Structural Optimization Research Of Solid Electric Heating Element Based On Multi-physics Coupling

With the rapid expansion of the domestic wind power industry,overcoming the challenges of wind power consumption has become an issue that must be addressed.The utilization of large-capacity solid electric heat storage devices is a feasible solution to the problem of wind power consumption and the "three abandonment" conundrum.However,because it is using pure resistance heating,the electric heating element is the device’s core component,and one of the most important issues limiting the device’s capacity is the element’s temperature and voltage level.As a result,research into the link between the multi-physical fields inside the device under high temperature and high pressure circumstances,as well as the design of the device’s structure and form,are essential.This study investigates the following issues with breakage,short circuit,wire burning and insulation of electric heating elements:Firstly,the multi-physical field of the electric heating element in the device is theoretically studied,and the electric heating element’s multi-field coupling model is provided.The mathematical heat transfer model of the electric heating element is obtained through the analysis of the heat transfer principle of the electric heating element,and four parameters related to the temperature of the electric heating element are deduced: the surface area of the electric heating element,the applied power of the electric heating element,the surface emissivity of the electric heating element and the fluid flow velocity.Secondly,a new type of ribbon structure electric heating element is created based on the surface area of an electric heating element and a linear structure,and the calculation method and design flow of two types of electric heating element structure design are provided.The arrangement mode of the electric heating element structure is investigated;the partial voltage can be carried out using the series arrangement,and then the electric field strength can be reduced.The adoption of a parallel-series design can lower the voltage of the device by half while keeping the power constant,so avoiding the problem of device insulation failure.Thirdly,using a finite element tool and a numerical simulation approach,two types of electric heating elements are simulated and analyzed,and the distribution laws of electric,magnetic,temperature,and other physical fields are compared.The results show that the magnetic field strength,electric field strength,and electromagnetic force produced by the ribbon electric heating element under high temperature and high pressure conditions are much smaller than those produced by the linear electric heating element,and that the field strength distribution of the ribbon electric heating element is more uniform,with no electromagnetic sudden change.Furthermore,the strip-shaped electric heating element efficiently distributes heat,which may greatly raise the temperature of the heat storage brick.The heat storage brick of the heat storage brick is 23% more than that of the linear electric heating element under the same conditions for continuous heating for 7 hours.Finally,the electric heating element’s surface emissivity and fluid velocity are simulated and studied.Increasing the emissivity has little effect on the heat storage brick,but it can greatly enhance the surface temperature of the linear electric heating element,according to the simulation findings.It can also lower the surface temperature of ribbon electric heating components,albeit the impact is not as noticeable as linear.When the linear electric heating element’s surface emissivity is increased from 0.5 to 0.9,the element’s temperature drops by12.7 percent.Besides,increasing the fluid velocity in the device can drastically lower the temperature of the electric heating element and the heat storage brick,but the effect of fluid velocity on the temperature of the electric heating element is larger than that on the heat storage brick.The fluid velocity of the electric heating element may be correctly regulated throughout the heating process to minimize the temperature of the electric heating element and prevent the wire burning occurrence.