Numerical Simulation Of Heat Storage And Release Characteristics Of High Temperature Accumulator In Electric Boiler

China is a large country that mainly provides coal-fired boilers to provide heat energy for indoor heating in winter,which has caused great damage and pollution.In recent years,our country has vigorously developed the "coal to electricity" and "coal to gas" policies.The "coal to electricity" policy is more economical and environmentally friendly by replacing coal with electricity to generate heat.According to the country’s electricity price policy,a solid heat storage electric boiler,a device that uses cheap electric energy to store energy with solid heat storage materials during the low electricity period,appears.However,the traditional thermal storage boiler has many disadvantages,such as large volume,high cost,and lack of heat transfer law when there are gaps.Aiming at the problems existing in the traditional electric heat storage boiler,this paper designs a device to control the heat transfer of the low valley electric high temperature heat storage body,to innovate new heat storage equipment system and to optimize the solid heat storage device.The contents are as follows:(1)The analysis and theoretical research of heat transfer mode in the process of heat storage and release of solid heat storage electric boiler are carried out;(2)Aiming at the problems existing in traditional thermal storage boiler,a device to control the heat transfer of low-temperature heat storage is designed.The way of heat storage,the method of obtaining atmospheric water vapor and the working principle of the heat storage and discharge process of the high-temperature heat storage body are described.Compared with the traditional heat storage device,it has many advantages such as the volume of the device is reduced by 37%and the cost is low;(3)The heat transfer analysis and numerical calculation of the solid heat storage process are carried out and the three-dimensional model of heat storage in superheated steam area of regenerative electric boiler is established,the simulation results show that:the larger the Rayleigh number is,the more uniform the heat storage is;after eight hours of heat storage,the temperature difference of the heat storage body is 37 ℃ higher than that of the traditional electric heat storage boiler,which is 800℃.The distribution of the heat storage temperature is more uniform and achieves a certain optimization effect;the larger the thermal conductivity is,the smaller the temperature gradient of thermal storage is,the material with high thermal conductivity should be selected for solid heat storage electric boiler;(4)The heat transfer analysis and numerical calculation of the heat release process of solid regenerator are carried out and the heat release model of superheated steam zone of electric thermal storage boiler is established,and the uperheated steam at atmospheric pressure is used as heat exchange fluid,the results of exothermic simulation are as follows:the outlet temperature of steam is 577.8K after 10 h heat release;the higher the thermal conductivity of the heat storage brick,the more the temperature of the heat storage decreases during the heat release,the higher the steam temperature at the outlet of the heat exchange pipe;the higher the water vapor flow rate,the stronger the convection heat exchange,the higher the outlet temperature of the steam,the more the temperature drop of the heat storage;(5)The heat transfer value of the 5mm gap model is simulated by establishing a 5mm gap model:through the numerical simulation of heat storage and release,it is found that:the gap increases the temperature of the heat storage process,increases the temperature of the electric heating wire,and reduces the service life of the electric heating wire;compared with the model without gap,the outlet temperature of steam with gap is lower and the temperature of heat storage is much lower;To sum up,aiming at the existing problems of traditional electric thermal storage boiler,this paper designs a device to control the heat transfer of low valley electric high temperature thermal storage body,and obtained the influence of different working conditions on the heat storage and release process of the regenerator,and the gap model theory provides a theoretical basis for further improving the solid electric heat storage and release theory.This paper has 23 pictures,5 tables and 101 references.