| Dish solar stirling thermal power generation technology is a promising emerging technology in renewable energy.stirling thermal engine is one of the key basic equipment in stirling photothermal power generation system.Sunlight heats the collector structure of stirling heat engine and forms a relatively stable high temperature and high pressure fluid medium to drive the motor to generate electricity.The thermal energy conversion efficiency in stirling heat engine can affect the power generation efficiency of the whole power generation system to a certain extent.Therefore,the structural parameters of the heat absorber are optimized with the goal of homogenizing the distribution of energy flux density on the surface of the heat absorber tube.A way to improve the efficiency of solar thermal power generation system.In this paper,the mathematical models of tube length,tube number and reflection cone of stirling heat engine heat absorber cluster are constructed,and several sets of three-dimensional models are built and analyzed in optical software under the same optical conditions.The specific research process is as follows:Firstly,the parameters of the power generation system are drawn up,including the concentrator radius,focal length,edge angle and the number of heat absorber tubes,pipe diameter,pipe length,radius of base circle,radius of opening and overall height.Optical parameters include absorptivity,reflectivity,reflection type and light cone angle.According to the selected parameters,the model is established to build a photothermal power generation system.The relative position of the absorber and the concentrator is calibrated in the electrical system,and the appropriate amount of light is selected through the comparative simulation experiment.The results show that the distribution of energy flux density is the best when the number of light is 107 and the height of the absorber is 80 mm and the diameter of the opening circle is 105 mm.Secondly,in order to homogenize the energy flow density on the surface of the heat absorber,two parameters of the length and diameter of the heat absorber tube are optimized.Under the guidance of the formula of the optimal length-diameter ratio,the heat absorber tube diameter is taken as the optimization objective,and then the optimized tube diameter is calculated and substituted for the simulation experiment to verify the correctness of the optimization results of the tube diameter parameters.In the simulation experiment,energy flow span ratio and energy flow average difference are proposed to measure the uniformity of energy flow density,and the uniformity of energy flow density distribution can be more accurately distinguished.The results show that the uniformity of energy flow density spatial distribution is optimal when the diameter of tube is 6 mm,the number of tubes is 20 and the length of tube is 310 mm;the energy flow distribution of tube in the range of 6 mm-7 mm is the diameter parameter of tube.When the diameter of the tube is 4 mm and the number of tubes is 72,the energy flow density uniform range of the tube gap is about 2.0 mm.Finally,from the tangent angle of the reflecting cone busbar,the energy flow on the reflecting cone is supplemented to the area with low energy flow density distribution on the heat absorber tube,and the model is substituted into the optical simulation software.Through the comparison of several groups of reflecting cone types,the optimization ability of the new reflecting cone to achieve the desired goal is judged.The influence of different physical characteristics and initial conditions of working substance on the outlet temperature of stirling heat engine heat absorber tube was explored.The physical characteristics and initial conditions favorable to the heat absorption efficiency of working substance were screened out by using the temperature distribution at the outlet of heat absorber tube obtained by simulation software.The results show that:(1)the energy flux density of the new reflector cone fluctuates around 5×10~4w/m~2,which is higher than that of other reflector cones about1×10~4 w/m~2.(2)In the selection of the type of material and initial velocity,the temperature of hydrogen outlet with initial velocity of about 1m/s is about 100k higher than that of other types. |
PDF Full Text Request