Heat transfer study of free convection through a horizontal open ended axisymmetric cavity using holographic interferometry

In this work, experimental study using holographic interferometry was performed to investigate heat transfer in an open ended cavity between two horizontal parallel circular plates. The lower plate was upward-facing and isothermally heated whereas the upper plate was maintained at ambient temperature. Air was used as the heat transfer medium. To achieve accurate reconstruction of the axisymmetric temperature field, wavelet transformation and a proposed matrix form of the modified Fourier-Hankel were used for the phase extraction and the Abel inversion respectively. Isotherms were mapped in the cavity for several values of the plates spacing and the heated plate temperature. We provide an experimental correlation of the Nusselt number to the Rayleigh number (Ra) based on the heated plate-to-ambient temperature difference and the cavity height. Ra and aspect ratio ranges covered in this work extends from 7 × 103 to 4.5 × 105 and 0.35 to 1 respectively.