HEAT TRANSFER IN A GAS-TUBE BUNDLE EXPOSED TO SOUND VIBRATIONS

An experimental setup makes it possible to determine the heat exchange coefficient in each row of a gas pipe cluster during a transverse exposure to intense sound. The setup consisted of an aerodynamic tube containing a cluster of pipes in which hot water was circulated. Cold air flow was maintained past the pipes in the heat exchanger. Resistance thermometers were used to measure water and air temperatures. An acoustic motor-driven siren was used as the generator of intense sound. The motor speed was variable between 150 and 2500 rpm. The sound pressure was measured by a piezoelectric microphone. The intensity distribution pattern which was obtained indicated good axial symmetry of the sound field. The decrease in sound intensity due to passage through the heat exchanger was 20 db. During all experiments, the sound intensity was maintained constant. An increase in the heat exchange coefficient due to the effects of sound was observed. A frequency dependence was also established, with low sound frequencies being more effective. The volume resonance in the heat exchanger apparently had the effect of also increasing the efficiency of the heat exchange. Unedited rough draft trans. of Akustika i Ultrazvuk (USSR) n3 p53-58 1968.