Экспериментальное исследование осциллирующего течения в трубном пучке

Abstract

Oscillating reciprocating flows are found in a variety of engineering applications. The mechanisms of oscillating flows have not been sufficiently studied. Oscillating flows can be created artificially to increase heat transfer equipment by intensifying heat transfer. Thus, this paper studies the flow and heat transfer characteristics of a tube bundle under the influence of oscillating flow. The assessment of heat transfer and the hydrodynamic flow pattern in a tube bundle during flow oscillations is carried out on the basis of experimental studies. Flow oscillations have been created by a pneumatic system that drove a pulsator. The time characteristic of the pressure drop of the tube bundle has been recorded using an oscilloscope and pressure drop sensors. To assess the dynamics of flow velocity, the high-speed shooting method is used. The heat exchange of a tube bundle has been determined by the electrical power expended to maintain a constant temperature on the tube side of the bundle. For the first time, heat transfer and the hydrodynamic flow pattern with asymmetrical flow oscillations in an inline tube bundle are studied experimentally. It is shown that the shape of oscillations of flow velocity and pressure drop depend on frequency. It has been found that with increasing frequency there is an increase in the values of flow velocity and pressure drop. It has been determined that for certain moments of time, the flow velocity and pressure drop during asymmetrical oscillations exceed symmetrical ones. It has been established that the heat transfer rate of a bundle increases by 1,7 times with an increase in frequency. It has been shown that asymmetrical oscillations are more effective in intensifying heat transfer than symmetrical ones by an average of 1,1 times. Analysis of the results obtained has showed the possibility of intensifying heat transfer in a tube bundle using oscillating flows. Thus, oscillating flows can be used to increase the efficiency of heat exchange equipment. The results obtained on the hydrodynamic flow pattern can be used in mathematical modeling of oscillating flows, which are necessary to expand the operating parameters of the study and determine the most effective ones.