
FLUID COUPLINGS AND TORQUE CONVERTERS 231
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(b)
Figure 14.7 Relative force transmission by a jet of
fluid
directed against a plate
conditions, the vortex flow of the circulating fluid
changes from high to low and the rotary flow vice versa,
similar to that occurring in a plain fluid coupling. When
the turbine achieves a speed ratio of about 90 per cent,
or in other words about 90 per cent of the running
speed of the impeller, the vortex flow is entirely replaced
by rotary flow and torque multiplication ceases. The
torque converter is then said to have reached its coupling
phase.
At this point, and in the absence of vortex flow, ...