João Marcelo Vedovoto
Keyword(s):  
Two Dimensional ◽  
Square Cylinder ◽  
Dimensional Flow ◽  
Two Dimensional Flow
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