Design Of A Counter Flow Combined Air Cooler With Air Inducing And Air Blowing And Related Research

Conventional combined air cooler has an obvious problem, which is air temperature through the overhead of fan is so high that fan’s and motor’s lubrication and transmission component failure. This paper puts forward a new kind of flow duct combined air cooler, by putting the fan and motor between the finned tube bundle and mist precipitator. This design can avoid the inefficiency of lubrication of fan and motor because of high air temperature, can avoid the air shortcircuit and leak resulting from the belt going through the air duct when the fan is on the top. Based on the field observation and reference of conventional combined air cooler, a counter flow combined air cooler with air inducing and air blowing was designed under given technical conditions. The air speed and spray density are two available adjusting cold source conditions in combined air cooler. So the influence of air speed to air cooler heat transfer and the changing of extra-tubal water film thickness with speed density are researched by experiment method.On the water film evaporation air cooler experimental rig, 5 air speeds were chosen to investigate the impact of air speed on heat transfer of water film evaporation air cooler. It was demonstrated that air speed significantly influenced extra-tubal average heat transfer coefficient, and that the influence was relatively complicated, depending on the combined functions of sensible heat and latent heat in given working situation.On the experimental rig of measuring the water film thickness of horizontal pipe, with different spray density, pipe diameter and annular angle, the water film thickness of extra-tubal were researched.According to the experimental data, fitting curve which reflected the relation of film thickness to pipe diameter, the spray density and annular angle were drawn. The experiment data indicated that when the pipe diameter and spray density were certain, with annular angle increasing, water film would varied from thin to thick, and the thinnest water film thickness part appeared between annular angle 120°to135°. When spray density and annular angle were certain, the lager the pipe diameter was, the thicker the water film thickness was, and the bigger annular angle in which thinnest water film thickness appeared was. When pipe diameter and annular angle were certain, the greater the spray density was,the thicker the water film thickness was. Between the annular angle 140°and 150°, the water filmthickness difference of all kinds of pipe diameter was little.