Experimental Study On Condensation Heat Transfer Characteristics Of Air Cooled Round Tube Of Island Radiator

In recent years,with the implementation of China's sustainable development strategy,the proportion of non-fossil fuel power generation in the electric power production of our country has been greatly improved,but the amount of fossil fuel power generation still remains major proportion.In addition to the emission of dust and other pollutants,a large amount of water is consumed in the cooling of steam turbine exhaust gas in traditional thermal power generation mode,which has a certain influence on the power generation in the area of water shortage and less rain area of our country.The direct air cooling technology of the power station can be widely used in the areas where it is rich in coal and short of water,and the exhaust steam is directly cooled through the air cooling system,the water resources can be saved in a large amount.In this paper,an experimental model of condensation heat transfer is established for the radiator of the air cooling island of a power plant,the condensation heat transfer experiment for the tube radiator with an internal diameter of 4mm is conducted,and a comparative study is carried out under the same condition with the double louvered fin flat tube radiator.Due to the inclined arrangement of the air-cooled islands radiator in the power station,different inclination angles are considered to study the condensation heat exchange capacity of the steam in the radiator tubes.The inclination angle of the heat exchange unit varies from 30° to90°.In the condensation experiment,the pressure of inlet steam is kept constant for different inclination angles,and the steam flow rate is controlled by adjusting the frequency of blower.To obtain the heat transfer coefficient on steam side,the heat transfer experiment on the heat transfer between water and air of radiator is performed prior to the experiment on the heat transfer between steam and air,the correlations of the heat transfer coefficient against Reynolds number on air side and the total efficiency ?0 of the fin against Reynolds number are obtained by the heat transfer experiment on the heat exchange unit.During the two experiments,the relative error of heat absorption and heat release was less than 5%.The condensation heat transfer law of condensation heat transfer expressed as condensation heat transfer coefficient hs with Reynolds number in air cooling island tube is obtained by experiment.Through the experiments,it can be seen that when the steam at inlet is saturated steam and the steam at outlet becomes saturated water,the amount of heat exchange increases with the increase of the inclination angle both for round and flat tube bank fin radiators when the flow rate on the air side is kept unchanged,the amount of heat transfer reaches the largest for the inclination angle of 90°,while the heat exchange ability of the double louvered fin flat tube radiator is greater than that of the circular tube radiator.For the same inclination angle,with the increase of Reynolds number the condensation heat transfer coefficient in the tube is increased both for round and flat tube bank fin radiators.The influence of the inclination angle on the heat transfer coefficient in the tube is not obvious under the same Reynolds number of condensation,the heat transfer coefficient of the circular tube is larger than that of the fin and flat tube radiator.The experiment results can provide a reference for the actual use of air cooling islands.