Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN Print: 0-89116-130-9

International Heat Transfer Conference 6
August, 7-11, 1978, Toronto, Canada

INVESTIGATION INTO HYDRODYNAMICS AND HEAT EXCHANGE IN FILM FLOWS

Get access (open in a dialog) DOI: 10.1615/IHTC6.930
pages 487-491

Abstrakt

The paper reports the basic results of integrated theoretical and experimental investigations into the processes of hydrodynamics and heat exchange in film flows. Problems are investigated of hydrodynamics and heat exchange in two-phase flows with a cocurrent and lateral direction of phases and with zero vapour consumption - free falling liquid film. Studies into the internal structure of the flow, the fields of instantaneous and averaged velocities, liquid films and wavelike motion on the surface indicate a stable relationship between the velocity field in the film and the disordered oscillations of instantaneous thickness. The wave processes occurring on the film surface, both in free fall and with a cocurrent and lateral gas flow, obey the probability laws and have definite frequencies and distribution densities of instantaneous amplitudes. The saturation of the wave motion was attained in free fall at distances of 3.5−4.5 m from the entrance. An investigation into local heat transfer in free fall with cocurrent gas flow indicated that the wave motion exerts an effect on the local coefficient of heat transfer. The solution of the energy equation with an allowance for experimentally determined wave parameters of the film made it possible to work out a procedure for calculating heat transfer in a turbulent-wave flow pattern.