LA MEJORA CONTINUA 23

A Computational Fluid Dynamics approach using Ansys CFX was used to study the performance of Tesla Turbomachinery, focusing on the radial outflow case. Two disk geometries were studied, one with air and the other with water.

Back pressures were changed and pressure and efficiency was plotted against flow rate and Reynolds numbers. Another plot of dimensionless flow rate against dimensionless back pressure was used to reveal more results. Based on

this analyisis, the disk pump or compressor should be able to opperate at high efficiency at flow rates much higher than previously published results show.

There is a general insensitivity to increased flow between the disks. Flow pat-terns that vary from predicions from other researchers have been observed at many flow conditions and there is a great deal of understanding of these flow patterns missing from the literature. Both pure parabolic profiles and inflected flow profiles were revealed at optimum efficiency points. A critical dimension-less flow rate was discovered at which performance quickly changes. This flow rate was found to be about 0.07. This critical flow rate allows unification of results presented by Crawford and Rice and by J.H. Morris. Efficiencies of up to 98.88% were found for the flow conditions studied for air. Empirical equa-tions have been found which approximate the flow and performance and allow quicker design of Tesla Turbomachinery. A basic procedure for designing the rotor of a disk pump or compressor has been presented. Based on these results a venturi or some other flow restriction should be added to Tesla pumps and compressors to fix the back pressure and thus the flow rate at which the device opperates, allowing predictable and reliable performance.

More data is needed. The effect of changing radius ratio, gapsize, angular ve-locity and fluid must be studied in much more detail. A new form of Reynolds number is presented which shows reasonable but interesting results that re-quire more data points to explain fully. The effect of housing drag at the periphery of the disks with and without cupped end disks needs to be studied.

Ways of designing diffusers to optimally suit Tesla turbomachinery need to be developed. Modeling of the axial inlet of the rotor is required, this will reveal efficiency lossses in the inlet and allow prediction of the tangential component of the velocity at the inlet of the disk gap.

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