Ventilation of turbo alternators-concluding study multiple path radial systems

In 1924 two papers were presented before the A. I. E. E. on Turbo Alternator Ventilation. In one of the papers tests on two models for two methods of ventilation were described, and data from the tests were given. The other paper contained a mathematical treatment for one system of ventilation, which was based upon the data obtained from the tests. It was recognized that the tests were not sufficiently accurate to evaluate the loss co-efficients, nor was it possible to obtain data on the distribution of volumes for the intake vents. For that system, (see Fig. 1), it was found that the influence of rotation upon total volumes and their distribution could be neglected; consequently the investigation could be continued on stationary models. Those tests, the methods of determining the losses and the equations derived therefrom are given in this paper. Since the effect of rotation could be neglected, the test could be reduced to a model which represented only one axial row of vent ducts. On this model the stator vent ducts were imitated by square brass tubes wvith a plaster of paris restriction cast in one end to imitate the rent duct restriction so that the pressure drop obtained for either direction of flow was approximately the same as in a stator vent. A long steel channel or duct represented the section of the air-gap. Some of these brass tubes, representing intake vents, lead from a large sheet metal box to the gap channel.