Views:1 Author:Site Editor Publish Time: 2020-10-28 Origin:Site
Air cooler is abbreviated as air cooler. It uses air as a coolant and can be used as a cooler or a condenser. The air cooler is mainly composed of tube bundles, brackets and fans. The hot fluid of the air cooler flows in the tube, and the air blows through the tube bundle. Due to the large amount of ventilation required for heat exchange and low wind pressure, the type and material of tube bundles of axial fans (see fluid conveying machinery) are often used to greatly affect the performance of the air cooler. Because the heat transfer coefficient of the air side is very small, fins are often added outside the tube to increase the heat transfer area and fluid turbulence, and reduce thermal resistance. Most air coolers use radial fins. Air coolers usually use light tubes with an outer diameter of 25mm, low-fin tubes with a fin height of 12.5mm, and high-fin tubes with a fin height of 16mm. The fins are generally made of materials with high thermal conductivity (the most commonly used is aluminum), wound or inlaid on the light pipe. In order to strengthen the heat transfer effect of the air cooler, water can be sprayed in the inlet air for humidification. This not only reduces the air temperature, but also increases the heat transfer coefficient. The use of air coolers can save a lot of industrial water, reduce environmental pollution and reduce infrastructure costs. Especially in water-scarce areas, replacing water-cooling with air-cooling can alleviate the contradiction of water shortage.
The high-quality air cooler is mainly composed of three parts: tube bundle, ventilator and frame. The tube bundle includes heat transfer tubes, tube boxes, side beams and cross beams. It can be arranged in three basic forms: horizontal, vertical and inclined top (herringbone). Among them, the horizontal arrangement has a large heat transfer area, uniform air distribution, and good heat transfer effect; when the inclined ceiling arrangement, the fan is installed in the central space of the herringbone, which occupies a small area and has a compact structure. In order to offset the effect of the lower heat transfer coefficient on the air side, a tube with fins on the outer wall of the light tube is usually used. The finned tube is used as a heat transfer tube to expand the heat transfer area. The finned tubes are arranged in layers, and the two ends are connected to the tube box by welding or expansion. The pipes are generally 3 to 8 rows. The tube bundle series can be up to 12 meters long. The outer diameter of the light pipe is usually 25 mm and 38 mm, the fin height is generally 12-15 mm, and the tube bundle width is 100-3000 mm. The finned tube is the core element of the air cooler, and its form and material directly affect the performance of the equipment. The tube can be made of carbon steel, copper, aluminum, stainless steel, etc.; the fin material is determined according to the use environment and manufacturing process, mostly industrial pure aluminum, and copper is also used in the case of high anti-corrosion requirements or special manufacturing process conditions Or stainless steel. The fins can be arranged horizontally or vertically. The basic forms of finned tubes are: coiled, insert, rolled, sleeve, welded, elliptical, turbulent (including spokes, slotted and corrugated, etc.). The structure of the pipe box mainly includes flange type, pipe plug type and collecting pipe type. Generally the former is used for medium and low pressure, and the latter two are used for high pressure. In order to adapt to the thermal expansion of the tube bundle, one end of the tube box is not fixed, allowing displacement along the length of the tube. The ventilator usually uses an axial fan.