| Energy is an important foundation for ensuring the stable development of the national economy and the long-term stability of the people’s livelihood and society.Under the dual carbon goal,my country will establish a new energy system with green and efficient energy as its main development goal.As the refrigeration and air-conditioning industry plays an increasingly important role in economic and social development,reducing the energy consumption of refrigeration equipment has become an urgent issue.This paper summarizes the development of evaporative condensers at home and abroad in recent years,and based on the relevant knowledge of heat transfer,simplifies the heat and mass transfer model,and establishes a mathematical model of heat and mass transfer for evaporative condensers.An air-assisted nozzle cooling traditional evaporative condenser experimental bench was built,and the influence of parameters such as fan suction volume,spray-assisted air pressure,and spray water flow on the heat and mass transfer performance of the whole system and the coils in different parts was studied.draw the following conclusions:（1）.With the increase of the air suction volume of the fan,the heat and mass transfer performance of the evaporative condenser shows an increasing trend.When the air suction volume of the fan changes from 208m~3/h to 220m~3/h,the increase rate of the total heat transfer coefficient of the system increases from 18%to 23%.The heat transfer coefficient of a single row is consistent with the trend of the total heat transfer coefficient of the system.When the air suction volume of the fan is constant,the heat exchange coefficient of the first row of pipes at the top of the heat exchange space is the largest,and the heat transfer coefficient of the 41st row of pipes at the bottom is the smallest.（2）.The heat and mass transfer performance of the system increases with the increase of spray auxiliary air pressure.With the increase of the spray auxiliary air pressure,the droplet size gradually decreases and the evaporation rate increases.When the spray auxiliary air pressure increased to 0.4MPa,the increase rate of the total heat transfer coefficient decreased from 20%to 5%.When the spray auxiliary air pressure is constant,the heat transfer coefficient of the first row in the heat exchange space is the largest,and the heat transfer coefficient of the 41st row is the smallest.（3）.With the increase of spray water flow,the heat and mass transfer performance of the system increases first and then tends to be flat.When the spray water flow increased to 32L/h,the system performance reached a stable value.At this time,the total heat transfer coefficient of the system was 0.64 k W/（m~2~2K）,and the mass transfer coefficient of the system was0.62kg/（m~2~2s）.A three-dimensional model of the spray cooling condenser was established by ANSYS,and its Fluent module was used to simulate the temperature distribution,water mass distribution and velocity distribution in the heat exchanger.The conclusions are as follows:（1）.When the spray flow rate is constant,the uniformity of the cooling temperature and the distribution of water mass fraction of the flat nozzle are better than those of the single nozzle.By comparison,it is found that the bypass path has a great influence on the single-nozzle spray,and basically does not affect the spray path of the plane nozzle.（2）.When the flow rate of a single nozzle is increased,the temperature uniformity is enhanced,and the mass distribution of the water is also more uniform.When the nozzles are increased to increase the spray flow,the temperature uniformity is better than that of a single nozzle,and the mass fraction distribution of water can cover most of the heat exchange space.When the spray flow rate of the plane nozzle increases,the cooling capacity is significantly improved,the uniformity of the mass fraction distribution of water is also significantly increased,and the effect of the bypass path on the speed is also reduced. |
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