Year1
- T：
- 8T-1000T
Working process of cooling tower: The working process of circular counter-flow cooling tower is an example: hot water passes through the pipe cross throat and curved throat at a certain pressure through the water pump in the main machine room. The central throat pressurizes the circulating water into the water spreading system of the cooling tower, and spreads the water evenly on the filler through the small holes in the water spreading pipe. The dry, low-humidity air enters the tower through the bottom air inlet net under the action of the fan. Inside, when hot water flows through the surface of the filler, it forms a water film and performs heat exchange with the air. The hot air with high humidity and high value is drawn out from the top, and the cooling water drips into the bottom basin and flows into the main machine through the outlet pipe. Under normal circumstances, the air entering the tower is dry air with low wet bulb temperature. There is an obvious concentration difference and kinetic energy pressure difference of water molecules between water and air. When the fan is running, under the action of the static pressure in the tower, the water Molecules continue to evaporate into the air and become water vapor molecules. The average kinetic energy of the remaining water molecules will decrease, thus causing the temperature of the circulating water to drop. From the above analysis, we can see that evaporative cooling has nothing to do with the temperature of the air (usually the dry bulb temperature) being lower or higher than the water temperature. As long as water molecules can continue to evaporate into the air, the water temperature will decrease. However, the evaporation of water into the air will not continue indefinitely. When the air in contact with water is not saturated, water molecules continue to evaporate into the air. But when the air on the water-vapor contact surface reaches saturation, the water molecules cannot evaporate out, but are in a state of dynamic balance. The number of water molecules evaporated is equal to the number of water molecules returned from the air to the water, and the water temperature remains unchanged. It can be seen from this that the drier the air in contact with water, the easier it is to evaporate, and the easier it is for the water temperature to decrease.
According to the ventilation method, there are natural ventilation cooling towers, mechanical ventilation cooling towers, and hybrid ventilation cooling towers.
According to the contact method between hot water and air, there are wet cooling tower, dry cooling tower and dry and wet cooling tower.
According to the flow direction of hot water and air, there are three types: counterflow cooling tower, crossflow (AC) cooling tower and mixed flow cooling tower.
Four types are divided into general air-conditioning cooling towers, industrial cooling towers, and high-temperature cooling towers according to their uses.
Five types are divided into ordinary cooling towers, low-noise cooling towers, ultra-low-noise cooling towers, and ultra-quiet cooling towers according to noise levels.
< Waste heat generated during industrial production or refrigeration processes is generally directed away by cooling water. The function of the cooling tower is to exchange heat between the cooling water carrying waste heat and the air in the tower, so that the waste heat is transferred to the air and dispersed into the atmosphere. For example: in a thermal power plant, the boiler heats water into high-temperature and high-pressure steam, which drives the steam turbine to do work to make the generator generate electricity. After the steam turbine does work, the waste steam is discharged into the condenser, where it exchanges heat with the cooling water and condenses into water, which is then pumped by a water pump. Return to the boiler for recycling. During this process, the waste heat of the exhaust steam is transferred to the cooling water, causing the water temperature to rise. The cooling water carrying the waste heat transfers heat to the air in the cooling tower, and is discharged from the air duct into the atmospheric environment. Scope of application of cooling towers: Mainly used in air-conditioning cooling systems, refrigeration series, injection molding, tanning, foaming, power generation, steam turbines, aluminum profile processing, air compressors, industrial water cooling and other fields. The most widely used areas are air-conditioning, cooling, refrigeration, plastics and chemical industries.
< In order to save energy, large cooling towers often use natural ventilation for cooling. The tower is composed of a ventilator herringbone column ring base water sprinkling device and tower core materials.
< Ventilator is mostly a reinforced concrete hyperbolic rotating shell, which has good structural mechanics and fluid mechanics properties. The lower edge of the shell is supported on equidistant shaped or shaped inclined pillars to form the air inlet of the cooling tower. The load of the shell is transmitted to the foundation through the inclined pillars. The foundation is often made into a ring-shaped foundation with an inclined plane to withstand part of the ring tension transmitted by the inclined pillars, or it can also be made into a separate single foundation or pile foundation. The diameter of the throat of the ventilator is the smallest. When the pressure of the shell is calculated to be stable, the shell wall is the thinnest. From this, the diameter gradually increases upward to form the airflow outlet diffusion section. There is a rigid ring at the top of the tower, and the throat below is in a hyperbolic shape. Gradually expanding, the lower shell wall is also thickened accordingly, forming a lower ring beam with a certain stiffness. The ventilator can also be made into a frustoconical shell or a combined cone shell, or a polygonal tower with a steel frame covered with wooden sheathing or asbestos cement sheathing. A meter-high dry cooling tower at the Schmeilhausen nuclear power plant in Germany uses a cable-structured tower, covered with aluminum sheathing plates, which has better earthquake and wind resistance.
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