Numerical Investigation of Jet-Wake and Secondary Flows in a Hydrodynamic Torque Converter

2017 ◽  
Author(s):  
Jie Chen ◽  
Guangqiang Wu
Keyword(s):  
Numerical Investigation ◽  
Torque Converter ◽  
Secondary Flows

Experimental and Numerical Investigation of Stator Exit Flow Field of an Automotive Torque Converter

1996 ◽  
Vol 118 (4) ◽  
pp. 835-843 ◽  
Author(s):  
B. V. Marathe ◽  
B. Lakshminarayana ◽  
Y. Dong
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Numerical Investigation ◽  
Three Dimensional ◽  
Axial Flow ◽  
Torque Converter ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Complex Flow ◽  
Rate Of Decay

The objective of this investigation is to understand the nature of the complex flow field inside each element of the torque converter through a systematic experimental and numerical investigation of the flow field. A miniature five-hole probe was used to acquire the data at the exit of the stator at several operating conditions. The flow field is found to be highly three dimensional with substantial flow deviations, and secondary flow at the exit of the stator. The secondary flow structure, caused by the upstream radial variation of the through flow, induces flow overturning near the core. Flow separation near the shell causes flow underturning in this region. The rate of decay of stator wake is found to be slower than that observed in the wakes of axial flow turbine nozzles. The flow predictions by a Navier–Stokes code are in good agreement with the pressure and the flow field measured at the exit of the stator at the design and the off-design conditions.

scholarly journals Laser Velocimeter Measurements in the Pump of an Automotive Torque Converter Part II – Effect of Pump Speed and Oil Viscosity

2000 ◽  
Vol 6 (3) ◽  
pp. 181-190 ◽  
Author(s):  
Ronald D. Flack ◽  
Steven B. Ainley ◽  
Klaus Brun ◽  
Leonard Whitehead
Keyword(s):  
Rotational Speed ◽  
Three Dimensional ◽  
Torque Converter ◽  
Secondary Flows ◽  
Working Fluid ◽  
Speed Ratio ◽  
Oil Viscosity ◽  
Low Velocity ◽  
Pump Speed ◽  
Mass Flows

The velocity field inside a torque converter pump was studied for two separate effects: variable pump rotational speed and variable oil viscosity. Three-dimensional velocity measurements were taken using a laser velocimeter for both the pump mid- and exit planes. The effect ofvariable pump rotational speed was studied by running the pump at two different speeds and holding speed ratio (pump rotational speed]turbine rotational speed) constant. Similarly, the effect of viscosity on the pump flow field was studied by varying the temperature and]or using two different viscosity oils as the working fluid in the pump. Threedimensional velocity vector plots, through-flow contour plots, and secondary flow profiles were obtained for both pump planes and all test conditions. Results showed that torque converter mass flows increased approximately linearly with increasing pump rotational speed (and fixed speed ratio) but that the flow was not directly proportional to pump rotational speed. However, mass flows were seen to decrease as the oil viscosity was decreased with a resulting increased Reynolds number; for these conditions the high velocity regions were seen to decrease in size and low velocity regions were seen to increase in size. In the pump mid-plane strong counter-clockwise secondary flows and in the exit plane strong clockwise secondary flows were observed. The vorticities and slip factors were calculated from the experimental results and are presented. The torque core-to-shell and blade-to-blade torque distributions were calculated for both planes. Finally, the flow fields were seen to demonstrate similitude when Reynolds numbers were matched.

Numerical investigation of viscous gas secondary flows in a rotating cylinder with sources and sinks

1990 ◽  
Vol 24 (4) ◽  
pp. 520-524 ◽  
Author(s):  
V. D. Borisevich ◽  
E. V. Levin ◽  
V. V. Naumochkin
Keyword(s):  
Numerical Investigation ◽  
Rotating Cylinder ◽  
Secondary Flows ◽  
Viscous Gas ◽  
Sources And Sinks

Laser Velocimeter Measurements in the Pump of an Automotive Torque Converter: Part I—Average Measurements

1996 ◽  
Vol 118 (3) ◽  
pp. 562-569 ◽  
Author(s):  
J. K. Gruver ◽  
R. D. Flack ◽  
K. Brun
Keyword(s):  
Angular Position ◽  
Torque Converter ◽  
Secondary Flows ◽  
Speed Ratio ◽  
Exit Plane ◽  
Centrifugal Pumps ◽  
Torque Distribution ◽  
Average Flow Velocity ◽  
Pump Shaft ◽  
Pump Inlet

A torque converter was tested for two turbine/pump rotational speed ratios, 0.065 and 0.800, and a laser velocimeter was used to measure three components of velocity within the pump. Shaft encoders were used to record the instantaneous pump angular position, which was correlated with the velocities. Average flow velocity profiles were obtained for the pump inlet, mid-, and exit planes. Large separation regions were seen in the mid- and exit planes of the pump for a speed ratio of 0.800. Strong counterclockwise secondary flows were observed in the midplane and strong clockwise secondary flows were seen in the exit plane of the pump for all conditions; vorticities were evaluated and are reported. Velocity data were also used to find the torque distribution. For both speed ratios the torque was approximately evenly distributed between the inlet and exit. Finally, slip factors were evaluated at the mid-and exit planes. At the midplane they were approximately the same as for conventional centrifugal pumps; however, at the exit plane the slip factors are larger than for centrifugal pumps.

Fundamental Analysis of the Secondary Flows and Jet-Wake in a Torque Converter Pump—Part I: Model and Flow in a Rotating Passage

2005 ◽  
Vol 127 (1) ◽  
pp. 66-74 ◽  
Author(s):  
R. Flack ◽  
K. Brun
Keyword(s):  
Suction Side ◽  
Torque Converter ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Experimental Results ◽  
Wake Flow ◽  
Rossby Number ◽  
Geometrical Parameters ◽  
Shell Side ◽  
The Core

Previously, experimental results for the velocity field in a torque converter pump showed strong jet/wake characteristics including backflows and circulatory secondary flows. To understand the fundamental flow behavior simplified analytical/numerical Navier-Stokes flow models were developed herein to independently analyze the pump pressure-to-suction side jet/wake flow, the core-to-shell side jet/wake flow, and the secondary flows. Parametric studies were undertaken to evaluate the effect that operating conditions and geometry had on the characteristics. Two relatively simple models were employed: (i) a rotating two-dimensional straight-walled duct to model the pressure-to-suction side jet/wake flow due to rotational Coriolis forces and (ii) a 180 deg flow bend to model the core-to-shell side jet/wake flow due to rapid radial/axial flow turning. The formation and development of the pump jet/wake flow was studied in detail. Results showed that the suction side wake, which was due to the counter-rotational tangential Coriolis force, was almost only a function of the modified Rossby number and independent of the Reynolds number. Increasing the modified Rossby number increased the pressure-to-suction side jet/wake flow. A geometric parameter that was seen to affect the pump flow was the backsweeping angle for the pressure-to-suction side jet/wake. Results showed that using backswept blades can completely eliminate the pressure-to-suction side jet/wake flow effect. Other geometrical parameters were tested but only a small to moderate influence on the jet/wake flow phenomena was found. Predicted trends compared favorably with experimental results.

Perspective: Fluid Dynamics and Performance of Automotive Torque Converters: An Assessment

1996 ◽  
Vol 118 (4) ◽  
pp. 665-676 ◽  
Author(s):  
T. W. von Backstro¨m ◽  
B. Lakshminarayana
Keyword(s):  
Measurement Techniques ◽  
Torque Converter ◽  
Fast Response ◽  
Secondary Flows ◽  
Experimental Investigations ◽  
Meridional Plane ◽  
Suction Surface ◽  
Pressure Surface ◽  
Torque Converters ◽  
Pump Inlet

Experimental investigations by various groups over the past decade have uncovered the main features of the flow in hydraulic torque converters. Measurement techniques include laser and hot wire velocimetry, fast response and conventional five-hole probes, and blade and wall static pressure measurement. In both the pump and turbine, the through flow velocity is high near the pressure surface shell corner while the flow in the suction surface core corner is highly turbulent and may be separated and reversed. The position of the stator in a passage curved in the meridional plane leads to secondary flow and low velocities at the core near the pump inlet. Velocity gradients coupled with flow turning and rotor rotation lead to strong secondary flows. By using data from a combination of measurement techniques, torque converter torque, power and efficiency are calculated, and the effect of element efficiency on overall efficiency is demonstrated. It is concluded that design methods should be developed that allow for nonuniform velocity profiles, flow separation, secondary circulation and interaction effects between elements.

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