双曲冷却塔表面三维绕流特性及风压相关性研究

为探究双曲冷却塔表面的三维绕流特性以及空间相关性，以某大型冷却塔为例进行刚体模型同步测压风洞试验，对表面平均和脉动风压分布以及环向和子午向的相关性进行了分析。研究发现，冷却塔的长细比较小，上下端均存在明显的三维绕流特性，并以塔筒上端尤为显著；端部效应主要表现在侧风区平均风压幅值下降、脉动风压激增、平均和脉动风压幅值最大点的后移以及风压环向相关性减弱。风压的环向相关性可以分为两个区域：“相关区域”(0°≤|θ|≤100°)和“非相关区域”(100°≤|θ|≤180°)，其子午向相关性可以分为三个区域：“强相关区”(0°≤|θ|≤100°)、“弱相关区”(100°≤|θ|≤150°)以及“中等相关区”(150°≤|θ|≤180°)；这使得冷却塔表面风压的双向(空间)相关性只存在于0°≤|θ|≤100°范围内。另外，在迎风点和侧风点，平均风压和脉动风压基本同时达到幅值的峰值，并且在环向和子午向存在极高的相关性，这都将显著增加风压分布的环向不均匀性以及风致结构响应。

WIND TUNNEL STUDY ON THE THREE DIMENSIONAL FLOW AND SPATIAL CORRELATION PROPERTIES OF WIND LOADS ON HYPERBOLOIDAL COOLING TOWERS

Simultaneous pressure-measured tests on the rigid model of a large hyperboloidal cooling towers were conducted in wind tunnel tests and the characteristics of wind loads including the three dimensional flow and the spatial correlation were illustrated. Due to the low slenderness ratio,distinct three dimensional flow is highlighted at the bottom and especially the top edges,which is called edge effects and characterized by the decrease of mean suction and surge of fluctuation in sideward. Also,the latitude correlation decreases and the location of the maximal mean suction fluctuation moves behind. In the latitude direction,it can be divided into two regions named related area (0°≤|θ|≤100°) and unrelated area (100°≤|θ|≤180°) according to the latitude correlation. Three regions named high-related area (0°≤|θ|≤100°),low-related area (100°≤|θ|≤150°) and mid-related area (150°≤|θ|≤180°) are divided according to the meridian correlation similarly. Additionally,the maximal amplitudes of mean and fluctuation pressure both occur at the stagnation point and two C_P,min points,coupled with the high correlation among the three points,so the non-uniformity of the latitude wind pressure and the wind-induced responses will be aggregated consequently.