Simulation With Environmental Wind Tunnel And Numerical Analysis For The Cavity Area Of Natural Draft Cooling Towers With Flue Gas Injection

Based on cooling tower in flue gas injection of natural draft cooling tower(NDCT),we focus on the range and distribution feature of the cavity area in the cooling tower.The relationship between cavity area and number of cooling tower and the relationship between topographic condition and outside curve are mentioned by using environmental wind tunnel experiment and numerical simulation.Besides,the relationship between the range of cavity area and altitude of cooling tower and its outlet diameter is analyzed quantitatively.Then,we discuss the method setting atmospheric environment protection zone in the technology of NDCT with flue gas injection and provide scientific basis for the feasibility of the technology of NDCT.The cavity area is located in the down wind of cooling tower,which can extend to triple or double height of cooling tower.The distribution of cavity area is a circle area,which firstly increases and then decreased with the increase of horizontal distance of cavity area.Under the condition of double towers,the range of complex geography as well as slim and tall cooling towers are relatively lager.It is vital to pay attention to anticorrosion of cooling towers when there are presence of double towers,which leads to superposed cavity area and causes pollutants gathering.It has positive correlation between the length of cavity area and its outlet diameter.Fitting curve shows that the length of cavity area is 2.14 times to that and the height of cavity area is 1.25 times to the height of tower.The correlation coefficients are 0.65 and 0.77 respectively.The positive correlation also occurred between the height and outlet diameter.However,the length of cooling tower has little relation with the height and outlet diameter of cooling tower.It is easy to gather pollutants because of the cavity area of cooling tower.As the result,according to the range of cavity area,it is important to set the defending distance of NDCT with flue gas injection.If there are no environmental sensitive objects or the type of towers are normal,the defending distance can be set to 2?3 times height of cooling tower.If the shape of towers are abnormal or there are environmental sensitive objects,relevant experiments will needed to ensure the range of cavity area and used to setting the defending distance.