| Nowadays,the solar thermal power generation system mainly includes three types of trough,tower and dish.Contrasts to the three basic working principle of solar thermal systems and their advantages and disadvantages,it is concluded that the dish type solar thermal power generation system is popular for its high efficiency,small area and flexible layout.Dish solar concentrator is the most important component of dish thermal power generation system,which affects the performance of dish type solar thermal system of power generation efficiency,stability,cost and other factors of the system.Dish solar concentrator is a kind of bluff body,the wind load affects it greatly due to its the large size and the particularity of working environment,which not only will cause the concentrator mirror surface deformation,and may even cause structural damage,and result in reduced efficiency of the whole system.Therefore,it is necessary to study the wind load of dish solar concentrator in order to improve the wind load capacity of dish solar concentrator.Based on the 25 k W dish solar concentrator as the research object,using Pro/E3 D software simulation model drawing dish solar concentrator based on the known parameters,determining this topic air fluid motion for turbulent motion by the Reynolds number identification method,and the relevant fluid control equation and turbulence model are selected in accordance with this topic,the wind load simulation analysis is carried out according to the numerical wind tunnel simulation method.The specific research contents include:(1)Using Pro/E 3D software to draw the simplified model of the dish solar concentrator,the pre-processing by using fluid analysis software Gambit to complete the establishment of computational fluid domain and divide the grid,a numerical simulation of the dish solar concentrator model is carried out by using the Realizable k-ε turbulence model based on the Fluent14.0 software,the change regulation of wind load with different altitude angle and azimuth angle were analyzed,and the reasonableness of simulation results were verified by qualitative comparative analysis between load curve and parabolic radar antenna wind tunnel test.Moreover,the flow field characteristics around the dish solar concentrator and the wind pressure distribution under different working conditions were studied by simulation,and determined its best and worst working condition.(2)In order to study the influence of the size of the gap between mirrors on the25 k W dish concentrator of the wind load coefficient.Through Fluent 14.0 software,we built a watershed model of concenteator with different gap size of mirror in different conditions,and used the Realizable k-ε turbulence model for numerical simulation of watershed.The results show that the gap size has little effect on the wind load factor of the dish solar concentrator and the surrounding fluid flow;the maximum area of body coefficient is distributed in the first windward area of the dish solar concentrator.Besides,the extreme value of shape coefficient of the dish solar concentrator mainly shows the large middle small edge trend and the maximum value is 2.19.(3)For further analyze the influence of various factors—altitude angle,azimuth angle and the mirror gap size—on the wind load factor of dish solar concentrator,based on the fuzzy gray correlation theory,the simulation data of 24 different working conditions were selected,and the fuzzy grey correlation analysis model was established to analyze the weight analysis related influencing factors.The results show that altitude angle has the the greatest influence degree on the resistance coefficient and azimuth moment coefficient of dish solar concentrator,the fuzzy gray relational degree is 0.8336,0.7376,the influence degree of azimuth angle is second,and the mirror gap size has the least influence;as for the lift coefficient,lateral force coefficient,rolling moment coefficient,and overturning moment coefficient of dish solar concentrator,the azimuth angle has the greatest influence on it,the fuzzy gray correlation degree is 0.8244,0.7793,0.8117 and 0.7541 respectively.the influence of height angle is the second,and the mirror gap size has the least influence.In this paper,a systematic wind load study on dish solar concentrator is carried out,the change regulation of wind load were analyzed,and determine its best and worst working condition.The influence of mirror gap size on wind load coefficient and the distribution characteristics of the partition shape coefficient are dishussed.Based on fuzzy gray relation method,the influence factors of wind load coefficient of dish solar concentrator are analyzed at the end of this paper,the results are of great theoretical significance and reference value for wind-resistant design of dish solar concentrator. |
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