侧风下自然通风湿式冷却塔出口气流的试验研究  

Experimental Research for Outlet Airflow of Natural Draft Wet Cooling Tower Under Crosswind Conditions

作　　者：张磊[1] 孙奉仲[1] 高明[1] 赵元宾[1] 

机构地区：[1]山东大学能源与动力工程学院,山东省济南市250061

出　　处：《中国电机工程学报》2015年第4期891-897,共7页Proceedings of the CSEE

基　　金：国家自然科学基金项目(51106092)~~

摘　　要：基于热态模型试验,研究了自然通风湿式冷却塔塔顶侧风对出口气流的影响,以及由此带来的对冷却水温降和通风阻力系数的影响。通过在模型塔喉部至出口区域内布置热电偶,获得该区域内的温度场,根据温度场和速度场之间的联系,分析侧风下出口气流的流态。实验中,调节塔底侧风并保持一定风速后,通过控制塔顶侧风风机的启闭,研究塔顶侧风对冷却水温降和通风阻力系数的影响。结果表明,随着风速增大,塔顶侧风会对出口气流产生侵入、排挤、封盖和引射作用;静风时冷空气便会从塔出口侵入塔内,至风速为0.2m/s时达到最大,占出口气流的8%-10%,风速进一步增大,冷空气侵入量会逐渐减少。对水温降而言,当参考风速为0.3-0.6 m/s时,塔顶侧风可使其普遍减小2%-3%;而对冷却塔纵向通风阻力系数而言,在参考风速为0.5-0.8 m/s时,塔顶侧风影响可使其增大25%-35%。Based on hot-state model experiment, the influences of crosswind on outlet airflow pattern of natural draft wet cooling tower（NDWCT） and the resultant changes of its cooling range and ventilation drag coefficient were analyzed. Thermocouples were arranged in the space from tower throat to the top outlet to acquire the temperature field. According to the correlation of temperature filed and velocity filed, the patterns of outlet airflow under crosswind conditions were determined. In the tests, the lower fan was regulated and maintained to provide given crosswind speeds firstly, while the upper fan was controlled to open and close, hence the changes of cooling range and ventilation drag coefficient could be detected comparatively. Results show that as the crosswind speed increases, outlet airflow is invaded, extruded, sealed and sucked successively by upper crosswind. The incursion of surrounding cold air occurs even at windless condition and reaches the most（8%-10% of the outlet airflow rate） at the crosswind speed of 0.2 m/s. If the crosswind increases further, the incursion of cold air will be decreased gradually. However, owing to upper crosswind effect, the cooling ranges are mostly decreased by 2%-3% within the reference crosswind speeds of 0.3-0.6 m/s, and the ventilation drag coefficients could be increased by 25%-35% within the reference crosswind speeds of 0.5 m/s-0.8 m/s.

关 键 词：冷却塔 热态模型试验 侧风 出口气流 热力性能 

分 类 号：TK124[动力工程及工程热物理—工程热物理]