Measurement and analysis of flow in ducts and rod bundles
Abstract
Turbulent flow measurements were made in the subchannels of a nine rod square pitch rod bundle. A two-component dual beam laser Doppler velocimeter with polarized beams and frequency shift was developed for this purpose. Measured mean vertical velocities normalized with the bulk velocity had peak values of 1.45, 1.39 and 1.35 at Reynolds numbers of 10,000, 20,000 and 40,000, respectively. Vertical turbulence intensities close to the walls were 12 percent to 20 percent while minimum values of vertical turbulence were a little over 5 percent. The mean horizontal velocities measured were about 1 percent of the bulk velocity and suggest the existence of eight secondary flow loops in a subchannel. The horizontal turbulence intensities varied from 3.5 percent to 5 percent. The maximum values occur near walls and subchannel centers. The measured Reynolds stresses were found to be about half the expected values.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- December 1977
- Bibcode:
- 1977PhDT........24N
- Keywords:
-
- Flow Measurement;
- Pipe Flow;
- Turbulent Flow;
- Laser Doppler Velocimeters;
- Photodiodes;
- Velocity Distribution;
- Fluid Mechanics and Heat Transfer