| Facing the global energy crisis of fossil energy shortage,it is imperative to vigorously develop renewable energy such as wind and solar energy.However,the intermittent and unstable characteristics of renewable energy make it impossible to directly integrate into the grid after power generation.Therefore,the development of large-scale energy storage technology should be accelerated to realize the large-scale application of renewable energy.As a clean and flexible energy storage method,compressed air energy storage has great practical significance.It can be applied to global wind power and photovoltaic projects to solve global energy problems and has high commercial value.However,the problem of low energy storage efficiency has always hindered the further development and large-scale application of compressed air energy storage.Isothermal compressed air technology is an effective means to achieve high-efficiency compression,so it has always been a focus of attention and research by scholars.In this paper,an isothermal compression method for micron-scale water mist heat transfer is studied,the spray heat transfer and compression process are modeled and analyzed,and the system efficiency is finally improved.The main research work of the thesis is as follows:(1)Through the analysis of the water mist diffusion process,the heat transfer contact ratio Cr between the water mist and the air is defined,and the mathematical model of the water mist diffusion is established.Then the compression process and the air-water mist heat and mass transfer process are analyzed,according to the energy and mass the equations of flow and pressure establish basic mathematical models of isothermal compression system state,local and overall mass transfer and heat transfer.Finally,the energy consumption of water mist generation is analyzed and added into the calculation of the efficiency of isothermal compression system.(2)Verify the accuracy of the model and conduct a single-variable simulation study.Using Simulink software to analyze the mathematical model of the system,the effects of spray water pressure,spray angle,and nozzle diameter on the system state,compression work and compression efficiency are obtained.It is found that a spray angle of 60° is most conducive to air-water mist heat exchange;The increase in water pressure and the decrease in nozzle diameter can greatly suppress the temperature rise of the air.(3)Optimization of orthogonal test parameters.The energy consumption of the water mist will affect the efficiency of the isothermal compression system.Therefore,the orthogonal test method is used to optimize the parameters of spray water pressure,spray angle,and nozzle diameter with efficiency as the goal to obtain the most efficient optimal parameter combination.The extreme value analysis method is used to calculate the influence degree of the three parameters on the system efficiency.The conclusion is as follows: the degree of influence on the system efficiency is the spray water pressure,the nozzle diameter and the spray angle in descending order,and the system efficiency is up to 88% under the optimal parameter combination.(4)An experimental platform for the water mist heat exchange isothermal compression system was designed and built,and the experimental research on the water mist heat exchange isothermal compression system was carried out.During the air compression experiment,firstly,the air temperature when spraying water mist was compared to determine the effectiveness of the water mist heat transfer;secondly,the experiment was performed using the combination of the optimal solution parameters of the total efficiency of the orthogonal experiment and compared with the simulation results,Which proved the correctness and accuracy of the model;and finally calculated that the maximum efficiency of the isothermal compression system experiment was 86.62%. |
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