Experimental research of heat transfer of heating devices from extruded aluminum sections

Abstract

The efficiency of aluminum heating devices presented in the global heat supply market has been steady for several decades. This is due to the fact that the shape of the section of such a device is not possible for significant changes - it is due to the method of manufacturing aluminum heating devices, namely, casting. The technology has exhausted the possibility of further improvement of the thermo-technical characteristics of the devices, but the material itself - aluminum-alloy alloys - gives a wide space to find new forms of sharpening and optimization of its sizes. Attempts to use other technologies for the manufacture of sections of heating devices, namely, pressing through filters of heat-transferring surfaces, showed the broad possibilities of this method for increasing the efficiency of the sharpening of aluminum devices. New technological approaches to the creation of new designs of aluminum devices require their previous modeling and research. However, the data on the heat transfer of the necessary structures in the literature does not exist. Therefore, the article presents an new section design and an analytical and experimental study of the heat transfer of the device, namely the study of free convection in the channels formed by the proposed fineness of the device.Studies have shown that the temperature distribution on the ribs of the device in height is similar. The temperature of the ribs reaches its maximum at a mark of 250 mm to 350 mm, then it decreases. One can conclude that in this range the thickness of the boundary layer becomes maximum, after which its failure occurs. To avoid this, it is necessary to shorten the sections or to adapt a turbulizer in this range. Subsequent studies should be aimed at studying the velocities in the channel to precisely determine the criterion equations of convective heat transfer for the channels formed in the proposed section of the heating device.