In order to study the falling film flow process outside the horizontal circular tube, experiment is adopted in this paper to investigate the effects of liquid spray density and spray temperature on the liquid film flow pattern transformation and pattern distribution. Meanwhile, the temperature distribution characteristics of the horizontal tubes are analyzed. The high-speed camera was used to photograph the flow pattern of the liquid film, and the K-type thermocouples were used to measure the tubes wall temperature. The results show that (1) as the spray density increases, the liquid film is converted from a droplet flow to a columnar flow and then to a sheet flow; (2) the critical spray density of the flow pattern conversion will reduce with the spray liquid temperature increasing; (3) the critical spray density of 10% glycerol solution for flow pattern conversion is bigger than that of water; (4) the tube wall circumferential temperature increased with the increase of spray density, and the tubes wall circumferential temperature decreased with the increase of the circumferential angle in the range of the circumferential angle from 0Â° to 135Â° and rose slightly from 135Â° to 180Â°; (5) the tube wall circumferential temperature of water is higher than that of the 10% glycerol solution.
Keywords oily wastewater, falling film, flow pattern, heat transfer characteristics, horizontal tube