【作者】 马杰；

【导师】 李寿英； 陈宇；

【作者基本信息】 湖南大学 ， 土木水利， 2023， 硕士

【摘要】 在全球新能源革命的背景下,光伏产业发展十分迅速,柔性光伏支架系统凭借其地形适应能力强、跨越能力大和性价比高等优势,已逐步在实际光伏工程中得到应用。但是,柔性光伏支架结构系统频率低、质量轻,极易在风荷载作用下发生大幅振动。例如,光伏组件断面近似薄平板,且柔性光伏支架的第1阶扭弯频率比很小,颤振临界风速较低,可能发生颤振现象。颤振作为一种发散型自激振动,往往给结构带来毁灭性破坏,目前关于柔性光伏支架结构系统的颤振研究较少,为此,本文以某实际柔性光伏项目为工程背景,研究了柔性光伏支架结构系统的颤振性能,主要工作内容及成果如下:(1)设计并制作了柔性光伏支架系统的弹性悬挂节段模型,进行多种光伏组件倾角(倾角范围-39度～39度)下的测振风洞试验,研究了来流风速、光伏组件倾角等参数对柔性光伏支架系统颤振性能的影响规律。结果表明:光伏组件倾角对柔性光伏支架系统颤振临界风速有显著影响,随着倾角绝对值的增大,颤振临界风速呈现先减小后增大的趋势;倾角绝对值相同时,负倾角状态下的颤振临界风速均比正倾角高,说明来流方向为组件背风向时更易发生颤振;柔性光伏支架系统颤振频率随着光伏组件倾角绝对值的增大而增大。(2)采用计算流体力学软件ANSYS Fluent,基于分状态强迫振动法,识别了光伏组件在不同倾角下(0度、3度、6度)的颤振导数,据此得到了不同倾角下柔性光伏支架系统颤振临界风速,并与试验结果进行比较。结果表明:对于组件小倾角(α<6度)工况,在结构设计初期,基本动力参数确定的情况下,可以采用光伏组件颤振导数计算得到颤振临界风速,该结果与节段模型测振风洞试验结果相比偏于安全。(3)分别在光伏组件节段模型下表面和上、下表面同时设置中央稳定板,以探究两种中央稳定板布置方式对柔性光伏支架系统颤振性能的影响。结果表明:在0度倾角,同时设置上下中央稳定板能将组件颤振临界风速提高约11%,仅设置下稳定板则会起不利作用,使颤振在更低风速时发生;其他试验倾角下,两种设置中央稳定板的气动措施对于提高组件颤振稳定性效果均不佳。更多还原

【Abstract】 Under the background of global new energy revolution,the industry of photovoltaic is growing rapidly.Flexible photovoltaic support systems have gradually been applied in practical photovoltaic engineering due to their strong terrain adaptability,large spanning ability,and high cost-effectiveness.However,flexible photovoltaic support systems have low frequency and light weight,and are prone to significant vibration under wind loads.For example,the cross-section of photovoltaic modules is similar to a thin flat plate,and the first order bending frequency ratio of flexible photovoltaic brackets is very small,and the critical wind speed for flutter is low,which may cause flutter phenomenon.Flutter,as a divergent self-excited vibration,often causes destructive damage to structures.Currently,there is little research on flutter in flexible photovoltaic support structural systems.Therefore,this article takes a practical flexible photovoltaic project as the engineering background to study the flutter performance of flexible photovoltaic support structural systems.The main work content and achievements are as follows:(1)An elastic suspension segmental model of a flexible photovoltaic support systems was designed and fabricated,and wind tunnel tests were conducted to measure the vibration of various photovoltaic module inclinations(inclination range is-39° to39°).The effects of parameters such as incoming wind speed and photovoltaic module inclinations on the flutter performance of the flexible photovoltaic support systems were studied.The results show that the PV module inclination angle has a significant impact on the flutter critical wind speed of the flexible photovoltaic support systems.As the absolute value of the inclination angle increases,the critical wind speed of flutter increased first and then decreased;When the absolute value of inclination angle is the same,the critical wind speed of flutter under the condition of negative inclination angle is higher than that under the condition of positive inclination,indicating that flutter is more likely to occur when the inflow direction is in the leeward direction of the component;The flutter frequency of the flexible photovoltaic support systems increases with the absolute value of the inclination angle of the PV module.(2)Using the computational fluid dynamics software ANSYS Fluent,based on the forced vibration method with different states,the flutter derivatives of photovoltaic modules at different inclinations(0°,3°,6°)were identified,and the flutter critical wind speeds of flexible photovoltaic support systems at different inclinations were obtained,and compared with the test results.The results indicate that for components with small inclination angles,(α<6°)in the initial stage of structural design,with the determination of basic dynamic parameters,the critical wind speed of flutter can be calculated using the flutter derivatives of photovoltaic modules.The result is more safe compared to the wind tunnel test results of segmental model.(3)A central stabilizer plate is installed on the lower surface,upper and lower surface of the photovoltaic module segmental model to explore the impact of two central stabilizer plate arrangements on the flutter performance of flexible photovoltaic systems.The results show that at 0 degree inclination angle,setting both the upper and lower central stabilizing plates can increase the critical flutter wind speed of the assembly by about 11%,while setting only the lower stabilizing plate can have a negative effect,making flutter occur at lower wind speed;Under other test inclination angle,the two aerodynamic measures with a central stabilizer plate have poor effects on improving the flutter stability of the assembly.更多还原