Static and Dynamic Pressure Distributions in a Short Labyrinth Seal

As part of a study into turbine blade tip destabilizing forces, a seals test rig was built in which spin rate, circular whirl rate, direction and amplitude of inlet swirl angle, and eccentricity can all be controlled over wide ranges, and measurements can be made at gap Reynolds numbers up to about 2 x 10(exp 4). This facility is described and preliminary data is presented for a one cavity labyrinth seal with a flat, stator mounted land. The impact of different flow coefficients for the first and second knives on the rotordynamic coefficients was found. While this effect is dominant for the direct forces, it should also be incorporated into calculations of cross forces where it has an impact under many conditions

Transient heat transfer for laminar forced convection in the thermal entrance region of flat ducts

Fig. 5 Transient variation in the wall heat flux following a step change in the wall temperature larger the "outside Nusselt number, the better a step change in the ambient temperature can be approximated by a step change at the wall temperature. Acknowledgments The authors are grateful to the U.S. Department of Energy for their financial support of this overall research project. Also, the authors would like to express their thanks to Dr. R. Siegel of NASA Lewis Research Center for his valuable suggestions during the preparation of this paper. References Buoyancy Effects in the Entranc