Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN Print: 0-85295-345-3

International Heat Transfer Conference 10
August, 14-18, 1994, Brighton, UK

HEAT TRANSFER MEASUREMENT THROUGH HETERODYNE HOLOGRAPHIC INTERFEROMETRY

Get access (open in a dialog) DOI: 10.1615/IHTC10.3120
pages 273-277

Abstrakt

In the reconstruction of a double-exposure hologram, quantitative information on the interference phase is only reliable in the minima and maxima of the interference pattern of the two object wavefields. Classically, the interpolation between the fringes is not accurate. Furthermore, in regions of high fringe concentration, the image noise due to the laser speckles does not allow a fringe intensity measurement.
With heterodyne holographic interferometry these difficulties are nearly eliminated. The basic idea of this method is to introduce a small frequency shift between the optical frequencies of the two reference beams in the reconstruction of the double-exposure hologram. This results in an intensity modulation at the beat frequency of the two interfering light fields for any given point.
In this paper, the properties and experimental application of heterodyne holographic interferometry for heat transfer measurements are explained. The application on a test cell is presented and boundary conditions for finite element analysis are discussed.