Rotating Probe Measurements of the Pump Passage Flow Field in an Automotive Torque Converter

2000 ◽  
Vol 123 (1) ◽  
pp. 81-91 ◽  
Author(s):  
Y. Dong ◽  
B. Lakshminarayana
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Flow Pattern ◽  
Flow Separation ◽  
Torque Converter ◽  
Wake Flow ◽  
Speed Ratio ◽  
Relative Pressure ◽  
Rotating Frame ◽  
The Core

The relative flow in an automotive torque converter pump passage was measured at three locations inside the passage (mid-chord, 3/4-chord, and 4/4-chord) using a miniature high-frequency response five-hole probe in the pump rotating frame. A custom-designed brush-type slip-ring unit is used in the rotating probe system to transmit the amplified signal from the probe in the rotating frame to the stationary frame. At speed ratio of 0.6, a weak “jet-wake” flow pattern is observed at the pump mid-chord. High flow loss is observed in the core-suction corner due to the “wake” flow caused by the flow separation. A strong clockwise secondary flow is found to dominate the flow structure at the pump mid-chord. The Coriolis force and the through flow velocity deficit near the core at the pump inlet are the main reasons for this secondary flow. The jet-wake flow pattern at the 3/4-chord is enhanced by the upstream secondary flow. A jet-wake flow pattern is also observed at the pump 4/4-chord, with concentration of the flow near the passage pressure side. The secondary flow changes its direction of rotation from the 3/4-chord to 4/4-chord. This is mostly caused by the passage meridional curvature and the flow concentration. High loss is found in the core-suction corner wake flow due to a low kinetic energy flow accumulation and the flow separation. Finally, the pump flow field is assessed through the mass-averaged total pressure and relative pressure loss parameter. The data are also analyzed to assess the effect of the speed ratio on the flow field.

scholarly journals Flow Field in the Turbine Rotor Passage in an Automotive Torque Converter Based on the High Frequency Response Rotating Five-hole Probe Measurement Part I: Flow Field at the Design Condition (Speed Ratio 0.6)

2001 ◽  
Vol 7 (4) ◽  
pp. 253-269 ◽  
Author(s):  
Y. F. Liu ◽  
B. Lakshminarayana ◽  
J. Burningham
Keyword(s):  
Pressure Drop ◽  
Flow Field ◽  
Flow Separation ◽  
Suction Side ◽  
Torque Converter ◽  
Turbine Rotor ◽  
Stagnation Pressure ◽  
Wake Flow ◽  
Speed Ratio ◽  
The Core

The relative flow field in an automotive torque converter turbine was measured at three locations inside the passage (turbine 1/4 chord, mid-chord, and 4/4 chord) using a highfrequency response rotating five-hole-probe. “Jet-Wake” flow structure was found in the turbine passage. Possible flow separation region was observed at the core/suction side at the turbine1/4chord and near the suction side at the turbine mid-chord. The mass averaged stagnation pressure drop is almost evenly distributed along the turbine flow path at the design condition(SR=0.6). The pressure drop due to centrifugal and Coriolis forces is found to be appreciable. The rotary stagnation pressure distribution indicates that there are higher losses at the first half of the turbine passage than at the second half. The major reasons for these higher losses and inefficiency are possible flow separation and a mismatch between the pump exit and the turbine inlet flow field. The fuel economy of a torque converter can be improved through redesign of the core region and by properly matching the pump and the turbine. The Part I of the paper deals with the design speed ratio(SR=0.6), and Part II deals with the off-design condition(SR=0.065)and the effects of speed ratio.

Experimental Investigation of the Flow Field in an Automotive Torque Converter Stator

1999 ◽  
Vol 121 (4) ◽  
pp. 788-797 ◽  
Author(s):  
Y. Dong ◽  
B. Lakshminarayana
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Flow Separation ◽  
Free Stream ◽  
Torque Converter ◽  
Transitional Flow ◽  
Speed Ratio ◽  
Corner Flow ◽  
Stator Blade ◽  
Hot Film

The flow field at the exit of a torque converter stator exit was measured using a miniature conventional five-hole probe. The data at speed ratio 0.8, 0.6, and 0.065 are presented. At the speed ratio 0.6, the stator exit flow is dominated by a large free-stream, accompanied by the blade wake and corner flow separation. A strong secondary flow is observed at the stator exit, the flow is overturned near the core and underturned near the shell. The secondary flow at inlet produces large radial transport of mass flow inside the stator passage. The shell-suction corner flow separation has a large blockage effect, resulting in losses. To determine the nature of the transitional flow in the stator passage, the surface hot-film sensors were mounted on the stator blade surface. The data confirm that the stator flow field is turbulent.

scholarly journals Flow Characteristics at the Pump-Turbine Interface of a Torque Converter at Extreme Speed Ratios

2003 ◽  
Vol 9 (6) ◽  
pp. 419-426 ◽  
Author(s):  
A. Habsieger ◽  
R. D. Flack
Keyword(s):  
Flow Field ◽  
Mass Flow Rate ◽  
Flow Rate ◽  
High Velocity ◽  
Torque Converter ◽  
Speed Ratio ◽  
Shell Side ◽  
The Core ◽  
Velocity Gradients ◽  
Coupling Point

The average velocity field at the pump–turbine interface in a scaled version of a truck torque converter was studied. Seven different turbine-to-pump rotational-speed ratios were examined, ranging from near stall (0.065) to overspeed (1.050) so as to determine the effect of the speed ratio on the flow field and on the mass flow rate. Laser velocimetry was used to measure the flow velocity through the pump's exit and the turbine's inlet plane. At the pump's exit, as the speed ratio increases, the high velocities move to the pressure-shell corner and then to both the core-suction and the pressureshell corners. Concentrated velocity gradients are largest at the lowest speed ratio, but areas of velocity gradients are largest near the coupling point. Near the coupling point, the flow field is most nonuniform, which yields a highly periodic flow into the turbine inlet. Above the coupling point, the high velocity remains in the pressure-shell corner but separation is seen to develop at the highest speed ratio. At the turbine's inlet, reverse flow is seen at low speed ratios and is an indicator of flow leakage through the core. Velocity gradients are very large at low speed ratios. As the speed ratio increases to the coupling point, the high velocities remain on the shell side. Above the coupling point, the high-velocity flow migrates from the shell side to the core side. The mass flow rate decreases significantly and nonlinearly with the increase of the speed ratio, but for speed ratios greater than 1.000, the negative slope decreases.

Fundamental Analysis of the Secondary Flows and Jet-Wake in a Torque Converter Pump: Part 2 — Flow in a Curved Stationary Passage and Combined Flows

2003 ◽  
Author(s):  
R. Flack ◽  
K. Brun
Keyword(s):  
Secondary Flow ◽  
Suction Side ◽  
Torque Converter ◽  
Secondary Flows ◽  
Wake Flow ◽  
Streamwise Vorticity ◽  
Shell Side ◽  
The Core ◽  
Flow Circulation ◽  
Vorticity Component

Previously, experimental results for the velocity field in a torque converter pump showed strong jet/wake characteristics including backflows and circulatory secondary flows. 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. Two relatively simple models were employed: (i) a rotating 2-D straight-walled duct and (ii) a 180° flow bend. Parametric studies were undertaken to evaluate the effect that operating conditions and geometry had on the characteristics. Using the modified equations for the generation of streamwise vorticity and the results from the two-dimensional jet/wake model for the normal and binormal vorticity components, trends for the secondary flows in the torque converter pump were predicted. Predicted secondary flows in the torque converter pump circulated in the counter-clockwise direction (positive streamwise vorticity) in the pump mid-plane and in the clockwise direction (negative streamwise vorticity) in the pump exit plane. These trends agreed with experimental observations. Both the Reynolds number and the modified Rossby number were seen to have a significant influence on the streamwise vorticity and, thus, on the magnitude of the secondary flow velocities. The pump mid-plane counter-clockwise secondary flow circulation was primarily caused by the interaction of the pressure-to-suction side jet/wake non-uniform flow (and the associated normal vorticity component) with the high radial/axial flow turning angle the flow underwent while passing through blade passage. Similarly, the pump exit plane clockwise secondary flow circulation was caused by the core-to-shell side jet/wake non-uniform flow (and the associated binormal vorticity component) being rotated about a fixed centerline (pump shaft). Thus, the pump streamwise vorticity, which was responsible for the generation circulatory secondary flows, was directly related to the pump jet/wake phenomena.

Fundamental Analysis of the Secondary Flows and Jet-Wake in a Torque Converter Pump—Part II: Flow in a Curved Stationary Passage and Combined Flows

2005 ◽  
Vol 127 (1) ◽  
pp. 75-82 ◽  
Author(s):  
R. Flack ◽  
K. Brun
Keyword(s):  
Reynolds Number ◽  
Secondary Flow ◽  
Suction Side ◽  
Torque Converter ◽  
Secondary Flows ◽  
Wake Flow ◽  
Streamwise Vorticity ◽  
Shell Side ◽  
The Core ◽  
Vorticity Component

Previously, experimental results for the velocity field in a torque converter pump showed strong jet/wake characteristics including backflows and circulatory secondary flows. 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. Two relatively simple models were employed: (i) a rotating two-dimensional straight-walled duct and (ii) a 180 deg flow bend. Parametric studies were undertaken to evaluate the effect that operating conditions and geometry had on the characteristics. Results from the model showed that the core side wake, which was due to flow separation caused by rapid radial flow turning, was primarily a function of the Reynolds number; increasing the Reynolds number increased the core-to-shell side jet/wake flow. The passage length (or curvature) strongly affected the core-to-shell jet/wake. Using the modified equations for the generation of streamwise vorticity and the results from the two-dimensional jet/wake model for the normal and binormal vorticity components, trends for the secondary flows in the torque converter pump were predicted. Predicted secondary flows in the torque converter pump circulated in the counterclockwise direction (positive streamwise vorticity) in the pump midplane and in the clockwise direction (negative streamwise vorticity) in the pump exit plane. These trends agreed with experimental observations. Both the Reynolds number and the modified Rossby number were seen to have a significant influence on the streamwise vorticity and, thus, on the magnitude of the secondary flow velocities. The pump midplane counter-clockwise secondary flow circulation was primarily caused by the interaction of the pressure-to-suction side jet/wake nonuniform flow (and the associated normal vorticity component) with the high radial/axial flow turning angle the flow underwent while passing through blade passage. Similarly, the pump exit plane clockwise secondary flow circulation was caused by the core-to-shell side jet/wake nonuniform flow (and the associated binormal vorticity component) being rotated about a fixed centerline (pump shaft). Thus, the pump streamwise vorticity, which was responsible for the generation circulatory secondary flows, was directly related to the pump jet/wake phenomena.

scholarly journals Laser Velocimeter Measurements in the Stator of an Automotive Torque Converter

2000 ◽  
Vol 6 (6) ◽  
pp. 417-431 ◽  
Author(s):  
Steven B. Ainley ◽  
Ronald D. Flack
Keyword(s):  
Secondary Flow ◽  
Mass Flow ◽  
Torque Converter ◽  
Speed Ratio ◽  
Pressure Side ◽  
Suction Surface ◽  
General Direction ◽  
Flow Rates ◽  
Pressure Surface ◽  
Mass Flow Rates

The flow field in the stator of a clear torque converter was studied using laser velocimetry. Five planes in the stator were studied at a speed ratio of 0.800 and three planes were studied at a speed ratio of 0.065. Data complements previously available pump and turbine data. Flow in the stator inlet plane is highly non-uniform due to the complicated flow exiting the turbine. At the 0.800 speed ratio, separation regions are located in the 1/4 and mid-planes in the corepressure corner region. In the 3/4 and exit planes, separation regions are located in the shellsuction corner. In the inlet plane a region of high velocities is located along the shell near the pressure side for a speed ratio of 0.800. The high velocity region migrated to the shell-suction corner and suction side in the 1/4 and mid-planes. The overall velocity field for the speed ratio of 0.065 changes significantly from the inlet plane to the mid-plane. The velocity magnitude generally decreases from the suction to the pressure side of the inlet plane and the general direction of the tangential velocity is from pressure-to-suction surface. At the speed ratio of 0.065 a strong secondary flow in the inlet from suction surface to pressure surface was seen. However, at the high speed ratio a moderate secondary flow in the inlet from pressure surface to suction surface was observed. Mass flow rates at the different planes are within the experimental uncertainty and also within the uncertainty of pump and turbine mass flow rates. The flow in the stator inlet plane are significantly influenced by the turbine relative blade position. The turbine influence on the mid-plane data is significantly less than on the inlet plane data. The influence of the pump blade position on the stator exit plane is small.

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.

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.

scholarly journals Analysis of Flow Within Pump Impeller of Torque Converter

1996 ◽  
Author(s):  
Hoshio Tsujita ◽  
Shimpei Mizuki ◽  
Eiji Ejiri
Keyword(s):  
Coordinate System ◽  
Secondary Flow ◽  
Three Dimensional ◽  
Internal Flow ◽  
Torque Converter ◽  
Flow Patterns ◽  
Speed Ratio ◽  
Meridional Plane ◽  
Pump Impeller ◽  
Simple Method

It is difficult to measure flow patterns within rotating elements of a torque converter due to the complicated construction. Therefore, the numerical calculation is considered to be an effective tool to know the internal flow. Three-dimensional incompressible turbulent flow within a pump impeller of an automotive torque converter was analyzed numerically at three different speed ratios, 0.02, 0.4 and 0.8 under the same inlet boundary condition. The speed ratio was defined as the ratio of rotating speed of the turbine impeller to that of the pump. The governing equations using the k-ε model in the physical component tensor form were solved with a boundary-fitted coordinate system fixed on a rotating impeller. The solution algorithm was the SIMPLE method applied to the curvilinear coordinate system. The computed results were compared with those obtained experimentally by an oil film flow visualization technique for the pressure, suction, core and shell surfaces. Moreover, the results at three different speed ratios were examined in detail in order to clarify the behavior of secondary flow patterns. The computed results showed good agreement with the experimental results and clarified the behavior of the complicated flow patterns. The secondary flow patterns were strongly influenced by the correlation between the intensities of the Corinlis force (COF) and the centrifugal force due to the passage curvature in the meridional plane (CMF).

scholarly journals Flow Field in the Turbine Rotor Passage in an Automotive Torque Converter Based on the High Frequency Response Rotating Five-hole Probe Measurement Part II: Flow field at the off-design condition and effects of speed ratio

2001 ◽  
Vol 7 (4) ◽  
pp. 271-284 ◽  
Author(s):  
Y. F. Liu ◽  
B. Lakshminarayana ◽  
J. Burningham
Keyword(s):  
Pressure Drop ◽  
Flow Field ◽  
High Frequency ◽  
Flow Measurement ◽  
Torque Converter ◽  
Turbine Rotor ◽  
Speed Ratio ◽  
High Frequency Response ◽  
Measurement Results ◽  
Overall Performance

The flow field at the design condition was presented and interpreted in Part I. The flow field at one off-design condition (Speed Ratio 0.065) is presented and interpreted in this part. In addition, the hydraulic performance is analyzed by using flow measurement results both upstream and downstream of the turbine and inside the turbine rotor passage. It is found that at the off-design conditions, especially the near stall condition (Speed Ratio 0.065), most of the pressure drop occurs in the first half of turbine passage. About 82% of the total torque is extracted between the turbine inlet and the middle plane. In addition, the shell develops torque at nearly five times the rate of core. Furthermore, the higher the speed ratio, the higher the total pressure drop. Loss is maximum at the near stall condition and varies almost linearly with the speed ratios. A compromise has to be made between the design and the off-design performance in order to improve the overall performance and fuel economy of torque converters.

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