Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7055054 | International Journal of Heat and Mass Transfer | 2017 | 14 Pages |
Abstract
Temperatures were measured at the inner surface of an annulus between two coaxial tubes, where three water streams mixed. These temperatures were sampled at either 100Â Hz or 1000Â Hz. The acquisition time was set to 120Â s. Two water streams at 549Â K, with a Reynolds number between 3.56Â ÃÂ 105 and 7.11Â ÃÂ 105, descended in the annular gap and mixed with a water stream at 333Â K or 423Â K, with a Reynolds number ranging from 1.27Â ÃÂ 104 to 3.23Â ÃÂ 104. Water pressure was kept at 7.2Â MPa. Inner-surface temperatures were collected at eight azimuthal and five axial positions, for each combination of boundary conditions. To better analyze these temperatures and mixing in the vicinity of the wall, scalars estimating the mixing intensity at each measurement position were computed from detrended temperature time series. Fourier and Hilbert-Huang marginal spectra were calculated for the time series giving rise to the highest values of a mixing estimator of choice. The relationship between temperature and velocity was explored by examining the results of an LES simulation using the same boundary conditions as in one of the experimental cases.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Fluid Flow and Transfer Processes
Authors
Mattia Bergagio, Roman Thiele, Henryk Anglart,