Shown in Figure 17 is the first of four immersion-view images taken from a flythrough animation sequence which follows the trajectory of the red particle depicted above and in Figure 16. In this scene, the observer travels just to the left of the temperature-mapped outboard streamribbon slightly downstream of the flow channel inlet. The streamribbon

Figure 17. Scene showing streamribbons downstream of barrier fluid inlet.

trace representing the trajectory of the yellow inboard fluid particle is also visible. Below the streamribbons is the (adiabatic) sleeve which rotates away from the observer. Near the top of the scene are displays indicating the local speed (m/s) and temperature (C) of the red glyphed particle, as well as the elapsed time (ms) from release of the particles.

Figure 18. View of flow outlet with streamribbons leaving barrier fluid channel.

Figure 18 shows a frame taken from the same animation (below) at a later time (55 ms) into the trajectories. In this view, we see both streamribbons, induced by low pressure (Figure 9), bend radially inward toward the sleeve as they bypass the (red-colored) flow outlet, and begin their journey to the axial extremities of the domain. The particles, at this point, have picked up some speed (about 25%), and have increased in temperature by about 5 C.

In Figure 19, we see another frame later in the sequence showing a view near the outboard sealing interface. The streamribbon segment here represents a fluid particle temperature of 61 C, about 12 C warmer than that illustrated in the previous scene (Figure 18). The particle speed has also increased dramatically to a near maximum value of 6.1 m/s, as it flows along next to the rotating radial seal face surface on the extreme right. Also clearly visible is the radial gradient of fluid pressure mapped onto the heat conducting walls of the domain. The streamribbon segment visible on the left is part of the same flow path, one revolution earlier in the trajectory.

Figure 19. Streamribbon near the warmer outboard seal interface region.

The final immersion scene taken from the flythrough animation is shown in Figure 20. The red colored streamribbon indicates that near this location the fluid particle, after absorbing heat from the outboard sealing interface (visible to the right of the scene), reaches the maximum temperature of 62 C that it will attain along its flow trajectory through the domain. Note that the speed of the fluid particle has decreased about 20% from that of the previous scene (Figure 19) as it moves along the outboard stationary

Figure 20. Streamribbon trajectory of returning outboard fluid particle.

seal face boundary. Segments of the same trajectory, corresponding to earlier times (and temperatures) along the path of the fluid particle, are seen on both sides (axial ends) of the view.

Figure 21 shows a 3D representation of the fluid temperature within the flow channel region, again for the tapered surface design. The temperature rise from the inlet to the outlet of the domain is predicted to be about 11 C. As noted above, these rises in fluid temperature are used to estimate the heat removal rates and thermal efficiencies of the various design/operational scenarios.

Figure 21. Barrier fluid temperature in region of flow distribution channel.

In order to verify the analysis of the CFD flow simulation model, laboratory tests were conducted replicating exact design configurations and conditions of operation used to compute selected case results. The data shown in Figure 22 correspond to the tapered surface design prediction (Figure 21). As can be seen, the measured difference in barrier fluid temperature between the inlet and outlet was about 10 C (within 1 C, or 10% of the calculated value) for this 4-hour test.