Experimental Research On Heat Transfer Performance Of Closed-cooling Tower With Mechanical Ventilation

Energy is a national or regional economic and social development of the most important natural resources and material foundation. With population increasing and social-economic development, the water resources demand grow, energy and water resources utilization problems have become increasingly prominent, which seriously constrains human survival and development, so rational utilization of water resources and energy conservation is the national economic growth needs and environmental protection needs.Previous research has shown that the efficiency of the open-cooling tower cooling is better than the efficiency of the closed-cooling tower, but cooling water system of open cooling tower communicates with the atmosphere, causing water pollution, corrosion of equipment easily and fast. But closed-cooling tower in natural cold source applications is better than open-cooling tower and have a suitable cooling effect in many occasions, it has advantages of widely use, strong ability to adapt to the environment and cooling heat water, etc.The paper take closed-cooling tower with mechanical ventilation as research subjects, through theoretical analysis and specific experiments, make an in-depth study of the heat transfer performance of the cooling towers for cooling-coil diameter changes and other ways to improve the performance of cooling towers, research the heat and humidity exchange efficiency, the main research work done by the following:1. According to preliminary theoretical analysis, first determine the structure of the cooling tower, built a closed-cooling tower with the mechanical ventilation model, to facilitate the closed-cooling tower with the mechanical ventilation experiment research. On the basis of the previous design, the laboratory model into account the air flowing in the outlet section added a defogging device. In order to facilitate simulation of cooling water, use of electric heating to heat the cooling water, thus ensuring the long-running experiment.2. In the light of the heat and mass transfer characteristics of the closed-cooling tower with the mechanical ventilation, and conditions in the theoretical analysis based on the assumption, Based on the thermal balance and calculus theoretical mathematical model, determined from the cooling water inside the cooling coil to the total outside tube heat transfer coefficient of water spray and spray water from outside the tube to the total volume of air mass transfer coefficient.3. According to the experimental data, from the amount of air into the tower, spray water, the air wet bulb temperature, cooling coil diameter, ratio of air to water to discuss five aspects of closed-cooling tower with the mechanical ventilation the case of thermal performance. Through the analysis of factors affecting cooling tower to identify the optimal operating parameters and the tower structure.4. Factors combined with the air flow and air flow is governed by the conservation equation, no filler on mechanical ventilation and cooling tower closed aerodynamic characteristics are analyzed, through experiments and the experimental data, response to mechanical ventilation was established closed cooling tower without packing air flow resistance of the criterion equation.