A preliminary study was made of the flow phenomena within the rotating passages of a 48-inch radial-inlet impeller at low tip speeds. Total and static pressures were measured within the impeller passages, at tip speeds of 500 and 700 feet per second, by using a suitable pressure-transfer device to transmit the pressures from the rotating passages to the stationary measuring station.nThese studies indicated that the local pressure coefficients were very similar for the two tip speeds. The total-pressure distribution across the passage indicated a region of lower efficiency along the trailing face. The trend in static-pressure distribution agreed with that theoretically determined for straight radial blades. At the maxi¬mum weight flow, the large negative angle of attack resulted in flow separation at the driving face and secondary flows, which in turn caused a large loss in total pressure. Little variation was found in pressure from hub to shroud along the blade faces. The power input determined by the integration of pressure difference across the blades agreed closely with the work input obtained from weight-flow and air temperature-rise measurements.
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