Vibration Effects on Convective Heat Transfer in Enclosures

Abstract

The effect of mechanical vibrations on natural convective heat transfer in an enclosure of rectangular cross-section was investigated experimentally. The enclosure was comprised of two vertical and opposed surfaces which were maintained at different temperatures, surrounded by four other adiabatic surfaces. Vibration stresses were applied to this heat transfer cell by mounting it vertically on the armature of an electrodynamic vibrator. Frequencies from 0 to 4000 Hertz and accelerations from 0 to 110 g’s were utilized in the investigation. The results show that vibration of a thermally active enclosure can have a significant effect on its heat transfer characteristics especially near the resonant natural frequency of the column of fluid contained within the enclosure. Increases in convective heat transfer coefficients of as much as 50 percent were obtained during this investigation. A correlation equation was developed by utilizing the dynamic response characteristics of the fluid column when considered as a seismic mass.